DRAFT
PROCEDURES
FOR
CONDUCTING AIR PATHWAY ANALYSES
FOR
SUPERFUND APPLICATIONS
VOLUME IV
Procedures for Dispersion Modeling
and
Air Monitoring
for
Superfund
A1r Pathway Analysis
by
NUS CORPORATION
910 Clopper Road
Galthersburg. Maryland 20877
Contract No. 68-01-7310
Work Assignment No. 62
Mr. Nark E. Garrison. Work Assignment Manager
U.S. ENVIRONMENTAL PROTECTION AGENCY - REGION III
841 CHESTNUT BUILDING
PHILADELPHIA. PA 19107
DECEMBER 1988
"I
§
-------
DRAFT
PROCEDURES
FOR
CONDUCTING AIR PATHWAY ANALYSES
FOR
SUPERFUND APPLICATIONS
VOLUME IV
Procedures for Dispersion Modeling
and
Air Monitoring
for
Super-fund
A1r Pathway Analysis
by
NUS CORPORATION
910 Clopper Road
Galthersburg, Maryland 20877
Contract No. 68-01-7310
Work Assignment No. 62
Mr. Mark E. Garrison. Work Assignment Manager
U.S. ENVIRONMENTAL PROTECTION AGENCY - REGION III
841 CHESTNUT BUILDING
PHILADELPHIA, PA 19107
DECEMBER 1988
-------
DISCLAIMER
This document was prepared for the U.S. Environmental Protection
Agency by NUS Corporation, Galthersburg, Maryland,* under Contract No. 68-
01-7310, Work Assignment No. 62. The contents are reproduced herein as
received from the contractor. The opinions, findings, and conclusions
expressed are those of the authors and not necessarily those of the U.S.
Environmental Protection Agency.
11
-------
CONTENTS
Figures .................... 1v
Tables .................... J
Acknowledgment .................. 1x
1 Introduction .............. 1-1
2 Atmospheric Dispersion Modeling Procedure .... 2-1
Overview ............. 2-1
Step 1 - Collect and review Input Information . 2-11
Step 2 - Select modeling sophistication level . 2-27
Step 3 - Develop modeling plan ...... 2-41
Step 4 - Conduct modeling ........ 2-64
Step 5 - Summarize and evaluate results . . . 2-72
Example application .......... 2-89
3 A1r Concentration Monitoring Procedure ..... 3-1
Overview ............. 3-1
Step 1 - Collect and review Input Information . 3-6
Step 2 - Select monitoring sophistication level. 3-17
Step 3 - Develop monitoring plan ..... 3-31
Step 4 - Conduct monitoring ....... 3-96
Step 5 - Summarize and evaluate results . . . 3-107
Example application .......... 3-124
4 References .............. ~
Appendix A Bibliography of A1r Monitoring Standard Operating
Procedures .............. A~l
Appendix B Excerpt from Technical Assistance Document . . * . B-l
Appendix C Background Information .......... C-l
111
-------
FIGURES
Number
1-1 Relationship of Volume IV to Volumes I-III .... 1-3
1-2 Superfund air pathway analyses technical procedures -
general format 1-5
2-1 Superfund air pathway analyses dispersion modeling
protocol 2-9
2-2 Step 1 - Collect and review Input Information . . . 2-12
2-3 Step 2 - Select modeling sophistication 2-28
2-4 Selection of screening versus refined dispersion
modeling 2-30
2-5 Evaluation of hazard Index and APA uncertainty
factors 2-32
2-6 Select modeling constituents . 2-46
2-7 Representation of an Irregularly shaped area source
by 11 square area sources 2-54
2-8 Example of nested subdivision of area source . . . 2-55
2-9 Step 4 - Conduct modeling 2-66
2-10 The dispersion modeling process 2-68
2-11 Step 5 - Summarize and evaluate results ... . 2-73
2-12 Example of a computer generated ground level
Isopleth plot 2-75
2-13 Example atmospheric dispersion (dilution) pattern. . 2-77
2-14 Drainage flow smoke test results 2-86
2-15 Drainage flow Impact area and dilution factors . . . 2-87
2-16 Example site plan for air dispersion modeling . . . 2-90
2-17 Receptor grid close to the site 2-96
3-1 Superfund air pathway analyses air monitoring
protocol 3-4
3-2 Step 1 - Collect and review Input Information ... 3-7
1v
-------
FIGURES (Continued)
Number
3-3
3-4
3-5
3-6
3-7
3-8
3-9
3-10
3-11
3-12
3-13
3-14
3-15
3-16
3-17
3-18
Step 2 - Select monitoring sophistication level . . .
Selection of screening versus refined air
Evaluation of hazard Index and APA uncertainty
Specify meteorological monitoring program
Superfund air monitoring QA/QC strategy
Example of downwind exposures at air monitoring
Example application of downwind frequency analyses . .
Example atmospheric dispersion (dilution) pattern . .
Example site plan and air monitoring network ....
Pace
3-18
3 10
-22
3M M
-24
3-32
3-35
3-41
3-49
3-90
3-97
3-104
3-108
3-116
3-119
3-121
3-123
3-125
-------
TABLES
Number
Page
2-1 Summary of dispersion modeling recommendations and
objectives 2-3
2-2 Sources associated with Superfund activities and their
characteristics 2-6
2-3 Example - Superfund Air Dispersion Modeling Input
Information Form 2-15
2-4 Example of Input requirements for various source
categories 2-19
2-5 Summary of Input meteorological data for jse 1n
dispersion modeling for Superfund APAs 2-24
2-6 A summary of dispersion modeling techniques for
Superfund APAs 2-36
2-7 A summary of dispersion modeling refined techniques
for Superfund APAs 2-39
2-8 An outline for the dispersion modeling plan for a
Superfund APA 2-4Z
2-9 Classification of organic and Inorganic compounds for
ambient air modeling studies 2-47
2-10 Suggested meteorological data screening criteria . . . 2-70
2-11 Example criteria for Identifying the geographic area of
applicability for dispersion modeling results relevant
to receptors of Interest 2-80
2-12 Example format for evaluation of hazard Index values for. 2-82
toxicants and carcinogens at receptor locations
associated with the maximum concentrations
2-13 Example format for evaluation of hazard Index values
relevant to ARARs at locations associated with maximum
concentrations 2-85
2-14 Target constituents modeled for each of the sources at
the site 2-93
3-1 Summary of air Monitoring applications 3-2
3-2 Example - Superfund A1r Monitoring Program Input
Information Form 3~10
v1
-------
TABLES (Continued)
Title
3-3 Summary of technical air monitoring objectives 3-19
3.4 An overview of screening air monitoring/sampling
techniques 3-27
3-5 An overview of refined air monitoring/sampling
techniques 3-30
3-6 Classification of organic and Inorganic compounds for
ambient air monitoring studies 3-36
3-7 Recommended system accuracies and resolutions 3-44
3-8 Recommended response characteristics for meteorological
sensors
3-45
3-9 Factors and associated elements that affect the design of
air monitoring programs for Superfund APAs 3-47
3-10 A1r monitoring station number and location recommendations
3-11 A summary of key probe siting criteria for air monitoring
stations
3-55
3-12 Program duration and frequency of monitoring as a function
of the Superfund project step 3-59
3-13 Summary of air monitoring method recommendations .... 3-61
3-14 Summary of screening techniques for detection of organic and
Inorganic compounds 1n ambient air -.. . . 3-69
3-15 A summary of refined sampling and analysis techniques for
organlcs and Inorganics 1n air ..... 3-72
3-16 Summary of sampling and analytical methods for refined
monitoring for organic and Inorganic compounds 1n ambient
air - volatile aromatlcs 3-74
3-17 Summary of sampling and analytical methods for refined
monitoring for organic and Inorganic compounds 1n ambient
air - volatile halogenated hydrocarbons 3-78
3-18 Summary of sampling and analytical methods for refined
monitoring for organic and Inorganic compounds 1n ambient
air - volatile oxygenates 3-79
-------
TABLES (Continued)
Title £SS1
3-19 Summary of sampling and analytical methods- for refined
monitoring for organic and Inorganic compounds 1n ambient
air - semivolatile phenolIcs 3-80
3-20 Summary of sampling and analytical methods for refined
monitoring for organic and Inorganic compounds 1n
ambient air - semivolatile base/neutral extracts .... 3-81
3-21 Summary of sampling and analytical methods for refined
monitoring for organic and Inorganic compounds 1n
ambient air - semivolatile pestlcldes/PCBs 3-82
3-22 Summary of sampling and analytical methods for refined
monitoring for organic and Inorganic compounds 1n
ambient air - volatile Inorganics 3-83
3-23 Summary of sampling and analytical methods for refined
monitoring for organic and Inorganic compounds In
ambient air - developing technologies 3-84
3-24 Typical commercially available screening monitoring
and analysis equipment for organ1cs and Inorganics 1n
air 3-85
3-25 Summary of refined screening monitoring equipment for
organic compounds 1n ambient air 3-88
3-26 Quality assurance (QA) activities to be specified In
program plan 3-101
3-27 Calibration requirements for sampling and analysis
Instrumentation 3-105
3-28 Typical sampling/analysis frequencies for QC samples . 3-106
3-29 Suggested meteorological data screening criteria . . . 3-110
-------
ACKNOWLEDGMENT
This document was prepared for the U.S. Environmental Protection
Agency (EPA) by NUS Corporation. The project was managed by Mr. Mark
Garrison. National Oceanic and Atmospheric Administration, who Is assigned
to the EPA, Region III. The principal authors were Dr. Ami ram Roffman and
Mr. Ronald Stoner. The authors would like to thank Mr. J1m Vlckery and
Mr. Joseph LaFornara of the EPA Office of Emergency and Remedial Response
as well as Mr. Joseph Padgett, Mr. Stan Sleva, Mr. Joseph Tikvart, and Mr.
Jack Durham of the EPA Office of A1r Quality Planning and Standards, and
Mr. Al ClmorelH of the EPA, Region III, for their guidance and direction.
The authors would also like to acknowledge Mr. Robert Jubach, Mr. Thomas
laccarino, Mr. Henry Flrstenberg, Mr. Jeffrey Panek, and Ms. Elizabeth
Butler for their overall contribution to this document.
-------
SECTION 1
INTRODUCTION
The multlvolume set of Procedures for Conducting A1r Pathway Analyses
for Suoerfund Applications has been developed In response to Increased
concern by the U.S. Environmental Protection Agency (EPA) regarding
potential hazardous air emissions from Superfund sites. These emissions
can occur at hazardous spill locations and undisturbed Superfund sites, as
well as during site cleanups. Under the Comprehensive Environmental
Response, Compensation, and Liability Act (CERCLA) and the recent
Superfund Amendments and Reauthorlzatlon Act (SARA), EPA has the
responsibility for assessment and cleanup of these Superfund sites.
Although there have been potential human health risks from air emissions
at these sites, comprehensive national guidance did not exist concerning
methods that could be used to determine the magnitude and Impact of these
emissions. Therefore, the goal of these Procedures 1s to provide
technical recommendations for the conduct of air pathway analyses (APAs)
that meet the needs of the Superfund process, presenting alternative
technical approaches for the conduct of APAs and providing recommendations
for preferred or default approaches. The Procedures are Intended for use
by EPA Remedial Project Managers (RPMs), Enforcement Project Managers
(EPMs), and air experts, as well as by EPA Superfund contractors.
The Procedures for Conducting A1r Pathway Analyses for Superfund
Applications consists of four volumes:
1-1
-------
• Volume I - Application of Air Pathway Analyses for Suoerfund
Activities
• Volume II - Procedures for Developing Baseline Emissions from
Landfills and Lagoons
• Volume III - Procedures for Estimating A1r Emissions Impacts
from Remedial Activities at NPL Sites
• Volume IV - Procedures for Dispersion Modeling and A1r
Monitoring for Suoerfund A1r Pathway Analyses.
