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pdfQAPP ID: J-EPD-0033261-QP-1-0
Version Date: July 28, 2022
Page 1 of 91
U.S. Environmental Protection Agency
Office of Research and Development
Ecosystem Processes Division
Immediate Office
Quality Assurance Project Plan (QAPP)
Title: Soil Gas Safe Communities – Designation and Method Development
QA Category: A ☐ B ☒
QAPP Developed: Intramural ☐
Extramural ☒
QAPP Accessibility: QAPPs will be made internally accessible via the ORD QAPP intranet site and
RAPID upon final approval unless the following statement is selected.
☐ I do NOT want this QAPP internally shared and accessible on the ORD intranet site.
Project Type(s) (check all that apply):
☐ Analytical Methods Development ☐ Animal/Cell Culture Studies ☐ Existing Data
☒ Measurements and Monitoring ☐ Model Application and Evaluation
☒ Social Science ☐ Software and Application Development
ORD National Program:
SHC 403
Project QAPP ID:
J-EPD-0033261-QP-1-0
Approvals
Director of CEMM:
Alice Gilliland
Signature
Date
Signature
Date
Associate Director, CEMM:
Gayle Hagler
Division Director, EPD/ EPA Task Order Contract Officer Representative (TOCOR):
Brian Schumacher
Signature
Date
EPA Alternate Task Order Contract Officer Representative (ALT TOCOR):
John H. Zimmerman
Signature
Date
Signature
Date
QA Manager:
Kara Godineaux1
1
The approval date of the QAPP is the date of EPA QA Manager approval unless otherwise specified.
QAPP ID: J-EPD-0033261-QP-1-0
Version Date: July 28, 2022
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Additional QAPP Signatures
Katherine Bronstein
RTI Task Order Leader
Chris Lutes
Jacobs Task Order Leader
Cindi Salmons
RTI Quality Assurance Officer
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Version Date: July 28, 2022
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Table of Contents
1
2
Project Background ............................................................................................................................. 10
1.1
Vapor Intrusion Background ....................................................................................................... 11
1.2
Expected Variability in Vapor Intrusion Studies.......................................................................... 14
1.2.1
Spatial Variability ................................................................................................................ 15
1.2.2
Temporal Variability ............................................................................................................ 16
1.3
Potential for Use of Radon as a Vapor Intrusion Tracer ............................................................. 18
1.4
Availability of and Quality of Meteorological Forecasts ............................................................. 21
Research Approach Summary and Project Management ................................................................... 23
2.1
Project Objectives ....................................................................................................................... 23
2.2
Description of Research Activities & Expected Products ............................................................ 23
2.2.1
Task 1. Assistance in Developing Criteria for the Soil Gas Safe Community Designation .. 23
2.2.2
Task 2. ITS Method Development and Planning ................................................................. 23
2.2.3
Task 3. QAPP Development................................................................................................. 24
2.2.4
Task 4. Field Testing for Method Development (Optional based on availability of funds) 26
2.2.5
Task 5. Application of ITS Methodology to a New Community – Community Pilot Study
(Optional based on availability of funds) ............................................................................................ 27
2.2.6
2.3
Timeline for Expected Products/Sub-Products ........................................................................... 31
2.4
Team Roles, Responsibilities and Distribution List ..................................................................... 33
2.4.1
3
Task 6. Final Evaluation of ITS Effectiveness (Optional based on availability of funds) ..... 31
Project Organization Chart.................................................................................................. 34
Documents, Records, and Data Management .................................................................................... 36
3.1
Documents and Records ............................................................................................................. 36
3.2
Data Management ...................................................................................................................... 39
3.2.1
Primary Data ....................................................................................................................... 39
3.2.2
Secondary Data ................................................................................................................... 39
3.2.3
Data Reduction.................................................................................................................... 41
3.2.4
Data Review and Verification .............................................................................................. 41
3.2.5
Initial Data Screening for Risk Communication and Study Design Alterations ................... 42
3.2.6
Data Analysis ....................................................................................................................... 43
3.2.7
Data Storage........................................................................................................................ 45
3.3
Non-detect Values ...................................................................................................................... 45
3.4
Data Reporting ............................................................................................................................ 45
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4
3.5
Assessment Oversight ................................................................................................................. 46
3.6
Development of Research Conclusions....................................................................................... 46
Quality Objectives and Criteria ........................................................................................................... 47
4.1
4.1.1
Bias ...................................................................................................................................... 55
4.1.2
Precision .............................................................................................................................. 55
4.1.3
Completeness...................................................................................................................... 56
4.1.4
Comparability ...................................................................................................................... 56
4.1.5
Representativeness ............................................................................................................. 57
4.1.6
Repeatability and Reproducibility ....................................................................................... 57
4.1.7
Method Detection Limit and Practical Quantitation Limit.................................................. 57
4.2
5
Data Quality Indicators ............................................................................................................... 55
Assessment and Oversight .......................................................................................................... 58
4.2.1
Field Activities ..................................................................................................................... 58
4.2.2
Corrective Action Procedures ............................................................................................. 58
Project Implementation ...................................................................................................................... 59
5.1
Community Selection .................................................................................................................. 59
5.2
Sampling and Real Time Monitoring Methods ........................................................................... 59
5.2.1
Measuring/Documenting Building Characteristics ............................................................. 59
5.2.2
External, Passive Soil Vapor Probe Construction for Use During Initial Screening ............. 61
5.2.3
Passive VOC Sample Collection from External Soil Vapor Probes Using Sorbents ............. 62
5.2.4
Passive Air Sample Collection for VOCs .............................................................................. 63
5.2.5
Radon Monitoring in Indoor Air .......................................................................................... 64
5.2.6
Outdoor Air and Soil Vapor Radon Monitoring................................................................... 66
5.2.7
Indoor Meteorological Measurements ............................................................................... 67
5.2.8
Outdoor Meteorological Methods ...................................................................................... 69
5.2.9
Decontamination Procedures ............................................................................................. 69
5.2.10
Field Notes .......................................................................................................................... 69
5.2.11
Sample Nomenclature ........................................................................................................ 70
5.2.12
Sample Chain-of-Custody .................................................................................................... 70
5.2.13
Packaging and Shipment ..................................................................................................... 71
5.3
Analytical Methods ..................................................................................................................... 71
5.3.1
Overview of Analytical Measurements ............................................................................... 71
5.3.2
Real-Time/Field Portable Instruments for Radon ............................................................... 72
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5.3.3
6
Quality Assurance and Quality Control ............................................................................................... 77
6.1
Detection Limits .......................................................................................................................... 82
6.2
Consideration of Background Sources of Indoor Air Contamination.......................................... 82
6.3
Consideration of Spatial, Seasonal, and Temporal Variability .................................................... 82
6.4
Consideration of Random or Systematic Error ........................................................................... 83
6.5
Analytical QA/QC Checks ............................................................................................................ 84
6.5.1
6.6
7
Analytical Methods for VOCs .............................................................................................. 72
Summary of Performance Requirements for VOC Analytical Methods.............................. 84
Field Quality Control Samples ..................................................................................................... 84
6.6.1
Field Blanks ......................................................................................................................... 84
6.6.2
Field Duplicates ................................................................................................................... 85
References .......................................................................................................................................... 86
Appendices.................................................................................................................................................. 91
Appendix A: Occupied Dwelling Questionnaire
Appendix B: Standard, Miscellaneous, and Field Operating Procedures
B1: SOP for Utility Clearance Inside Buildings
B2: SOP for Indoor, Crawl Space, and Ambient Air Sample Collection Using Sorbent Tubes
B3: Posting for Air Sampling Canisters
B4: Air Sampling Log
B5: SOP for Pressure Differential Monitoring to Support Vapor Intrusion Investigations
B6: SOP for Installing Subslab Probes and Collecting Subslab Soil Gas Samples Using Canisters
B7: SOP for Installation and Abandonment of Permanent and Semi-Permanent Exterior Soil
Vapor Probes
B8: Soil Vapor Probe Diagram
B9: SOP for Soil Vapor Sampling from Exterior Soil Vapor Probes
B10: Exterior Soil Vapor Sampling Form
B11: Soil Vapor Probe Purge Volume Calculations
B12: SOP for Radon Monitoring and Sampling to Support Vapor Intrusion Investigations
B13: 2-56 MOP: AlphaGuard: Operation of the AlphaGuard Portable Radon Monitor
B14: SOP for Temperature Monitoring in Support of Vapor Intrusion Investigations
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B15: Weather Monitoring to Support Vapor Intrusion Investigations
Appendix C: Corentium Pro Monitor Manual
Appendix D: Radon Eye Plus 2 Manual
Appendix E: MiniRAE 2000 Portable VOC Monitor PGM 7600 Operation and Maintenance Manual
Appendix F: Radiello Manual (selected sections)
Appendix G: Rad7 Manual
Appendix H: Example Chain-of-Custody Form
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List of Tables
Table 1-1.
Table 1-2.
Table 2-1.
Table 2-2.
Table 3-1.
Table 4-1.
Table 4-2.
Table 5-1.
Table 5-2.
Table 5-3.
Table 5-4.
Table 5-5.
Table 5-6.
Intervals
Table 5-7.
Table 6-1.
Meteorological Predictor Variables Used to Guide Prediction ........................................... 21
Ability to Forecast Weather of Major Providers at an Example Location........................... 22
Project Completion Timeline .............................................................................................. 31
Roles and Responsibilities ................................................................................................... 33
Documents and Records to be Generated During This Project .......................................... 36
Quality Objectives and Criteria for this Project .................................................................. 48
Test Matrix: Sample Type and Frequency ........................................................................... 50
Extractive Sample Preservation and Holding ...................................................................... 71
Target VOCs......................................................................................................................... 73
TO-17 Soil Gas Compound Reporting Limits and QC Acceptance Criteria .......................... 73
Summary of Calibration and QC procedures for Method TO-17 Soil Gas........................... 74
Thermal Desorption Radiello Compound Reporting Limits and QC Acceptance Criteria ... 75
Thermal Extracted Diffusive Sample Reporting Limits (µg/m3) for Various Collection
............................................................................................................................................. 75
Summary of Calibration and QC Procedures for Thermal Radiello Analysis....................... 76
Measurement Quality Objectives and Methods of Assessment for Critical Measurements .
............................................................................................................................................. 78
Table 6-2.
Measurement Quality Objectives and Methods of Assessment for Noncritical
Measurements ............................................................................................................................................ 80
List of Figures
Figure 1-1.
Figure 1-2.
Figure 2-1.
Figure 5-1.
An Overview of Important VI Pathways .............................................................................. 12
Measured Soil Gas and Groundwater Concentrations of TCE Below a Slab. ...................... 16
Project Organization Chart.................................................................................................. 35
Example Sampling Rack....................................................................................................... 63
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Revision History
Date
QAPP ID
7/19/2022
J-EPD-0033261-QP-1-0
7/28/2022
J-EPD-0033261-QP-1-0
Author(s)
Kate Bronstein,
Chris Lutes
Kate Bronstein,
Chris Lutes
Description of Revision & Comments
Initial version
Revisions to address EPA QA Manager
comments
Acronym/Abbreviations/Definitions
Abbreviation
°C
°F
BFB
bgs
CCV
CEMM
CF
CO2
COC
CVOC
DCE
DNAPL
EJ
EPA
GC/MS
Hg
hPa
HVOC
IA
ICAL
ICV
IS
ITS
LCS
LNAPL
m3
mBar/hPa
MDL
MOP
NDIR
Definition
degrees Celsius
degrees Fahrenheit
Bromofluorobenzene
below ground surface
continuing calibration verification
Center for Environmental Measurement and Modeling
chloroform
carbon dioxide
chain-of-custody
chlorinated volatile organic compound
cis-1,2-Dichloroethene
dense non-aqueous phase liquid
environmental justice
Environmental Protection Agency
gas chromatography/mass spectrometry
mercury
hectopascal pressure units
halogenated VOCs
indoor air
initial calibration curve
initial calibration verification
internal standard
indicators, tracers, and surrogates
laboratory control samples
light non-aqueous phase liquid
cubic meters
millibar per hectopascal pressure units
method detection limit
Manual of Procedures
Non-Dispersive Infra-Red
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Abbreviation
ng
NOAA
ORD
ORCR
pCi/L
PCE
PID
PM2.5
ppb
ppm
ppmv
Project
(aka Research Effort)
QA
QAM
QAPP
QC
QA
QC
RH
RL
RME
RPD
RSD
RT
SGI
SGP
SOP
SV
TCE
TOL
TO
TOCOR
T
VI
VOC
Definition
nanogram
National Oceanic and Atmospheric Administration
Office of Research and Development
Office of Resource Conservation and Recovery
picocuries per liter
tetrachloroethene
photoionization detector
particulate matter below 2.5 microns
parts per billion
parts per million
parts per million by volume
The research effort undertaken to fulfil a discrete set of objectives; a project
typically results in the generation of one or more RAP Products
Quality Assurance
Quality Assurance Manager
Quality Assurance Project Plan
Quality Control
Quality assurance; management activities involving planning, implementation,
assessment, reporting, and quality improvement to ensure that a process, item,
or service is of the type and quality needed and expected.
Quality control; technical activities that measure the attributes and
performance of a process, item, or service against defined standards to verify
that they meet the stated requirements
relative humidity
reporting limit
reasonable maximum exposure
relative percentage difference
relative standard deviation
retention time
soil gas intrusion
soil gas probe
Standard Operating Procedure
soil vapor
trichloroethene
Task Order Lead
Task Order
Task Order Contracting Office Representative
temperature
vapor intrusion
volatile organic compounds
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1 Project Background
Vapor intrusion (VI) assessment is complicated by spatial and temporal variability, largely due to
compounded interactions among the many individual factors that influence the vapor migration
pathway from subsurface sources to indoor air (Schuver et al., 2018). Past research on highly variable
indoor air datasets demonstrates that conventional sampling schemes can result in false negative
determinations of potential risk corresponding to reasonable maximum exposures (RME). While highfrequency chemical analysis of individual chlorinated volatile organic compounds (CVOCs) in indoor air is
conceptually appealing, it remains largely impractical when numerous buildings are involved and
particularly for long-term monitoring. To help reduce the need for intrusive, time consuming, and
expensive indoor air analysis, the EPA’s Office of Resource Conservation and Recovery (ORCR) has been
researching alternative approaches to help guide discrete sampling efforts and reduce sampling
requirements while maintaining acceptable confidence in exposure characterization. Indicators, tracers,
and surrogates (ITS), which include a collection of quantifiable metrics and tools, have been suggested
as a potential solution for making VI pathway assessment and long-term monitoring more informative,
efficient, and cost-effective. EPA’s Office of Research and Development (ORD) has also conducted
studies in support of this effort, examining, for example, how radon and VOCs vary jointly over time and
testing the effectiveness of consumer grade radon monitoring equipment.
As the ITS approach for determining when to sample has advanced, the need to expand to the
community scale, instead of only select individual homes and buildings, has been identified. Areas
encompassing hundreds to thousands of structures are often in need of evaluation at VI sites. Yet
government and principle responsible parties (PRPs) resources are frequently insufficient to conduct
sampling at all of those structures using current sampling approaches. Moreover, recent studies have
highlighted the high risk of false negative results when evaluating a building based on a small number of
randomly timed or seasonally scheduled samples. These problems occur in neighborhoods of all income
levels but are believed to be especially common in areas with environmental justice concerns (Schuver
et. al., 2021).
EPA would like to be able to quickly identify: (a) homes and buildings ‘at risk’ for VI (i.e., are
overlying/proximate to VI ‘sources’) within a community; (b) contaminants of concern for VI in the
subslab soil gas below a structure’s foundations, and; (c) ‘baseline’ measurements showing elevated
subslab soil gas intrusion into indoor air. Following the collection of baseline measurements, subsequent
samples will be collected at varying intervals, as determined by both a standard calendar-triggered
schedule, which VI guidance currently suggests as best practice, and ITS-triggered schedule, which EPA
would like to demonstrate as a defensible approach for assessing the VI pathway.
To accomplish these goals, EPA recognizes that community involvement and community
scientists/occupants are needed to be an active part of the process. EPA would like each community
member ‘at risk’ for VI in their respective structure(s) to:
•
•
have easy access to participate and collaborate with the remedial program decision makers as
an equal participant (along with their expert consultants),
be given an opportunity to share their own building-specific evidence of subslab soil gas
intrusion (SGI), and
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•
be a part of the risk management decision making for their residence or building (for example,
continuous soil gas ITS monitoring by the community scientists/occupants).
In cases where the community is economically-challenged or in a vulnerable environmental justice (EJ)
community, EPA would: support the ITS monitoring with meters to monitor changing conditions; provide
training in chemical sampling for verifying SGI is occurring; and provide training and guidance on means
and controls to reduce SGI.
As the program is grown within a community, this new continuous-ITS-monitoring approach could be
considered a response that offers potentially-impacted, including communities with EJ concerns, with an
opportunity to have more input and decision-making power in their indoor air quality. This is important
as society changes over time such as buildings being ‘weatherized’, and more time being spent indoors.
It is anticipated that the societal cost for using this approach is far less than current approaches that
emphasize contaminant attribution but provide far fewer benefits to those communities with EJ
concerns (Lutes et al., 2021). Ultimately, with the inclusion of numerous community scientists
throughout a community providing valuable inputs on changing conditions and collecting SGI samples,
an EPA ORCR Soil Gas Safe Community designation is planned to help communities acknowledge that
progress is being made towards safer indoor air quality as well as to remove some of the negative
stigma associated with a community having VI issues.
1.1 Vapor Intrusion Background
VI, the migration of subsurface vapors to indoor air, has emerged as a priority contaminant pathway at
hazardous waste sites nationwide, including Superfund, RCRA, and Brownfields sites. VI occurs due to
the pressure and concentration differentials between indoor air and soil gas. Indoor environments are
often negatively pressurized with respect to outdoor air and soil gas. This pressure difference allows
subsurface vapors to migrate into indoor air through advection. In addition, concentration differentials
may cause VOCs to migrate from areas of higher to lower concentrations through diffusion.
VI is a complex process influenced by a variety of geological, meteorological, and building operational
factors that cause substantial temporal variability in indoor concentrations. Current practice for
evaluating the VI pathway consists of a combination of mathematical modeling and direct
measurements in groundwater, external soil gas, subslab soil gas, and indoor air. No single line of
evidence is considered definitive, and direct measurements can be costly and can have significant spatial
and temporal variability requiring repeated measurements at multiple locations to accurately assess the
chronic risks of long-term VOC exposure. This project will focus on the collection of external soil gas and
indoor air to research how ITS, such as radon, carbon dioxide, temperature, and pressure differentials as
driven by barometric pressure change, may provide a better understanding of how sample timing
impacts the potential for capturing the reasonable worst case VI exposure so that the need for
mitigation/remediation can be assessed more accurately. Most of the in-depth chemical VI research to
date has been performed on residential structures, but large non-residential buildings are also affected
and may behave differently. The intention for this project is to focus on residential structures (single or
multi-family), to the extent possible.
The VI exposure pathway extends from the contaminant source — which can be free product or VOCs
sorbed to vadose zone soil, or VOC-contaminated groundwater — to indoor air exposure points.
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Contaminated matrices therefore may include groundwater, soil, soil gas, and indoor air. Contaminants
of concern typically include halogenated VOCs (HVOCs) such as trichloroethene (TCE), tetrachloroethene
(PCE), chloroform (CF), and vinyl chloride (VC), but may also include aromatic VOCs such as benzene,
toluene, and xylenes. These contaminants can be present in the dissolved phase, as free phases, or
sorbed to the geological matrix. This project will focus on HVOCs, which are resistant to biodegradation
in aerobic soils and groundwater. Of the chemicals subject to investigation under this project, HVOCs,
like TCE and PCE, are generally considered quite resistant to biodegradation.
An overview of important VI pathways is shown in Figure 1-1.
Figure 1-1.
An Overview of Important VI Pathways
Source: US EPA 2015
Three main pathways of VOC migration into buildings have been defined for VI:
1. Movement of vapors from shallow soil sources through the unsaturated (vadose) zone
2. Transport of VOCs through groundwater, followed by partitioning of VOCs from the shallowest layer of
groundwater into vadose zone soil gas
3. Vapor migration through conduit pathways such as utility corridors either directly into structures or
into the subslab layer.
In portions of these three pathways, transport is dominated by advective forces, while in other portions,
it is dominated by diffusive forces.
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In at least the first two pathways, the final step of VI typically involves soil gas moving from the
immediate subslab space into the indoor air. This subslab space is often significantly more permeable
than the bulk vadose zone soil, either because a gravel drainage layer was intentionally used, or the soils
have shrunk back from the slab in places. In these cases, the subslab space is expected to serve as a
common plenum allowing the lateral mixing of VOCs that reach the building through multiple pathways.
Vapor and liquid transport processes and their interactions with various geologic and physical site
settings (including building construction and design), under given meteorological conditions, control
migration through the VI pathway. Variations in building design, construction, use and maintenance,
site-specific stratigraphy, subslab composition, temporal variation in atmospheric pressure,
temperature, precipitation, infiltration, soil moisture, water table elevation, and other factors combine
to create a complex and dynamic system. Important factors controlling VI at many sites include:
•
Biodegradation of VOCs as they migrate in the
vadose zone
•
•
Fluctuations in water table elevation
Temporal and interbuilding ventilation system
• Site stratigraphy
operational variations for
commercial/industrial buildings (NJ DEP, 2018;
• Soil moisture and groundwater recharge
US EPA, 2015a).
Current soil gas sampling U.S. federal and state regulatory guidance (ASTDR, 2016; DoD, 2009; EPA,
2015) indicates that the primary contamination source need not be on the property of interest to pose a
potential SGI risk. The primary source may be present on a neighboring property which can contain
contamination by vapor-forming chemicals due to migrating plumes of contaminated groundwater or
migrating soil gases. At many sites, the subsurface vapor source (e.g., in soil or groundwater) is not in
contact with the bottom of the subject building. Under these circumstances, vapors emanating from the
source medium enter the pore space around and between the subsurface soil particles in the soil
column above the groundwater table, which is called the unsaturated soil zone or vadose zone. If the
subsurface vapor source is in the vadose zone, the vapors have the potential to migrate radially in all
directions from the source via diffusion or wind induced pressure differentials (EPA, 2015). Due to this
potential migration, it is generally considered appropriate to evaluate structures located within 100-feet
of a contaminant source by using multiple lines of evidence, such as subslab soil gas, exterior nearsource soil gas, indoor air, and outdoor air, as well as ITS parameters. However, one disadvantage of
subslab sampling is its intrusiveness to the occupants and the building envelope.
State-specific guidance also generally calls for a minimum of two sampling rounds to collect a sufficient
data set for decision making about a site. However recent studies have shown that small numbers of
sampling rounds have a high probability of underestimating exposure (Lutes, 2021a; Schuver, 2021).
More details will be provided in Subtask 2A on current state and regional requirements.
Based on the various guidance documents, including comparative studies of regulatory guidance (Levy
et al., 2019; Eklund et al., 2018; Rolph et al., 2012), this project will focus on collection of exterior soil
gas and indoor air samples to assess the potential SGI pathway in each structure. This will reduce the
intrusion on building occupants and their respective structures. In addition, the project will consist of
multiple sampling events structured around conventional calendar-based sample scheduling (i.e., three
events approximately 4 months apart) and a triggered sampling approach using ITS monitoring to
dictate when the likelihood of SGI to be occurring may increase.