Volume I defines the general approach for the conduct of APAs and
references appropriate sections within Volumes II-IV for detailed
technical procedures regarding modeling and monitoring techniques. Volume
II provides procedures for developing baseline air emission estimates, and
Volume III provides procedures for estimating air emission Impacts from
remedial actions. Specifically, Volumes II-IV present alternative and
preferred or default modeling techniques and monitoring techniques for
Implementing the APA approaches selected based on Volume I
recommendations. This Information will be primarily of Interest to EPA
air experts and Superfund contractors responsible for the conduct of APAs.
However, the technical procedures provided 1n Volumes II-IV are not
specific to Superfund activities. Therefore, Volumes II-IV will also be
useful to state air staff responsible for supporting hazardous waste site
cleanup.
The emphasis of Volume IV 1s on providing technical procedures for
dispersion modeling and air monitoring. The relationship of Volume IV to
Volumes I-III 1s Illustrated 1n Figure 1-1. Volume IV provides the
procedures for Implementing activity and source-specific dispersion
model1ng/a1r monitoring recommendations provided 1n Volume I. Volumes II
and III also cross-reference Volume IV for certain air emission
characterization approaches that require the conduct of dispersion
modeling and/or air monitoring. In addition, Implementation of Volume IV
1-2
-------
APA RECOMMENDATIONS (VOLUME 0
VOLUME II
CEDURE8 FOR
DEVELOPING BASE-
LINE AIR EMIS-
SION ESTIMATES
i
VOLUME IV PRO-
CEDURES FOR
DISPERSION MOD-
EUNQ AND AIR
MONITORING
VOLUME III PRO-
ESTIMATING AIR
EMISSION IMPACTS
FROM REMEDIAL
ACTIONS
SECTION 2
DISPERSION
MODELING
PROCEDURES
SECTION 3
AIR
MONITORING
PROCEDURES
Flgur* 1-1. Relationship of Volume IV to VolUMOO Mil.
-------
procedures frequently necessitates source emission rate Inputs based on
application of Volumes II and HI.
Volume IV presents technical procedures for the following types of
APAs:
• Dispersion modeling procedures
• A1r monitoring procedures
Section 2 presents procedures for the application of atmospheric
dispersion modeling as a methodology to assess potential exposures
associated with air emissions from a Superfund site. This material will
Include criteria as well as recommendations for selecting models,
obtaining required Input data, and Interpreting modeling results. These
procedures address technical Issues that are significant for Superfund
applications. Therefore, the procedures presented In Section 2 should be
considered as supplemental to, but not replacements for, the Guideline On
Air Quality Models (U.S. EPA, 1986).
Section 3 presents procedures for the application of air
concentration monitoring to characterize downwind exposure conditions from
Superfund air emission sources. These procedures discuss the technical
challenges Involved In the design and Implementation of an air toxic
monitoring program. Again, the emphasis has been on providing
recommendations specific to the conduct of Superfund APAs. Therefore,
available standard procedures for the conduct of air toxic monitoring
programs are Identified and summarized. However, the material has also
been adapted and supplemented as necessary to address Superfund
applications.
The technical procedures presented 1n Sections 2-4 are based on the
general format Illustrated 1n Figure 1-2 and discussed In Volume I. The
major elements of these procedures are as follows:
1-4
-------
APA RECOMMENDATIONS
(Velum* I)
o Aotrvfty-Speclflo
Reoommond'atlona
o Souree-Speelflo
Reoommondatlona
e Mo«elln0XMonnorlne
Reeommene'atlene
1
COLLECT AND REVIEW
APA INPUT INFORMATION
e Environmental
SELECT APA
SOPHISTICATION
o Screening
e Refined
EPA
Teohnleal
Oultfellnee
>A PLAN
Evaluate APA uaaortataty
CONDUCT APA
Quality Control
1
mguro 1-a. euporfund Air Pathway Analyaoa Technical Proootfuroa
aanoral format.
1-5
-------
Collect and review APA Input Information
• Select APA sophistication level
• Develop APA plan
Conduct APA
• Sunnarlze/evaluate results
• Evaluate need for additional analyses.
The following 1s a brief discussion of each of these procedural
steps.
Step 1 - Collect and Review Input Information—This Initial step
addresses the process of collecting and compiling existing Information
pertinent to previous site-specific APAs based on a literature survey. It
Includes obtaining available source, receptor, and environmental data.
Once the existing data have been collected, compiled, and evaluated, data
gaps carT be defined and a coherent monitoring plan or modeling plan
developed based on the site-specific requirements.
Step 2 - Select APA Sophistication Level—This step Involves the
selection of the APA sophistication level considering screening versus
refined monitoring and modeling techniques. This selection process
depends on program objectives as well as available resource and technical
constraints. Technical aspects that should be considered Include the
availability of appropriate monitoring and modeling techniques.
Step 3 - Develop APA Plan—This step Involves preparation of.an APA
plan. The APA should Include documentation of the selected technical
approach (e.g., nonrepresentatlve Input data, modeling Inaccuracies and
monitoring limitations). The application of Data Quality Objectives
(DQOs) will be an Important aspect In the development of an APA plan. The
selected approach should be based on EPA technical guidelines, as
available. The APA plan also facilitates peer review of the technical
approach and a formal process for approval of the APA by the RPM/EPM. The
peer review process may Involve EPA air experts or contractor support.
1-6
-------
Step 4 - Conduct APA—This step Involves the Implementation of the
APA plan developed during Step 3. The emphasis during Step 4 1s on
conducting the APA commensurate with appropriate QC measures and OQO
criteria. This also Involves documentation of' the APA process (to
facilitate the QC process and establish an Information base that may be
useful for APAs at other Superfund sites).
Step 5 - Summarize and Evaluate Results—This step Involves reviewing
data and evaluating APA results for validity. Additional components of
this step should Include (a) data processing; (b) preparation of
statistical summaries; (c) comparison of upwind and downwind concentration
results; and (d) concentration mapping. 1f possible. Estimates of data
uncertainties based on Instrument limitations and analytical technique
Inaccuracies should also be obtained and used to qualify air monitoring
results. Results can be compared to applicable or relevant and
appropriate (ARAR) air criteria and other Superfund health and safety
criteria. The results of Step 5 can also provide Input to the Superfund
risk assessment process.
This approach ensures that a common thought process and strategy are
used to plan and conduct APAs for Superfund application. As demonstrated
1n Sections 2-3, this general approach has been adapted for each of the
technical procedures presented 1n Volume IV.
1-7
-------
SECTION 2.0
ATMOSPHERIC DISPERSION MODELING PROCEDURE
2.1 OVERVIEW
Atmospheric dispersion modeling Is an air pathway analysis (APA) that
provides calculations of concentrations of air toxic contaminants at receptor
locations of Interest based on Input emission rate and meteorological data.
Atmospheric dispersion modeling for Superfund activities 1s an Integral part
of the planning and decision-making process as related to the protection of
public health and the environment. This section provides procedures for the
selection and application of atmospheric dispersion modeling approaches for
Superfund APAs.
The major Superfund APA dispersion modeling applications can be
summarized as follows:
Emission APAs: Dispersion models can be used to estimate
concentrations at receptors of Interest using Input emission rate
data based on air emission modeling. Dispersion models can also be
used to estimate concentrations at receptors of Interest using
Input emission rate data based on emission rate monitoring.
Confirmatory air monitoring APAs: Dispersion modeling can be used
to assist In designing an air monitoring program (I.e., to
determine appropriate monitoring locations and monitoring period)
as well as 1n Interpretat1ng and extrapolating monitoring results.
2-1
-------
Atmospheric dispersion models can be used for monitoring program design
applications to Identify offsite areas of high concentration relative to
actual receptor locations. High-concentration areas that correspond to
actual receptors are priority locations for air Bon1tor1ng stations.
Dispersion models can also be used to provide seasonal dispersion
concentration "patterns' based on available representative historical
meteorological data (either onslte or offsite). Dispersion patterns based on
modeling results can be used to evaluate the representativeness of the air
monitoring data collection period. Representativeness Is determined by
comparing the dispersion concentration patterns for the air monitoring period
with historical seasonal dispersion concentration patterns.
Frequently. 1t may not be practical to place air monitoring stations at
actual offsite receptor locations of Interest. However. It will be necessary
to characterize concentrations at these locations to conduct a health and
environmental assessment. In these cases, dispersion patterns based on
modeling results can be used to extrapolate concentrations monitored at the
Superfund site to offsUe receptor locations.
A summary of Superfund APA dispersion modeling recommendations and
objectives 1s presented In Table 2-1. These recommendations are presented as
a function of source classification and Superfund activities. Emission rate
Inputs for dispersion modeling applications should be based on technical
procedures presented 1n Volumes II and III. Meteorological modeling Input
data should preferably be based on an onslte monitoring program.
(Recommendations for the conduct of an onslte meteorological monitoring
program are discussed In Sections 2.2. and 3.0 of this volume). The
preferred dispersion model for Superfund APA applications Is the Industrial
Source Complex (ISC) model. This model can be used for estimating short-term
concentrations (I.e., the ISCST version) and long-term concentrations (I.e..
ISCLT version) for a variety of Superfund sources. Further discussions of
the dispersion model selection for Superfund APAs are Included 1n Sections
2.3 and 2.4. In addition, 1t Is recommended that an onslte capability be
developed to provide near real-time concentration estimates associated with
nonroutlne air releases. A combination of monitoring/modeling approaches 1s
2-2
-------
TABLE 2-1
SUNHWY OF DISKRSION MODELING RECMCIIMTKMS MB OUCaiVES
Source Classification
Dispersion Modeling Objectives
AM Recommendations
Superfuntf Activities
Uncontrolled source
Provide sufficient data base on
concentrations of air toxic contaminants
for performing a detailed risk assessment
of public health and the environment for
onslte, perimeter and offslte receptors for
the baseline conditions (no-action
alternative).
Provide sufficient data base on
concentrations of air toxic contaminants
for performing a detailed risk assessment
of public health and the environment for
onslte. perimeter and offslte receptors for
the various remedial alternatives.
Provide Input to the design of air
monitoring program step.
Characterize baseline air concentration
Obtain emission rate estimates based on
procedures presented In Volumes II and III.
Obtain meteorological Input data based on
an onslte monitoring program pursuant to
recommendations presented In Volume IV -
Section 3.0.
Conduct dispersion modeling based on
considering ISC as the preferred model for
Superfund APA applications.
RI/FS •
Screening/refined APA
Remediation source
Provide Input to the design of air
monitoring program for this step.
Provide air quality data to assess the
affects of the remedial action evaluated.
Characterize air concentration during
remedial/removal activities
- Obtain emission rate estimates based on
procedures presented In Volumes II and III.
- Obtain meteorological Input data based on
an onslte monitoring program pursuant to
recommendations presented In Volume IV -
Section 3.0.
- Conduct dispersion modeling based en
considering ISC as the preferred model for
Superfund APA applications.
Remedial design (pilot
field studies)
-------
TABLE 2-1
SWMMV OF DISPERSION NDKLING REOMCHMTiaiS MB OBJECTIVES (Continued)
Source Classification
Dispersion Modeling Objectives
APA Recommendations
Superfund Activities
Renedlatlon source
Provide Input to the design of air
monitoring program for this step.
Provide data on calculated concentrations
of air toxic contaminants for routine and
non-routine releases In support of
protecting workers, the public and the
environment•
Provide data as a component of the
emergency repsonse system employed at the
site to be used together with Measured
concentrations*
Provide calculated concentration data In
support of protective actions during the
remedial action activities.
Characterize air concentrations during
remedial/removal activities
Obtain emission rate estimates based on
procedures presented In Volumes II and HI.
Obtain meteorological Input data based on
an onslte Monitoring program pursuant to
recommendations presented In Volume IV -
Section 3.0.
Conduct dispersion modeling based on
considering ISC as the preferred model for
Superfund APA-applications.
Develop/Implement a site-specific APA
emergency field guide based en a combined
monitoring/modeling approach to obtain near
realtime dispersion estimates (see example
1n Appendix C).
Reaedlal actions
(full-scale
operations)
Controlled source
Provide air quality data base at the site
perlMeter and offslte as a part of
assessing the effectiveness of the renedltl
action iMpleMented.
Provide air quality data base at the site
perlMeter and offslte to demonstrate the
protection of public health and the
env1ronMent.
Confirm controlled source air concentrations
Obtain emission rate estimates based on
procedures presented In Volumes II and III.
Obtain meteorological Input data based on
an onslte monitoring program pursuant to
recommendations presented In Volume IV -
Section 3.0.
Conduct dispersion modeling based on
considering ISC as the preferred model for
Superfund APA applications.
Operation and
Maintenance
(post-remedial
activities)
-------
recommended to provide this capability. An example of this approach 1s
provided 1n Appendix C.
The recommendations and objectives presented 1n Table 2-1 and throughout
Section 2.0 have been specified based on consideration of Superfund
applications (which are frequently quite different from typical air
permitting/regulatory applIcatlons).
Atmospheric dispersion modeling for Superfund activities Includes a mix
of sources that. In general, are different 1n configuration and
characteristics from the sources traditionally modeled for air permitting
applications. The traditional sources modeled for air permitting
applications are usually point sources (e.g., stacks) emitting combustion
products such as sulfur dioxide, nitrogen oxides, carbon dioxide, and
partIculate matter.
In contrast, the Superfund activities Include mainly fugitive-area,
volume, and line sources, and, to a small extent, point sources. A 11st of
the types of sources associated with the various Superfund activities 1s
presented 1n Table 2-2. Superfund-area sources generally Include landfills,
lagoons, contaminated soil surfaces, and solidification/stabilization
operations. Volume sources Include structures within processing facilities,
tanks, and containers. Line sources Include, In general, paved and unpaved
roads, and point sources Include air strippers, Incinerators, and 1n situ
venting operations. Most Superfund sources are considered ground-level or
near-ground-level, nonbuoyant releases. In general, traditional sources are
considered elevated, buoyant releases
In addition, compared with air emission from traditionally modeled
sources. Superfund activity emissions exhibit more Involved and complex
processes that govern the rate and type of air emissions. Air emissions from
Superfund activities could be continuous or Intermittent releases, or a one-
time release over a defined period of time. The releases can be routine or
nonroutlne due to an unusual event that could occur during the source
remediation. Both gas and partlculate emissions could be Involved. The gas
emissions Include volatile and semlvolatlle constituents, and .line
partlculate emissions Include semlvolatlle, base neutrals, metals and other
2-5
-------
PO
0»
TABLE t-f
SOURCES ASSOCIATED WITH SUPERHMD ACTIVITIES MO THEIR OttRACTERISTICS
Superfund Source
• Landfills
• Lagoons
• Contaminated soil
• Containers
• Process
• Storage Tanks
Remediation sources
• Soil handling
• Air stripper*
• Incinerator*
Source
Configuration*
Fugitive area
fugitive area
fugitive area
fugitive area,
VOlUK
fugitive area.
voluw line, point
fugitive area
fugitive area
VOllflK
point, volime
point, voluw
Important Air Emission Mechanises
Gas Phase
volatilization.
blodegradatlon
volatilization.
blodegradatlon
volatilization.
blodegradatlon
volatilization.
blodegradatlon
volatilization,
coabustlon
volatilization
volatilization
volatilization
conbuttlon
Partlculate Phase
Hind erosion,
•echanlcal disturbances
wind erosion.
•echanlcal disturbances
wind erosion.
•echanlcal disturbances
•echanlcal disturbances
wind erosion.
•echanlcal disturbances
Hind erosion.
•echanlcal disturbances
coabustlon
coabustlon
Cailsslon Node
Gas Phase
continuous
continuous
continuous.
Internment
continuous.
Intermittent
continuous.
Intermittent
i— ^— ^— — ^
Partlculate
Phase
Interalttent
Interalttent
continuous
continuous
Routine/
Nonroutlne
Release
routine/
nonroutlne
routine/
nonroutlne
routine/
nonroutlne
*Snal1 stacks where plwe Is frequently In the dowmash cavity.
-------
TABLE 2-2
SOURCES ASSOCIATED UITN SUPERFUNO ACTIVITIES AMI THEIR CHARACTERISTICS (Continued)
Superfund Source
• In-sltu venting
• Solidification/
Stab llzatlon
Controlled sources
• Landfills
• Lagoons
• Soil surfaces
• Containers
Source
Configuration*
fugitive area
fugitive area.
volume
fugitive area
fugitive area
fugitive area
fugitive area.
volime
Important Air Emission NechanlSK
Gas Phase
volatilization
volatilization
volatilization.
blodegradatlon
volatilization.
blodegradatlon
volatilization.
blodegradatlon
volatilization.
blodegradatlon
Partlculate Phase
--
Mind erosion.
mechanical disturbances
Mind erosion.
•echanlcal disturbances
Mind erosion.
•echanlcal disturbances
Mind erosion.
•echanlcal disturbances
•echanlcal disturbances
Emission Node
Gas Phase
continuous.
Internment
continuous.
Internment
continuous
continuous
continuous
continuous
Partlculate
Phase
-•
Internment
Intermittent
Intermittent
Intermittent
Intermittent
Routlne/Nonr
outlne
Release
routine/
nonroutlne
routine/
nonroutlne
routine
routine
routine
routine
• most superfund sources are ground level or near ground level nonbuoyant releases
-------
Inorganic constituents. Table 2-1 lists the general type of gas and
participate emissions associated with various Superfund activity sources as
well as the anticipated nature of the release.
The factors discussed above clearly Imply that many of the currently
employed air dispersion models for traditional sources, as outlined 1n the
U.S. Environmental Protection Agency's (EPA's) Guidelines on Air Quality
Models (Revised) (EPA-450/2-78-027R. July 1986). have very little application
to the Superfund APA. Only a limited number of models 1n the EPA Guidelines
are applicable to the Superfund APA, as discussed 1n subsequent sections. It
1s therefore Important to define the sources Involved, their configuration.
and their characteristics before a suitable model 1s selected.
It can also be concluded that the added complexity of air dispersion
modeling for Superfund activities 1s mainly associated with estimating
emission rates for the specific source under consideration. It 1s therefore
vital to develop emission Inventory data for the sources Involved based on
the procedures outlined 1n Volumes II and III of this Guideline for
uncontrolled sources, remediation sources, and controlled sources. It 1s
also critical to subdivide large-area sources to smaller sources 1n
accordance with the guidelines provided 1n this section to provide for a
reasonably accurate simulation of air releases, transport, and dispersion.
Although some of the emissions from Superfund activities Include reactive
constituents, they are handled 1n this section as passive constituents. This
1s a reasonable approximation because the source-receptor distances Involved
do not exceed 10 to 15 kilometers and the plume travel time for these
distances ranges from less than 1 hour to 1 or 2 hours.
The various technical factors discussed above will be further elaborated
on 1n Sections 2.2 through 2.6.
The procedures for atmospheric dispersion modeling APAs presented In
this section are based on a five-step process (Illustrated 1n Figure 2-1):
Step 1 - Collect and review Input Information
Step 2 - Select modeling sophistication level
• Step 3 - Develop modeling plan
2-8
-------
APA
VOM. u A in
••view
a aaurea Data
Data ••«
Bfflrtramnaiital
Data
Available.
Monitoring
Data
SELECT MODEL
CLASS AND SOPHIS-
TICATION LEVEL
e Soroonlng
e Roflnod
EPA
Modeling
Quldollnoa
a aVaiwata
EPA
RovlowX
Approval
aUMMAIUZBXBVALUATB
a Prapan
auMMartaa
Uneartalnty
l_
INPUT TO
OBCMION
a-1. aup«rfund Air Pathway An«ly«»« Olaparalon Medallng
Protocol.
2-9
-------
• Step 4 - Conduct modeling
Step 5 - Summarize and evaluate results
Additional technical discussion on dispersion modeling 1s found 1n the
EPA's Guidelines on Air Quality Models.
The following 1s a brief discussion of each of these steps. An expanded
discussion 1s presented 1n the following subsections.
Step 1 - Collect and Review Incut Information—This Initial step
addresses the process of collecting and compiling existing Information
pertinent to the air dispersion modeling based on a literature survey. It
Includes obtaining available source, receptor, and environmental data (land
use classification, demography, topography, meteorology, and others). Once
the existing data have been collected, compiled, and evaluated, data gaps can
be defined and a coherent dispersion modeling plan developed based on site-
specific requirements.
Step 2 - Select Modeling Sophistication Level—This step Involves
selection of the dispersion modeling sophistication level considering
screening and refined modeling techniques. This selection process depends on
program objectives as well as available resource and technical constraints.
Screening models generally use limited and simplified Input Information to
produce a conservative estimate of exposure. Use of a screening model allows
for an Initial determination of whether the Superfund site or site activity
will present an air pathway problem. If a problem Is detected after
screening modeling has been performed, or a determination 1s already made
that an air pathway problem must be addressed, the emission sources should
then be evaluated with either a more sophisticated screening technique or a
refined model. Technical aspects that should be considered Include the
availability of appropriate modeling techniques for the Superfund 11st of
toxic constituents. Modeling approaches should be evaluated considering site
specific factors, Including source configuration and characteristics,
applicability, limitations, performance for similar applications, and
comparison of advantages and disadvantages of alternative modeling methods.
2-10
-------
Step 3 - Develop Modeling Plan—This step Involves preparation of a
dispersion modeling plan. Elements that should be addressed 1n the plan
Include (a) overview of the Superfund site area, (b) selection of
constituents to be modeled, (c) modeling methodology (emission Inventory.
meteorology, receptor grid, rural/urban classification, models to be used,
concentration averaging time, and special situations such as wake effects).
and (d) documentation of the air modeling plan.
Step 4 - fondue! Modeling—This step Involves the actual activities of
conducting air dispersion modeling for a Superfund site. It Includes the
following: (a) develop emission Inventory, (b) preprocess and verify model
Input data (emission Inventory, meteorology, receptor grid, and others), (c)
set model switches, (d) run model test cases, (e) perform dispersion
calculations, and (f) obtain printout of modeling Input and output.
Step 5 - Summarize and Evaluate Results—This step Involves reviewing
and assessing the dispersion modeling results. Additional components of this
step should Include (a) preparation of data summaries, (b) concentration
mapping (Isopleths), (c) estimation of uncertainties, and (d) assessment.
2.2 STEP 1 - COLLECT AND REVIEW INPUT INFORMATION
2.2.1 Overview
The first step In Implementing an air dispersion modeling analysis Is
the compilation and evaluation of available Information. A summary of this
process 1s presented 1n Figure 2-2.
Careful selection of Input for dispersion modeling for a Superfund APA
1s critical for meaningful results. Input data requirements Include source,
receptor, and environmental data—specifically, emission Inventories, source
characteristics, meteorology, and the receptor grid. It 1s therefore
paramount to collect Input data that meet the following basic objectives of
dispersion modeling calculations:
High accuracy of data to the extent possible and practicable
Sound methods and assumptions used to derive the Input data
2-11
-------
SOURCE DATA
e Slta Layout Map
e Source Specifications
e Contaminants List
o Toxlolty Faotora
o Offalto Soureoa
RECEPTOR DATA
o Population Distribution
o Sensitive Raeaptora
o Slta Work Zonaa
o Local Land Uaa
ENVIRONMENTAL DATA
o Olaparalon Data
o Climatology
o Topography
o Soil and Vagatatlon
PREVIOUS APA DATA
o Meteorologies!