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1.2 Expected Variability in Vapor Intrusion Studies
Through measurements of radon and VOC VI under various conditions, several studies have provided
insight of the complexity of temporal variability in indoor air concentrations attributable to VI—the
primary focus of this project. Nazaroff et al. (1987) studied how induced-pressure variations can
influence radon transport from soil into buildings with roughly hourly resolution. In a more recent study,
Mosley (2007) presented the results of experiments, showing that induced building pressure variations
influence both the temporal and spatial variability of both radon and HVOCs in subslab samples and in
indoor air. Schuver and Mosley (2009) also reviewed numerous studies of radon indoor concentrations,
in which multiple repeated indoor air samples were collected with hourly, daily, weekly, monthly, 3month, and annual sample durations for study periods of up to 3 years; however, detailed soil gas radon
data sets are rarer.
Several radon studies have demonstrated that barometric pressure fluctuations can affect the transport
of soil gas into buildings (Robinson and Sextro, 1997). The impact of barometric pressure fluctuations on
indoor air is influenced by the interaction of the building structures and conditions, as well as other
concurrent factors, such as wind (Luo et al., 2009). Changes in atmospheric conditions (e.g., pressure,
wind) and building conditions (e.g., open doors and windows) may temporarily over- or under-pressurize
a building. Based on long-term pressure differential datasets acquired by EPA’s National Exposure
Research Laboratory (NERL) at an Indianapolis study site at which both radon and VOCs were measured
in both subslab and indoor air, other factors that may cause temporal and spatial variability in soil vapor
and indoor air concentrations include:
•
•
•
Fluctuation in building air exchange rates due to occupant behavior/HVAC operations
Fluctuations in outdoor/indoor temperature difference
Rainfall events and resultant infiltration and fluctuations in the water table elevation (US EPA, 2012b,
2015b, and 2015c).
The pressure difference between a house-sized building and the surrounding soil is usually most
significant within 1 to 2 meters (m) of the structure, but measurable effects have been reported up to 5
m from the structure (Nazaroff et al., 1987). Temperature differences or unbalanced mechanical
ventilation are likely to induce a symmetrical pressure distribution in the subsurface, but the wind load
on a building adds an asymmetrical component to the pressure and distribution of contaminants in soil
gas.
Folkes et al. (2009) summarize several large groundwater, subslab, and indoor air data sets collected
with sampling frequencies ranging from quarterly to annually during investigations of VI from HVOC
plumes beneath hundreds of homes in Colorado and New York. They analyzed these datasets to
illustrate the temporal and spatial distributions in the concentration of VOCs. In a study of the VI
pathway at the Raymark Superfund Site, EPA (2005a) showed that measured subslab concentrations of
HVOCs exhibited spatial and temporal variability between neighboring houses and within individual
houses. Similar variability in subslab HVOC concentrations within and between houses has been
observed during VI evaluations of several sites in New York state (Wertz and Festa, 2007).
In scenarios with coarser soils (e.g., sands, gravels), the soil gas permeability is high, and changes in
building pressurization may affect the airflow field and the resultant soil vapor concentration profiles
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near buildings. In scenarios with fine-grained soils (e.g., silts, clays), the soil gas permeability is low and
soil gas flowrates (Qs) may be negligible and not affect the subsurface concentration. Nevertheless, in
both soil type scenarios, over-pressurization of the building may still significantly reduce the indoor air
concentration due to the reversal of soil gas flow direction from the building into the soil (Abreu and
Johnson, 2005 and 2006).
A wind-induced, nonuniform pressure distribution on the ground surface on either side of a house may
cause spatial and temporal variability in the subslab or near-foundation soil vapor concentration
distribution if the wind is strong and the soil gas permeability is high (Luo et al., 2006). In addition,
during or after a rainfall event, the subsurface beneath the building may have a lower moisture content
than the adjacent areas due to water infiltration.
1.2.1 Spatial Variability
Spatially, reports of several orders of magnitude variability without apparent patterns between indoor
air and subslab concentrations for adjacent structures in a neighborhood are very common (see for
example Dawson, 2008). Six orders of magnitude in subslab concentration variability were reported by
Eklund and Burrows (2009) for one building of 8,290 sq. ft.
As shown in Figure 1-2, Schumacher and colleagues (2010) observed more than three orders of
magnitude concentration variability in shallow soil gas below a slab outside a building over 50 lateral
feet, suggesting a strong effect of impervious surfaces both in limiting soil gas exchange with the
atmosphere and in maintaining relatively high concentrations of VOCs in shallow groundwater. They
also observed two orders of magnitude concentration variability with a depth change of 10 ft in the
unsaturated zone within one bore hole.
Lee and colleagues (2010) observed two orders of magnitude variability in subslab concentration within
a small townhouse. Studies by McHugh and others (2007) have generally found markedly less variability
in indoor air concentrations than in subslab concentrations, probably due to the greater degree of
mixing in the indoor environment.1
1
See also Lee 2010 op. cit.
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Figure 1-2.
Measured Soil Gas and Groundwater Concentrations of TCE Below a Slab.
Figure source: Schumacher et al., 2010
In results from the Indianapolis test house from the 2012 EPA report, VOCs and radon were seen in high
concentrations directly beneath the slab (subslab probes) and 6 ft soil gas probes (SGPs), but these were
not seen in the shallow external SGPs (3.5 ft SGPs). There was substantial variability among the external
SGPs at the 6-ft below ground surface (bgs) level. These values would have underpredicted subslab
conditions. When comparing the deeper SGPs, PCE concentrations were lower and more variable
outside the building. Average concentrations of chloroform and radon had close agreement both inside
and outside the building (USEPA, 2012b).
Studies of VI processes in commercial buildings have generally shown significantly better attenuation
factors than have been observed in typical residences (Venable et al., 2015).
1.2.2 Temporal Variability
ITRC (2007) summarizes temporal variability in Section D.4.10:
Variations in soil gas concentrations due to temporal effects are principally due to
temperature changes, precipitation, and activities within any overlying structure.
Variations are greater in samples taken close to the surface and dampen with increasing
depth. In 2006 there were a number of studies on temporal variation in soil gas
concentrations, and more are under way or planned in 2007 by USEPA and independent
groups. To date these studies have shown that short-term variations in soil gas
concentrations at depths 4 feet or deeper are less than a factor of 2 and that seasonal
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variations in colder climates are less than a factor of 5 (Hartman 2006). Larger variations
may be expected in areas of greater temperature variation and during heavy periods of
precipitation, as described below.
• Temperature. Effects on soil gas concentrations due to actual changes in the
vadose zone temperature are minimal. The bigger effect is due to changes in an
overlying heating or HVAC system and the ventilation of the structure due to
open doors and windows. In colder climates, worse-case scenarios are most likely
in the winter season. The radon literature suggests that temporal variations in
soil gas are typically less than a factor of 2 and that seasonal effects are less than
a factor of 5. If soil gas values are more than a factor of 5 below acceptable
levels, repeated sampling is likely not necessary regardless of the season. If the
measured values are within a factor of 5 of allowable risk levels, then repeated
sampling may be appropriate.
• Precipitation. Infiltration from rainfall can potentially impact soil gas
concentrations by displacing the soil gas, dissolving VOCs, and by creating a
“cap” above the soil gas. In many settings, infiltration from large storms
penetrates into only the uppermost vadose zone. In general, soil gas samples
collected at depths greater than about 3–5 feet bgs or under foundations or
areas with surface cover are unlikely to be significantly affected. Soil gas samples
collected closer to the surface (<3 feet) with no surface cover may be affected. If
the moisture has penetrated to the sampling zone, it typically can be recognized
by difficulty in collecting soil gas samples. If high vacuum readings are
encountered when collecting a sample or drops of moisture are evident in the
sampling system or sample, measured values should be considered as minimum
values.
• Barometric Pressure. Barometric pressure variations are unlikely to have a
significant effect on soil gas concentrations at depths exceeding 3–5 feet bgs
unless a major storm front is passing by. A recent study in Wyoming (Luo et al.
2006) has shown little to no relationship between barometric pressure and soil
gas oxygen concentrations for a site with a water table at ~15 feet bgs.
In summary, temporal variations in soil gas concentrations, even for northern climates,
are minor compared with the conservative nature of the risk-based screening levels. If
soil gas values are a factor of 5–10 times below the risk-based screening levels, there
likely is no need to do repeated sampling unless a major change in conditions occurs at
the site (e.g., elevated water table, significant seasonal change in rainfall).
Section D.8 of ITRC (2007) also notes:
Short-term temporal variability in subsurface vapor intrusion occurs in response to
changes in weather conditions (temperature, wind, barometric pressure. etc.), and the
variability in indoor air samples generally decreases as the duration of the sample
increases because the influences tend to average out over longer intervals. Published
information on temporal variability in indoor air quality shows concentrations with a
range of a factor of 2–5 for 24-hour samples (Kuehster, Folkes, and Wannamaker 2004;
McAlary et al. 2002). If grab samples are used to assess indoor air quality, a factor of
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safety (at least a factor of 5) should be used to adjust for short-term fluctuations before
comparing the results to risk-based target concentrations. Long-term integrated average
samples (up to several days) are technically feasible, using a slower flow rate this is the
USEPA recommended approach for radon monitoring). Indoor air sampling during
unusual weather conditions should generally be avoided.
In Section D.11.8, ITRC (2007) discusses the effect of meteorological changes on VI:
A variety of weather conditions can influence soil gas or indoor air concentrations. The
radon literature suggests that temporal variations in the soil gas are typically less than a
factor of 2 during a season and less than a factor of 5 from season to season). Recent
soil gas data from Forensics Used at Colorado’s Redfields Site Forensic approaches were
used at the Redfield Rifles site in Colorado to determine whether the source of subslab
contaminants was in the vadose zone or the overlying structure (McHugh, De Blanc, and
Pokluda 2006). D-28 Endicott, New York and Casper, Wyoming are in agreement with
the radon results. For soil gas, the importance of these variables will be greater the
closer the samples are to the surface and are unlikely to be important at depths greater
than 3–5 feet below the surface or structure foundation.
Recent work in the VI field has highlighted the importance of climate zone and the location of the source
relative to the building in controlling the type of temporal variability observed (Barnes and McRae 2017;
Brewer et al. 2014, Claussen et al. 2019, Lutes et al. 2019). For example, the temporal variability at
commercial buildings in Alaska and New Hampshire has varied from the standard stack effect driven
pattern: higher concentrations have been observed in summer, likely due to the source being directly
under the slab and the climate.
Barometric pressures generally show a regular diurnal “tidal” pattern of up to 3 millibars variation (300
pascal or 0.089 inches of mercury) in tropical areas and 0.3 millibars (30 pascals, or 0.0089 inches of
mercury) in polar areas (Le Blancq, 2011). Larger variations occur during the periodic passage of weather
fronts or cyclonic storms and contribute in some cases to peak VI events through barometric pumping of
soil gas (Schuver, 2018; Lutes, 2021b; Lutes, 2021c; US EPA, 2015b; US EPA, 2015c).
There have been limited studies of the long-term temporal variability of VI in industrial buildings. The
available studies suggest substantial temporal and spatial variability (Barnes and McRae 2017, Brenner
2010, Lund et al. 2019).
Recent studies have highlighted the following indicators and tracers of temporal variability (Lutes, 2021a
and 2021b; Lutes, 2022; Schuver, 2015; Schuver, 2018; Schuver, 2021):
•
•
•
Radon concentration, and change in indoor radon concentration
Differential temperature (warmer indoor than out), and increases in differential temperature
(getting colder)
Significant changes in barometric pressure beyond the daily diurnal cycle.
1.3 Potential for Use of Radon as a Vapor Intrusion Tracer
Radon, a naturally occurring radioactive gas, is a potentially useful tracer or surrogate for assessing VI of
VOCs. This is because the physics of radon intrusion into indoor air is nearly identical to VOC VI. Radon is
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ubiquitous in the soil and present at measurable quantities throughout the United States. Indeed, much
of the research in VOC VI is an expansion of earlier work on radon intrusion.
Radon provides a nearly unique tracer for VI because its presence in the indoor environment is usually a
result of radon in the soil gas. In addition, the entry mechanisms are believed to be the same for VOCs
and radon in soil gas. Thus, measured radon entry rates should be a good predictor of relative entry
rates for VOCs. The advantages of using radon as a tracer for VI characterization include:
•
Measurements of radon are easier and much less expensive than canister measurements of VOCs
(typically less than 10% of the VOC analysis cost).
•
•
High levels of indoor radon identify buildings as vulnerable to soil gas entry.
•
Because of the low sampling/analytical costs, it is possible to increase the number of field
measurements. This, in turn, increases confidence in the field evaluation.
Passive indoor sampling for radon costs approximately $5-20 per sample. Active radon sampling
(indoor air and subslab) uses some of the same equipment and setup as for VOCs. This minimizes
sampling times and cost.
•
Radon measurements before and after installation of VI mitigation systems can be used to assess
mitigation system performance.
In summary, the limited data gathered to date suggest that radon may be an inexpensive, reliable tracer
or surrogate for characterizing VI, and may significantly enhance VI characterization and decision
making, particularly when used in conjunction with subslab or soil gas sampling. However, several key
aspects and assumptions of this approach need to be verified before it can be put into widespread use.
For radon to be a valuable tracer:
•
Radon detection in building interiors should be quantitatively possible across the wide range of
subslab concentrations encountered in the United States. Ideally these measurements can be made
with inexpensive passive methods (i.e., charcoal or electrets).
•
Radon route and mechanism of entry should be similar to that of VOCs of interest, once both species
are present in the subslab soil gas. This would imply that the subslab attenuation factors for radon and
VOCs were similar.
•
Variance in the natural vadose zone radon concentration across a given building should be low enough
to allow radon to be a useful indicator.
•
Concentrations of radon and the VOCs of concern should be well correlated in subslab soil gas or nearfoundation exterior soil vapor. This would not necessarily be expected as radon and VOCs have
different sources. However, they may be approximately correlated if the VOC(s) of interest and radon
are both widely dispersed in deep soil gas. In this case, the concentrations of both radon and VOCs at
various locations in the subslab may be controlled primarily by the ratio of flow from the deep soil gas
to the flow from ambient air (in which both VOC and radon concentrations would be expected to be
low).
•
•
Interior sources of radon should be negligible.
The concentration of radon in soil gas must be sufficient to provide a suitable tracer after the expected
attenuation across the building envelope. Note, however, that radon may not always be sufficiently
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sensitive to observe relatively small or diluted soil gas entries that could still result in VI concerns
related to VOCs if the subslab VOC concentration is unusually high. To evaluate this, compute the ratio
of the indoor air screening level to the measured SSSG concentration for the VOC of interest. This ratio
would correspond to the minimum attenuation factor for which the indoor air concentration would
exceed its screening level. Multiply the ratio by the measured subslab radon; the result (in pCi/L)
corresponds to the “threshold” indoor radon concentration above ambient background that would be
measured if the VOC indoor air screening level was exceeded. Then for radon to be a suitable tracer,
indoor radon concentration must be readily distinguishable from the local ambient air background.
The loss rates to sink effects in the indoor environment should be similar or negligible for radon and
VOCs so that the air exchange rate forms the primary control of indoor air concentration once VI has
occurred.
This concept was applied in a relatively small study (Cody et. al. 2003) at the Raymark Superfund Site in
Connecticut. The study compared the intrusion behavior of radon and individual VOCs by determining
attenuation factors between the subslab and indoor (basement) air in 11 houses. The results indicated
that the use of radon measurements in the subslab and basement areas was promising as a conservative
predictor of indoor VOC concentrations when the subslab VOC concentrations were known. Further
work at the Raymark Site (US EPA 2005a) statistically compared basement and subslab concentration
ratios for radon and VOCs associated with VI. Of six test locations, three showed that basement/subslab
concentration ratios for radon and VOCs associated with subsurface contamination were similar. Three
test locations had statistically different ratios, suggesting that further research was needed to evaluate
the usefulness of radon in evaluating VI. Conservative VOCs (those believed to be associated only with
subsurface contamination) were a better predictor of other individual volatile compounds associated
with VI than was radon.
A three-building complex, commercial case study of the radon tracer approach was published by
Wisbeck et al. (2006). Radon and indoor air attenuation factors were calculated for five sampling points
and were generally well correlated. Subslab radon concentrations varied by approximately a factor of 10
across the five sampling points.
Results of an earlier test program at Orion Park Housing units at Moffett Field have been preliminarily
reported (Mosley 2007). Results showed:
•
•
Low levels of radon can be measured with sufficient accuracy to be used in analysis of VI problems.
•
Unexpectedly, the subslab areas under each unit were segmented. The four subslab sampling points
installed in one unit were not in good communication with one another. An introduced tracer, SF6
moved very slowly and not very uniformly under the slab
•
Results showed that for soils like these with poor communication, a subslab measurement at a single
point is not very reliable for estimating potential VI problems. The average value of subslab
measurements at several locations also may not yield a reliable estimate of indoor concentrations.
When subslab communication is poor, one must identify a connection between subslab contaminants
and a viable entry path.
Radon is a promising, low-cost surrogate for soil gas contaminants; however, as with VOCs themselves,
the complete distribution under the slab must be known to properly interpret its impact on indoor
measurements.
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The potential usefulness of the radon tracer was studied over 2007–2010 by EPA at Moffett Field in
California (Lee, 2010; Lutes, 2010b), in the Wheeler Building in Indianapolis (Lutes, 2010b), and in the
Indianapolis Duplex Study (Lutes et al., 2015; US EPA, 2012b; US EPA, 2015b). Potential applications of
radon in VI studies have been summarized by Schuver and Steck (2015). The use of radon and other ITS
to predict peak VOC concentrations has been recently evaluated (Lutes, 2021b). The effectiveness of
various radon-based decision rules was evaluated in (Lutes, 2021a; Lutes, 2022).
1.4 Availability of and Quality of Meteorological Forecasts
We expected the indoor air concentration (our dependent variable) to depend on the VI flux from soil
gas, which in turn is controlled or influenced by a number of other variables that can affect the VI
process. These variables will be collected as follows:
•
Weather-related variables, including air temperature, barometric pressure, and wind, were collected
from standard National Weather Service (NWS) forecasts (Table 1-1).
•
Weather forecast accuracy is not perfect even for fewer than 3 days in the United States, as shown for
Indianapolis in Table 1-2. Weather forecast accuracy statistics for various U.S. locations can be
obtained at http://www.forecastadvisor.com/.
Table 1-1.
Parameter
Exterior
Temperature
Meteorological Predictor Variables Used to Guide Prediction
Proposed Trigger Point
A differential temperature of
>20°F between inside and
outside.
Prediction Source
Monitoring Method
Local weather station, available 5
to 7 days ahead.
Internet access; 7 day
forecasts are commonly
available from National
Weather Service and many
Apps.
This could be predicted by a
meteorologist but is not typically
widely reported due to limited
general public interest. Individuals
may be susceptible to predicting
this change based on body/health
concerns (e.g., migraines, joint
damage).
https://barometricpressure.ap
p/ provides a fairly easy to
use 5 day graphical forecast.
This can only be observed on a
radon monitor and cannot be
directly predicted except based
on structure-specific experience.
Radon map provided by
USEPA is accessible at
https://www.epa.gov/radon/e
pa-map-radon-zones-andsupplemental-information
and can help individuals
identify their typical/expected
concentrations within their
zone based on geography.
On site monitoring will
Low temperature decrease of
10°F or more.
(The intent is to set a criterion
that would be realistic to occur
for a given site while
representing a significant driving
force for that site. For example,
we are seeking a criterion that
would narrow the sampling days
to 35 - 70 days per year).
Barometric
pressure
Indoor radon
concentration
A sudden change in barometric
pressure over less than 6 hours
of 1000 Pa or 0.3 in of Hg.
>90th percentile of the first
month’s radon concentration or
Day over day radon
concentration change of +1.0
pCi/L or more or an increase of
1.5x day over day.
weatherstreet.com provides
pressure forecasts in form of
weather map for various
future dates.
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Parameter
Proposed Trigger Point
Prediction Source
Monitoring Method
require purchased or rented
equipment, operated by the
interested or contracted
party.
Rainfall
A predicted significant rain
event of approximately 1” of
rainfall or greater.
Table 1-2.
Local weather station, available 5
to 7 days ahead.
Internet access – 7 day
forecasts are commonly
available from National
Weather Service and many
Apps.
Ability to Forecast Weather of Major Providers at an Example Location
Weather Forecast Accuracy Data Last Year (2013)
Provider
High Temp
Low Temp
Icon Precip
Text Precip
Overall
The Weather Channel
76.12%
75.25%
79.30%
79.30%
77.49%
MeteoGroup
73.03%
75.94%
80.40%
80.40%
77.44%
National Weather Service
70.86%
72.31%
77.15%
75.65%
73.99%
WeatherBug
68.52%
68.58%
79.32%
79.32%
73.94%
AccuWeather
67.16%
66.40%
78.81%
80.30%
73.17%
Weather Underground
68.36%
67.60%
79.54%
76.45%
72.99%
Foreca
72.58%
67.23%
75.77%
75.77%
72.84%
CustomWeather
67.16%
66.30%
77.71%
77.71%
72.22%
Persistence
30.27%
28.11%
57.43%
57.43%
43.31%
Source: ForecastAdvisor, 2014.
Table notes:
Example site is Indianapolis, Indiana.
Forecastadvisor.com describes their statistics as follows: “All the accuracy calculations that appear
on ForecastAdvisor are averaged over one to three days out forecasts. The percentages you see for
each weather forecaster are calculated by taking the average of four accuracy measurements. These
accuracy measurements are the percentage of high temperature forecasts that are within three
degrees of what actually happened, the percentage of low temperature forecasts that are within
three degrees of actual, the percentage correct of precipitation forecasts (both rain and snow) for
the forecast icon, and the percentage correct of precipitation forecasts for the forecast text. The
percentages you see are specifically for the listed city. About 90 forecasts from each provider make
up the monthly percent (30 days in a month times 3 days of forecasts per day), and over 1000
forecasts from each provider make up the yearly percent.”
http://www.forecastadvisor.com/docs/accuracy/ downloaded 6/28/14
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2 Research Approach Summary and Project Management
For this study, the ideal test site(s) will have identifiable concentrations of radon in the exterior soil gas,
a known VOC plume (contaminants and approximate concentrations and boundary), and mostly
residential structures within the study area. Success of this study will depend on involvement of building
occupants/owners during the initial screening phase, as well as during the optional community science
phases. The objectives and approach, including currently funded and optional tasks, are outlined below.
2.1 Project Objectives
The three large-scale objectives of this project are to:
•
conduct a pilot study at a community willing and interested in being designated a Soil Gas Safe
Community.
•
examine the protectiveness of the ITS methodology and approach as compared to the “traditional”
standard chemical sample site selection process, and
•
assist EPA in collecting and analyzing the breadth of information needed to establish a Soil Gas Safe
(SGS) Community designation.
2.2 Description of Research Activities & Expected Products
2.2.1 Task 1. Assistance in Developing Criteria for the Soil Gas Safe Community Designation
This task seeks to establish criteria for SGS Community designation in collaboration with an Expert
Working Group and a study brochure to assist with community outreach.
2.2.2 Task 2. ITS Method Development and Planning
This task seeks to test the protectiveness of ITS in real world situations and settings, as compared to
standard or typical chemical sampling techniques at sites throughout the United States.
The RTI Team will work in conjunction with EPA in selecting at least one initial community to test the ITS
method’s capabilities to predict the best time for sampling of SGI. Additional sites may be selected at
EPA’s request. Desirable characteristics of the community(ies) selected include being: (a) communities
with EJ concerns, (b) a Tribal community, and/or (c) a site undergoing a current VI investigation that
need assistance to help making a remedial decision with regard to the potential VI pathway at the site
(i.e., traditional convenience sampling practices have not provided a definitive answer). The VI
assessment conducted as part of this study may recommend community scale remediation/mitigation
through a technology such as soil VI mitigation for individual structures, as appropriate.