Monitoring Dsts
e •mission Hate ModellngX
Monitoring
s Air Monitoring
s ARAM Summery
COLLECT
AVAILABLE
INFORMATION
COMPILE
AND
EVALUATE
INFORMATION
(TABLE 2-3)
INPUT
TO
STEP 2 - Salaet Monitoring
Sophistication Laval
AND
STEP 3 - Davalop Monitoring
Plan
Figure 2-2. 8t«p 1 • Collect and Movlow Input Information.
2-12
-------
The following Information, at a minimum, should be collected and
reviewed to support the air modeling program design:
Source data
• Receptor data
• Environmental data
This type of Information serves a dual purpose:
It provides an overall understanding of site-specific features that
can affect dispersion modeling
It provides the necessary Input to drive the dispersion model
Most of the site-specific Information required for Step 1 1s available
from the Superfund Remedial Project Manager/Enforcement Project Manager
(RPM/EPM). The quality of available Information will depend on the nature
and extent of the previously performed studies. For example. Information
available at the Initiation of the Remedial Investigation/Feasibility Study
(RI/FS) may be limited 1n nature. However, Information available for the
Implementation of remedial actions may be very thorough depending on the
level of effort and extent of the RI/FS. In any event, available Information
and data should be evaluated for the following factors:
Data quality objectives (DQO) for this study
Technical soundness of methodologies employed
Completeness and quality of the data
Quality assurance/quality control (QA/QC) 1n support of the
Information gathered
Compatibility and applicability of the data
Data gaps
Supplemental Information gathered through a literature search 1s
available from records and documents from sources such as the following:
National Weather Service
U.S. Environmental Protection Agency
2-13
-------
• State and local agencies
• Contractor studies
• Other Federal government offices
The Information collected during Step 1 should 'be documented using a
form similar to the example presented In Table 2-3. This form should be used
to Identify and evaluate available data. In addition, copies of data
summaries should be attached to the form to provide a convenient, complete
documentation package.
The following subsections provide a further discussion of the various
types of data that should be collected during Step 1.
2.2.2 Source Data
Site-specific Information on the nature and extent of the contamination
1s critical for estimating the magnitude of air emissions from each of the
sources and 1n defining the primary emission constituents. In addition.
Information on source configuration 1s vital. As discussed 1n Section 2.1
and summarized 1n Table 2-1, area sources constitute the majority of sources
1n a typical Superfund site. In general, the areas Involved range from small
(e.g., a fraction of an acre) to large (tens of acres), and their division by
source characteristics and size could be critical to the success of this
modeling analysis. The data should be available from the Superfund RPM/EPM.
Specific Information that should be collected, evaluated, and prepared as
Input Into the dispersion model Includes the following:
• Number and type of sources at the site and their locations based on
past site activities and Information on the extent of
contamination. (Example sources are lagoons, drainage ditches,
landfills, processing facilities, Incinerators, air strippers, and
roads.) The temporal and spatial variability of these sources
should also be addressed. Source variability 1s an extremely
Important consideration for Superfund APAs. In particular,
emission/source conditions during remediation can vary
significantly.
2-14
-------
TABLE 2-3. EXAMPLE - SUPERFUND AIR DISPERSION MODELING INPUT INFORMATION FORM
Data Type
Sour£e Da(a
• Site Layout Map
• Contaminants List
• Emission Inventory
• Contaminant Toxlclty
Factors
• Offslte Sources
Receptor Data
• Population Distribution
Nap
• Identification of
Sensitive Receptors
• Site Work Zones Map
• Local Land Use
Environmental Data
• Dispersion Data
- Hind Direction/Wind
Speed
Data Obtained
(Yes or No)
(Attachment
No.)
Evaluation Factors
Technical
Methods
Employed
Acceptable
(Yes or No)
Completeness
and Quality
of Data
Acceptable
(Yes or No)
QA/QC
Appropriate
(Yes or No)
Data
Relevant for
this
Application
(Yes or No)
Data Gaps
Significant
(Yes or No)
Comments
•
I
»-•
Ul
-------
TABLE 2-3. EXAMPLE - SUPERFUND AIR DISPERSION MODEL IKG INPUT INFORMATION FORM (Continued)
Data Type
Environmental Data (Cont'd)
• Climatology
- Temperature
- Humidity
- Precipitation
• Topographic Haps
- Site
- Local Area
• Soil and Vegetation
Previous APA Data
• Emission Rate Modeling
• Emission Rate Monitoring
• Dispersion Modeling
• Air Monitoring
• ARAR Summary
Data Obtained
(Yes or No)
(Attachment
No.)
Evaluation Factors
Technical
Methods
Employed
Acceptable
(Ves or No)
Completeness
and Quality
of Data
Acceptable
(Yes or No)
QA/QC
Appropriate
(Yes or No)
Data
Relevant for
this
Application
(Yes or No)
Data Gaps
Significant
(Yes or No)
Comments
O»
-------
Configuration and classification (based on Information presented 1n
Table 2-2 and site-specific considerations) of sources such as area
(e.g.. lagoons, landfills), volume (e.g., processing facilities,
tanks), line (e.g., roads, drainage ditches), and point (e.g.,
Incinerator and air stripper stacks).
Dimensions of each area, volume, and line source. Including the
shape of sources (e.g., 1s the area source a rectangle, triangle,
or other shape, does the line source constitute a straight or
curved line) and the portions of a line source that do not have
emissions. Nonsquare-area sources have to be approximated by a
square for use 1n the dispersion model. If the square covers a
large area, It may be advisable to subdivide 1t Into smaller
squares 1f calculated concentrations are required at short
distances from the source. Similarly nonregular-volume sources
have to be approximated by a cube and nonregu1ar-shaped-11ne
sources have to be approximated by minimizing the curvatures
Involved.
Stack parameters, Including stack height, exit diameter, exit
velocity, and exit temperature for point sources.
Identification of constituents associated with each source grouped
as organic* (volatile*, semivolatlies, base neutrals, pesticides,
polychlorlnated blphenyls (PCBs), and Inorganics (metals and other
toxic compounds (HgS, HCN, etc]).
Physical and chemical characteristics of the constituents Involved,
Including density relative to air (for gaseous- emissions) and
particle size distribution (for part1culate emissions).
Estimated typical long-tern emission rates and typical as well as
maximum short-term emission rates for each source under
consideration. The emphasis for Superfund APAs 1s to define, as
practical, realistic source Input data for dispersion modeling
purposes. For Superfund APA applications the uncertainties
associated with the Input data as well as the accuracy of the
2-17
-------
dispersion model are considered during the data Interpretation
stage. This Is different from air quality permitting applications
for traditional sources, which are generally based on conservative
source emission assumptions. The methods to estimate emission
rates for various undisturbed and disturbed 'sources at a Superfund
site are presented 1n Volume II and III. repectlvely. of this
document. These volumes provide guidance on methods and protocols
for estimating the emissions from various types of sources
utilizing direct emission measurement techniques, Indirect emission
measurement techniques, air monitoring techniques, emissions
predictive models, and mass balance calculations.
Table 2-4 represents an example of Input requirements for various source
categories. As noted 1n Section 2.1, 1n contrast to conventional air
emission sources that are considered mainly as point sources, Superfund
sources consist mainly of area, volume, and line sources. Only a limited
number of cases Include point sources, mainly during remedial cleanup
activities. It 1s therefore Important to define the source configuration and
to best approximate Its shape to the shape acceptable by the employed
dispersion model.
2.2.3 Receptor Data
Receptor data that correspond to data used for the Superfund risk
assessment process should be Identified. These data will provide the basis
for specifying a calculatlonal (receptor) grid for Superfund APA dispersion
modeling application.
Specific receptor Information that should be collected and evaluated
before the selection of the receptor grid Includes the following:
• Population distribution by 22.5-degree sectors 1n 2-kilometer
Increments for a distance of 10 kilometers from the site 1f "total
risk" 1s to be considered
Sensitive receptors within 10 kilometers of the site and Individual
residences and buildings within 1 kilometer of the site
2-18
-------
TABLE 2-4
EXAMPLE OF INPUT REQUIREMENTS FOR VARIOUS SOURCE CATEGORIES
Input
Parameter
Source
location
Source
dimension
Source
emission rate
for each
constituent
under
consideration
Adjacent
obstructions
Initial
dilution
Particle mass-
size distri-
bution and
deposition
velocity
Source Category
Point
Coordinates of
the point (m)
Stack height
(m), exit
diameter (m),
exit velocity
(m/sec), exit
temperature
(OK)
Mass per unit
time
Height (m),
width (m),
length (m)
Line
Coordinates of
the center of
the line (m) .
Length (m),
width (m),
height (m)
Mass per unit
time per unit
length, or
mass per unit
time 1f
simulated by
an array of
Volume sources
"~
Initial
horizontal and
vertical
dimensions (m)
Area
Coordinates of
the southwest
corner of the
area
approximated
by a square
(m)
Width of the
square area
source (m)
Mass per unit
time per unit
area
— •
Initial
horizontal and
vertical
dimensions (m)
Volume
Coordinates of
the center of
the source (m)
Height of the
volume source,
(m), width (m)
Mass per unit
time
^—
Initial
horizontal and
vertical
dimensions (m)
Fraction of mass 1n each size group
Average deposition velocity for each mass size group (m/sec)
2-19
-------
Site work zones as Identified 1n the Health and Safety Plan
• Local land use characterization (e.g.. residential, commercial)
within 3 kilometers of the site
Sensitive receptor locations Include schools and hospitals associated
with sensitive population segments, as well as locations where sensitive
environmental flora and fauna exist, Including parks, monuments, and forests.
2.2.4 Environmental Characteristics
Information on environmental characteristics pertinent to a Superfund
site 1s a necessary component for defining air pathway exposure potential.
In the case of dispersion modeling, the environmental characteristics serve
as key Input to the modeling calculations. Environmental characteristics
that should be evaluated and assessed prior to the Implementation of air
dispersion modeling Include the following:
Climate (historical summaries from available onslte and offslte
sources)
Annual and monthly or seasonal wind roses
Annual and monthly or seasonal tabular summaries of mean wind
speeds and atmospheric stability distributions
Annual and monthly or seasonal tabular summaries of
temperature and precipitation
• Meteorological survey results
Hourly listing of all meteorological parameters for the entire
monitoring period
Daytime wind rose (at coastal or complex terrain sites)
N1ght1me wind rose (at coastal or complex terrain sites)
2-20
-------
Sunnary wind rose for all hours
Summary of dispersion conditions for the Monitoring period
(joint frequency distributions of wind* direction versus wind
speed category and stability class frequencies)
Tabular summaries of means and extremes for temperature and
other meteorological parameters
Definition of soil conditions (for landfills and contaminated soil
surfaces)
Narrative of soil characteristics (e.g.. temperature, porosity
and organic matter content)
Characterization of soil contamination conditions (e.g., 1n
waste piles and land treatment units)
Definition of site-specific terrain and nearby receptors
Topographic map of the area within 10 kilometers of the site
(U.S. Geological Survey 7.5-mlnute quadrangle sheets are
acceptable)
Maps that Indicate the location of the nearest residence for
each of the sixteen 22.5-degree sectors that correspond to
major compass points (e.g.. north, north-northwest), the
nearest population centers, and sensitive receptors (e.g.,
schools, hospitals and nursing homes)
Maps showing the topography of the area, the location of the units
of concern, and the location of meteorological monitoring equipment
A narrative description of the meteorological conditions during the
air sampling periods, Including qualitative descriptions of weather
events and precipitation, which are needed for data Interpretation
2-21
-------
Sensitive environmental areas (e.g.. wildlife preserves, parks,
etc.)