Site selection criteria will include EPA’s preference for a community with EJ concerns, a tribal
community, and/or a site undergoing a current VI investigation needing assistance with a remedial
decision. Sites with cooperative regulatory agencies and responsible parties who need assistance to help
make a remedial decision on particular buildings or neighborhoods will be sought because this will
facilitate a cost-effective and timely study. Selecting a community with freezing winter temperatures
during the heating season would be preferable, but not a required sampling frequency under PWS Tasks
3, 4, and 5 and to understand the temporal variability in VI.
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Considering the desired timeline to get into the field and obtain community buy-in to complete the
initial screening under Task 3 by September 2022, complete all tasks within the period of performance,
and be cost-effective, we recommend the following bounds be made around the selected community in
addition to EPA’s preferences noted above:
•
Selected community site(s) are within 30 miles of an RTI Team firm office. Between Jacobs and
Geosyntec, there are more than 150 offices nationwide, most in major metro areas, where many
communities with EJ concerns and CERCLA and RCRA sites are located.
•
•
The size of the inclusion area will range from 30 to 200 structures.
•
Selected community site(s) are those where the primary known soil gas hazards are chlorinated VOCs
or radon. Communities where CH4 is the primary hazard may be of interest in a future project.
To the extent feasible, we recommend selecting a community where radon is most likely to be
detectable, but only above EPA’s 4 pCi/L action level in a minority of structures. We will confirm
whether potential communities are in a county with radon Zone 1 or Zone 2 designation (EPA, 2015c
and use finer-scale radon susceptibility data where available [Churchhill 2016]. Note that selecting a
community in Zone 1 (higher risk) may result in identifying several homes with a radon issue and may
prompt mitigation action.
The Expert Working Group will review and provide feedback on the list of potential communities (up to
five communities) prepared by the RTI Team. The EPA TOCOR and Alt-TOCOR will take the Expert
Working Group’s feedback into consideration during site selection but will ultimately make the decision
themselves.
RTI consultant, Lenny Siegel, will lead community engagement efforts to engage with community
leaders (e.g., mayor, neighborhood associations, environmental groups) to confirm whether obtaining
enough volunteers to participate in this project is feasible. Once the community is confirmed and onboard, Jacobs field staff will engage with homeowners/occupants and/or business owners within the
potential site inclusion area via door-knocking. We anticipate a time-consuming process of community
engagement to recruit willing participants, obtain permission to access numerous structures, and gain
acceptance of the community to perform the ITS method development under Task 4.
The expected products from this task include the following:
•
•
•
A list of potential candidate communities to the TOCOR via email.
A conference call discussion on the potential communities with the TOCOR and Expert Working Group.
Meeting minutes from any community meetings delivered to the TOCOR via email within 2 business
days of the meeting.
2.2.3 Task 3. QAPP Development
Two distinct and sequential activities are included in the PWS – QAPP development and an initial
screening of structures in a community in preparation for field testing under Task 4. These activities are
presented as separate subtasks for project tracking convenience.
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2.2.3.1 Task 3a. QAPP Development
Due to the schedule, the RTI Team will prepare a draft QAPP to complete the initial screening planned
under Task 3b with placeholder information to be amended after the communities where field work will
occur are selected. This draft QAPP will document the proposed field testing to examine results from ITS
guided/triggered SGI sampling versus standard convenience VI sampling protocols (e.g., seasonal
sampling twice a year) identified in Task 1.
The QAPP will be amended after the initial community is selected to include site-specific details such as
the statistically valid study design to compare a population of buildings, spatially and temporally, of ITSindicated sampling vs convenience sampling selection.
The amended QAPP will be submitted to the EPA after Task 3b is largely complete and prior to the
beginning of Task 4.
The QAPP will be revisited and may be amended prior to beginning Task 5.
2.2.3.2 Task 3b. Initial Screening
This task will include the following initial site/building screening:
•
•
Preparation of a health and safety plan (HASP) to cover both the task 3B and 4A activities.
•
Continuous indoor radon monitoring and passive sampling of indoor air for VOC analysis for a period
of 7 days in each of the 30 potential buildings.
Soil gas sampling for VOCs at four locations around each of the potential buildings collected using 7
calendar day passive sorbers (e.g., a total of 120 soil gas locations from 30 buildings). If the buildings
are adjacent, then one sample can be used to meet part of the data needs for both buildings,
potentially reducing the data need slightly below 120 soil gas locations. A single measurement of soil
gas radon will also be conducted with a field portable instrument at each of these locations. A GPS unit
will be used to log the coordinates of the soil gas samples.
•
A brief initial building survey will be conducted in each building to obtain information about air
movement, indoor sources of VOCs, previous mitigation systems, HVAC, and occupancy. Given the
substantial efforts associated with the initial screening work, we assume that the initial building
surveys may be succinct in content but may be supplemented later under Task 4 (as trust is gained
from the homeowners or occupants). It is expected that the structure(s) will be screened using a
handheld MultiRae PID and pictures/videos (pending permission of the occupant) will document
condition of the building envelope, including floor plan, and potential background VOC sources which
may be present.
We assume a 90% completion rate and no resampling of soil gas due to uncontrollable damage from
burrowing animals, lawnmowers, or other sources. The external soil gas sampling locations will be
installed in unpaved areas to a depth 5 feet using a person portable power auger. During this effort, the
open hole at each location will be screened for CH4 and H2S with a four-gas meter. Instantaneous
measurements of soil gas radon will be made with an EPA-supplied continuous radon monitor (i.e., Rad7 or AlphaGUARD) at each of the soil gas sampling locations and in three sewer manholes to evaluate
the strength of the radon tracer. Outdoor radon will also be measured with this instrument.
In addition to the external soil gas sampling, a radon meter (provided by EPA) and a passive sampler
shall be placed in each potential building to determine baseline Rn concentration distributions and
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completeness of the VI pathway, respectively. Passive samplers shall be left for 7-days. This initial
sampling effort of the indoor air will represent a typical convenience sampling.
The passive sorbers will be analyzed by EPA with samples being shipped to: USEPA, attn. John
Zimmerman, Chemical Services, Room E-178, Building E Loading Dock, 109 T.W. Alexander Drive, RTP,
NC 27709 using SOP: WECD-MMB-SOP-4350-0 “Analysis of Volatile Organic Compounds in Soil Vapor
using Thermal Desorption / Gas Chromatography / Mass Spectrometry”.
Personally identifiable information (PII) such as building owner/occupant names will be “blinded” by
using a unique case identification number per building that Jacobs will manage.
2.2.4 Task 4. Field Testing for Method Development (Optional based on availability of funds)
2.2.4.1 Task 4a. Field Sampling Preparation and Testing
Field testing will occur under this task to determine the effectiveness of ITS methods in predicting when
to collect an indoor air sample for decision making purposes of whether to mitigate or not. In task 4 the
ITS based sample timing decisions will be made by the RTI team. Information developed in Task 1 when
defining the criteria for the SGS community designation will be used in creating a sampling design to
determine the success or failure of the ITS methods when compared to the standard or typical
convenience VI investigation methodology and compared to long-standing EPA exposure criteria for
short- and long-term exposure risks.
Field sampling will follow procedures defined in this EPA-approved QAPP and is expected to include one
standard convenience calendar-based sampling and up to three ITS-driven sampling events in each of
three seasons (summer, winter, spring/summer) for indoor air collection, for a total of up to 12 sampling
events. The primary planned sample type is the 7 day Radiello passive sample, but an optional task 4A
for a one day passive sample at the beginning of each of three convenience sampling events and each of
three ITS scheduled events is included. It is expected that the predictive ability of the ITS measures may
be stronger for daily samples immediately after the ITS decision then for weekly samples. Additionally,
the combination of weekly and daily samples provides additional information on short term temporal
variability that may be relevant to short term development risks. No external or subslab soil gas
sampling will be conducted (since external soil gas was already sampled in task 3).
EPA ORD’s laboratory will continue to supply passive samplers and support analyses of the passive
indoor samples collected under this task. Samples will be shipped to USEPA, attn. John Zimmerman,
Chemical Services, Room E-178, Building E Loading Dock, 109 T.W. Alexander Drive, RTP, NC 27709.
Using SOP: WECD-MMB-SOP-4350-0 “Analysis of Volatile Organic Compounds in Soil Vapor using
Thermal Desorption / Gas Chromatography / Mass Spectrometry”.
2.2.4.2 Task 4b. Database Preparation
RTI will develop and manage a database to store the data from Task 4a after receiving the analytical files
from the TOCOR. Data files are expected to undergo QC checks by the TOCOR before delivery to the RTI
team. The RTI Team will conduct a data verification level review and engage with the TOCOR regarding
corrective actions and data review questions. A minimum of 10% of each dataset provided by the EPA
laboratory will be reviewed for outliers and calculation errors. The database will be delivered to the
TOCOR upon completion of the project.
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The RTI database and tables, figures, summaries, etc. will not include any PII for individual houses. A
separate confidential key will be maintained with home contact information and a code designation for
each structure. The identity of the community being studied however will be public.
2.2.5 Task 5. Application of ITS Methodology to a New Community – Community Pilot Study
(Optional based on availability of funds)
Task 5 will leverage the procedures defined under and findings from Tasks 1, 2, and 4 and test them in a
new (pilot) community considered to be an EJ or Brownfields community. The approach will incorporate
community science into the ITS assessment for SGS communities by training and assisting the
community to be the primary collectors of the radon meter readings and passive samplers.
2.2.5.1 Task 5a. Community Selection
RTI will collaborate with the TOCOR to select a pilot community to test the ITS method’s capabilities to
predict the best time for sampling of SGI when the citizen scientist makes the sampling decisions. The
RTI Team will amend the initial list of communities provided to the TOCOR under Task 1 and assist the
EPA in their selection of the pilot community.
As of July 2022, activities are scoped for one pilot community under this task.
After the community has been selected by the TOCOR, Lenny Siegel will initiate community
engagements with members of the selected community. Meeting minutes from community meetings
will be provided to the TOCOR within two business days.
RTI/Lenny Siegel anticipates working with community outreach groups in the selected communities and
may post low-cost advertisements on community social networks such as Nextdoor and Facebook as
well as posting advertisements for interested volunteers via local universities, schools, libraries, activist
groups, and similar sources. We may develop a simple questionnaire to gauge community interest and
willingness to participate. This questionnaire could include questions confirming they live in the selected
sampling zone, are willing to participate for the duration of the study and have interest in sample
collection and participating in the community science training. We do not anticipate collecting any
household demographics other than that already included in the standard ITRC (2007) VI survey form
which includes:
•
•
•
•
•
•
number of household occupants
Age of occupants2 (can be reported as broad ranges for example 0-6, 6-12, 12-18; 18-65; >65)
Whether occupant is owner or renter
Contact information for occupant and/or owner/landlord
structure construction style and age
information about air movement,
Note that EPA 2015a says “As such, EPA recommends the CSM also identify and consider sensitive populations,
including but not limited to:
• Elderly,
• Women of child-bearing age,
• Infants and children,
• People suffering from chronic illness, or
• Disadvantaged populations (i.e., an environmental justice situation).” But there may be legal restrictions on collecting
some of this information on an individual household basis.
2
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•
•
•
indoor sources of VOCs,
previous mitigation systems,
HVAC system type.
Personally identifiable information will be protected via appropriate privacy security measures such as
anonymizing building addresses and using case IDs. Additional demographic information to allow
comparison of communities may be available from US census bureau data.
The Jacobs field team will ask each participating building owner or occupant to sign a brief consent form
that grants the field team access to the premises to conduct sampling activities. We anticipate building
on the standard EPA consent form and standard ITRC VI survey form.
2.2.5.2 Task 5b. Community Science Training
Our technical experts and Community Engagement Specialist will develop a community science training
program that is accessible in terms of common language (minimal to no jargon) and disabilities; succinct
(to maintain interest and attention); and easy to understand and implement. We plan to engage
community members over one training that may last 2 to 3 hours. The training will start with an ice
breaker to get to know the Community Engagement Specialist and a key technical field team member
who would be interacting with community members to address questions and troubleshoot on the
ground, and EPA representatives (if desired). Specific details on the training will be developed after
award, but we generally envision the training will:
•
•
Describe the research objectives, general timeline for the study and their roles and responsibilities
Educate the participants about the basics of VI and exposure risks including some general information
about the use of ITS as indicators of VI, probably formatted as “Rules of thumb” such as sample when
radon is high or increasing, sample when CO2 is high, sample when it is cold outside or getting colder in
the fall.
•
Educate the participants about sample collection, how to operate the equipment, collect samples, and
package them for shipping. We will also compile a sampling checklist and guidebook that compiles the
training materials and a list of resources for more information (provided in hard copy at the training).
A field team member will conduct a household visit after the training to deliver the sampling kits and
follow-up on the training to confirm a designated household member understands what needs to be
done. We may also engage a trusted community stakeholder from the selected community to review
and comment on the training materials to make them more accessible, assist with getting community
members to attend the trainings, and/or facilitate the trainings. One important aspect that will be
determined after community selection is whether to offer the trainings more than once to
accommodate individual schedules and general availability (e.g., work schedules, child care, elder care).
We may also need translation services; however, at this stage, we are anticipating the training materials
will be developed in English and anticipate EPA staff could provide significant translation services (if
feasible and desired by EPA).
We plan to pull from existing resources to develop the training materials for this task, including the
following:
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•
Basic introductory materials on VI, such as the Minnesota Pollution Control Agency’s “What is Vapor
Intrusion,” and radon risk, such as EPA’s “A Citizen’s Guide to Radon”
•
SOPs from the approved QAPP (simplified if recommended by our Community Engagement Specialist)
and ITS measurements developed by the RTI Team for EPA under previous funding (see Appendix B-12
Radon Monitoring and Appendix B-14 Temperature Monitoring).
•
Existing publicly available videos on the use of passive samplers such as
https://www.youtube.com/watch?v=ZQ5Hp4ZeIB0 and
https://www.youtube.com/watch?v=0buReBuI96A.
2.2.5.3 Task 5c. Field Sampling and Database Development
The RTI Team assumes that the additional site in Task 5c will be sampled to the same degree as the site
in Task 4a, with the exception that the community members will oversee the timing and collection of
samples under Task 5 using Radiello passive samplers to be analyzed by the EPA ORD laboratory. The
sampling efforts will span a period of 11 months covering at least three seasons. We anticipate that at
least 30 buildings will be supplied with radon monitoring instrumentation transferred from Task 3 or
Task 4a and selected for indoor air sampling. The community members will be encouraged to collect 7
day samples at both random times (3 samples or 1 per season) and ITS-driven times (9 samples or 3 per
season) for the purpose of evaluation and to designate the reason in the data reporting form. In this
case “Data reporting form” will fulfill the function of a chain of custody as well as potentially contain
other information such as the reasons for sampling. We assume that each of the 12 samples can be
shipped in individual post-paid mailers with data reporting sheets by USPS priority mail to the EPA
laboratory without refrigeration but with a thermal protective mailers [22]. In addition to the sampling
efforts detailed above, Task 5c also includes an optional cost which includes the use of 1-day samplers
for three convenience sampling events and three ITS-scheduled sampling events, for a total of 6
sampling events with 1-day samplers.
Twelve mailers will be provided per structure. The RTI Team will receive from EPA large stocks of readyto-deploy Radiello cartridges and will distribute them to individual homeowners/occupants as sampling
kits in time for each round. As the samples are received, the EPA laboratory will maintain a database
(spreadsheet) and be able to communicate back to RTI/Jacobs how many samples had been received
from which houses at what time. Community scientists are expected to provide basic information for
each sample collected, to identify them from one another upon receipt by the lab. However, the EPA lab
will ultimately be responsible for assigning a sample name which removes the attachment of any PII to
an individual sample (that is, no street addresses or names). The EPA laboratory will need to store the
COCs in a locked filing cabinet or drawer. For the envelopes, once the COC is checked against the
samplers received, they should be shredded.
One picked volunteer per neighborhood will be asked to also conduct ambient air sampling. Thus,
ambient air samples will not be contemporaneous with all of the individual house indoor samples.
Another picked volunteer can be asked to conduct duplicate sampling. Field blanks will be created by
Jacobs field staff who will open and the Radiello and immediately mail it to EPA following the
instructions given to homeowners. This will reduce the complexity of the tasks that homeowners need
to be trained in.
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Conducting assessments of homes or businesses with volunteer community scientists will inevitably
introduce unique challenges, resulting in attrition during the sampling period and potential data quality
issues. We will therefore need to recruit and enroll more than the minimum number of structures to
provide valid data in each community. Potential challenges we may encounter, and address include:
•
Not all participants will engage at the same level. Some will require reminders or encouragement to
complete study activities. Others will not be able to complete study activities due to moving, job or
childcare constraints, or changes in family circumstances.
•
Engaged participants may be impatient with typical externally driven timelines or the needs of the
overall study design protocol for ITS-driven sampling. Some community members may want to move
rapidly to a decision on management of their structure to end uncertainty (i.e., mitigation of exposures
above screening levels or a no action decision).
•
Samples will be collected individually and thus will flow to the EPA laboratory on irregular timings.
Residents may expect rapid, predictable analytical results and may want to interpret each set of results
after sampling. The RTI Team will develop a letter template that is suitable for transmission to
individual owners or occupants with individual building analysis results and/or anonymized
neighborhood results if desired. We have assumed that twelve letter reports will be provided per
building, with each letter report corresponding to a sampling event.
•
Residents/occupants may be focused on their own exposure experience versus regulatory timelines
for decision making on the site (community) as a whole, or on EPA ORD timelines for evaluation of the
ITS approach.
•
There is a moderate chance the COVID-19 pandemic may adversely impact field sampling if
community members refuse or are uncomfortable with field staff entering their household, regardless
of masking and vaccination status.
To prevent and mitigate these potential challenges, the RTI Team proposes several actions below and
will collaborate with EPA social scientists after award. These actions include:
•
Completing a data verification review of each EPA laboratory report and provide brief interpretative
comments in cover letters for data transmittals.
•
Addressing homeowner/building occupant questions that cannot be addressed sufficiently through
the FAQ sheet developed under Task 2c. Particular attention will need to be paid to balancing the
needs to take rapid action to address problematic exposure while documenting the effects of those
actions on the study design.
•
Visiting a structure if necessary to collect radon and temperature data at the end of the 6-month
period if it cannot be remotely (electronically) downloaded from installed equipment by the field
team.
•
Record, using structure coded forms, the reasons homeowners/building occupants give for
terminating or suspending participation or not being able to sample. Similarly record the general
nature of technical questions asked by the homeowners/occupants.
•
Suggesting general mitigation measures for a building or group of buildings, as may be warranted by
radon or VOC concentrations.
o Provision of mitigation is not included in the current project budget; however, it is
important to consider the potential for mitigation to be funded/performed by others
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o
when selecting study structures during site selection. A general set of mitigation measures
(i.e., not specific to each building) can be developed within the current project budget.
Funding for VOC mitigation is generally provided by potentially responsible parties or by
government agencies in the case of “orphan” sites. Funding for mitigation of radon, a
natural hazard, is generally the responsibility of individual homeowners; however, there
are some governmental and charitable resources that can provide grants or loans for
radon mitigation on a limited basis that can be provided to building occupants; see for
example:
▪
▪
▪
▪
https://sosradon.org/Mitigation-financial-assist
https://tooelehealth.org/wp-content/uploads/2018/01/Summary-URC-Low-IncomeRadon-Mitigation-Assistance-Program.pdf
https://www.ncdhhs.gov/divisions/health-service-regulation/north-carolina-radonprogram/partnerships
https://www.hokecounty.net/484/NC-Radon-Program.
2.2.5.4 Task 5d. Database and Journal Article Preparation
RTI will follow the same approach proposed for Task 4b to compile the database and prepare a second
draft journal article. RTI will also submit the database and draft article within the agreed-upon timeline
(within 37 months of the project kick-off date or by March 2025). The RTI database and tables, figures,
summaries, etc. will not include any PII.
2.2.6 Task 6. Final Evaluation of ITS Effectiveness (Optional based on availability of funds)
The RTI Team will evaluate the effectiveness of the ITS approach in providing consistent and comparable
equivalent spatial and temporal protectiveness for an SGS Community. Factors to be assessed will
include, but are not limited to:
•
•
•
Radon and VOC concentrations
Environmental parameters (e.g., pressure, temperature), and
The influence of contractor versus community member sampling (i.e., key differences between Task 4
and 5) on factors such as number of samples collected, quality of results, cost, and other factors to be
determined in collaboration with the TOCOR.
The fact sheet and training materials will be amended accordingly to reflect changes and lessons learned
from Task 4 and 5 activities.
2.3 Timeline for Expected Products/Sub-Products
The project timeline is generally presented in Table 2-1. A detailed schedule is being maintained on
Smartsheet; access can be granted by the TOL, Kate Bronstein, as requested. The timeline will be
reviewed and revised regularly (weekly or as needed). Copies of the project schedule will be provided to
the EPA TOCOR for EPA to maintain in their project study files.
Table 2-1.
Project Completion Timeline
Year 1 (4/22 - 3/23)
Task and Key
Activities
Q1
Q2
Q3
Q4
Q1
1. Assistance in Developing Criteria for SGS Community Designation
Year 2 (4/23 - 3/24)
Q2
Q3
Q4
Year 3 (4/243/25
Q1 Q2 Q3
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Task and Key
Activities
List of potential
Working Group (WG)
participants
Recruit WG participants
/ Initiate WG
WG meetings
Year 1 (4/22 - 3/23)
Q1
Q2
Q3
Fact sheet
2. ITS Method Development and Planning
2a. Initial Assessment
2b. Model
Comparison
2c. Community
Selection
Develop initial list of
potential communities
Short list of
communities
Community meetings
and meeting
summaries
Final selection of 2
communities
3. QAPP Development
3a. Draft QAPP
3a. Final QAPP (with
final study design)
3b. Installation of radon
meters and near
building VOC samplers
3b. VOC sample
analysis and
interpretation
3b. QAPP review and
amendments prior to
Task 5
4. Field Testing for Method Development (Optional)
4a. Field Sampling
Preparation and
Testing
HASP (draft and final)
Community meetings
(prior to sampling) and
meeting summaries
Field sampling (3
sampling periods of
summer, winter, spring)
Community
engagement during and
post sampling
Sample analysis and
interpretation
4b. Journal Article
and Database
Preparation
Draft letter of
recommended changes
for Task 5
Update/finalize fact
sheet
Develop and populate
database
Year 2 (4/23 - 3/24)
Q4
Q1
Q2
Q3
Q4
Year 3 (4/243/25
Q1 Q2 Q3
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Task and Key
Activities
Draft journal article
Year 1 (4/22 - 3/23)
Q1
Q2
Q3
Year 2 (4/23 - 3/24)
Q4
Q1
Q2
Q3
Q4
Year 3 (4/243/25
Q1 Q2 Q3
5. Application of ITS Methodology to a New Community - Community Pilot Study (Optional)
5a. Community
Selection
5b. Citizen Science
Training (develop
materials and deliver
trainings)
5c. Field Sampling and
Database Development
5d. Database and
Journal Article
Preparation
6. Final Evaluation of ITS Effectiveness (Optional)
Letter report on
effectiveness of ITS
approach
Modify fact sheet and
training materials
2.4 Team Roles, Responsibilities and Distribution List
The roles and responsibilities of key individuals involved in performing research activities and
developing products within this project are identified below in Table 2-2. Additional personnel, based on
their expertise (e.g., members of the External Working Group not presented in Table 2-2) and other EPA
staff, including social scientists, may be included during the project. This project will also involve
community scientists who will remain unnamed in this QAPP for privacy reasons. The TOL will be
responsible for the distribution of the most current signed approved version of the QAPP to participants
as indicated in Table 2-2.
Table 2-2.
Roles and Responsibilities
Name &
Organization
Contact Information
(E-mail)
Project Role(s)
Project Responsibilities
Kate Bronstein*
[email protected]
Task Order Lead
(TOL)
Maintain and distribute the official, approved QA project
plan (QAPP) to participants.
RTI
Update project schedule and manage project financials.
Prepare monthly reports.
Prepare meeting agendas and notes for meetings with
EPA.
Final review of deliverables.
Work with the RTI STREAMS IV QA Manager to resolved
data quality issues.
Rohit Warrier
[email protected]
Technical support
RTI
Provide technical support to the team, including
subcontractors with respect to community identification,
review of analytical results, preparation of journal article
content.
Assist with facilitation of the Expert Working Group
meetings.
Linda Andrews
RTI
[email protected]
Database Manager
Set up database to store analytical results from Tasks 3,
4, and 5; run queries to pull data for data tables and
figures.
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Name &
Organization
Contact Information
(E-mail)
Project Role(s)
Project Responsibilities
Cindi Salmons*
[email protected]
STREAMS IV QA
Manager
Complete QA review of the QAPP and work with the RTI
TOL to resolve data quality issues throughout the project.
[email protected]
Community
Engagement
Specialist
Provide social science and VI perspective for the RTI
team; assist with developing SGS community designation
criteria; community selection and pros/cons of each site.
RTI
Lenny Siegel
Assist with developing communications materials; lead
engagement with community leaders from selected
community for task 3 and 4 activities; and deliver
community trainings.
Chris Lutes*
Jacobs
Christopher.Lutes@ja
cobs.com
Jacobs TOL,
Subject Matter
Expert
Jacobs is leading Tasks 2a, 3a, 3b, 4a, and 5c, which
include data collection and analysis, field sampling,
analysis of analytical results, and interaction with
community members.
Participate in the Expert Working Group; provide
technical direction to the Jacobs team related to the
QAPP study design, field sampling, data analysis, and
community trainings; coordinate with RTI’s database
manager on data entry of analytical results; co-author
journal articles and other report deliverables.
Laurent Levy
Jacobs
Laurent.Levy@jacobs
.com
Subject Matter
Expert
Lead the Task 2a initial assessment report; technical
review of the overall study design; assist with site
identification; QAPP development.
Provide input into the data management strategy; serve
as a QA manager of field sampling efforts.
To be Named,
Jacobs
Field Team
Leader/Site
coordinator
Lead homeowner/resident interaction on day-to -day
basis.
Manage field data collection quality and safety.
Schedule and oversee field staff.
Chase Holton
Geosyntec
CHolton@Geosyntec.
com
Geosyntec TOL,
Subject Matter
Expert
Participate in the Expert Working Group.
Provide technical expertise primarily in tasks 1, 2, 4, 5,
and 6. Provide technical direction of the model evaluation
in task 2a.
Serve as co-author of journal articles and other
deliverables.
Matthew Jenny
Geosyntec
MJenny@Geosyntec.
com
Lead on Task 2b
Model Evaluation
Provide technical support to Chase Holton on Task 2a
initial assessment and lead Task 2b Model Evaluation.
* Copies of the approved QAPP will be sent to the individuals indicated.
2.4.1 Project Organization Chart
Figure 2-1 provides a visual representation of the working relationships and lines of communication
among key project participants identified in Table 2-2.
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Figure 2-1.
Project Organization Chart
EPA TOCORs
rian Schumacher (TOCOR)
ohn immerman (Alt TOCOR)
Study Advisors
enry Schuver
lara Crincoli
EPA A Manager
ara Godineaux
RTI TO
atherine
ronstein
Community
Engagement ead
enny Siegel
RTI A Manager
Cynthia Salmons
acobs TO
Chris utes
Geosyntec TO
Chase olton
acobs Sta
aurent evy
Field sta (to be
determined)
Geosyntec Sta
Ma hew enny
Field sta (to be
determined)
RTI Sta
Rohit Warrier
inda Andrews
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3 Documents, Records, and Data Management
This section identifies all research documentation and records that will be needed to support the
findings and conclusions of the research products, including those documents that provide objective
evidence for the quality of the environmental data collected.
3.1 Documents and Records
The required data package deliverables during each aspect of the project include (1) sample collection
and field measurement records, (2) analytical records, and (3) data assessment records. All records will
be made available to EPA upon request. All records will be maintained by RTI during the period of
performance and then archived for long-term storage.
Sample collection and field measurement records generally include field logbooks, photographic
documentation, equipment decontamination records, sampling instrument calibration records, soil
boring logs, chain of custody forms (see Appendix H for an example form), and air bills.
The data for the analytical deliverables will be provided electronically as a PDF file if from a commercial
laboratory and in excel files from US EPA laboratories. The data provided by the laboratory must be
legible and properly labeled.
Data assessment potentially includes verification, review, validation, evaluation, and usability
assessment. Only data verification, review, evaluation, and useability assessment are included in this
project budget, not functional guidelines data validation. The data review process will be documented
with emails between Jacobs, RTI, and the EPA RTP laboratory to facilitate efficient and accurate
assessment of data quality and usability. The overall usability of the data is indicated with appropriate
qualifiers.
Table 3-1 provides a list of documents and records that will be generated for this project, the parties
responsible for generating and maintaining those records, and storage locations, and applicable EPA
Records Schedule. The project team will maintain the project files in electronic and/or hard copy
formats for the duration of the contract POP. Electronic project files will be maintained on a Jacobs
project SharePoint site until transfer of custody to EPA.
Table 3-1.
Documents and Records to be Generated During This Project
Document
Field notebooks and Daily
Reports
Generator
Where Maintained
Field Team / Field Quality
Manager, Jacobs or Geosyntec
Electronic copies in the project file. Hard
copy (bound notebook) in the Jacobs project
file. Archived at project closeout.
Field Team / Field Quality
Manager, Jacobs or Geosyntec
Electronic and hard copies in the project file
(maintained by EPA RTP laboratory). EPA
RTP laboratory staff would need to scan and
email COCs to Jacobs or RTI if these files
are to be maintained by either party.
Archived at project closeout.
Field Team / Field Quality
Manager, Jacobs or Geosyntec
Electronic PDF copies in the project file.
Hard copy in the project file. Archived at
project closeout.
Chain-of-custody records1
Corrective action forms
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Document
Electronic field data
deliverables
Generator
Where Maintained
Field Team / Field Quality
Manager, Jacobs or Geosyntec
Loaded in the field database then transferred
to the SQL data warehouse (maintained by
RTI) as the final repository.
Various field measurements
Field Team / Field Quality
Manager, Jacobs or Geosyntec
Recorded in field notebook and stored in
SQL data warehouse (maintained by RTI) as
the final repository.
All field equipment calibration
information
Field Team / Field Quality
Manager, Jacobs or Geosyntec
Recorded in field logbook. Also recorded, as
needed, in calibration documentation
associated with instrument.
Pertinent telephone
conversations
Field Team / Field Quality
Manager, Jacobs or Geosyntec
Conversations among project team members
recorded in field logbook
Information about
occupant/owner participation
and questions about project
procedures1
Field Team / Field Quality
Manager, Jacobs or Geosyntec
Conversations with homeowners or
occupants would potentially constitute PII
and will be recorded in an electronic phone
log (by Jacobs) organized by structure code
number and a non-name identifier such as
“adult female” or an initial “JJ”. The names of
the persons conversed with would not be
recorded, but initials or a description as in
“adult male tenant” or “adult female property
owner” can be included.
Field equipment maintenance
records
Field Team / Field Quality
Manager, Jacobs or Geosyntec
Inspected by FTL. Not maintained in the
Jacobs or RTI project file but kept with
instrument records.
Sample receipt, custody, and
tracking records
Field Team, Jacobs or
Geosyntec
Project Chemist, EPA ORD
(verifier)
Electronic PDF copies in the Jacobs project
file. Hard copy in the full data package and
stored in project file.
Sample prep logs
Lab/Project Chemist, EPA ORD
Hard copy in the full data package. Archived
at project closeout.
Run logs
Lab/Project Chemist, EPA ORD
Hard copy in the full data package. Archived
at project closeout. See section 3.2.
Lab/Project Chemist, EPA ORD
Maintained in project file to the extent it is
project-specific. See section 3.2 for EPA
RTP laboratory. Archived at project
closeout.
Reported results for field
samples, QC checks, and QC
samples
Lab/Project Chemist, EPA ORD
Electronic copy in the EPA RTP laboratory
provided data package. See section 3.2 for
EPA RTP laboratory. Archived at project
closeout.
Instrument printouts (raw data)
for field samples, QC checks,
and QC samples
Lab/Project Chemist, EPA ORD
See section 3.2 for EPA RTP laboratory.
Archived at project closeout.
Lab/Project Chemist, EPA ORD
See section 3.2. Calibration information
normally maintained by the laboratory that
are not provided to the RTI team; thus, the
RTI team does not verify this information.
The EPA laboratory does apply data flags
Equipment (lab) maintenance,
testing, and inspection logs
Standards and calibration
information for EPA analytical
instruments; results of
continuing calibrations, internal
standards, and laboratory
blanks.
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Document
Generator
Where Maintained
based on this information as needed and
provide flagged data to the RTI team.
1
Sample disposal records
Lab/Project Chemist, EPA ORD
Maintained by the laboratory. See section
3.2.
Extraction/cleanup records
Lab/Project Chemist, EPA ORD
Maintained by the EPA RTP laboratory. See
section 3.2.
Field sampling audit checklists
Field Quality Manager / Project
TOL, Jacobs or Geosyntec
If audit completed, hard copy in the RTI
project file. Archived at project closeout.
Fixed laboratory audit
checklists
Lab/Project Chemist, EPA ORD
If audit completed, hard copy in the RTI
project file. Archived at project closeout.
Analytical laboratory data
packages
Lab/Project Chemist, EPA ORD
RTI project file. Electronic PDF copies in the
project file. Archived at project closeout
Electronic Data Deliverables
(EDDs)
Lab/Project Chemist, EPA ORD
RTI project file. Electronic PDF copies in the
project file. Archived at project closeout
Minutes from the calls and
community meetings1
Community Engagement
Specialist, TOL, or their
designee, RTI
RTI project file. Archived at project closeout.
List of potential participants
and proposed dates and times
of team meetings
RTI TOL or their designee
RTI project file. Archived at project closeout.
Draft and final fact sheet laying
out the key parameters/points
that will define a Soil Gas Safe
Community
RTI TOL or their designee
RTI project file. Archived at project closeout.
Letter reports and PowerPoint
presentation of the salient facts
of the current state of practice
for SGI and the decision
criteria of convenience
sampling
RTI TOL or their designee
RTI project file. Archived at project closeout.
Presentation, via PowerPoint,
of the resultant
evaluation/comparison of
Radon:VOC
relationships/differences
RTI TOL or their designee
RTI project file. Archived at project closeout.
Initial list of potential candidate
communities
RTI TOL or their designee
RTI project file. Archived at project closeout.
Draft, revised, and amended
QAPPs
RTI TOL or their designee
RTI project file. Archived at project closeout.
Letter reports, fact sheets, draft
journal articles, and training
materials
RTI TOL or their designee
RTI project file. Archived at project closeout.
These documents are anticipated to contain personally identifiable information (PII) and will be stored in
temporary files during the project and destroyed at project end.
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3.2 Data Management
This section describes the data management approach for records generated that will be used to
provide traceability from environmental data collection to final use or storage (e.g., the field, laboratory,
the office). The types of documents to be generated and how and where they will be stored during the
project are summarized in Table 3-1. Both primary and secondary data will be used to achieve the
objectives of this project.
File names will include a brief descriptive title, the date created or submitted to the EPA TOCOR, and the
version number (as applicable).
3.2.1 Primary Data
Data resulting from field sampling, laboratory analyses, and other project activities will be uploaded to a
Microsoft Teams site managed by RTI or a password-protected FTP directory where as needed research
team members will have access. The website will be set up and maintained by RTI. As the data are
assembled for analysis and interpretation, they will be compiled into a single database by RTI, in the
format and software specified by EPA and delivered to the TOCORs at the end of the project.
For the EPA analytical laboratory, paper copies of all paper records will be stored in the analysis
laboratory, RTP room E-264A or the TOCOR/PI’s office, RTP room E-267. Paper records include
certification and calibration certificates for reference standards, anything for which no electronic copy is
available, and which is not contained in the electronic laboratory notebook which is kept by the analyst
on the specific analytical instrumentation that is utilized for sample analyses for this project with a
backup copy on their EPA laptop.
Raw chromatographic and spectral data is automatically recorded electronically and will be backed up at
least once a month. Processed data will be stored on the TOCOR/PI’s EPA laptop and on an external USB
storage drive, which will be maintained by the TOCOR/PI. Raw data files downloaded from the GC-MS
computer will be maintained in their original state and considered read only.
3.2.2 Secondary Data
Secondary data on potential communities to be involved in the field testing and pilot will be collected
under Tasks 4 and 5. Specific elements addressed by this QAPP for secondary data include the following:
•
identifying the sources of secondary data (e.g., publisher, authors, year of publication, funding
sources, and resident provided building-specific evidence of subslab soil gas intrusion),
•
describing the review process and data quality criteria and metrics used for inclusion in
assessments,
•
discussing QC checks and procedures for transcription from the original source into the data
management tool(s),
•
explaining how data will be managed (e.g., Excel spreadsheet), analyzed, and interpreted in a
QA/QC and Methodology section of the work product.
In compiling input parameters, efforts will be made to identify and select data sources that have
undergone peer and/or public review to varying degrees. These parameters are not always readily
available from literature and some data elements may be calculated using appropriate estimation
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procedures. These estimation procedures will be documented in a Methodology section of the work
product in a transparent way to facilitate replication and QC review.
For each defined parameter to be included in the work product, RTI, Jacobs, and Geosyntec will:
•
Document the data source (author, title, year of publication, hyperlink if available),
•
Include relevant notes useful for data analysis and interpretation,
•
Identify any significant limitations to the selected data, and
•
Ensure that the data are appropriate for their intended use (i.e., relevant to the work product
scope, of reliable data quality, within the desired range of timeliness).
Spreadsheets and tabular databases will be used to store and relate data. The design of these tools will
be adequate and appropriate for use. The actual data management format and data coding for each
work product will be discussed with and approved by the TL to ensure that the format will be effective
to meet the purpose(s) of the task.
Cross-cutting data management procedures are defined below:
•
Missing data: A pre-defined notation key will be used where no data are provided for a category
within the data management tool. For example, the cell may be left blank, or clearly marked to
indicate a lack of data as opposed to a zero value.
•
Zero values: If the reported data is zero, the number “0” will be used.
•
Abbreviations: Abbreviations will be defined and used consistently throughout the data
management tool.
•
Availability of Data: If a qualitative indication of the presence or absence of data is collected,
consistent markings for present or absent will be used (e.g., yes/no, 1/0).
•
Analytical Data: All analytical data will be reported to the detection limit of the analytical
technique and the detection limit will be defined within the data management tool. In cases of
non-detect or reported below the detection limit, the data will be recorded with a less than sign
and the detection limit (e.g., <0.01).
o
Concentration data will be labeled with the constituent’s name and concentration units
(e.g., Hg (mg/l), or Mercury (mg/l)).
o
Time will be reported in 24:00 increments.
o
Dates will be reported as mm/dd/yyyy.
o
Geographical data will be reported as latitude and longitude in decimal degrees.
The QC procedures to be used when transcribing data from information sources into the data
management tool are described below:
•
Data Entry QC: All manually-entered data will be independently checked against the relevant
information source(s) for accurate transcription of values and units. These QC checks specifically
confirm the data element name, value, and units were correctly transcribed. We typically
perform a random 10% to 20% QC check on individual data elements across the entire data
management tool. If transcription errors are identified, a higher percentage of QC checks of the
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data elements will be performed as deemed necessary by the TOL to ensure overall work
product quality.
•
Data Transfer and Analysis QC: Electronic data transfers of groups of data from internally
maintained databases (which have already undergone QC checks of data entry) to a spreadsheet
table, chart, figure, etc. will be checked. Specific QC checks will be performed for trends to
identify outliers, missing data, systematic errors (e.g., calculation formulas or data
interpretation). If any quality concerns are identified, additional QC checks will involve sampling
of data elements from the internal database to ascertain whether data transfers occurred
without error. The sample size of these QC checks is typically 5%. Other, more complete reviews
as indicated by the results of the initial checks will be implemented as necessary.
3.2.3 Data Reduction
The chemical data from discrete samples will be compiled into a simple database that will facilitate data
analysis. Data from continuous monitors for chemical and physical parameters will be managed
separately as discussed below.
Initial VOC data review will be done by the analyst using the analytical instrument. Spectra, peak shape,
baseline integration are among the parameters that will be examined manually. QA sample data will be
compared to their respective acceptance criterion and flagged as necessary. The following definitions
are intended to assist the data user by providing an explanation of the qualifiers (flags) appended to
organic analysis results by the laboratory and/or data reviewer. The purpose of data flagging is to
facilitate appropriate data use, consistent with the project objectives. EPA will use its SOP WECD-MMBSOP-4350-0 titled “Analysis of Volatile Organic Compounds in Soil Vapor using Thermal Desorption / Gas
Chromatography / Mass Spectrometry.”
Qualifier Flag Descriptions
J
The reported result is an estimate. The value is less than the minimum calibration level but
greater than the method detection limit (MDL).
U
The analyte was not detected in the sample at the MDL.
E
Exceeds calibration range.
B
Analyte found in sample and associated blank.
I
internal standard associated with target analyte is outside of project QC parameters.
C
Calibration verification standard associated with target analyte is outside of project QC
parameters.
3.2.4 Data Review and Verification
All sources of secondary data will be cited and identified in individual task work products and in the final
report/memorandum. Sources will be identified as to their quality (See Section 3.2.1), which is an
indicator of peer-reviewed or non-peer-reviewed status.
Any manually-entered data and information will be independently checked against the data sources for
accurate transcription of values and units. Any data that are generated (e.g., summary statistics for the
numerical data) will also be checked for accurate transcription of values from the studies and accurate
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equation setup in Excel. Electronic data transfers of data will be checked for a selected sample (typically
5 to 10 percent) for units and values to ensure completeness and accuracy of data transfers and to
identify potential systematic errors. Checks will involve a sampling of data elements from the database
and will be used to ascertain whether data transfers occurred without error.
All data handling procedures, including data entry and any unit conversion calculations will be reviewed
for completeness and accuracy, for relevance of the technical content, and a check of the data for data
entry or transposition errors. A minimum of 5 percent of the data entries will be reviewed for correct
entry to the product spreadsheet/database. This includes the verification of spreadsheet/database cell
calculations for unit conversions, as applicable.
The following items will be included in the QC review:
•
Data selected for use in the reports and analyses under this QAPP meets the QA/QC criteria defined
Section 3.2.1.
•
•
•
Any unit conversion calculations performed will be verified to be correct.
Data supplied will be checked back to original sources.
Final data will be reviewed as an entire set to ensure that values for different parameters appear
reasonable and consistent.
Documentation of the implementation of the above-mentioned QA/QC process will be maintained for
internal purposes. Any noted quality deficiencies will be documented and communicated, in writing, to
the Jacobs TOL.
In the case where subcontracted laboratories are used (although not currently anticipated), data
packages from the subcontracted laboratories will contain Level II QA/QC data. Subcontracted
laboratories will be required to include a case narrative or similar analysis in which a second chemist
reviews the dataset and summarizes any deviations from QA/QC criteria. We will evaluate this
information during the data analysis process. Data verification (as described in US EPA 2002a) will be
conducted by the acobs A Officer or that person’s designee to ensure the data’s suitability for the
intended purpose. A functional guidelines data validation is not planned at this time. However, we will
obtain a sufficiently detailed data package to permit a data validation process to be performed should it
be directed by the EPA TOCOR.
For internally generated data (from EPA CEMM facilities), the EPA alternate TOCOR will review 100% of
the data for reasonableness and completeness. The Jacobs QA officer or that person’s designee will
conduct a data verification and useability level review of the EPA CEMM produced data for every data
set which is normally provided as a simple spreadsheet of results including surrogate recovery and field
generated blank results.
3.2.5 Initial Data Screening for Risk Communication and Study Design Alterations
During the data verification process, the Jacobs data reviewer will be alert for two potential situations
that may potentially require a risk communication and a study design alteration:
•
Observation of concentrations exceeding a rapid action level or removal management level in the
applicable jurisdiction. Observations of this type will be rapidly discussed with the EPA TOCOR and
local regulatory liaison (within one week).
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•
Observations of concentrations of target analytes that, while below rapid action levels and removal
management levels, are nevertheless implausible for VI and indicative of a dominant indoor source.
The primary basis for judging this implausibility will be observation of concentrations above what
would be expected from 95th percentile based attenuation factors from EPA (2012c) and available sitespecific data. Observations of this type are less urgent and will be discussed with the EPA TOCOR
during a scheduled project call and/or by e-mail (typically within two weeks).
In either situation, additional information can be reviewed to evaluate whether the observed indoor air
concentrations are truly the result of VI, or are more likely attributable to an indoor source such as the
following:
•
•
•
compound ratios between soil gas and indoor air; among the VOCs and with radon
•
whether the observed concentrations exceed those commonly observed in background structures (US
EPA, 2011)
whether CVOC constituents are observed that are not observed in soil gas
whether constituents that are rarely present in indoor sources, such as cis-DCE are observed in indoor
air
•
a follow up to the building survey to discuss with the homeowner or occupant whether any new
indoor sources could have been introduced, and to review with them potential indoor sources that
could be consistent with the data in order to identify potentially hidden chemical storage.
Depending on the results of this review, consideration can be given of requesting the homeowner to
properly dispose of unwanted stored chemicals, or to relocate storage to an outbuilding. Additionally
depending on the availability of EPA resources additional sampling locations for VOCs, radon etc. within
the structure can be established. With additional sampling locations insight into whether the primary
source is likely VI or indoor sources could be gathered.
In the final project data analysis, if strong evidence is developed that certain samples may have been
dominated by indoor sources, the analysis can be performed both with and without that portion of the
data set (see also Section 6.2).
3.2.6 Data Analysis
The project team will analyze collected data to answer the quality objectives and criteria included in
Table 4-1. For example, the team will review data to understand if the forecasted weather conditions
occurred, whether the anticipated response in indoor air occurred, and whether the indoor air
concentrations were controlled by VI versus other indoor air sources.
Data analysis will be accomplished through a series of statistical tests and graphical analysis of data.
Statistical analysis usually starts with exploratory analysis, which involves calculation of summary
statistics (mean, standard deviation, range, median, and other percentiles) to provide a characterization
of the distribution of the data, as well as graphs that display the characteristics of the data. Because the
data might not follow a normal distribution function, the Mann–Whitney U-test (also known as the
Wilcoxon rank sum test and the Mann–Whitney Wilcoxon test), and the H-test of Kruskal–Wallis can be
used to detect significant differences between independent groups of data. For dependent data (e.g., to
compare analysis results from replicates), the Wilcoxon signed-rank test and the Wilcoxon matched
pairs signed-rank test can be used to assess differences. Box plots, histograms, and cumulative
distribution plots can be used to represent summaries of the statistical distributions
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3.2.6.1 Field Testing Data Analysis
Preliminary field sample analysis will be performed using ChemStation on the GC-MS instrument
computer. EPA SOP: WECD-MMB-SOP-4350-0 “Analysis of Volatile Organic Compounds in Soil Vapor
using Thermal Desorption / Gas Chromatography / Mass Spectrometry”. Processed data will be copied
to the TOCOR/PI’s laptop and subsequent analysis will use software programs such as R, SAS, MAT A ,
Python, or others.
The primary datasets in Task 3 will be VOC and radon concentrations in external soil gas samples, which
will be analyzed by:
•
•
•
•
Compound
Location (structure code number)
Depth
GPS coordinates
These will be primarily analyzed as summary statistics site-wide, summary statistics per structure, and
based on spatial distribution on a site map.