Like emission Inventory and source data, meteorological data are another
key component of the basic data required as an Input Into the dispersion
model. In searching for meteorological data, 1t Is Important to consider the
following factors:
Meteorological data drive the dispersion model and govern the
advectlon and dispersion of contaminants released from a source.
It 1s therefore Important to utilize data that are considered
representative of the site area and vicinity.
• The length of record for the data base should be considered to
avoid a potential bias 1n the dispersion calculations. A minimum
of 1 year of data are required to run most refined dispersion
models, with 5 years being preferred. If long-term risk 1s the
Issue a meterologlcal data period longer than 5 years may be
deslreable to characterize the expected exposure period.
The deployment of an onslte meteorological program 1s recommended as a
part of the Superfund project planning phase. Although data collected from
an onslte meteorological station may not have the long record required for
their direct use 1n dispersion calculation, their benefits are substantial
because
They contain site-specific data that could be used to assess the
correlation with offsite meteorological data and the applicability
of the offslte data to the site under consideration.
They contain site-specific data showing the diurnal variation of
the meteorological parameters affecting plume advectlon and
dispersion.
2-22
-------
They contain vital site-specific Information on topography-Induced
flow. Including drainage and valley flows and the effect of water
bodies on wind flow. Including coastal zone flow.
Therefore. 1t 1s recommended that an onslte meteorological monitoring
program be Initiated Immediately after a site 1s Included on the National
Priorities List (NPL) 1f representative data are not available from the
National Weather Service. (In general, National Weather Service data will be
representative of site conditions for simple, flat-terrain settings.) The
meteorological monitoring program should continue throughout the post-NPL
phases. Elements of an onslte meteorological program (e.g., recommendations
on the number and siting of meteorological stations) for a Superfund site are
discussed 1n Section 3.0 of this volume.
Dispersion meteorological and cllmatologlcal data available from a
National Weather Service (NWS) station or other suitable offslte source
should be utilized. From a practical viewpoint. NWS data should be
considered 1n most applications, since such data are subject to reasonable
QA/QC programs and are processed by the National Climatic Center for use 1n
dispersion models. Data available from state or Industrial facilities should
be evaluated for their applicability, the availability of parameters needed
for Input Into the dispersion calculations, and the QA/QC programs they have
been subject to. In any event, dispersion meteorological and cllmatologlcal
data should be obtained from a station that 1s considered representative of
the general dispersion characteristics of the site. Factors such as
proximity, topography, the existence of water bodies, and urban/rural
Influences should be considered 1n assessing the applicability of the
meteorological data to the site under consideration.
Data available from the NWS are collected from either 7- or 10-meter
towers. These heights are considered applicable for most Superfund low-level
sources. Data from NWS stations are also applicable to the potential
elevated releases, either directly or through the use of wind power law
profiles.
Table 2-5 provides a summary of meteorological data for use 1n
dispersion modeling for Superfund APAs.
2-23
-------
TABLE 2-5
A SUMMARY OF INPUT METEOROLOGICAL DATA FOR USE IN DISPERSION MODELING
FOR SUPERFUND APAs
Input Meteorological Data
Source
Length of Record
I. Superfund Step: RI/FS.
Remedial Design, Operation and
Maintenance
Hourly average wind speed
Hourly average wind direction
Hourly average atmospheric
stability
Minimum and maximum dally
mixing heights
Hourly ambient temperature
NWS
State
Industlral
Facilities
(onslte)
• one year
minimum
• five years
preferred
(a longer data
set may be
appropriate
depending on the
potential
exposure period)
II. Superfund Step:
Action
A-Routine Releases
Remedial
Hourly average wind speed
Hourly average wind direction
Hourly average atmospheric
stability
Hourly ambient temperature
Estimated mixing height
Onslte
Meteorological
Program
N/A
B-Non Routine Releases
!5-m1n. average wind speed
15-mln. average wind direction
15-min. average atmospheric
stability
15-mln ambient temperature
Estimated mixing height
Onslte
Meteorological
Program
N/A
2-24
-------
Topographic features and water bodies can affect the dispersion and
transport of airborne toxic constituents. It Is therefore Important to
understand local wind flows and to Identify areas with topography and/or
water bodies that might Influence the dispersion and transport of
constituents released from the site. For example, a site located downslope
of an elevated terrain feature might be affected by diurnal drainage flows.
Terrain heights relative to release heights will affect ground-level
concentrations. Terrain obstacles such as hills and mountains can divert
regional winds. Valleys can channel wind flows and also limit horizontal
dispersion. In addition, complex terrain can result 1n the development of
local diurnal wind circulations and affect wind speed, atmospheric
turbulence, and stability conditions. Although difficult to model, such
situations should be recognized and quantified to the extent possible as part
of the dispersion modeling analysis. Topographic maps of the facility and
adjacent areas are needed to assess local and regional terrain. The utility
of an on-site meteorological program also becomes apparent In these
situations.
Large water bodies can also affect atmospheric stability conditions and
the dispersion of air contaminants. In general, large water bodies tend to
Increase the stability of the atmosphere 1n the air layer adjacent to the
water, thus reducing the dispersion of air contaminants. Local diurnal wind
patterns may also be present seasonally at coastal locations. Again, onslte
meteorological data can be used to Identify and characterize these local wind
patterns.
Soil characteristics and conditions can affect air emissions from
Superfund sites and the wind erosion of contaminated surface soils. It 1s
therefore Important to understand soil conditions such as porosity, silt
content, particle size distribution, soil type, and source data.
Surface obstructions, Including structures, trees, and vegetation, could
affect air flow by generating wake effects or Increasing plume dispersion due
to surface roughness. It 1s therefore Important to obtain pertinent
Information for use In the dispersion,modeling.
2-25
-------
2.2.5 Previous APA Data
Previous air quality data that address calculated air concentrations of
constituents known to exist at the site can provide Insight Into existing
levels of air toxic constituents of Interest. Compound-specific Information
will be useful 1n assessing what Indicator compounds should be modeled and
what nodellng methodologies should be employed. Site-specific Superfund
documents (e.g.. site Investigations (Sis). RI/FSs. records of decision
(ROOs). etc.) should be reviewed to Identify available APA Information.
Results of existing dispersion calculations should be evaluated for
acceptability and representativeness before use. Factors to be evaluated
Include
Dispersion modeling techniques employed. These Include modeling
sophistication level (I.e.. screening or refined).
Input data used 1n the modeling. Including emission Inventory.
meteorology, and receptor grid.
Assumptions used to develop the Input data base, the quality of
data used, and their applicability to the case under consideration.
Number of compounds modeled for and the assumptions Involved.
Assessment of the quality of the dispersion modeling analysis.
Existing air monitoring.data for the site area can be used 1n designing
the receptor grid and selecting compounds to be modeled. These data can also
be used In evaluating the performance of dispersion modeling by comparing
calculated with measured air concentrations. Most Importantly, they can
provide Insight on existing background concentrations.
High accuracy of data to the extent possible and practicable
• Sound methodology and assumptions used to derive the Input data
2-26
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2.3 STEP 2 - SELECT MODELING SOPHISTICATION LEVEL
2.3.1 Overview
Selection of the dispersion modeling sophistication level and model Is
the cornerstone for a meaningful Superfund APA. A summary of this process 1s
presented 1n Figure 2-3. Coupled with the sophistication level Is the
applicability of the model to the Superfund site and activity Involved and
Us ability to reasonably simulate transport and dispersion of air toxic
contaminants from the sources Involved. The appropriate model
sophistication, applicability, and capabilities will depend on the following
factors:
Source-specific APA recommendations presented 1n Volume I
• Superfund dispersion modeling objectives
Data quality objectives for the dispersion modeling activities.
• Input data from Step 1
Legal and liability aspects of the Superfund project
• Pragmatic aspects of the program
Availability of good quality Input data and the constraints
Involved
Applicability of existing dispersion models to site-specific
characteristics
Ability of existing dispersion models to reasonably simulate
the transport and dispersion of air toxic contaminants
released from the site, considering physical and chemical
factors and processes Involved
2-27
-------
SOURCE-SPECIFIC
APA
RECOMMENDATIONS
(Volume I)
STEP 1 - INPUT
DATA
(Section 2.2)
AIR MODELING
OBJECTIVES
(Table 2-1)
AVAILABILITY
OF APPROPRIATE
MODELING
TECHNIQUES
(Tables 2-6 end 2-7)
MODELING
SOPHISTICATION
(Figure 2-4)
STEP 3 -
INPUT
TO
D«v*lop Modeling
Plan
Flour* 2-3. Step 2 - 8*l*et Modeling Sophistication L*v»l.
2-28
-------
Ability to accomplish the dispersion modeling objectives with
modest uncertainties, and the availability of the required
resources.
Source-specific APA recommendations have been presented In Volume I. as
referenced In Figure 2-3. These recommendations are based on a standard
sequence of APAs, as Illustrated 1n Figure 2-4. The APA strategy presented
1n Figure 2-4 1s based on the premise that Initially a screening APA should
be conducted. The need for a refined APA Is then determined based on an
evaluation of screening results considering the potential to exceed health
criteria (as Indicated by the Hazard Index) and modeling Inaccuracies (as
Indicated by the Uncertainty Factor).
The Hazard Index (HI) for systemic toxicants 1s determined as follows:
n
HIT = r
1=1
where
EI = exposure level of the 1th toxicant
ALi = maximum acceptable level for the 1th toxicant
n = total number of toxicants
The HI for carcinogens (Hie) 1s similar:
Hie = i — — (2'2)
J-l DRJ
where
Ej = exposure level of the jth carcinogen
DRj • dose at a set level of risk for the Jth carcinogen
m = total number of carcinogens
2-29
-------
CONDUCT
SCREENING
APA
EVALUATE
HAZARD INDEX
AND MOOEUNd
UNCERTAINTY FACTORS
CONSIDER
MODELING
DETECTION
LIMITS
CONDUCT
REFINED
APA
1
EVALUATE
HAZARD INDEX AND
MODELING
UNCERTAINTY FACTORS
(••• Flgur* 2-6)
INPUT TO
'A I
Ml
Flflur* 2-4.
a«l«otlon of
Mod»ltng.
V»r«u« R*fln«d Ol»p«r»lon
2-30
-------
If any calculated HI exceeds unity (I.e., 1), then health criteria may
be exceeded. However. 1t 1s also necessary to consider the uncertainty of
modeling results. Because of these uncertainties, the air concentrations and
associated HI values could represent underestimates or overestimates of the
true HI value. Therefore, as Indicated 1n Figure 2-5, It Is necessary to
compare HI values and Uncertainty Factor (UF) values to determine the
adequacy of APA results to provide exposure Input data to characterize the
potential health Impact of Superfund air emission sources.
Based on Figure 2-5, 1t may be appropriate to conduct refined modeling
follow-up to screening modeling If Information Is not sufficient to
definitively characterize the results. Consider the following example:
• HI = 2 based on screening modeling results (I.e.,
predictions Indicate that health criteria will be
exceeded by a factor of 2)
UF » ±5 for modeling results, considering the combined
uncertainty 1n the Input data and the model (I.e.,
modeling results may overestimate or underestimate
air concentrations by up to a factor of 5)
For this case the HI value can be characterized as follows:
UF>HI>1/UF (2-3)
which 1s equivalent to
5.0>2.0>0.2 (2-4)
Therefore, for this example, based on the evaluation criteria presented
In Figure 2-5, It Is warranted to consider the conduct of refined air
modeling to confirm modeling results.