The primary datasets in Tasks 4 and 5 will consist of distributions of indoor concentrations by:
•
•
•
•
•
•
Compound
Location (structure code number, and floor/location)
Season
Basis for collection (convenience or ITS driven)
Specific ITS based rationale
Sample duration.
This dataset will likely be amenable to analysis using pivot table summary statistics and ANOVA.
An additional dataset in Tasks 4 and 5 will be formed from the radon, indoor temperature, and CO2 data
in each structure and local meteorological information. That information will be aggregated to daily
averages, and the hourly as well as daily data used to prepare temporal trend plots for semiquantitative
analysis.
3.2.6.2 Spatial Analysis
Spatial trends in indoor VOC and radon concentrations will also be explored graphically across the study
site. Spatial variability exists when the distribution or pattern of concentration measurements changes
from one location to another (most typically in the form of differing mean levels). Such variation may be
natural or synthetic, depending on whether it is caused by natural or anthropogenic factors. The main
assumption for considering spatial variability is that sites that are close together in space are often more
alike than those that are apart.
Methods for assessing spatial variation include the use of box plots, variograms (plots to determine how
similar values are with distance), and linear models that incorporate the latent spatial structure. It is also
possible for the mean concentration levels to differ across sample sites but vary in a seemingly random
way with no apparent connection to the distance between the sampling points. In that case, the
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concentrations between pairs of sites are not correlated with distance, yet the measurements within
each site are strongly associated with the mean level at that location, whether due to a change in soil
composition or another factor.
This program will use the guidance described in the EPA National Geospatial Data Policy (NGDP) (U.S.
EPA, 2005b), and the NGDP Procedure for Geospatial Data Metadata Management (U.S. EPA, 2007).
Records management will be consistent with the U.S. EPA National Records Management Program
Records Program, specifically Schedule 1035 (U.S. EPA, 2022).
The location of the site will be specified at geospatial accuracy tier 4 or better. Accuracy within the site
will be at geospatial accuracy tier 2 or better.
3.2.6.3 Temporal Analysis
Time series plots show the data against a time axis (e.g., days, week, year) that display seasonality or
trends in the data. Of particular interest, are the plots of radon or VOC concentrations, and
meteorological variables versus time. These plots can be examined and show any seasonal or weather
front effects observed in the data. These plots are expected to be semi-quantitatively interpreted in the
context of the existing knowledge about ITS and VI as described in Section 1 to select potential sampling
times.
3.2.7 Data Storage
We expect to collect and primarily use electronic documents and data. All sources used for the
deliverables under this QAPP will be saved as a PDF, Microsoft Word, .CSV, .TXT, Microsoft Excel, or
Microsoft Access file on an appropriate server space. A Microsoft Teams site will be maintained by RTI
for short-term storage (i.e., during the period of performance) of limited documents that are actively
being worked on. Other documents will be shared with key team members using email. If data from
Web sites are used (e.g., weather-related data), the link to the webpage will be saved with descriptive
information (e.g., author, year, brief title, and date the website was accessed).
3.3 Non-detect Values
A common issue in environmental data analysis is the frequent presence of non-detect values, known in
statistical terms as left-censored measurements. The magnitude of these sample values is known only to
lie somewhere between zero and the detection or reporting limit; hence the true concentration is
partially “hidden” or censored on the left and side of the numerical concentration scale. ecause most
statistical analysis assume that all the sample measurements are known and quantified and not
censored, depending on the magnitude of the non-detects issue, we can apply methods for non-detect
as discussed by Zhao and Frey (2006) and Helsel (2005) or apply non-parametric test alternatives after
accounting for the non-detects.
3.4 Data Reporting
We will prepare a final report in accordance with the EPA Handbook for Preparing ORD Reports, which
allows for multiple formats including project reports and journal articles. The journal article(s)/final
report is anticipated to include the following:
•
Introduction including a brief site description, with citations to other sources in which the reader can
find more detailed information
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•
Summary of the sampling and analysis methods used by the project team and the subcontracted
laboratories, along with a reference to the approved quality assurance plan in which more detailed
information can be found
•
Chemical, physical, and quality assurance data in sufficient detail that interested parties can assess the
utility of the results
•
•
Data quality problems, necessary corrective actions, and any other limitations of the utility of the data
Detection/quantitation limit information.
RTI/Jacobs will compile the project chemical data from discrete samples into a simple database that will
include data from subcontracted laboratories and any discrete samples analyzed on site or by EPA
personnel. Data from continuous monitors for chemical and physical parameters will be managed
separately as discussed below but will be included and documented in the final data package delivered
to EPA.
To the extent that they are not included in the final report or journal article(s), we will provide EPA with
the following information as a supplementary final report in electronic (CD) format:
•
•
Full version of the discrete sample chemical database discussed above
•
Photographs as needed and available to depict field sites, sampling locations and deviations from
plans.
Data from field instruments in spreadsheet format
o Radon (continuous and discrete instruments)
o Temperature, CO2, and atmospheric pressure data
o Information regarding accreditation or auditing of subcontractor laboratories.
3.5 Assessment Oversight
Assessment oversight for field and analytical QA/QC will be handled by the Jacobs QA Officer or their
local designee.
3.6 Development of Research Conclusions
Development of conclusions will largely be the responsibility of the EPA TOCORs with contributions from
the research team.
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4 Quality Objectives and Criteria
Table 4-1 summarizes the quality objectives and criteria for this project. Each objective is expressed first
qualitatively in words similar to the EPA PWS. Then each objective is expressed in quantitative/statistical
terms where possible. The planned measurements that will be used to achieve each objective are then
listed. More details on the measurements to be made are given in the test matrix, which appears below
as Table 4-2. The test matrix is written using the Corentium Airthings View Plus as the primary indoor
monitor for radon, indoor temperature, and CO2; with the Radon Eye Plus 2 as an optional supplement
to provide higher sensitivity/temporal resolution on the radon measurements.
If the number of sites chosen and EPA equipment stocks suggested the use of the Radon Eye Plus 2 as
the only indoor radon monitor, it would be necessary to supplement it with additional instruments for
the other parameters. Indoor temperature monitoring devices that may be available from previous
projects include the following:
•
•
Omega PRTC110 (no longer sold), and the
•
Aranet4 Home Indoor air quality monitor (to measure CO2, temperature, humidity, and barometric
pressure with wireless Bluetooth connectivity ($299), and
•
Autopilot Desktop CO2 Monitor with Memory and Data Storage ($103.65; does not have internet
connectivity but would store one year of data for download).
Onset Hobo UX100 Temp ($85).
Low cost instruments monitoring of CO2 in indoor air that may be suitable are also available for purchase
include the following:
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Table 4-1.
Quality Objectives and Criteria for this Project
Study Question
Qualitatively Stated (from SOW
Objectives when applicable)
Quantitatively/Statistically Stated
Measurement
Used to Support Study
Question
Performance or Acceptance Criteria for This
Question/Description of Data Set Anticipated
Examine the protectiveness of the ITS methodology and approach as compared to the “traditional” standard chemical site election process and conduct a pilot study at a
community willing and interested in being designated as a Soil Gas Safe Community.
Document/quantify the current state
of practice for SGI sampling by
collecting data on the typical number
and timing of samples for VI
decisions, whether the data
supported the need for mitigation or
not, and if possible, what decision
criterion were being used to make the
decision to mitigate or not
What are the type and number of samples
that different states require to support the
need to mitigate?
Determine relationship of radon to
VOC concentrations at the test site in
soil gas.
Is radon in soil gas in a sufficient and uniform
concentration to allow it to be used as a
useful tracer on a neighborhood scale?
The number and timing of
samples for VI decisions
across states.
We are seeking to determine if the study design
fits within the type and number of samples
currently used at the state level to make
mitigation decisions. This assessment may also
identify states where certain samples are
required that are not currently included in the
scope of this project (e.g., subslab).
Radon and VOC
measurements in external
soil gas.
We are seeking to establish if a correlation is
present here. The absolute values for VOCs are
expected to vary several orders of magnitude
between structures. The variability for radon is
likely to be one order of magnitude. Replicate
measurements are expected to be ±30% which
should be adequate to establish if a correlation
exists between radon and VOCs within a large
dataset.
Radon and VOC
measurements in indoor
and ambient air.
We are seeking to establish if a correlation is
present here. This analysis can be done using
either the calendar-driven or IT-driven data sets.
The absolute values are expected to vary
spatially between structures. Replicate
measurements are expected to be ±30%, which
should be adequate to establish if a correlation
exists between radon and VOCs within a large
dataset.
What other decision making criteria do states
use to make a decision to mitigate or not?
Is the VOC distribution in soil gas sufficiently
widespread to make the demonstration site
suitable? (this does not require uniformity)
Is there a statistically significant spatial
correlation of radon to VOC concentrations at
the test site in soil gas?
Determine relationship of radon to
VOC concentrations at the test site in
indoor air.
Is there a statistically significant correlation of
radon to VOC concentrations at the test site
in indoor air temporally?
Is there a statistically significant correlation of
radon to VOC concentrations at the test site
in indoor air spatially?
Does the direction of change in radon
concentration predict or track with change in
VOC concentrations?
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Study Question
Qualitatively Stated (from SOW
Objectives when applicable)
Quantitatively/Statistically Stated
Measurement
Used to Support Study
Question
Performance or Acceptance Criteria for This
Question/Description of Data Set Anticipated
Examine relationship between
changes in barometric pressure and
indoor air concentrations of VOCs
and radon.
Do significant changes in barometric pressure
(beyond what is typical in the locality for daily
variation) lead to higher indoor air
concentrations of radon and VOCs?
Radon and VOC
measurements in external
soil gas and indoor air.
Can VI experts (from the RTI project
team) use ITS information to time
indoor sampling rounds to have a
higher probability of observing
reasonable maximum indoor
concentration then random or
seasonally timed samples?
Are the concentrations observed by the ITS
timed samples greater than those observed
by the randomly timed samples?
VOC measurements in
randomly timed samples
and ITS directed samples
Measurement of indoor concentrations within
±30% is expected to be adequate.
If home or business owners are
provided with temperature- and
radon-measuring devices, can they
reliably take samples based on ITS
indicators?
Did a high percentage of the home and
business owners participate?
Can we compare results of calendar and IT
samples and show that the IT samples are equal
to or greater than in quality to the results for the
calendar samples?
Are homeowners/occupants able to state a
technically relevant reason for choosing to
sample when they did?
We are providing home and
business owners with VOC
sampling kits, Airthings for
temperature monitoring,
and Radon detectors in
order for them to make
their assessments of
proper sampling times
based on given criteria.
We will provide
homeowners with
information about
barometric pressure from
local weather stations.
What percentage of building
owners/occupants approached originally
agreed to participate?
Logs of
homeowner/occupant
outreach and participation.
The project team will strive for 100%
completeness of these records but given human
nature some information will likely be incomplete.
For example, some persons may just stop
responding to questions/participating with no
explanation.
Are building owners/occupants willing
to participate in an ITS based SGS
monitoring program?
Are the concentrations observed by the ITS
timed samples greater than those observed
by the randomly timed samples?
What percentage of those who originally
agreed to participants continued to participate
for the duration of the 9 month test period?
Barometric pressure measurements by local
weather stations are typically reported to 0.01
inches of Hg which is adequate.
Measurement of exterior soil vapor and indoor
concentrations within ±30% is expected to be
adequate. This analysis can be done using either
the calendar-driven or IT-driven data sets.
ANOVA or T-test used to compare randomly
timed and ITS directed samples.
Can we show that just taking IT-driven samples
is the better way to go?
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Table 4-2.
Test Matrix: Sample Type and Frequency
Media
Sampled
Sample Method
Primary Samples
Task 3b – Initial Screening Event (30 structures)
7-day time-integrated
120 = 4 single-depth (approx. 5 feet bgs) locations nearby
VOC samples using
each of the 30 individual structures proposed for optional
passive sorbent
follow-on sampling. The soil gas probe will be sampled by
tubes, analyzed by
deploying a passive sorbent tube for approximately 7-calendar
USEPA Method TOday duration.
17
a
Soil Gas
120 = 4 single-depth (approx. 5 feet bgs) locations nearby
each of the 30 individual structures proposed for optional
follow-on sampling. The soil gas probe will be sampled for
Field screening for
radon using a Rad7 or similar equipment (i.e., AlphaGuard)
radon
upon retrieval of VOC sampler, with a final measurement
recorded once readings at the probe stabilize. Duplicates the
same location as for VOCs.
60 = Up to 2 locations within the breathing zone of each of the
30 individual structures proposed for optional follow-on
7-day time-integrated
sampling. Both samples will be collected from the lowest level
VOC samples using
of the structure if slab on grade, or from one level below
Radiellos, analyzed
ground surface and one level at ground surface if structure
by Method TO-17
has a basement or is split-level. Radiellos will remain in place
for approximately 7-calendar days.
Indoor Airb
Field monitoring for
radon, temperature,
humidity, and carbon
dioxide
30 (1 location within the breathing zone inside each of the 30
individual structures proposed for optional follow-on sampling).
Data will be collected continuously at each location by
deploying Corentium Airthings (optionally also Radon Eye
Plus 2) connected to the internet for remote accessibility.
Total
Number of
Samples
Duplicate
QA/QC Samplesc
Field
Blank
Ambient
4
(for 1
sampling
event)
4
(for 1
sampling
event)
2
(for 1 sampling
event)
130
4
(for 1
sampling
event)
None
Up to 10 = once
per day from the
breathing zone on
site
134
6
(for 1
sampling
event)
Up to 4 =
once per
week
(for 1
sampling
event)
Up to 4 = once per
week
(for 1 sampling
event)
74
None
None
None
30
NA
NA
3
3 = Three sewer manhole locations on site, nearby selected
structures, within the headspace zone. Radon data will be
Field screening for
Sewer Gas
collected using a Rad7 or similar equipment (i.e., AlphaGuard)
NA
radon
upon retrieval of VOC sampler, with a final measurement
recorded once readings at the probe stabilize.
Task 4a – Optional (25 of the 30 initially screened structures; assumptions included below are per site)
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Media
Sampled
Outdoor Air
Meteorology
Indoor Airb
Sample Method
RAD-7 Continuous
Radon Monitor
Primary Samples
Outdoor air at 1 location
Duplicate
None
QA/QC Samplesc
Field
Blank
Ambient
None
Total
Number of
Samples
NA
Outdoor air
radon
continuous
through full
project period.
Two hour time
intervals.
National Weather
Service
Meteorological data (such as temperature, wind speed and
direction, barometric pressure, and hourly precipitation) will be
obtained with data from the closest National Weather Service
facility.
NA
NA
NA
One to two
closest
stations per
neighborhood/
site will be
used. Hourly
data for
approximately
9 months will
be acquired.
7-day time-integrated
VOC sampling by
Radiellos, deployed
on a calendar-driven
schedule, analyzed
by Method TO-17
50 samples per sampling event, with up to 3 calendar-driven
sampling events: Summer/Fall, Winter, Spring/Summer = 50 x
3 = 150 total primary samples.
Two 7-day Radiellos deployed within the breathing zone of 25
pre-screened structures. Samples collected from the
basement (if present) and ground floor, or ground floor only. If
a building does not have a basement, consideration will be
given to placing the second Radiello as a duplicate, in an
easily accessible crawlspace or separate section of the house.
In some cases, only 1 sample may be collected per residence.
Ambient samples will be collected at 1 location per
neighborhood. Two samples per season allows some offset in
time to cover multiple exact start dates across houses.
Up to 15
(5 per
sampling
event)
Up to 3 (1
per
sampling
event)
6
(2 per sampling
event)
174
7-day time-integrated
VOC sampling by
Radiellos, deployed
on an ITS-driven
schedule, analyzed
by Method TO-17
50 per sampling event with up to 9 ITS-driven sampling
events: Summer/Fall (x3 triggered deployments); Winter (x3
triggered deployments); Spring/Summer (x3 triggered
deployments) = 50 x 9 = 450 total primary samples.
Up to 45
(up to 5
per
sampling
event)
Up to 18
(up to 2
per
sampling
event)
Up to 18
(up to 2 per
sampling event)
531
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Media
Sampled
Optional
Addition:
Indoor Airb
Sample Method
Primary Samples
Two 7-day Radiellos deployed within the breathing zone of 25
pre-screened structures. Samples collected from the
basement (if present) and ground floor, or ground floor only.
Multiple field blanks and ambient samples per event allows
some offset for sampling different structures at different times
and maintaining one field blank per cooler shipment.
Field monitoring for
radon, temperature,
humidity, and carbon
dioxide
25 = 1 location within the breathing zone inside each of the 25
individual structures. Data will be collected continuously at
each location by deploying Corentium Airthings (optionally
also Radon Eye Plus 2) connected to the internet for remote
accessibility.
1-day time-integrated
VOC sampling by
Radiellos, deployed
on a calendar-driven
schedule, analyzed
by Method TO-17
50 per sampling event with up to 3 calendar-driven sampling
events: Summer/Fall, Winter, Spring/Summer = 50 x 3 = 150
total primary samples.
Two 1-day Radiellos deployed within the breathing zone of 25
pre-screened structures. Samples collected from the
basement (if present) and ground floor, or ground floor only.
1-day time-integrated
VOC sampling by
Radiellos, deployed
on an ITS-driven
schedule, analyzed
by Method TO-17
50 per sampling event with up to 3 ITS-driven sampling
events: Summer/Fall, Winter, Spring/Summer = 50 x 3 = 150
total primary samples.
Two 1-day Radiellos deployed within the breathing zone of 25
pre-screened structures. Samples will be collected from the
basement (if present) and ground floor, or ground floor only.
Duplicate
QA/QC Samplesc
Field
Blank
Ambient
Total
Number of
Samples
None
None
None
25 datasets
each
approximately
9 month long
with 1 hour
time intervals
15
(5 per
sampling
event)
Up to 3 (1
per
sample
shipment,
may be
shared
with other
durations)
9
(3 per sampling
event)
177
15
(5 per
sampling
event)
Up to 3 (1
per
sampling
event may
be shared
with other
durations))
9
(3 per sampling
event)
177
NA
Outdoor air
radon
continuous
through full
project period.
Two hour time
intervals.
Task 5c – Optional (up to 30 structures per each of two sites)
Outdoor Air
RAD-7 Continuous
Radon Monitor
Outdoor air at One location
None
None
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Media
Sampled
Meteorology
Indoor Air
Optional
Addition:
Indoor Air
Sample Method
Primary Samples
Duplicate
QA/QC Samplesc
Field
Blank
Ambient
Total
Number of
Samples
National Weather
Service
Meteorological data (such as temperature, wind speed and
direction, barometric pressure, and hourly precipitation) will be
obtained with data from the closest National Weather Service
facility.
NA
NA
NA
One to two
closest
stations per
neighborhood
/ site will be
used. Hourly
data for
approximately
9 months will
be acquired.
7-day time-integrated
VOC sampling by
Radiellos, deployed
on a calendar-driven
schedule, analyzed
by Method TO-17
Up to 3 calendar-driven sampling events, similar to described
under Optional Task 4a.
30 x 3 = 90 total primary samples (180 if two sites are
selected)
9
(3 per
sampling
event for
1 site)
9
(3 per
sampling
event for 1
site)
9
(3 per sampling
event for 1 site)
One site –
117
Two sites –
234
7-day time-integrated
VOC sampling by
Radiellos, deployed
on an ITS-driven
schedule, analyzed
by Method TO-17
30 per sampling event with up to 9 ITS-driven sampling
events, similar to described under Optional Task 4a.
30 x 9 = 270 total primary samples (540 if two sites are
selected)
9
(3 per
sampling
event for
1 site)
9
(3 per
sampling
event for 1
site)
9
(3 per sampling
event for 1 site)
One site –
297
Two sites –
594
Field monitoring for
radon, temperature,
humidity, and carbon
dioxide
30 per sampling event = 1 location within the breathing zone
inside each of the 30 individual structures (60 if two sites are
selected). Data will be collected continuously at each location
by deploying Corentium Airthings (optionally also Radon Eye
Plus 2) connected to the internet for remote accessibility.
None
None
None
30 structure
specific data
sets for 9
months each
with 1 hour
time intervals
1-day time-integrated
VOC sampling by
Radiellos, deployed
on a calendar-driven
schedule, analyzed
by Method TO-17
30 per sampling event with up to 3 calendar-driven sampling
events, similar to described under Optional Task 4a.
30 x 3 = 90 total primary samples (180 if two sites are
selected)
9
(3 per
sampling
event for
1 site)
9
(3 per
sampling
event for 1
site)
9
(3 per sampling
event for 1 site)
One site – up
to 117
Two sites –
up to 234
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Media
Sampled
Sample Method
1-day time-integrated
VOC sampling by
Radiellos, deployed
on an ITS-driven
schedule, analyzed
by Method TO-17
Primary Samples
30 per sampling event with up to 3 ITS-driven sampling
events, similar to described under Optional Task 4a.
30 x 3 = 90 total primary samples (180 if two sites are
selected)
Duplicate
9
(3 per
sampling
event for
1 site)
QA/QC Samplesc
Field
Blank
Ambient
9
(3 per
sampling
event for 1
site)
9
(3 per sampling
event for 1 site)
Total
Number of
Samples
One site – up
to 117
Two sites –
up to 234
Notes:
a Initial
screening results will be reviewed to assess the presence of PFAS in soil gas and refine post-screening sampling design, as necessary.
b
total VOC field screening performed using handheld PID during building survey to identify potential sources of background VOCs which may be present within selected structures.
c
Trip blanks will not be collected for field observations. Instead, field blanks in the frequency specified will be collected. A field blank is briefly opened in the field to simulate how
samples are collected, while trip blanks are not opened at all and stay in the cooler. Field blanks are considered more rigorous in identifying contamination compared to a trip blank.
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4.1 Data Quality Indicators
4.1.1 Bias
ias is the difference between an observed value and the “true” (or “target”) value of the parameter
being measured. For chemical analysis, bias is typically expressed as percent bias from a known standard
or percent recovery of a spiked quantity in the matrix being analyzed.
To measure bias, begin by calculating the average of all measurements of a parameter. The average
(x )
of a set of measurements is given by:
(x ) = xn
n
i
i =1
(3-1)
where:
x i = a given measurement
n = the number of measurements.
Percent bias (%B) is given by the difference between the average of a measurement and the true value
(T) of a reference standard.
%B =
(
100 x − T
T
)
(3-2)
Bias can be positive or negative and is estimated by percent recovery (%recovery) of a reference
standard.
%re cov ery =
x(100)
T
(3-3)
Another way to measure bias is to calculate the percent recovery of a standard solution.
%re covery =
(
100 A − B
T
)
(3-4)
Where:
A = Average measurement of the standard samples
B = Average measurement of the blank samples
T = Documented value of standard.
4.1.2 Precision
Precision is the level of agreement among multiple measurements, made at the same conditions and
with the same method, of the same parameter. The sample standard deviation, s, and the sample
coefficient of variation, CV, are used as indices of precision. When precision estimates are obtained from
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analysis of replicated measures, the range, R (maximum value – minimum value), the relative range, and
the relative percent difference (RPD) are frequently used.
Precision is typically expressed as RPD for duplicate measurements or relative standard deviation (RSD)
for replicate measurements.
𝑅𝑃𝐷 = (
2⋅|𝑥2 −𝑥1 |
) ⋅ 100
𝑥1 +𝑥2
(3-5)
Where:
x1 = initial measurement
x2 = duplicate measurement
The variance, s2, of a measurement is given by the sum of the squares of the differences between each
measurement and the average, divided by the degrees of freedom of the measurement, (n – 1):
(x − x )
2
n
s2 =
i =1
i
n −1
(3-6)
Standard deviation (s) is the square root of the variance and is a measure of the precision of the
measurement.
s = s2
(3-7)
Precision can be expressed as the CV or RSD. Both are expressed as follows.