The dispersion modeling objectives for specific Superfund activities
(e.g., RI/FS, remedial action) are also Important Input for the selection of
modeling sophistication levels. These activity-specific objectives have been
summarized 1n Table 2-1. Input from the RPM/EPM should be obtained to
2-31
-------
AIR PATHWAY ANALYSES
MODELING/MONITORING
RB8ULT8
COMPUTE
HAZARD INDEX
CHI)
UMeiftTAIMTV FACTORS
CSWW*
HI > UF
UP > HI > 1/UP
HI
1/UF
Information !•
Sufficient To
Cnaraotorlso
Roloaao As
Significant
Information !•
Not Sufficient
To Definitively
Chsrsetorlzf)
Tho Roloaao
Information la
Sufflolont To
Cnaraotorlza
Roioaao Aa
Inaignlfloant
INPUT TO
EPA REMEDIAL/
REMOVAL
DECISION
MAKING
ADDITIONAL
AIR PATHWAY
ANALYSES SHOULD
BE CONSIDERED
INPUT TO
EPA REMEDIAL/
REMOVAL
DECISION
MAKING
• UF Is aaumod to bo <. 1.O
Flgura 2-6. evaluation of Hazard Indax and APA
Uncertainty Faetora
2-32
-------
confirm site-specific dispersion modeling objectives and to ensure that the
dispersion modeling level selected Is consistent with these objectives.
The availability of appropriate meterologlcal data and modeling methods
1s probably the most significant factor for the modeling sophistication level
decision-making. Synthesized meterologlcal data are generally limited to
screening modeling while actual meterologlcal data are appropriate for
screening applications. The capability of dispersion models to reasonably
simulate the transport and dispersion of air toxic contaminants released from
a Superfund site will dictate how far to carry dispersion modeling.
2.3.2 Selection of Models as a Function of Sophistication Levels
A1r dispersion models are employed 1n a wide range of air quality
studies to provide spatial and temporal fields of calculated concentrations
due to air emissions from various existing and proposed sources. The
calculated concentrations are used to fill data gaps generated by air
monitoring programs that cannot provide measured concentrations at a large
number of locations. Dispersion models provide a concentration field based
on the use of a large number of receptors and consideration of a wide range
of scenarios. As such, air dispersion models serve as a vital tool 1n
assessing compliance with regulations for existing and proposed sources.
They also are used extensively 1n the regulatory development process.
The air dispersion models utilized 1n air regulatory studies can
conveniently be grouped Into four classes: Gaussian, numerical, statistical
or empirical, and physical. Of these four classes, the Gaussian models are
the most widely used because of their simple formulation, ease of
understanding, and their ability to simulate the transport and dispersion of
air contaminants for a large number of applications. Most of the Gaussian
dispersion models employed 1n air quality studies are point source models.
They are the dominating tools In all air regulatory applications, as noted 1n
the EPA's Guidelines on A1r Quality Models. The four classes are based on
the following:
2-33
-------
• Gaussian models are based on the assumption that plume dispersion
1n the crosswlnd and vertical directions follows a Gaussian
distribution In a uniform wind field.
• Numerical models Include the continuity, •momentum, and energy
equations that are solved numerically using various techniques.
Plume transport Is 1n a nonunlform wind field. These models
require extensive Input and substantial computer and manpower
resources.
• Statistical or empirical models Incorporate factors and modules
that are based on experimental data. Such models can be very site-
specific and may not be applicable to most of the Superfund sites
and associated activities.
• Physical models are based on the use of wind tunnels or other fluid
(e.g.. water, oil) modeling facilities. They require major
resources and are applicable for extremely difficult situations
that require laboratory simulations. From a practical viewpoint,
these models may not be applicable to Superfund APAs.
Superfund APAs are one application of air dispersion models, with the
Gaussian dispersion models being particularly useful. The range of Gaussian
dispersion-type models applicable to Superfund APAs Is quite limited because
of the Superfund source configurations and characteristics. As discussed 1n
Sections 2.1 and 2.2.2, the majority of Superfund sources are area sources,
followed by line and volume sources. Only very few sources, mainly those
present during the remedial action step, are classified as point sources.
Since the majority of the Gaussian dispersion models are for point sources,
the selection of dispersion models for Superfund applications Is limited.
However, the models available are considered extremely useful tools for
•
Superfund APAs.
Alternative modeling sophistication levels for Superfund APA
applications can be classified as follows:
• Screening models
2-34
-------
Refined models
Screening dispersion models are applicable mainly for the screening step
of the RI/FS. Their applicability and utility for any of the other Superfund
activities are very limited. Screening dispersion model analyses are based
on conservative assumptions and/or Input data. Therefore, screening modeling
results provide conservative estimates of air quality Impacts for a specific
source. Screening dispersion models are designed to eliminate the need for
further detailed modeling if they show that the Impact on air quality does
not pose a risk to public health and the environment. If results of
screening dispersion calculations indicate a potential risk to public health
and the environment, a refined modeling APA 1s warranted.
Table 2-6 provides a summary of screening dispersion modeling techniques
applicable to Superfund APAs. The modeling techniques are based on EPA
Guidelines and Workbooks for dispersion modeling developed for similar
applications. The references for the modeling techniques are also included
1n Table 2-6. From Table 2-6, 1t 1s apparent that most of the screening
modeling techniques apply to point sources. Such models can be used in
screening analysis to approximate other source configurations, such as area
sources, but the calculations involved become tedious. The preferred
screening techniques, when applicable, for Superfund APA applications are
based on the use of ISC 1n a screening mode and supplemented, as necessary by
those stipulated 1n A Workbook of Screening Techniques for Assessing Impacts
of Toxic Air Pollutants (U.S. EPA, 1988).
Refined dispersion models utilize analytical techniques that provide
more detailed treatment of the physical and chemical atmospheric processes,
more detailed and precise Input data, and more specialized concentration
estimates than the screening techniques. These models consist of
computerized codes and can handle massive volume of Input data (e.g., several
years of hourly meteorological data). Refined models generally provide more
accurate estimates of the Impact of Superfund sources on public health and
the environment. Frequently the conduct of a refined dispersion modeling
analysis will involve a "refined screening" modeling as a preliminary step.
The purpose of the refined screening modeling 1s to Identify locations of
high concentration using a relatively dense calculatlonal grid network.
2-35
-------
o»
TABLE 2-6
A SUMMARY OF DISPERSION MODELING SCREENING TECHNIQUES FOR SUPERFIMD APAs (page 1 of 2)
Feature
1. Source Configuration:
Point
Line
Area
VoluM
2. Release Node:
Continuous
Instantaneous
3. Contaminant Physical
State
Gas
Partlculate
4. Hake Effect
5. Downwash
Screening Modeling Technique
Guidelines for Air
Quality Maintenance.
Planning, and
Analysis. Volume 10
(Revised) Procedures
for Evaluating Air
Quality Impacts of New
Stationary Sources.
US EPA. 1977 (1)
Yes
No
No
No
Yes
No
Yes
Yes
No
No
A Workbook of
Screening Techniques
for Assessing
(•pacts of Toxic Air
Pollutants.
US EPA. March 1988
Yes
No
Yes
Yes
Yes
Yes*
Yes
Yes
Yes
No
workbook of
Atmospheric
Dispersion
EstlMtes.
0. Bruce Turner.
1969
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes
Rapid Assessment of
Exposure to
Parttculate Emissions
from Surface
Contamination Sites.
US EPA. September 1984
No
No
Yes
No
Yes
No
No
Yes
ISC
Dispersion
Model (screening
mode)
Yes*
Yes*
Yes*
Yes*
Yes*
No
Yes*
Yes*
* Preferred technique when applicable
(1) These Guidelines are currently being revised and will also Include a computerized model SCREEN which carries out the
screening calculations (should be available In 1989)
-------
TABLE 2-6
A SUNMRY OF DISPERSION MODELING SCREENING TECHNIQUES FOR SUPERFUND APAs (page 2 of 2)
Feature
6. Heavier than Atr Gas
Nodule
7. Number of Sources
Handled
8. Concentration
Averaging Times
9. Conoents
Screening Modeling Technique
Guidelines for Air
Quality Maintenance.
Planning, and
Analysis. Volume 10
(Revised) Procedures
for Evaluating Air
Quality Impacts of Mew
Stationary Sources.
US EPA. 1977 (1)
No
Single
1, 3. and 24-hour s,
annual
Ibis document contains
f omul as and a large
timber of nooograros
for norm It zed
concentrations that
are useful for staple
screening
calculations. A
computerized version
of thts technique Is
tn the for* of the
PTPLU-2 node).
A Workbook of
Screening Techniques
for Assessing
Impacts of Toxic Air
Pollutants.
US EPA. March 1988*
Ves*
Single
Various
Averaging
Times*
This document
contains formulas
for screening hand
calculations. Also
Included are
examples of
calculations*
Workbook of
Atmospheric
Dispersion
Estimates.
D. Bruce Turner.
1969
No
Single
Various
Averaging
Times
This document
contains formulas
and a large number
of nomograms for
normalized
concentrations that
are useful for
simple screening
calculations. Also
Included are
examples of
calculations
Rapid Assessment of
Exposure to
Paniculate
Emissions from
Surface
Contamination Sites.
US EPA. September
1984
No
Single
24 Hour and Annual
This document
provides a
methodology for
screening estimates
of air
concentrations from
surface releases
from Super fund sites
and alike.
ISC Dispersion Model
(screening mode)
No
Multiple*
1. 3. 8 and 24-hours
and annual
The ISC dispersion
model combines
various dispersion
algorithms Into a
set of two computer
programs that can be
used to assess the
air quality Impacts
of emissions from a
wide variety of
sources.
f\>
I
* Preferred technique when applicable
(I) These Guidelines are currently being revised and will also Include a computerized model SCREEN which carries out the screening
calculations (should be available In 1989)
-------
Thus, the refined modeling analysis can be conducted 1n a cost-effective
manner by limiting the calculatlonal grid points to those which characterize
actual receptor locations and high concentration areas of concern on a site-
specific basis. Frequently, the same model can be used for both the refined
screening and refined modeling analyses. Further reference to refined
modeling APAs in Section 2 1s based on this two-step process which Includes
the conduct of a refined screening analysis, as warranted.
Refined dispersion modeling provides the user with high flexibility by
accommodating multiple sources and providing a concentration field for varied
time averages at a large number of receptors, none of which could be obtained
from hand calculations using screening methodologies. Table 2-7 provides a
summary of refined dispersion models applicable for Superfund APAs.
The Industrial Source Complex (ISC) dispersion model, the Point, Area,
and Line Dispersion Deposition (PAL DS) model, and the Mesoscale Puff
(MESOPUFF II) model are Included 1n the EPA's Guideline on Air Quality
Models. The ISC dispersion and PAL DS models are applicable to continuous
sources with several configurations, while the MESOPUFF model 1s applicable
to Instantaneous releases and can handle point and area sources. Of these
three, the ISC dispersion model 1s the preferred model for most applications
and should be selected as the model of choice for use 1n the Superfund APA
for the RI/FS, remedial design, and operation and maintenance activities. It
can be augmented as required by the use of the MESOPUFF II, Integrated Puff
(INPUFF), or Dense Gas Dispersion (DEGADIS) models 1f special air release
situations exist that could be simulated by any of these models.
The ISC dispersion model should also be used as the model of choice
under the remedial action activities to simulate routine air releases. A
model like the INPUFF or the procedure outlined 1n Appendix C should be
utilized for APA under nonroutine air releases.