% RSD = CV =
s (100)
x
(3-8)
4.1.3 Completeness
Completeness is a measure of the quantity of valid data successfully collected from a measurement
system compared to the amount intended in the experimental design and is calculated by Equation 310.
%𝐶𝑜𝑚𝑝𝑙𝑒𝑡𝑒𝑛𝑒𝑠𝑠 = 100 (
𝑣𝑎𝑙𝑖𝑑 𝑑𝑎𝑡𝑎 𝑐𝑜𝑙𝑙𝑒𝑐𝑡𝑒𝑑
𝑑𝑎𝑡𝑎 𝑝𝑙𝑎𝑛𝑛𝑒𝑑
)
(3-9)
4.1.4 Comparability
Comparability is a measure of the confidence with which one data set can be compared to another. To
show comparability between data sets, the sets are expressed in the same units. The conditions under
which the data are taken are well defined.
Data comparability is used to describe analytical data quality for measurements of the same thing made
using different sampling/analytical methods. For example, the Radiello and TO-17 samples that are used
to measure VOC concentrations for comparable periods can be compared. Ideally, in order to maximize
the potential for data comparability, one needs to determine the minimum data elements, including
background information, to be included in the data collection effort. An operational framework for
comparability ensures that data are well documented, consistent, and of known quality. An operational
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framework includes the design of data collection methods in the field and laboratory that address study
objectives and goals and follow specified data quality objectives. Such a framework is included in later
sections of this QAPP.
Several factors can contribute to, or detract from, data comparability. These can be grouped into two
general categories: factors related to sample collection and handling and factors related to the analytical
methods used. Sample collection issues include sample design, acquisition techniques, environmental
conditions at the time of sampling, and sample handling/preservation methods. Analytical issues related
to data comparability include sample preparation, cleanup, and determinative methods used.
Standard methods for evaluating data comparability are the use of split samples and regression analysis
or correlation coefficients. In the case of regression analysis, the adjusted coefficient of determination is
often quoted as a measure of comparability. In the case of correlation coefficients, it is the correlation
coefficient itself that measures the linear relationship between two sets of analytical results derived
from sample splits.
4.1.5 Representativeness
Representativeness expresses the degree to which data accurately and precisely represent a measured
characteristic of a condition of a population or a process.
Representativeness requires that the scale (spatial, temporal, chemical, etc.) of the sampled data be the
same (within tolerable uncertainty bounds) as that observed in study region. Representativeness
involves two concepts: sample representativeness and analytical representativeness, both of which play
a critical role in data uncertainties. Sample representativeness includes procedures related to sampling
design, sample selection, collection of data, preservation, and sub-samples. Sample representativeness
can be achieved by selecting the sampling design that captures any spatial and temporal dimensions of
the study region. Analytical representativeness involves selecting an appropriate analytical method that
produces test results that are representative of the decision.
4.1.6 Repeatability and Reproducibility
Repeatability is the variation in data generated on a single sample by a single analyst and/or instrument
over a short period. Repeatability can be measured by calculating RPD.
Reproducibility is the variation in data over an extended period and/or by various analysts or
laboratories. Reproducibility can be expressed as RSD.
4.1.7 Method Detection Limit and Practical Quantitation Limit
Definitions of these terms are quoted here from an EPA (2003b) document: “EPA uses two measures of
analytical capability, the Method Detection Limit (MDL) and the Practical uantitation imit (P ).”
•
The MDL is a measure of method sensitivity. As defined in 40 CFR Part 136 Appendix B, the MDL is "the
minimum concentration of a substance that can be reported with 99% confidence that the analyte
concentration is greater than zero." MDLs can be operator, method, laboratory, and matrix specific.
Due to normal day-to-day and run-to-run analytical variability, MDLs may not be reproducible within a
laboratory or between laboratories. The regulatory significance of the MDL is that EPA uses the MDL
to determine when a contaminant is deemed to be detected and it can be used to calculate a PQL for
that contaminant.
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•
The PQL is defined as "the lowest concentration of an analyte that can be reliably measured within
specified limits of precision and accuracy during routine laboratory operating conditions" as defined in
the preamble to a November 13, 1985 rulemaking (50 FR 46906). The Agency has used the PQL to
estimate or evaluate the minimum concentration at which most laboratories can be expected to
reliably measure a specific chemical contaminant during day-to-day analyses of drinking water
samples.” A PQL is determined either through using interlaboratory study data or, in absence of
sufficient information, through the use of a multiplier of 5 to 10 times the MDL.
When the measurement is at or near the limitations of the instrument used to perform the
measurement, the detection limit must be known and reported. The MDL for each environmental
measurement method is determined by analysis of seven or more replicates of spiked matrix samples.
The standard deviation of the responses (sm) is used to calculate the MDL as follows:
MDL = sm (t0.99 )
(3-10)
Where:
t0.99 = Student’s t value for a one-tailed test at the 99 percent confidence level and a standard deviation
estimate with 𝑛 − 1 degrees of freedom. For seven replicates,𝑡0.99 = 3.14 for 𝑛 − 1 = 6 degrees of
freedom.
4.2 Assessment and Oversight
Assessment oversight for field and analytical QA/QC will be handled by the Jacobs QA Officer or their local
designee.
4.2.1 Field Activities
Assessment and oversight for field and analytical QA/QC will be handled by the Jacobs QA Officer or
their local designee.
Audits
At this time, there are no scheduled audits or performance evaluations associated with this TO planned
for RTI, Jacobs, or EPA CEMM personnel except as discussed below. We will work with the EPA QAM or
designee should any additional audits be required by EPA. This TO will be subjected to random internal
system audits performed by the Jacobs QA Officer. The Jacobs QA Officer will also perform a data quality
assessment for this project during report preparation.
4.2.2 Corrective Action Procedures
During research and testing, every effort is made to anticipate and resolve potential problems before
the quality of the measurement performance is compromised. Personnel responsible for
instrumentation and testing activities are cognizant of activities that can affect data quality. Personnel
will be familiar with the contents of the QAPP and QA/QC requirements.
Problems that may adversely impact data quality will be corrected by the analyst who is responsible for
interpreting the results of the daily calibration check and resolving potential problems based on the
procedures referred to in the QAPP and will be reported to the RTI TOL. If the problem is reported by
Jacobs staff, the Jacobs TOL will advise the RTI TOL and EPA TOCORs of problems and corrective actions
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that have been implemented. The field personnel will document corrective actions in bound notebooks.
The Jacobs TOL is also responsible for reporting data quality problems and corrective actions to the
Jacobs QA Officer, who will review the information. Data quality problems and necessary corrective
actions will be reported to the RTI TOL and the EPA TOCOR as soon as they are identified.
5 Project Implementation
5.1 Community Selection
Site selection criteria will include EPA’s preference for E (economic justice), economically challenged or
Tribal communities. Sites with cooperative regulatory agencies and responsible parties who need
assistance to help make a remedial decision on particular buildings or neighborhoods will be sought
because that will facilitate a cost effective and timely study. In addition, for cost effectiveness, it is
assumed that a site within 30 miles of an office of an RTI team firm will be selected (these firms have
extensive national office networks in major urban areas). The size of the inclusion area is assumed to be
at least 30 structures. To the extent feasible, communities should be selected in an area where radon is
most likely to be detectable but only above action levels in a minority of structures. As a costing
assumption we are assuming the communities will be ones in which the primary known soil gas hazards
are chlorinated VOCs and radon (i.e., not methane or petroleum VOCs). The ideal model would be a site
where conduit driven transport is not dominant. Additionally, some seasonal variability is critical. The
site does not necessarily need freezing temperatures in winter, but the ideal site should run the heater
in the winter and the air conditioning in the summer.
5.2 Sampling and Real Time Monitoring Methods
5.2.1 Measuring/Documenting Building Characteristics
5.2.1.1 Building Surveys
Building features will be noted during initial site visits to obtain access. Walk-through inspections will be
conducted, and a survey form will be completed to detail or confirm the layout, construction (e.g., slabon-grade, crawl spaces), potential VOC sources (e.g., cleaning products, VOC sinks such as carpets,
furniture, draperies, etc.), and operating processes (i.e., type of heating, cooling system, etc.) of the
units that may influence contaminant entry. During the survey, the dimensions of each room in the units
to be tested will be measured, and the volume of the unit will be calculated. The spacing of interior
features will be documented. The control settings of the HVAC system will be noted in a project
notebook when changed. The survey form to be used (Appendix A) will be similar to that recommended
in ITRC (2007). If any household products or chemicals are found that could contribute to background
levels of VOCs or radon in indoor air, the homeowner will be encouraged to remove those sources from
the building (if feasible). However, as this is a long term study of an occupied building, it is likely that
many potential indoor sources will remain; although the short target analyte list will somewhat
minimize the potential for interferences. In cases with extensive stored chemicals, it may be beneficial
as an optional task to do a few additional Radiello indoor air samples for one or two rounds in storage
areas such as utility closets.
We do not anticipate collecting any household demographics other than that already included in the
standard ITRC (2007) VI survey form which includes:
•
number of household occupants
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•
•
•
•
•
•
•
•
•
Age of occupants3 (can be reported as broad ranges for example 0-6, 6-12, 12-18; 18-65; >65)
Whether occupant is owner or landlord
Contact information for occupant and/or owner/landlord
structure construction style and age
information about air movement,
indoor sources of VOCs
previous mitigation systems
HVAC system type
Occupancy by floor (the survey team will attempt to use these questions to also obtain some
general information as to whether the occupants are normally home during work/school hours.
That information will be useful in interpretating CO2 sensor data).
For the purposes of project planning, it will be necessary to determine if each homeowner has internet
access and whether that can be used in the project (for example for the homeowner obtaining weather
forecasts, communication with the homeowner by email or for ITS data logging). For the purpose of this
project, it should also be documented when the occupant or owner of a study building changes during
the study.
During the initial screening phase of work in Tasks 3 and 4, at a minimum, a succinct building survey will
be performed within each structure proposed for sampling. The building survey is expected to be brief,
although will aim to detail pertinent information regarding use of the structure, typical potential
background sources observed, and general condition of the building envelope. In addition to
documenting the broad types of potential background sources of VOCs present within an individual
structure, the structure will be screened for total VOCs using a handheld MultiRae PID device. To control
cost, consumer products may be documented photographically in groups rather than preparing a
detailed item by item inventory. The PID screening will consist initially of PID measurements outside the
house and in the rooms where sampling is likely to occur. Screening may also include sites of significant
chemical storage such as a basement shop or closet in which many cleaning products are kept. However,
the project level of effort does not allow for a detailed drawer by drawer/object by object PID survey. If
through the visual inspection or PID screening any significant potential background VOC sources are
identified, they will be documented, and occupants will be instructed to restrict usage nearby deployed
samples. Identified items will not be removed from structures, nor will occupants be told usage of the
items is prohibited. But a reasonable effort will be made to explain the important of collecting an
unbiased sample and the benefits of storing VOC containing products in well ventilated places. Data
from the consumer product inventory and PID survey will be used to help evaluate the VOC sample
results to assess whether an indoor source is likely dominating VOC concentrations in indoor air.
Note that EPA 2015a says “As such, EPA recommends the CSM also identify and consider sensitive populations,
including but not limited to:
• Elderly,
• Women of child-bearing age,
• Infants and children,
• People suffering from chronic illness, or
• Disadvantaged populations (i.e., an environmental justice situation).” But there may be legal restrictions on collecting
some of this information on an individual household basis.
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If additional optional work is selected where the community science effort will be completed under task
5, occupants within each structure will be taught how to identify and document potential background
VOC sources, but no pre-screening is anticipated with a handheld MultiRae device. Under Task 5, the
building surveys will be conducted by the residents, but some data management will be performed by
the RTI team.
5.2.1.2
Controlling Air Exchange Rate through HVAC Operation, Doors, Windows, and Other Building
Openings
The structures will be operated by the owners in as realistic a manner as possible. In general, the
operations will be controlled by the regular business/residential occupants. In cases where unoccupied
space is sampled, we will simulate actual business/residential occupancy, consistent with the constraints
of:
•
•
Personnel and property security
Work periods and hours of access and operability of the site.
Building operational parameters will be initially assessed in the pre-sampling building survey. Any
changes in the routine position or settings of interior and exterior doors, windows, and HVAC systems
will be documented in the project notebook or on a data collection form in Task 4 when the project
team visits the interior of a building. This information will only be available in Task 5 to the extent that
the homeowners self-report it.
5.2.2 External, Passive Soil Vapor Probe Construction for Use During Initial Screening
The initial screening event (Subtask 3b) will require four external, passive soil vapor probes to be
installed outside each of the 30 structures to be screened after utility locates are performed at each
structure. Soil vapor boreholes will be approximately 2 inches by 5 feet deep. Each of these boreholes
will be located at each of the four main sides of each structure. However, if the structures are abutting
then one location can be counted against the requirement for two structures. They will be located in
unpaved rights-of-way or property yards. Drilling will be performed by 1- or 2-person portable, gas or
hydraulic powered augers. A PID and MiniRAE will be used for safety monitoring during the borehole
drilling. A GPS unit will be used to locate the points after installation.
The sampling points will be constructed according to the following SOPs:
•
•
Utility Clearance for Intrusive Operations (Appendix B1)
•
•
Soil Vapor Sampling from Exterior Soil Vapor Probes (Appendix B9)
Installation and Abandonment of Permanent and Semi-Permanent Exterior Soil Vapor Probes
(Appendix B7)
MiniRAE 2000 Operation and Maintenance Manual (Appendix E). A low range photo ionization
detector (PID), such as the PPB RAE (with a detection limit of approximately 5 ppb/34 µg/m3 for PCE),
will be used for three purposes:
o Health and safety monitoring. Given the VOC concentrations expected at this site, no
acute health risks are expected during well and soil gas point installation, but PID
screening will be done as a precaution.
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o
o
Field screening of soil for VOCs. Given the concentrations expected at this site, this may
not detect anything, but if high results are observed it would be of interest.
Field screening of external soil vapor points. At least some soil vapor points are expected
to be in the detectable range with this instrument.
5.2.3 Passive VOC Sample Collection from External Soil Vapor Probes Using Sorbents
VOCs in soil vapor will be determined during the initial screening event by modified EPA Compendium
Method TO-17 for passive soil vapor sampling. Passive soil vapor samples can be collected using tube
style thermal desorption tubes (Markes ATD or Perkin Elmer equivalent) with diffusive end caps which
for PCE with Tenax have an uptake rate of 0.41 ml/min (ISO, 2003). Applications to soil vapor
quantitative passive sampling is possible as long as the uptake rate of the sampler is the rate-limiting
step (i.e., the rate of diffusive delivery of vapors from the surrounding soil or fill materials is not the rate
limiting step) (McAlary et al., 2014a, b, c, d). The rate of diffusive delivery from the soil depends on the
porosity and moisture content of the soil as well as the size of the boring in which the samplers are
emplaced. It is desired to select a soil vapor sampler with an uptake rate <0.5 mL/min. The storage caps
are briefly removed in the field and replaced with diffusion caps immediately before sampling. The
passive samplers should be surrounded by a stainless steel or wire mesh cage to protect them from
direct contact with soil. The hole into which the passive samplers are inserted is then sealed with a
rubber stopper wrapped in aluminum foil hammered into the soil with a mallet. At the conclusion of
sampling and before shipment the diffusion caps are replaced with the storage caps.
5.2.3.1 Media Preparation
Stainless steel thermal desorption tubes with dimensions of 3.5” x 0.25” OD packed with
approximately 0.2 g of Tenax TA are used for sample collection in external soil vapor during the initial
screening event. A unique identifier is etched on the stainless steel tube by the vendor for tracking
purposes which will be recorded on the COC. The Tenax TA sorbent tubes are commercially available
from MARKES International Ltd. or equivalent vendors.
Sorbent tubes are cleaned prior to deployment to the field by conditioning at approximately 335°C for a
minimum of 30 minutes under nitrogen flow rates of 50-100 mL/min. Tubes are certified as clean by
analyzing tubes for the compounds of concern at a frequency of 1 in 20 tubes cleaned. The associated
batch of tubes is considered acceptable if there are no detections above the reporting limit for the
target compounds.
After cleaning, each tube is sealed with Swagelock caps and inert ferrules and wrapped in aluminum foil
to minimize ingress of trace levels of contaminants during storage and shipment. Wrapped tubes are
shipped in sealable metal containers with packets of silica gel/charcoal. A clean refrigerator is used for
the storage of clean tubes awaiting shipment to the field. Tubes are transported to the field packed in
coolers with blue ice.
5.2.3.2 Field QC Samples
Field blanks are collected by removing the caps from a clean sample tube and attaching it to the syringe
but not pulling any air through it. The tube is then detached and treated as the soil gas probe samples.
Duplicates can be collected by installing two side by side boreholes with one sampler in each. The
frequency of field QC samples is specified in Table 4-2 (no duplicates are included for soil vapor sampling
during the initial screening under Task 3B).
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5.2.4 Passive Air Sample Collection for VOCs
5.2.4.1 Passive Air Samples for VOCs in Indoor Air
VOCs in indoor air for both the initial screening event and tasks 4 and 5 will be determined using by
modified EPA Compendium Method TO-17 for passive indoor air sampling (note that there is an option
for 1-day sampling during tasks 4 and 5 using diffusive sorbent samplers [Radiellos]. These would be
used concurrently with the 7-day TO-17 passive Radiello indoor air samplers). Samples will normally be
collected over a 1-week period. Samplers are normally hung (on a wire ring forming a hook) at a height
above the floor approximating the breathing zone (3 to 5 ft). The samplers should be placed away from
sources of heat and cold as well as direct air currents. To minimize competition for VOC adsorption, the
samplers will be spaced approximately 6 inches (or greater) from each other. Normally existing
household racks are used to support the sampler (Figure 5-1). In each structure, the arrangement of
passive indoor air samples will be either one basement and one first floor sample or one sample on one
floor plus a duplicate (taken concurrently on the same rack as the parent but 6 inches or more away).
Figure 5-1.
Example Sampling Rack
The optimal diffusive sampler configuration for this period has been selected based on sampler
sensitivity and sampling rate stability. The sampler sensitivity is a function of analytical sensitivity and
sampler sampling rate. The lower the analytical reporting limit and the higher the sampling rate, the
lower the sampler reporting limit. Additionally, the sampler reporting limit decreases as the collection
time increases. However, the sampling rate can decrease with time as the sorbent reaches saturation or
experiences back diffusion of weakly retained VOCs.
Analysis is later accomplished by heating the sorbent and sweeping the desorbed compounds onto a
secondary “cold” trap for water management and analyte refocusing. The secondary trap is rapidly
heated for efficient transfer of compounds onto the GC/MS.
5.2.4.1.1 Media Preparation
Each Radiello passive sampler has three components—the diffusive body that controls the sampling
rate, a sorbent resin bed that adsorbs the VOCs, and a stand and/or clip for ease of deployment. The
Radiello diffusive body is described in Appendix E.
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The Radiello thermally desorbed samplers require the 350 ± 10 mg graphitized charcoal cartridge
(RAD145), the general-purpose diffusive body (RAD120), and a triangular base plate. The RAD145
cartridges require no conditioning prior to use when first received from the manufacturer. In principle,
the thermal desorption analysis leaves a conditioned cartridge that can be used for another sampling. In
practice, the manufacturer recommends re-conditioning the cartridges after analysis, keeping them at
350 °C for 8 hours under nitrogen flow (while not included in the manufacturer’s recommendation, a
flow rate of 50 to 100 mL/min will be used). Cartridges are certified as clean by analyzing the cartridges
for the compounds of concern at a frequency of 1 in 20 tubes cleaned.
The diffusive bodies require no preparation prior to use in the field. Per manufacturer’s instructions, the
bodies can be reused with no conditioning or cleaning unless sampling in a high particulate
environment. New diffusive bodies will be purchased and dedicated to the project. Because sampling
will be conducted indoors, minimal issues with particulates clogging the diffusive bodies are anticipated
and bodies will be dedicated to a sampling location with just a simple replacement of the cartridge. In
addition, the triangular support plates will be dedicated to each sampling location and will not be
replaced during the project.
In Task 4, Jacobs staff will collect QA samples in accordance with Table 4-2. In Subtask 5c one picked
volunteer per neighborhood will be asked to also conduct ambient air sampling. Thus, ambient air
samples will not be contemporaneous with all of the individual house indoor samples. Another picked
volunteer can be asked to conduct duplicate sampling. Field blanks will be created by Jacobs field staff
who will open and close the Radiello and immediately mail it to EPA following the instructions given to
homeowners. This will reduce the complexity of the tasks that homeowners need to be trained in.
The graphitized charcoal samplers do not require shipment on ice. Once in the field, the sorbents are
stored in a cool, solvent-free area.
5.2.5 Radon Monitoring in Indoor Air
EPA has available for this project:
•
•
•
35 new Radon Eye Plus 2 (click here for more information)
35 new Airthings View Plus (click here for more information)
10 RD 200 Radon Eye instruments previously used in Fairbanks, AK.
Both the Radon Eye Plus 2 and Airthings View Plus have Wi-Fi communication capabilities (with no hub
needed for the Airthings – the instrument itself can work as a hub), so remote access should be possible
for the Task 4 and Subtask 5c monitoring (1-year duration), and Subtask 3b (1 week-long monitoring).
The Airthings View Plus provides the Task 4 desired measurements (radon, temperature, CO2) and also
has a few other parameters considered ancillary for this project (humidity, PM2.5, total VOCs, and
barometric pressure). The Radon Eye Plus 2 measures only radon. These instruments are new, and
factory calibrated. They are not capable of field calibration for radon.
The Airthings equipment provides an “App and Dashboard” that reportedly includes short and long term
graphs and notifications. The Radon Eye interfaces RMNS (Radon Monitoring Network Service) is an
internet web service that allows you to check the data from RadonEye Plus 2 from a distance at any time
and provides a 7 day or 30 day graph.
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The test matrix is written using the Corentium Airthings View Plus as the primary indoor monitor for
radon, indoor temperature, and CO2; with the Radon Eye Plus 2 as an optional supplement to provide
higher sensitivity/temporal resolution on the radon measurements. The non-radon functions of the
Airthings View Plus are included in the equipment manual subsection, Indoor Meteorological
Measurements.
5.2.5.1 Consumer-grade Model Radon Detector: new-generation Corentium Airthings View Plus
For radon data to be obtained and monitored in real time, 25 consumer-grade continuous reading radon
monitors will be deployed during the initial survey and tasks 4 and 5 for indoor radon monitoring, with
time resolutions of approximately 1 hour. However, although the instrument reports a data point every
hour what is reported is actually a 24 hour running average (Tylkowski, 2022). New-generation
Corentium Airthings Wave Plus devices have not only radon, temperature, humidity, CO2, and
barometric pressure monitoring capabilities, but also web-based, remote access capabilities. These
features are critical for real-time monitoring and thus scheduling the site visits for sampling. Jacobs will
provide these devices to the homeowners or building occupants where they are expected to remain in
service for approximately 1 year (including periods before and after a decision to go to indoor air
sampling). It is assumed that an internet connection with Wi-Fi access will be made available by the
homeowners or occupants in most of the buildings studied to allow remote data access by the project
team. No Internet subscription cost is included in the project pricing.
The manufacturer states the following specifications for the radon portion of the instrument:
•
•
•
•
•
•
•
•
•
•
•
Radon sampling: Passive diffusion chamber
Detection method: Alpha spectrometry
Sensor interval 60 min (fixed)
Measurement range: 0 – 20,000 Bq/m3
0 – 500 pCi/L
Typical accuracy after more than 30 days of
Continuous measuring at 200 Bq/m3
5.4 pCi/L
7-day average: ±10 %,
2-month average: ±5 %
Expected precision at 1 pCi/l after 24 hours 1 pCi/L +/- 0.25 pCi/L (standard deviation).