In this respect, the ISC dispersion model can be considered the default
air dispersion model for Superfund APA applications. (The ISCLT model is
also Included 1n the EPA's Graphical Exposure Modeling System, which is
standard for use 1n conducting Superfund risk assessments.)
2-38
-------
TABLE 2-7
A SUMMARY OF DISPERSION MODELING REFINED TECHNIQUES FOR SUPERFUND APAs (page 1 of 2)
Feature
1. Source Configuration
Point
Line
Area
Volume
2. Release Mode
Continuous
Instantaneous
3. Contaminant Physical State
Gas
Partlculate
4. Make Effect
5. Downwash
6. Heavier than Air Gas Module
7. Number of Sources Handled
8. Number of Meteorological
Towers
Modeling Technique
ISC
Dispersion
Model 1*
Yes*
Yes*
Yes*
Yes*
Yes*
No
Yes*
Yes*
Yes*
Yes*
No
Multiple
Single
PAL OS Modell
Yes
Yes
Yes
No
Yes
No
Yes
Yes
No
No
No
Multiple
Single
INPUFF2
Yes
No
No
No
Yes
Yes
Yes
No
No
Yes
No
Single
Multiple
DEGAOIS3
Yes
No
No
No
Yes
Yes
Yes
No
No
No
Yes*
Single
Multiple
* Preferred techniques when applicable
-------
ro
k
TABLE 2-7
A SUMMARY OF DISPERSION MODELING REFINED TECHNIQUES FOR SUPERFUND APAs (page 2 of 2)
Feature
9. Concentration Averaging Time
10. Applicability to Superfund
Activities
Modeling Technique
ISC
Dispersion
Modell*
1,3,8, and
24 hour,
annual
All steps
(1) Included In the EPA Guideline on Air Qual
ISC = Industrial Source Complex; PAL OS =
Deposition; MESOPUFF = Mesoscale PUFF mod
PAL OS Modell
1 through 24
hours
All steps
INPUFF2
Hourly
Remedial
Action
Step
ity Models (Revised), July 19
Point, Area, and Line Source
el;
DEGADIS3
Remedial
Action
Step and
Selected
Use for
Other
Steps
B6;
Dispersion
(2) US EPA INPUFF = A single source Gaussian Puff Dispersion Algorighm - Users Guide;
INPUFF = Integrated Puff
(3) US EPA, Dispersion Model for Evaluating Dense Gas Jet Chemical Releases Vol 1 and
2, April, 1988; DEGADIS = Dense Gas Dispersion
Preferred technique when applicable
-------
Other Guideline models, such as the Multiple Point Gaussian Dispersion
Algorithm with Terrain Adjustment (MPTER) model, CRSTER model, and
CUmatologlcal Dispersion Model (COM 2.0), are not considered useful for
Superfund APA applications.
The INPUFF and the DEGADIS models were Included for handling
Instantaneous releases, with the DEGADIS model having the capability to
handle heav1er-than-a1r gases. These two models could be useful as a part of
the remedial action step on a case-by-case basis.
2.4 STEP 3 - DEVELOP MODELING PLAN
2.4.1 Overview
A dispersion modeling plan should be developed for each Superfund APA
application. The objective of the plan 1s to document the modeling methods,
Input data requirements and modeling output and use, consistent with the APA
objectives and the dispersion modeling DQO. The plan also provides an
opportunity for peer review and RPM/EPM approval of the modeling program.
The modeling plan becomes an Integral part of the Superfund APA. Developing
a modeling plan Involves the following major elements:
Select constituents to be modeled
Define emission Inventory methodology
Define meteorological data base
• Design receptor grid
• Detail modeling methodology
• Estimate background concentrations
Define dispersion calculations to be performed
• Document modeling plan.
Major Input to the development of the dispersion modeling plan should
Include the Information collected under Step 1 (Collect and review Input
Information) and Step 2 (Select modeling sophistication level.)
Procedures for development of a dispersion modeling plan are provided in
the subsections that follow. Table 2-8 provides an outline for the modeling
2-41
-------
TABLE 2-8
AN OUTLINE FOR THE DISPERSION MODELING PLAN FOR A SUPERFUND APA
I. INTRODUCTION
General site background (site location, topography, nearby water
bodies, demography, vegetation, general site activities)
II. DISPERSION MODELING DATA QUALITY OBJECTIVES
Modeling objectives (consistent with the Superfund activity
involved and the overall project objective
• Overall rationale for the modeling approach
Modeling uncertainties and their implications to the Superfund APA
III. CONSTITUENTS TO BE MODELED
IV. EMISSION INVENTORY
• Sources to be modeled (number; configuration (i.e., point, line,
area volume); locations)
Source characteristics (constituents Involved)
Methods for estimating emissions (see Volumes II and III)
Content of the emission inventory database (see Table 2-4)
Particle size distribution
Physical and chemical properties of constituents to be modeled
Dimensions of obstructions
V. METEOROLOGICAL DATA
• Source of meteorological data
• Length of record
Parameters to be utilized in the dispersion modeling
Quality of the data
VI. RECEPTOR GRID
Ons1te receptors (number and locations)
• Perimeter receptors (number and locations)
• Offsite receptors
Regular (number and locations)
2-42
-------
TABLE 2-8
AN OUTLINE FOR THE DISPERSION MODELING PLAN FOR A SUPERFUNO APA (Continued)
Anticipated locations of high concentration (number and
locations)
Environmentally sensitive locations (number and locations)
VII. MODELING METHODOLOGY
• Selected model(s) and rationale
Model application to the Superfund activity APA
• Model features
Rural/urban classification
Wake and/or downwash effects
Particle deposition
Plume rise
Dispersion parameters
• Setting of model switches
• Testing the model against bench mark test cases
VIII. ESTIMATED BACKGROUND CONCENTRATIONS
XI. DISPERSION CALCULATIONS
• Averaging times
Data summaries (tabular, graphical)
Comparison with guideline values
Input to the risk assessment
X. REFERENCES
2-43
-------
plan. Each of the major elements of the modeling plan is discussed 1n the
following subsections.
2.4.2 Dispersion Modeling Data Quality Objectives
The purpose of this section 1s to outline the main objectives of the
dispersion modeling as a part of the Superfund APA and how to meet them. It
should address applicable or relevant and appropriate requirements (ARARs)
for each of the Superfund activities and the level of air dispersion modeling
that 1s necessary to provide adequate Input Into the Superfund APA.
Elements included 1n this section should address
The overall rationale for the modeling approach
Model output and anticipated uncertainties, considering Input data.
model formulation and assumptions Involved, and output
Implications of model uncertainties on the Superfund APA (e.g., are
they acceptable)
In this respect, dispersion modeling DQOs provide consistency 1n
selection of the modeling tool, modeling Input (emission inventory,
meterological and other data) and output, and in the overall requirements of
the air dispersion modeling for the specific application under consideration.
2.4.3 Select Modeling Constituents
Selection of air toxics constituents for dispersion modeling is
generally less critical than for monitoring APAs. Selection of monitoring
constituents 1s significantly limited by technical, budget, and schedule
constraints. However, dispersion modeling results from one target
constituent for a particular source can generally be scaled to obtain, on a
cost-effective basis, concentrations for numerous other constituents of
interest.
2-44
-------
A summary of the recommended procedure for selection of dispersion
modeling target constituents 1s presented 1n Figure 2-6.
A 11st of the compounds Included In the Hazardous Substances List (HSL)
developed by EPA for the Superfund program 1s presented 1n Table 2-9. This
11st Is a composite of the Target Compound List (TCL) for organlcs and Target
Analyte List (TAL) for Inorganics. Table 2-9 also Includes examples for
additional potential Superfund air emission constituents (e.g., HCN, H2S,
HC1). Therefore, Table 2-9 represents a comprehensive Initial 11st of target
compounds for air dispersion modeling for Superfund APA.
Emission rate APA results should be obtained prior to the conduct of
dispersion studies based on Volume I recommendations. These results, as well
as dispersion modeling results (as available), should be used to Identify
appropriate site and source-specific modeling constituents from Table 2-9.
In addition, constituents Included 1n ARARs Identified during Step 1 should
also be used to Identify candidate modeling constituents.
The limited set of candidate modeling constituents based on previous
APAs and ARAR considerations should be used to compute constituent-specific
HI values. Instructions for computing HI values were presented 1n Section
2.3.
The HI values computed should then be ranked from highest to lowest 1n
order to develop a priority 11st of candidate modeling constituents. The
final constituents selected for dispersion modeling should be a function of
the APA sophistication level (as Indicated 1n Figure 2-6).
Dispersion modeling for screening applications should Include all
site/source-specific constituents.
Dispersion modeling target constituents for refined APAs should, at a
minimum, Include all constituents with an Individual HI value greater than or
equal to 10 percent of the composite HI value for the total mix. These
constituents are expected to represent the greatest contributors to potential
health Impacts. This approach provides a practical basis to address refined
modeling APAs at sites with a large number of potential emission constituents
2-45
-------
AIM CONCENTRATION
•ST1MATV8 SA3BO ON
CMiaaiONS DATA
9trm* 1 INPUT
(T«bl« 2-3)
PREVIOUS OISPBRSION
MONITORINOXMOOCUNO
DATA - ST«P 1 INPUT
(Tabl* 2-3)
SUPERFUNO
HAZARDOUS SUB
STANCES LIST
(Table 2-9)
ARARa - STEP
INPUT
(Tabld 2-3)
COMPUTE
CONSTITUENT-
SPECIFIC HAZARD
INDEX (HI) VALUES
RANK
HI
VALUES
SCREENING
REFINED
MODEL ALL APPROPRIATE
siTtxsouRCE-spc
CONSTITUENTS
AT A MINIMUM.