5.2.5.2 Consumer-grade Model Radon Detector: RadonEye RD200
This consumer-grade unit has good sensitivity, agreement with certified devices, and hourly readability
(Carmona and Kearfott, 2019). The RadonEye is an ion chamber design, which is a type covered within
EPA guidelines for using continuous radon monitors (US EPA, 1992). Please see also the fact sheet
“Monitoring Radon as a Vapor Intrusion (VI) Tracer or Surrogate” (Appendix B12). The RD200P model is
a National Radon Proficiency Program (NRPP)-approved device.4 However, it sequentially numbers its
4
https://nrpp.info/devices/approved-devices/
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radon readings every hour, rather than creating a time/date stamp. This will require that the field
operative note the start and stop times so the running hours can be reconstructed in Excel when the
data are downloaded. Additionally, a power sensor can be used in conjunction with the radon detector
to detect periods of power outages to help explain data gaps (e.g., Avtech Power Sensor [RMA-PS1-SEN:
$65.00]).
Since the RadonEye RD200 does not have remote access capabilities via Wi-Fi, this unit could be used
during the initial screening event, but not during Tasks 4 and 5 under the current pricing assumptions.
They could perhaps be used for supplemental applications that would allow for periodic access via
onsite smartphone. For example, if a homeowner had a smartphone and was willing to install the
RadonEye app they could potentially use that instrument.
5.2.5.3 Consumer-grade Model Radon Detector: RadonEye Plus 2
The RadonEye RD200 and RadonEye Plus 2 have very similar technical specifications with the Plus 2
adding WiFi and Bluetooth low energy (BLE) communications. The one other difference in the published
specifications is a higher upper limit on the instrument range for the Plus 2 model. Methodology for
Ambient Air and Soil Vapor Sample Collection for Radon Both instruments provide a 10-min update
(based on a 60 min moving average).
5.2.6 Outdoor Air and Soil Vapor Radon Monitoring
Active, real-time (or near-real-time) samples will be collected from outdoor air and soil vapor using
professional-grade instrumentation (either the AlphaGuard or the RAD-7). During the initial screening
event, 1 single soil-vapor reading will be taken at each structure at the time of passive-sampler retrieval,
using either the AlphaGuard or RAD-7. Ambient radon will be taken at 1 location during each day radon
is measured during the screening, using either the AlphaGuard or RAD-7.
5.2.6.1 AlphaGuard Radiation Monitor
Genitron Instruments’ AlphaGuard5 may be used for onsite radon analysis of outdoor air and soil vapor
grab samples. The AlphaGuard is a portable, battery-operated radon monitor with high storage capacity.
In addition to the radon concentration in air, AlphaGuard measures and records almost simultaneously
ambient temperature, relative humidity, and atmospheric pressure with integrated sensors. The
instrument can operate in diffusion mode (e.g., long-term monitoring; 10-minute response, 60-minute
measuring cycle) or flow mode (1-minute response, 10-minute measuring cycle). In diffusion mode, the
instrument operates without a pump. The instrument radon measurement function is insensitive to
both high humidity and vibrations. The AlphaGuard can be used for short- or long-term examinations
inside or outside and can be set or programmed for continuous data acquisition; data can be
downloaded/uploaded to a computer for analysis.
Instrument setup and operation will be performed in accordance with the manufacturer’s instructions
and EPA guidelines for using continuous radon monitors (US EPA, 1992). A Miscellaneous Operating
Procedure (MOP) for the AlphaGuard instrument is provided as Appendix B13. We plan to use the
AlphaGuard or the RAD 7 owned by EPA/ORD/CEMM/WECD/MMB in the actively pumped mode to
collect the primary dataset for radon monitoring. AlphaGuard instruments owned by the EPA
5
https://www.bertin-instruments.com/product/radon-professional-monitoring/radon-alphaguard/
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EPA/ORD/CEMM/WECD/MMB may be used also in an active mode pulling sample through a heated
sample line to provide high resolution ambient air monitoring data for radon.
5.2.6.2 RAD-7 Radon Monitor
The Durridge RAD-7 radon monitoring unit may be used for onsite radon analysis of outdoor air and soil
vapor grab samples. The RAD-7 is a portable radon monitor (AC or DC capable) with good storage
capacity (1,000 cycles under long-term monitoring, lasting ~12 weeks). In addition to the radon
concentration in air, the RAD-7 measures and records ambient temperature and relative humidity, but
the relative humidity reading is to ensure accuracy of the measurement. The relative humidity must be
kept at 10% or less for the most accurate measurements (the unit comes with desiccant, drying tubes,
and moisture filters). The RAD-7 unit can run in continuous mode for 24- or 48-hour cycles, or in 2-hour
cycles up to 1,000 cycles; sniffing at entry points for at least 15 minutes; grab samples are taken over
four, 5-minute cycles, with a 30-minute processing period, and soil gas/subslab testing over 20-minute
cycles. Data may be read from the on-board LCD display, paper printout, or downloaded to a PC.
Instrument setup and operation will be performed in accordance with the manufacturer’s instructions
and with EPA guidelines for using continuous radon monitors (US EPA, 1992). An MOP for the RAD-7
instrument is provided as Appendix G. We plan to use the RAD-7 owned by EPA ORD in Durham, NC to
collect the primary dataset for outdoor air and soil vapor radon monitoring.
As the project is currently planned, the single ambient RAD-7 will be placed at a location where a
homeowner can allow it to operate without causing interference. For example, a garage or basement
with power and access to outdoor air may be needed. The RAD-7 is functional between 32 and 113 F so
requires shelter. A heated sample inlet line may be needed but was not included in the current project
budget. However, a heated sample line from the Fairbanks site may be available for one site. The RAD-7
when set to the “weeks” protocol will collect data for 1000 measurements at 2 hour intervals which
provides an 83 day collection duration. Data will be manually downloaded during a
“troubleshoot/support” site visit which are budgeted monthly.
5.2.7 Indoor Meteorological Measurements
5.2.7.1 Measurement method
Onsite meteorological measurements at the selected will be made using the new generation Corentium
Airthings View-Plus devices, which record (aside from radon) temperature (T), relative humidity (RH),
CO2, PM2.5, total VOCs, and barometric pressure within the manufacturer specifications presented
below. The recommended operating conditions are between 4°C and 40°C and 0% to 85% humidity.
•
Sensor Resolution:
o Temperature ± 0.1°C / °F
o Humidity ± 1%
o Pressure ± 0.15 hPa
•
Temperature, humidity, and pressure:
o Technology: solid state sensor
o Sensor interval 5 min (2.5 min with USB cable connected)
o Temperature Accuracy: ± 0.5 °C / ±1 °F
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o
o
Humidity Accuracy: ± 3% RH
Pressure Accuracy: ± 0.6 mBar/hPa.
•
Initial calibration time:
o VOC: ~7 days.
o CO2: after an initial calibration time of 7 days, it is self-calibrated using an automatic
baseline algorithm that updates once a week.
o The VOC and CO2 sensors continuously calibrate by using the cleanest level of air as a
baseline to distinguish from polluted air. For this reason, it is important that the sensor is
exposed to clean air on a weekly basis.
•
CO2 details:
o NDIR Sensor (Non-Dispersive Infra-Red)
o Measurement range 400–5000 ppm
o Optimum Accuracy ±50 ppm ±3% within 10 – 35°C / 50 - 95°F and 0 – 80% RH after initial
calibration time
•
VOC
o
o
o
o
o
•
Technology: Metal-oxide based gas sensor
Measurement interval 5 min (fixed)
Settling Time: ~7 days
Measurement range: 0 - 10,000 ppb
Self-calibrated using an automatic baseline algorithm that updates continuously based on
the cleanest air the sensor is exposed to.
Particulate Matter (PM2.5) details:
o Laser scattering based optical particle counter
o Particle size detection range: 300 nm to 10 μm
o Range: 0~200 μg/m³
o Measurement error (PM2.5): 0 ~100 μg/m3, ±10μg/m3,100 ~200 μg/m3, ±10%.
o Calibrated with a GRIMM using cigarette smoke source.
5.2.7.2 ITS interpretations of Meteorological Data
The proposed ITS trigger points were introduced in Section 1.4.
It is anticipated that the indoor temperature data will be used together with the outdoor temperature
measurements discussed in the next section to calculate differential temperature, an important
indicator for VI.
It is anticipated that the CO2 data can be used together with knowledge of the resident’s normal
occupancy patterns (and pets) as a measure of air exchange rate, which is expected to be inversely
proportional to indoor concentrations caused by VI.
The humidity data may be analyzed/reviewed. Previous analyses have suggested a possible association,
but not a monotonic one with VI (EPA, 2012b, 2015b, 2015c). In basements, it is known that moisture
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and radon are related since soil gas intrusion is one source of moisture. Since the causative mechanism
if any between humidity and VI has not been elucidated this ancillary parameter may be analyzed but
will not be used for timing VOC sampling.
It is anticipated that the total VOC sensor will most likely be more influenced by other sources of VOCs
in indoor air then VI. The data will be briefly considered to see if it has any application as an ITS.
It is not anticipated that the PM2.5 sensor data will be useful for this project.
The barometric pressure reported indoors will only be used as a backup/check for the outdoor
meteorological data. Changes in the outdoor barometric pressure reported by the national weather
service will be the primary ITS used for VOC sample timing.
5.2.8 Outdoor Meteorological Methods
Meteorological data (such as temperature, wind speed and direction, barometric pressure, and hourly
precipitation) will be obtained with data from the closest National Weather Service facility. Details of
measurement procedures and quality assurance are provided in NOAA (1998 and 2005).
5.2.9 Decontamination Procedures
Decontamination procedures are discussed in the following SOPs:
•
•
Appendix B6. Installing Subslab Probes and Collecting Subslab Soil Gas Samples Using Canisters SOP
Appendix B7. Installation and Abandonment of Permanent and Semi-Permanent Exterior Soil Vapor
Probes SOP.
5.2.10 Field Notes
5.2.10.1 Documentation of Sampling Timing Decisions
The following building and sampling specific information will be recorded in an Excel spreadsheet and
entered into the database managed by RTI:
•
•
•
•
The date and time a decision to initiate sampling is taken, and when it is desired to initiate sampling
The basis used to make that decision (e.g., radon observed to be rising, cold front forecast)
The date and time the sample was initiated
Constraints on sampling
o In Task 4 these may include EPA contractor staff availability and homeowner/resident
availability to provide access
o In Task 5, these may include homeowner/resident availability.
5.2.10.2 Field Research Logbooks
Field research logbooks will be used to document activities during this study along with the standard
Field Test Data Sheets provided in Method TO-17. Logbooks are used to document where, when, how,
and from whom any vital project information was obtained. Each activity up through Task 4 will be
documented in a logbook in such a manner that the study can be reconstructed in the future by a third
party. Individuals may choose to keep their own logbooks or use the main study logbook. However, all
pertinent information from these logbooks must be copied and included in the EPA project files.
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Logbooks should have consecutively numbered pages. All entries should be legible, written in ink, and
signed by the individual making the entries. The types of information to be recorded include:
•
•
•
•
•
•
Weather conditions
Concurrent sampling activities
Individuals present during the day
Exact sampling locations
Methods used to collect samples
•
Sample container identification or instrument
identification
•
•
•
•
Date and time of sample collection
Types of samples
Field instrument readings
Other field observations
Field instrument calibration and quality
control checks
In Task 5, notes will only be available for Jacobs field staff activities, and entries provided by
homeowners into requested sampling forms. Homeowners can be encouraged to make notes but will
not be trained in maintaining a scientific notebook.
5.2.10.3 Photographs
A digital image of each sampling location and description will be acquired at the time of first sampling in
Task 4 and included with the field notes if allowed by the homeowner. This information will not be
acquired in Task 5 by acob’s photographers under the current budget, although homeowners could be
requested to take photographs and email or upload them.
5.2.11 Sample Nomenclature
Each property will be given a property identification number (a two digit number e.g., 28). Sampling
nomenclature will be made from a room identification (i.e., BA = Basement, LR = living room) the
property identification number (a two digit number e.g., 28), the type of sample (indoor air [IA] or soil
vapor [SV], the sample number within that property (if there are 2 IA samples, then 01 or 02), the date
(YYMM), and if a field duplicate is taken, then FD will be added to the end. Grab sample types are for
VOCs in indoor air and soil vapor. VOC samples can be by TO-17 or Radiello. Sample names will then be
formed by combining the above elements, for example, BA-01-IA-01-2210 (FD, if needed).
In Task 5, it is anticipated that a simpler method of collecting the information will be used that is more
homeowner friendly. Homeowners will be asked to fill out a data reporting sheet with separate columns
for start and end date/time, location, Radiello number and the reason for sampling (scheduled or ITSbased). Then the EPA laboratory will use that information to generate the standardized sample numbers
according to the style above as they log in the samples.
5.2.12 Sample Chain-of-Custody
All samples will be submitted to the laboratories following COC procedures and with a COC form. The
COC records will contain the following information:
•
•
•
•
Field sample ID
Date and time collected (start and stop)
Analysis requested
Matrix
•
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•
Sample type
Sampler name and signature
Date and time relinquished
Remark
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•
Tube serial numbers if applicable
The COC record will be signed by the sampler and relinquished to the sample custodian. As discussed
above a multipurpose data reporting sheet will fulfill the requirements of a chain of custody in task 5.
5.2.13 Packaging and Shipment
Sorbent samples will be packed into appropriate containers supplied by the laboratories with the
sampling media. Sample shipping temperature may vary dependent on the type of sorbent used (see
Table 5-1). This information will be obtained from the laboratories selected and will be based on their
experience with sorbent on other research projects. If chilling is required, samples will be shipped in a
study ice chest with ice substitute (i.e., blue ice).
In Task 5, shipping is based on the USPS padded flat rate envelope priority mail shipped at post office or
online/from home. Additionally, costs are included to provide an inner “thermal bubble mailer” to
enhance protection and temperature control. Task 5 samples will not be shipped on ice and are allowed
a 30-day holding time.
5.3 Analytical Methods
5.3.1 Overview of Analytical Measurements
The parameters to be measured will include VOC, radon, temperature, humidity, and atmospheric
pressure. Air (ambient, indoor, and external soil gas) is the media to be sampled. The EPA laboratory in
Research Triangle Park, NC will conduct laboratory analyses for VOCs in indoor air, ambient air, and
exterior soil gas.
All of the VOC and radon data and all of the temperature, and atmospheric pressure are considered
critical measurements. Other measurements are considered noncritical Table 5-1 indicates the
measurement methods and the relevant MOP, EPA method, or other method.
Sample holding times and preservation requirements for extractive samples are also summarized in
Table 5-1.
Table 5-1.
Extractive Sample Preservation and Holding
Sample
Container/
Quantity of
Sample
Preservation/
Storage
Holding
Time(s)
Measurement
Analysis Method
VOCs in indoor
and ambient air
(passive)
Sample analysis performed by the EPA laboratory.
EPA Method TO-17 and Methods for the Determination of
Hazardous Substances (MDHS) 80: “Volatile Organic
Compounds in Air: Laboratory Method Using Diffusive Solid
Sorbent Tubes, Thermal Desorption and Gas
Chromatography”, August 1995. Published by the Health and
Safety Executive of the United Kingdom:
https://www.hse.gov.uk/pubns/mdhs/pdfs/mdhs104.pdf
Passive
Sampling
Tube
Cool (<20C),
solvent free,
tightly capped.
Shipment for
short durations
with only a
thermal bubble
wrap protection
will be used in
Task 5.
30 days
VOCs in
Exterior Soil
Gas
(active)
Sample analysis performed by the EPA laboratory.
EPA Method TO-17 modified and Methods for the
Determination of Hazardous Substances (MDHS) 80:
“Volatile Organic Compounds in Air: Laboratory Method
Using Diffusive Solid Sorbent Tubes, Thermal Desorption
and Gas Chromatography”, August 1995. Published by the
Tenax TA
Tube
4±2°C tightly
capped
30 days
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Measurement
Analysis Method
Health and Safety Executive of the United Kingdom:
https://www.hse.gov.uk/pubns/mdhs/pdfs/mdhs104.pdf
Sample
Container/
Quantity of
Sample
Preservation/
Storage
Holding
Time(s)
Radon in indoor
air and ambient
air
Airthings Corentium Wave-plus or Radon Eye Plus-2 or RD200
Consumergrade home
unit
Real-time home
unit
NA
Radon in
ambient air
exterior soil gas
EPA 1992; AlphaGuard or RAD7
AlphaGuard
radon
monitor or
RAD7
Real-time hand
unit
NA
5.3.2 Real-Time/Field Portable Instruments for Radon
Provision is made in this section for two alternate instruments depending on availability from EPA–the
AlphaGuard or RAD-7.
5.3.2.1 AlphaGuard Radiation Monitor
The AlphaGuard monitor incorporates a pulse-counting ionization chamber (alpha spectroscopy with 5
cpm at 3 pCi/L) and is suitable for continuous monitoring of radon concentrations between 0.05 and
50,000 pCi/L. More information on the AlphaGuard can be found at https://www.bertininstruments.com/product/radon-professional-monitoring/radon-alphaguard/
Analysis will be conducted in accordance with the instrument manufacturer’s instructions and with EPA
protocols for the use of continuous radon monitors (EPA 1992). An MOP for the AlphaGuard instrument
is provided as Appendix B13. This device would be classified as a “CR” type device by EPA. Operation of
CR devices is covered in Section 2.1 of EPA (1992). Calibration procedures are discussed in Sections 2.1.5
and 2.1.11 of EPA (1992).
5.3.2.2 The RAD-7 Radon Monitor
The RAD-7 monitor incorporates a passivated, implanted planar silicon detector (in sniffer mode, the
sensitivity is 0.2 cpm/pCi/L) and is suitable for continuous monitoring of radon concentrations between
0.1 and 10,000 pCi/L. Recovery time is 20 minutes after leaving a hot spot. The pump runs at a rate of
1 L/min, and cycles can be set from 2 minutes to 24 hours. More information on the RAD-7 can be found
at https://durridge.com/products/rad7-radon-detector/. The RAD-7 is an NRPP-approved device
(https://nrpp.info/devices/approved-devices/),
Analysis will be conducted in accordance with the instrument manufacturer’s instructions and with EPA
protocols for the use of continuous radon monitors (EPA 1992). An MOP for the RAD-7 instrument is
provided as Appendix G. Calibration of the RAD-7 instrument is done in house by the manufacturer, and
instrument drift is reported by the manufacturer as typically less than 2% per year.
5.3.3 Analytical Methods for VOCs
The target VOC list for this project is given in Table 5-2.
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Table 5-2.
Target VOCs
Compound
Emphasis
Rational for Inclusion
Tetrachloroethene
(PCE)
Key project analyte must be on
the calibration curve if at all
possible.
Detected in all media in screening analyses, results
strongly suggest VI. Known dry cleaning compound.
Trichloroethene
(TCE)
Key project analyte must be on
the calibration curve if at all
possible.
Known to be formed as a degradation byproduct of
PCE. Known use as dry cleaning agent (Linn et al.
n.d.). Seen in indoor air screening sample at this site.
cis-1,2Dichloroethene
(DCE)
Likely to be useful for
distinguishing soil gas from
indoor sources in some cases.
Known to be formed as a major biological degradation
byproduct of PCE and TCE.
trans-1,2Dichloroethene
Likely to be useful for
distinguishing soil gas from
indoor sources in some cases.
Associated with the abiotic degradation of TCE (Stroo
and Ward 2010).
5.3.3.1 Laboratory Analysis of VOCs in Soil Gas, Method TO-17, US EPA CEMM Laboratory
Upon receipt, sample tubes are stored in a clean refrigerator at <4°C until analysis. Analysis is performed
on an Automated Thermal Desorption (ATD) Unit interfaced with a GC/MS. The ATD has autosampler
capabilities and utilizes a two-stage thermal desorption process as described in Method TO-17.
Table 5-3 lists the analyte list, reporting limits, and acceptance criteria for EPA Method TO-17, and
Table 5-4 details the calibration and QC procedures.
Table 5-3.
TO-17 Soil Gas Compound Reporting Limits and QC Acceptance Criteria
Acceptance Criteria
Analyte
Reporting Limit (ng)
ICAL (%RSD)
LCS (%R)
CCV (%D)
Tetrachloroethene
5.0
30
70 – 130
30
Trichloroethene
5.0
30
70 – 130
30
cis-1,2-Dichloroethene
5.0
30
70 – 130
30
trans-1,2-Dichloroethene
5.0
30
70-130
30
Internal Standards
Analyte
CCV IS % Recovery
Sample IS % Recovery
1,4-Difluorobenzene
60 – 140
60 – 140
Chlorobenzene-d5
60 – 140
60 – 140
Analytical Surrogate
Analyte
Bromofluorobenzene
% Recovery
70 – 130
CCV IS = continuing calibration verification internal standard
ICAL (% RSD) = initial calibration curve (percent relative standard deviation)
LCS = laboratory control samples
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Table 5-4.
Summary of Calibration and QC procedures for Method TO-17 Soil Gas
QC Check
Minimum Frequency
Bromofluorobenze
ne (BFB) Tune
Check
Before initial and daily
calibration. Check is
valid for 24 hours.
SW – 846 tune criteria.
Acceptance Criteria
Correct problem then repeat tune.
5-Point Calibration
Prior to sample
analysis.
See Table 5-3
Correct problem then repeat initial
calibration curve.
Laboratory
Control Samples
(LCS)
After each initial
calibration curve and
daily with each batch
of samples not to
exceed 20.
See Table 5-3
Check the system and reanalyze the
standard. Re-prepare the standard if
necessary. Re-calibrate the
instrument if the criteria cannot be
met.
Continuing
Calibration
Verification (CCV)
At the start of each
24-hour clock after the
tune check.
See Table 5-3
Maintenance is performed and the
CCV test repeated. If the system still
fails the CCV, perform a new 5-point
calibration curve.
Laboratory Blank
After the CCV and
before the samples.
Results less than the
laboratory reporting limit (RL).
Inspect the system and reanalyze the
blank.
Internal Standard
(IS)
As each QC sample
and sample are being
loaded.
CCVs: area counts 60-140%,
Retention time (RT) within 20
sec of mid-point in ICAL.
CCV: Inspect and correct system
prior to sample analysis.
Field blanks: Inspect the system and
reanalyze the blank.
Samples: Investigate the problem by
verifying the instrument is in control
by running a lab blank. Reanalyze
recollected samples to verify
recovery. Report the run with
acceptable IS recovery. If both runs
are unacceptable, narrate and flag
associated data.
Field blanks and samples:
RT must be within ±0.33
minutes of the RT in the CCV.
The IS area must be within
±40% of the CCV’s IS area
for the blanks and samples.
Corrective Action
Analytical
Surrogates
As each QC sample
and sample is being
loaded.
70 – 130%
For field blanks: Inspect the system
and reanalyze the blank.
For samples: Review data to
determine whether matrix
interference is present. If so, narrate
interference and flag recovery. If no
interference is evident, verify the
instrument is in control by running a
lab blank. Reanalyze recollected
sample to verify recovery.
Field Blanks
Collected at a
frequency of 5% of
samples.
Artifact levels should be less
than the reporting limit or less
than 5% of the mass
measured on the sampled
tubes, whichever is less.
Flag associated results and evaluate
tube conditioning and storage
procedures.
Field Duplicates
Collected at a
frequency of 5% of
samples.
%RPD (relative percentage
difference < 50%
Narrate discrepancy.
5.3.3.2 Analysis of Passive Samplers for VOCs in Indoor Air, US EPA CEMM Laboratory
The EPA laboratory will use EPA Method TO-17 and Methods for the Determination of Hazardous
Substances (MD S) 80: “Volatile Organic Compounds in Air: Laboratory Method Using Diffusive Solid
Sorbent Tubes, Thermal Desorption and Gas Chromatography” to analyze samples under SOP: WECD-
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MMB-SOP-4350-0 “Analysis of Volatile Organic Compounds in Soil Vapor using Thermal Desorption / Gas
Chromatography / Mass Spectrometry”
The Radiello sample tube is heated while the carrier gas is flushed in the reverse direction as sample
collection, and the analytes are focused on a “cold” trap. Internal standards and the analytical surrogate
are automatically added to the trap by flushing a fixed volume loop connected to a 1 ppmv high
pressure internal standard cylinder. The ATD unit also has a recollection feature that allows for a portion
of the sample mass to split during the initial desorption to the cold trap and after the desorption of the
cold trap. The sample splits are recollected onto a clean sample tube. The recollected tube is stored until
the data have been reviewed against quality control requirements.
Table 5-5 lists the analyte list, reporting limits, and acceptance criteria for the thermal desorption
extraction method, and Table 5-6 details the thermal extracted diffusive sample reporting limits for
short-term intervals. Table 5-7 summarizes calibration and quality control procedures for thermal
desorption GC/MS analytical methods such as TO-17.
Table 5-5.
Thermal Desorption Radiello Compound Reporting Limits and QC Acceptance
Criteria
Analyte
Reporting
Limit (ng)
Acceptance Criteria
ICAL (%RSD)
ICV (% R)
CCV (%D)
LCS (%R)
Tetrachloroethene
100
20
80 – 120
20
70-130
Trichloroethene
100
30
70 – 130
30
70 – 130
cis-1,2-Dichloroethene
100
30
70 - 130
30
70 – 130
trans-1,2-Dichoroethene
100
30
70-130
30
70-130
Internal Standards
Analyte
CCV IS % Recovery
Sample IS % Recovery
1,4-Difluorobenzene
50 – 200
50 – 200
Chlorobenzene-d5
50 – 200
50 – 200
Surrogate
Analyte
Bromofluorobenzene
% Recovery
70 – 130
ICAL (% RSD) = initial calibration curve (percent relative standard deviation)
ICV = internal calibration verification
LCS = laboratory control samples
CCV IS = continuing calibration verification internal standard
Table 5-6.
Thermal Extracted Diffusive Sample Reporting Limits (µg/m3) for Various Collection
Intervals
Method Detection Limit (MDL)
TCE
PCE
MDL (8 hour, µg/m3)
0.62
0.83
MDL (24 hour, µg/m3)
0.21
0.28
0.03
0.04
MDL (7 day,
µg/m3)
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Table 5-7.
Summary of Calibration and QC Procedures for Thermal Radiello Analysis
QC Check
Minimum Frequency
Acceptance Criteria
Corrective Action
BFB Tune Check
Prior to calibration and at
the start of every 12-hour
clock.
Method 8260B tuning
criteria
Correct problem then
repeat tune. Analysis
does not proceed until
tune criterion is met.
Initial 5-Point Calibration
Prior to sample analysis.
%RSD<20% for
chloroform and PCE
Correct problem then
repeat initial calibration.
Initial Calibration
Verification (ICV)
Once per initial calibration.
Recovery = 80-120% for
chloroform and PCE
Verify concentrations and
standard preparation.
Continuing Calibration
Verification (CCV)
At the start of analytical
batch immediately after
the BFB tune check.
%D<20% for chloroform
and PCE
Investigate and correct
the problem, up to and
including recalibration if
necessary.
Internal Standards (IS)
IS added at the time of
extraction to all samples
and QC samples.
For CCVs: area counts 50
- 200%, retention time
(RT) within 30 sec of midpoint in ICAL.
For blanks, samples and
non-CCV QC Checks:
area counts 50 – 200%,
RT within 20 sec of RT in
CCV.
CCV: inspect and correct
system prior to sample
analysis.
For blanks: inspect the
system and reanalyze the
blank.
For samples: reanalyze; if
out again, flag data.
Surrogate
Surrogate is added at the
time of extraction to all
samples and QC samples.
Recovery = 70-130%
Same as for IS.
Solvent Blanks
Immediately after the
calibration standard or
after samples with high
concentrations.
Results less than
laboratory reporting limit.
Re-aliquot and reanalyze
solvent blank. If
detections remain, flag
concentrations in
associated samples.
Extracted Laboratory
Blank
Each set of up to 20
samples.
Results less than the
reporting limit.
Flag sample
concentrations in
associated extraction
batch.
Extracted Laboratory
Control Samples (LCS)
Each set of up to 20
samples.
Recovery = 70-130%
Re-aliquot and reanalyze
the extract. If within limits,
report the reanalysis.
Otherwise, narrate.
Field Blank
Collected at a frequency
of 5% of samples.
Artifact levels should be
less than the reporting
limit or less than 5% of the
mass measured on the
sampled tubes, whichever
is less.
Flag associated results
and evaluate
manufacturing lot
cleanliness and storage
procedures.
Field Duplicates
Collected at a frequency
of 5% of samples.
%RPD ≤ 50%
Narrate discrepancy.
This method is not widely used, and standardized performance evaluation materials are not available, so
bias will be assessed using a variety of lines of evidence: (1) the recovery of surrogates for the thermal
Radiellos; (2) the results of laboratory control spikes; and (3) the results of the laboratories’ independent
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performance evaluation samples and/or interlaboratory comparison programs for Method TO-15, which
shares a similar instrumental approach.
5.3.3.3 Laboratory Analysis of Passive Samplers for VOCs in Soil Gas, US EPA CEMM Laboratory
The EPA laboratory will use EPA Method TO-17 and Methods for the Determination of Hazardous
Substances (MD S) 80: “Volatile Organic Compounds in Air: aboratory Method Using Diffusive Solid
Sorbent Tubes, Thermal Desorption and Gas Chromatography” to analyze samples under SOP: WECDMMB-SOP-4350-0 “Analysis of Volatile Organic Compounds in Soil Vapor using Thermal Desorption / Gas
Chromatography / Mass Spectrometry.”
Analysis of these tubes is essentially identical to the analysis of the same tubes when actively sampled as
covered under Section 5.4.3.1 so the reporting limits, acceptance criteria, calibration requirements etc.
will be the same. However, the uptake rates will be adjusted for barometric pressure and temperature
as called for in EPA Method 325 (2017a).
5.3.3.4 Data Reporting
The data generated from passive samplers is expressed in units of mass (nanograms or micrograms).
Concentrations are calculated using the following equation:
Conc (µg/m3) = {Mass (ng)/[SR (mL/min) x Duration (min)]} x 1000 mL/L x 1000 L/m3 x µg/1000 ng
Where SR = Sampling Rate provided by the manufacturer.
6 Quality Assurance and Quality Control
Measurement quality objectives and methods of assessment for critical measurements for this project
are summarized in Table 6-1. Measurement quality objectives and methods of assessment for noncritical measurements for this project are summarized in Table 6-2. Bias objectives for the noncritical
parameters listed in Table 6-2 will be evaluated with a periodic comparison to similar/equivalent
sources in the selected sites for general reasonableness of the onsite reading. We will assess all
completeness objectives based on the planned measurements specified in Table 4-1.
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Table 6-1.
Measurement Quality Objectives and Methods of Assessment for Critical Measurements
Parameters
VOC
concentration in
air
Radon in Outdoor
air, Indoor Air and
Soil Gas
Method Type
Method
Citation
Bias (Accuracy)
Objective and
method of
Verification
Objective
Precision
Completeness
Detection or Reporting
Limit Objective and
Method of Verification
GC/MS (passive soil
gas sorbent tube
samples)
TO-17
modified
70-130% recovery of
analytical surrogate
BFB.
70-130% recovery in
laboratory control
spike except for
carbon disulfide and
methylene chloride,
which will be 50-150%.
30% except for
carbon disulfide
and methylene
chloride, which will
be 40%
90%
See Tables 5-3, 5-5, and 56 in Section 5.3.3
GC/MS (passive
Radiello samplers of
indoor and ambient)
MDHS 88,
MDHS 80,
TO-17,
modified
30%
30%
90%
See Tables 5-3, 5-5, and 56 in Section 5.3.3
RadonEye
EPA 402-R92-004 (EPA
1992); also
see
instrument
operation
manual
15%, not separately
evaluated in this
project; reference
made to NRPP testing
and Carmona and
Kearfott, 2019;
Warkentin et al., 2020
15%
90%
0.1 pCi/L over the long
term (sensitivity is 0.5
cpm/pCi/l) so 30 events are
observed per hour at 1
pCi/L, 3 at 0.1 pCi/L.
Airthings View Plus
EPA 402-R92-004 (EPA
1992); also
see
instrument
operation
manual
15%, not separately
evaluated in this
project; reference
made to NRPP testing
and Carmona and
Kearfott, 2019 and
Warkentin et al., 2020
15%
90%
Manufacturer has not yet
stated a detection limit.
Carmona and Kearfott and
Warkentin reported good
performance for Airthings
radon instruments, but
testing was conducted
under higher radon
conditions >13.5 pCi/l.
AlphaGuard radon
monitor (active)
EPA 402-R92-004 (EPA
1992); also
see
instrument
10%, not separately
evaluated in this
project; reference
made to NRPP testing
and Carmona and
10%
90%
0.1 pCi/L over the long
term when used in indoor
air. Sensitivity is
approximately 1.85
cpm/pCi/L for the
AlphaGuard. When used in
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Parameters
Method Type
RAD-7 radon monitor
Method
Citation
operation
manual
Bias (Accuracy)
Objective and
method of
Verification
Kearfott, 2019;
Warkentin et al., 2020.
EPA 402-R92-004 (EPA
1992); also
see
instrument
operation
manual
10%, not separately
evaluated in this
project; reference
made to NRPP testing
and Carmona and
Kearfott, 2019;
Warkentin et al., 2020
Objective
Precision
10%
Completeness
90%
Detection or Reporting
Limit Objective and
Method of Verification
soil gas 3 pCi/L is a
reporting limit objective
limited by carryover.
0.1 pCi/L over the long
term when used in indoor
air. Sensitivity is
approximately 0.5
cpm/pCi/L for the
AlphaGuard. When used in
soil gas 3 pCi/L is a
reporting limit objective
limited by carryover.
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Table 6-2.
Parameters
Measurement Quality Objectives and Methods of Assessment for Noncritical Measurements
Method
Type
Method Citation
Bias (Accuracy)
Objective and method
of Verification
Objective
Precision
Completeness
Detection or Reporting
Limit Objective and
Method of Verification
Total organic
vapor
Mini RAE
portable
continuous
VOC
monitor
Manufacturer O&M
manual in Appendix E;
specific applications
described in Jacobs
SOPs
35%, since this is a
screening instrument,
bias will not be verified
with a second source
calibration gas but will
be assessed through
rechecks of the initial
calibration gas
throughout the analytical
period
30% RPD, which can be
assessed with duplicate
measurements of the
calibration gas.
90%
10 ppbv detection limit for
TCE and PCE
(manufacturer indicates 5
ppb should be feasible)
Indoor
temperature
Airthings
View Plus
Manufacturer product
sheet; A Standardized
EPA Protocol for
Characterizing Indoor Air
Quality In Large Office
Buildings,
EPA/ORIA/IED and
AREAL, February 2003a,
Table C2.
+/-1 °F as reported by
manufacturer, no
assessment planned.
+/-1 °F as reported by
manufacturer, no
assessment planned.
90%
Solid state sensor,
manufacturer does not
report range, but
expected to be adequate
for room temperature
measurement.
Recommended operating
conditions are stated as 4
to 40 °C / 39 to 104 °F
Indoor
carbon
dioxide
Airthings
View Plus
NDIR Sensor,
manufacturer product
sheet; A Standardized
EPA Protocol for
Characterizing Indoor Air
Quality In Large Office
Buildings,
EPA/ORIA/IED and
AREAL, February 2003a,
Table C4.
±50 ppm ±3 %RH within
10 – 35 °C / 50 - 95 °F
and 0 – 80%RH, after
initial calibration time of
7 days Self-calibrated
using an automatic
baseline algorithm that
updates once a week
±50 ppm ±3 %RH within
10 – 35 °C / 50 - 95 °F
and 0 – 80%RH, after
initial calibration time of
7 days Self-calibrated
using an automatic
baseline algorithm that
updates once a week
90%
400 – 5000 ppm
Indoor air
total VOCs
Metal oxide
based gas
sensor
Manufacturer product
sheet and user manual
+/- 50%, not able to be
verified, will be used as
ancillary and relative
measurement
+/- 50%, not able to be
verified, will be used as
ancillary and relative
measurement
70% at sites
where Airthings
View Plus is
used
Not reported, not planned
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Bias (Accuracy)
Objective and method
of Verification
Objective
Detection or Reporting
Limit Objective and
Method of Verification
Method
Type
Method Citation
Indoor
Barometric
pressure
Airthings
View Plus
Manufacturer product
sheet user manual
0.6 mbar = 0.018 in of
Hg = 60 pascals
0.6 mbar = 0.018 in of
Hg = 60 pascals
90%
manufacturer does not
state range but expected
to be adequate since
normal barometric
pressure varies only
modestly
Indoor
Relative
humidity
Airthings
View Plus
Manufacturer product
sheet; A Standardized
EPA Protocol for
Characterizing Indoor Air
Quality In Large Office
Buildings,
EPA/ORIA/IED and
AREAL, February 2003a,
Table C3
±3% RH
±3% RH
90%
Recommended operating
conditions stated as 085% RH
Parameters
Precision
Completeness
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6.1 Detection Limits
Detection limit information is listed for most measurements in Table 6-1 and 6-2. Detection limits for
sorbent tube and Radiello samplers are covered in Section 5.3 by total collection duration.
6.2 Consideration of Background Sources of Indoor Air Contamination
A complicating factor of indoor air sampling for VI is the presence of VOCs in indoor air due to ambient
(outdoor) atmospheric contamination and the indoor use of common household products and solvents.
During the initial screening phase of work, at a minimum, a succinct building survey will be performed
within each structure proposed for sampling. The building survey is expected to be brief, although will
aim to detail pertinent information regarding use of the structure, typical potential background sources
observed, and general condition of the building envelope. In addition to documenting the broad types of
potential background sources of VOCs present within an individual structure, the structure will be
screened for total VOCs using a handheld MultiRae PID device. To control cost consumer products may
be documented photographically in groups rather than preparing a detailed item by item inventory. The
PID screening will consist initially of PID measurements outside the house and in the rooms where
sampling is likely to occur. Screening may also include sites of significant chemical storage such as a
basement shop or closet in which many cleaning products are kept. However, the project level of effort
does not allow for a detailed drawer by drawer/object by object PID survey. If through the visual
inspection or PID screening any significant potential background VOC sources are identified, they will be
documented, and occupants will be instructed to restrict usage nearby deployed samples. Identified
items will not be removed from structures, nor will occupants be told usage of the items is prohibited.
But a reasonable effort will be made to explain the important of collecting an unbiased sample and the
benefits of storing VOC containing products in well ventilated places.
If additional optional work is selected where the community science effort will be completed, occupants
within each structure will be taught how to identify and document potential background VOC sources,
but no pre-screening is anticipated with a handheld MultiRae device.
To account for outdoor VOC sources, ambient air sampling is planned at each site in parallel with indoor
sampling. Indicator compounds specific to VI (as opposed to indoor sources) such as cis-1,2-DCE may be
critical in many cases to discerning indoor sources.
6.3 Consideration of Spatial, Seasonal, and Temporal Variability
As one of the primary objectives of this TO, seasonal and temporal variability are going to be extensively
characterized (as outlined in the test matrix Table 4-2). Temporal variability will be assessed through
various sampling events conducted through approximately 12 months, spaced such that major seasons
are targeted for both the calendar-triggered sampling events as well as the ITS-triggered sampling
events (that is, winter, summer, and spring or fall). Spatial variability will be assessed by collecting soil
gas samples throughout a large area of a single site, which may potentially retain slight elevation
changes and slight subsurface condition changes (e.g., depth to water, soil type). Spatial variability will
also be evaluated through comparison of indoor air samples collected within separate zones of a single
structure (for example, basement and ground floor).
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6.4 Consideration of Random or Systematic Error
Evaluation of random and systematic error is an important part of any quality protocol development.
Some sources of error are manageable through proper QA planning and methodology as long as they
can be foreseen. To achieve the purposes of this TO, all manageable sources of systematic error will be
identified and minimized. Examples of manageable potential sources of systematic error include:
•
•
Reduction in vapor concentration due to poorly sealed probes (probe leakage)
•
Reduction of vapor concentration due to failure to cap passive samplers tightly (sample container
leakage)
•
Reduction in VOC concentration due to excessive purging prior to sampling (dilution of subsurface
vapors by excessive pumping)
•
Incomplete recovery of analytes from sample media, including sorbents (incomplete solvent extraction
or thermal desorption).
Increase in vapor concentration due to cross-contamination from sampling materials or background
sources
•
Non-recovery of proposed samples (non-responsive building occupants either before or after sample
deployment)
Assessment of vapor concentration dilution from poorly sealed vapor probes can be a challenge. There
is little published on methods to assess leakage in this type of monitoring system. Also, if leakage is not
severe, it may not significantly compromise data (i.e., leakage occurs but is relatively minor compared to
gas flow in subsurface material, as with a sand and gravel filled sub-base where gas permeability can be
expected to be very high (10-7 to 10-6 cm2). However, we will determine the amount and significance of
probe leakage by releasing a tracer gas into a shroud over the vapor sampling point and then sampling
for that tracer gas through the soil gas probes (SOP for leak check provided as part of Standard
Operating Procedure for Installing Subslab Probes and Collecting Subslab Soil Gas Samples Using
Canisters).
To avoid systematic error because of increases in vapor concentration due to materials used in vapor
probe construction, sample tubing and equipment will follow the recommendations provided in ORD’s
September 2005 report (US EPA, 2005a). As recommended in the report, subslab vapor samples will be
collected from the vapor probes using dedicated high purity FEP-lined polyethylene tubing, which offers
very low vapor and gas permeability, is non-photo reactive, and is a low-cost alternative to
fluoropolymer tubing.
Reduction of vapor concentration due to failure to cap passive samplers tightly (sample container
leakage) is a potential source of error that can be managed primarily through vigilance by the field
personnel.
Non-recovery of select proposed samples may occur if occupants/owner of a selected structure are
suddenly non-responsive after receiving initial agreement for access. It is unlikely that a building
occupant will lose contact with the project team once a sample is deployed but is most likely to occur
after access has been granted and before sampling begins (or after several rounds of sampling have
been completed and additional samples are needed). Although this error cannot be avoided as property
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owners and occupants cannot be forced to communicate with the project team, efforts can be made if
this situation occurs to meet with occupants face-to-face if interactions over the phone or email are
unsuccessful.
It is possible for any given test site to have characteristics that are not nationally valid. Therefore, we
will avoid drawing firm conclusions about the entire phenomenon of VI from a single test site. It will be
appropriate in the discussion section of the project report to qualitatively compare the results obtained
at this site to published results obtained at other sites. Extensive data sets have been published for
residences in Utah (Holton, 2015; Holton et al., 2012 and 2013) and Indiana (US EPA, 2012b and 2015b).
A significant data set was also acquired on the utility of the radon tracer and passive sorbent methods at
the Orion Park/Moffett Field site and Wheeler Building complex under previous EPA APPCD-sponsored
studies (Lutes, 2010a and 2010b).
6.5 Analytical QA/QC Checks
Laboratory quality control sample requirements such as calibration checks, method blanks, surrogate
recoveries, laboratory control samples, matrix spikes, and others will be performed according to the
requirements of the methods, as specified in the following sections.
6.5.1 Summary of Performance Requirements for VOC Analytical Methods
Performance requirements for these methods are listed in section 5.3
6.6 Field Quality Control Samples
Field quality control samples are intended to help evaluate conditions resulting from field activities and
are intended to accomplish two primary goals: (1) assessment of field contamination, and (2)
assessment of sampling variability. The former looks for substances introduced in the field due to
environmental or sampling equipment and is assessed using blanks of different types. The latter includes
variability due to sampling technique and instrument performance as well as variability possibly caused
by the heterogeneity of the matrix being sampled and is assessed by collecting sample replicates.
Blanks introduced during sample shipment, storage, and collection help evaluate whether samples may
be subject to false positives. Different types of air sampling devices have different affinities for blank
contamination. Any air sampling device may be subject to contamination in the presence of extremely
high levels of the contaminant. Specific types of sampling devices may be subject to specific or
systematic practices that may unknowingly introduce contaminates.
6.6.1 Field Blanks
Because there is no good indicator of sample media integrity during sample collection, field blanks will
be employed to evaluate potential background contamination during sample collection. Field blanks
prepared by the field team will be tracked through the serial number assigned to the device. The blank
media will be opened briefly during collection of field samples and then resealed, to be stored at
ambient temperature until sample shipment to the laboratory, at which point it may be placed on ice. If
contamination above the laboratory reporting limit is found in the blanks, concentrations in associated
samples up to five times that found in the blanks will be omitted from data analysis unless otherwise
shown to be valid.
The frequency of planned field blanks is defined in the test matrix presented in Table 4-2.
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6.6.2 Field Duplicates
Duplicate (or replicate) samples are collected simultaneously in separate containers from the same
source and under identical conditions. For example, Method TO-17 sorbent tube duplicates will be taken
by drawing soil gas through two sorbent tubes (one immediately after the other). Passive sample
duplicates will consist of co-located samplers. Each duplicate portion will be assigned its own sample
number so that it will be “blind” to the laboratory (i.e., the laboratory cannot tell it is a duplicate). A
duplicate sample is treated independently of its counterpart in the same laboratory to assess laboratory
performance through comparison of the results. Typically, at least one duplicate will be collected per
every 10 primary samples of a selected matrix (i.e., indoor air, soil gas). Agreement between duplicate
samples should meet the criteria indicated in Table 6-1. Data sets that do not meet these criteria will be
flagged as suspect and will be omitted from data analysis unless otherwise shown to be valid.
The frequency of planned field duplicates is defined in the test matrix presented in Table 4-2.
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Appendices
Appendix A: Occupied Dwelling Questionnaire
Appendix B: Standard, Miscellaneous, and Field Operating Procedures
B1: SOP for Utility Clearance Inside Buildings
B2: SOP for Indoor, Crawl Space, and Ambient Air Sample Collection Using Sorbent Tubes
B3: Posting for Air Sampling Canisters
B4: Air Sampling Log
B5: SOP for Pressure Differential Monitoring to Support Vapor Intrusion Investigations
B6: SOP for Installing Subslab Probes and Collecting Subslab Soil Gas Samples Using Canisters
B7: SOP for Installation and Abandonment of Permanent and Semi-Permanent Exterior Soil
Vapor Probes
B8: Soil Vapor Probe Diagram
B9: SOP for Soil Vapor Sampling from Exterior Soil Vapor Probes
B10: Exterior Soil Vapor Sampling Form
B11: Soil Vapor Probe Purge Volume Calculations
B12: SOP for Radon Monitoring and Sampling to Support Vapor Intrusion Investigations
B13: 2-56 MOP: AlphaGuard: Operation of the AlphaGuard Portable Radon Monitor
B14: SOP for Temperature Monitoring in Support of Vapor Intrusion Investigations
B15: Weather Monitoring to Support Vapor Intrusion Investigations
Appendix C: Corentium Pro Monitor Manual
Appendix D: Radon Eye Plus 2 Manual
Appendix E: MiniRAE 2000 Portable VOC Monitor PGM 7600 Operation and Maintenance Manual
Appendix F: Radiello Manual (selected sections)
Appendix G: Rad7 Manual
Appendix H: Example Chain-of-Custody Form
| File Type | application/pdf |
| Author | Tong-Argao, Sania |
| File Modified | 2022-08-17 |
| File Created | 2022-08-17 |