UOMB TITUBN f •
WITH HI 0.1 HI (TOTM. MIX)
U. srrcx
OOM»IIIUgKT» TO
INPUT TO
AIR MODELING
PLAN
RMVALUATC TAROBT
LIST BASED ON
CURRENT MONITORINQX
MOOCUNQ RESULTS
2-46
-------
TABLE 2-9 (PAGE 1 OF 4)
CLASSIFICATION OF ORGANIC AND INORGANIC COMPOUNDS
FOR AMBIENT AIR MODELING STUDIES
Broad Band
Volatile Organic*
-
Compound Class
Aliphatic*
Aromatics
Halogenated Species
Oxygenated Species
Sulfur-Containing
Species
Nitrogen-Containing
Species
Representative Compounds
vinyl acetate
benzene
toluene
ethylbenzene
total xylenes
styrene
chlorobenzene
carbon tetrachloride
chloroform
methyl ene chloride
chloromethane
1,2-dichloropropane
trans - 1 , 3-d 1 ch 1 oropropene
c1s-l,3-d1chloropropene
bromoform
bromomethane
bromod 1ch 1 oromethane
d 1 bromoch 1 oromethane
1 , 1 , 2,2-tetrachloroethane
1,1,1-trichloroethane
1,1,2-trichloroethane
1,1-dfchloroethane
1 , 2-d 1 ch 1 oroethane
chloroethane
tetrachloroethene
trlchloroethene
1,2-dichloroethene
I,l-d1chloroethene
vinyl chloride
acetone
2-butanone
2-hexanone
4-methyl-2-pentanone
carbon disulflde
benzonitrile*
2-47
-------
TABLE 2-9 (PAGE 2 OF 4)
CLASSIFICATION OF ORGANIC AND INORGANIC COMPOUNDS
FOR AMBIENT AIR MODELING STUDIES
Broad Band
Volatile Inorganics
Semi -Volatile
Organics
Compound Class
Acid Gases
Sulfur Containing
Species
Phenols
Esters
Chlorinated Benzenes
Amines
Representative Compounds
cyanide*
hydrochloric acid*
hydrogen sulfide*
phenol
2-methylphenol
4-methylphenol
2 ,4-di methyl phenol
2-chlorophenol
2,4-dichlorophenol
2,4,5-trichlorophenol
2,4,6-trichlorophenol
pentachlorophenol
4-chloro-3-methyl phenol
2-nitrophenol
4-nitrophenol
2,4-dinitrophenol
4, 6-dinitro-2-methyl phenol
b1s(2-ethylhexyl)phthalate
di-n-octyl phthalate
di-n-butyl phthalate
diethyl phthalate
butyl benzyl phthalate
dimethyl phthalate
1,2-dichlorobenzene
It3-d1chl orobenzene
1 , 4-d 1 ch 1 orobenzene
1,2,4-trichlorobenzene
hexach 1 orobenzene
nitrobenzene
2,6-dinitrotoluene
2,4-d1nitrotoluene
3,3'-dichlorobenz1dine
n-n1 trosodimethy 1 ami ne
n-n i trosod 1 -n-propy 1 ami ne
n-ni trosodipheny 1 ami ne
aniline
2-nitroan1line
3-nitroan1l1ne
4-nitroaniline
4-chloroannine
2-48
-------
TABLE 2-9 (PAGE 3 OF 4)
CLASSIFICATION OF ORGANIC AND INORGANIC COMPOUNDS
FOR AMBIENT AIR MODELING STUDIES
Broad Band
Compound Class
Representative Compounds
Ethers
bis(2-chloroethyl)ether
bis(2-chloroisopropyl)ether
bromopheny1-pheny1 ether
4-chlorophenyl-phenylether
Alkadlenes
hexachlorobutad1ene
hexach1orocyc1opentad1ene
Miscellaneous
Aliphatics and
Aromatics
benzole acid
benzyl alcohol
bis(2-chloroethoxy)methane
dibenzofuran
hexachloroethane
isophorone
Polynuclear Aromatic
Hydrocarbons (PAHs)
acenaphthene
acenaphthylene
anthracene
benzo(a)anthracene
benzo(b)f1uoranthene
benzo(k)f1uoranthene
benzo(g,h,i)perylene
benzo(a)pyrene
chrysene
dibenz(ath)anthracene
fluoranthene
fluorene
1ndeno(1,2,3-cd)pyrene
naphthalene
2-methy1naphthalene
2-chloronaphthalene
phenanthrene
pyrene
Pesticides
alpha-BHC
beta-BHC
delta-BHC
gamma-BHC
heptachlor
heptachlor epoxide
4,4'-DDT
4,4'-DDD
4,4'-ODE
endrin
endrin ketone
endrin aldehyde
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TABLE 2-9 (PAGE 4 OF 4)
CLASSIFICATION OF ORGANIC AND INORGANIC COMPOUNDS
FOR AMBIENT AIR MODELING STUDIES
Broad Band
Compound Class
Representative Compounds
Pesticides
endosulfan I
endosulfan II
endosulfan sulfate
aldrin
dieldrin
chlordane
methoxychlor
toxaphene
Polychlorinated
Biphenyls (PCBs)
Arochlor 1016
Arochlor 1221
Arochlor 1232
Arochlor 1242
Arochlor 1248
Arochlor 1254
Arochlor 1260
Non-Volatiles
Inorganic Metals and
Non-Metals
aluminum
antimony
arsenic
barium
beryllium
cadmium
calcium
chromium
cobalt
copper
iron
lead
magnesium
manganese
mercury
nickel
potassium
selenium
silver
sodium
thallium
tin
vanadium
zinc
Note: Compounds identified by an asterisk (*) are not contained on the USEPA
Hazardous Substance List (HSL).
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(e.g., over one hundred) of which only a limited subset significantly affect
Inhalation exposure estimates. However, it 1s generally recommended, as
practical, to also evaluate all appropriate site/source-specific constituents
for refined modeling APAs (especially 1f the cumulative effect due to
exposure to a mixture of constituents 1s used for comparison to health
criteria).
The dispersion modeling target constituents 11st should be reevaluated,
and revised 1f warranted, based on monitoring results.
It 1s recommended that dispersion modeling results Initially be obtained
1n terms of dispersion factors (I.e.. concentration divided by a unit
emission rate). This will provide a cost-effective basis for estimating
receptor exposure concentrations for a wide variety of emission constituents
(I.e., a constituent-specific concentration equals the dispersion factor of
the receptor location of Interest times the constituent-specific emission
rate).
2.4.4 Define Emission Inventory Methodology
Emission Inventory 1s a key Input to the Superfund air dispersion
modeling. Data obtained from Step 1 (Collect and review Input Information)
should be utilized 1n determining the number and nature of sources Involved.
The modeling plan should outline the procedures for
Estimating the dimension of the sources Involved. This Includes
estimating the contaminant distribution and defining the shape and
boundaries of sources.
• Classifying sources by configuration—area, line, volume, and
point—and subdividing them as necessary.
• Determining coordinates of the sources.
• Defining the constituents involved with each source based on the
output of Section 2.4.2.
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Defining the parameters required for estimating emissions that are
Identified 1n Volumes II and III, and the rationale for their
selection.
• Calculating emissions based on methods outlined 1n Volumes II and
III.
• Estimating particle size distribution for calculating participate
deposition.
• Accounting for downwash from nearby structures. This phenomenon 1s
particularly Important for onslte air strippers and Incinerators at
Superfund sites. These units frequently have low stack heights.
Therefore, releases from these stacks may be Influenced by adjacent
structures.
• Estimating the dimensions of obstructions and the distance of such
obstructions from the sources under consideration.
Program design objectives and OQOs should be an Integral part of the
methodology outlined.
The emissions Inventory should be tabulated 1n a format suitable for use
1n dispersion modeling. This table should Include physical and chemical
characteristics of the constituents to be modeled.
As discussed 1n Sections 2.1 and 2.2.2, most of the Superfund air
release sources are area sources, followed by line and volume sources and to
a lesser extent by point sources. Many of the area sources at Superfund
sites have Irregular shapes and many cover a large area (e.g., many acres).
The ISC dispersion model handles area sources only as squares. To
accommodate the ISC model Input requirements, 1t may be necessary to
subdivide a Superfund area source Into a number of smaller area sources,
square 1n shape. Source subdividing Into small, square area sources has the
following two major benefits:
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• The areas and shapes of Irregular sources can be approximated 1n
most cases by a number of small squares, as Illustrated 1n Figure
2-7.
• Receptors at or near the source can also be Included 1n the
dispersion modeling, as often required for the Superfund APA. This
Includes receptors at onslte work areas, at the site perimeter, and
Immediately offslte.
A specialized modeling approach 1s generally needed for standard
Gaussian dispersion models such as the ISC, 1n order to obtain concentration
estimates near the boundary of a large area source. For example, the nested-
area subdivision approach Illustrated 1n Figure 2-8 can be used. By
subdividing the area source such that the square nearest the receptor 1s less
than 10 meters on a side, 1t 1s possible for the ISC dispersion model to
provide estimates of concentration within 1 meter of the source boundary.
Models, which simulate the mlcroscale physics Immediately above a
ground-level emission surface, can also be used to estimate concentration at
and 1n the vicinity of an area source. Although these flux models can be
technically sophisticated, they generally lack extensive validation and are
not recommended as preferred models for Superfund APAs.
2.4.5 Define Meteorological Data Base
Meteorological data are also key Input to the dispersion calculations.
As noted, Input meteorology governs the transport and dispersion of the
contaminant plume. It 1s therefore Imperative to select the most appropriate
meteorological data. For most Superfund activities (RI/FS, remedial design,
and operation and maintenance), historical data are very useful. In the
absence of a long record of onslte data, data applicable for use 1n
dispersion modeling are generally available from NWS stations, state
meteorological programs, and private Industry. Generally at least one year
of meteorological data should be available for screening analyses. It 1s
desirable to have five or more years of meteorological data to support long-
term exposure assessments for refined APAs.
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FIGURE 2-7 REPRESENTATION OF AN IRREGULARLY SHAPED AREA SOURCE
2-54
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Wind Direction
Receptor at
site boundary
Nested subdivisions, as
necessary to yield areas
of <100m2
FIGURE 2-8
EXAMPLE OF NESTED SUBDIVISION OF AREA SOURCE
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As discussed In Section 2.2.4, onslte meteorological data should be used
• To determine how well offsite data correlate with It
• To provide site specific data showing the diurnal variations of the
meteorological parameters and the effects of topography and nearby
water bodies on the transport and dispersion of the air toxics
plume
• Define worst-case emission/dispersion scenarios to conservatively
evaluate short-term exposure conditions to support screening APAs.
The data base selected should
• Meet program and DQO objectives
• Have a record of sufficient length
• Include data representative of the site area
Meteorological data may be used to define worst-case emission/dispersion
scenarios to conservatively estimate short-term exposure conditions to
support screening APAs. For example, this approach would be appropriate for
use of ISCST for a screening APA. However, for a refined APA based on ISCST
a sequential file of hourly meteorological data may be warranted as modeling
Input.
The quality of the meteorological data should meet EPA requirements as
outlined In the following technical references:
• U.S. EPA. June 1987. On-S1te Meteorological Program Guidance for
Regulatory Modeling Applications. EPA-450/4-87-013. Office of A1r
Quality Planning and Standards. Research Triangle Park, NC 27711.
• U.S. EPA. February 1983. Quality Assurance Handbook for Air
Pollution Measurements Systems: Volume IV. Meteorological
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Measurements. EPA-600/4-82-060. Office of Research and
Development. Research Triangle Park. NC 27711.
U.S. EPA. July 1986. Guidelines on Air Quality Models (Revised).
EPA-405/2-78-027R. NTIS PB 86-245248. Office of A1r Quality
Planning and Standards. Research Triangle Park. NC 27711.
U.S. EPA. November 1980. Ambient Monitoring Guidelines for
Prevention of Significant Deterioration (PSD). EPA-450/4-80/012.
NTIS PB 81-153231. Office of A1r Quality Planning and Standards.
Research Triangle Park. NC 27711.
The modeling plan should also Identify the following Information with
respect to the meteorological data set:
• Source of meteorological data and rationale for selecting this data
base. This applies to both surface and upper-air data.
• Length of record. A minimum of 1 year of hourly data 1s required,
with 5 years of data being preferred.
Parameters to be utilized 1n the dispersion model, Including wind
speed, wind direction, atmospheric stability, ambient temperature,
and mixing height.
An onsite' meteorological program 1s recommended 1n the case of the
remedial action step. Section 3.0 addresses the requirements of onsite
meteorological programs for that step. Even flat terrain sites with nearby
National Weather Service data should Install and operate an onsite
meteorological station during remedial actions. The short-term temporal and
spatial variability of wind conditions limits the applicability of offsite
meteorological data for realtime decision-making (e.g.. during non-routine
air releases). Data collected through this step can be utilized as
historical data 1n making the dispersion calculations and 1n assessing
routine air releases, or as near real time data 1n estimating the Impact of
nonroutlne air releases. The modeling plan for the remedial action step
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should address the use of onslte meteorology 1n dispersion modeling for both
routine and nonroutlne releases.
Meteorological parameters used for each application should be
Identified, and an explanation should be given of their use.
2.4.6 Design Receptor Grid
The selection of the proper number and locations of receptors 1s
paramount for a meaningful dispersion modeling analysis. It is therefore
Important to carefully select receptors to ensure that the areas of potential
Impact Include the desired spatial distribution of receptors.
A receptor grid or network for a Superfund air dispersion model defines
the locations of calculated air concentrations that are used as a part of the
APA to assess the effect of air releases on human health and the environment
under the various Superfund site activities.
The process of setting the receptor grid should meet the following APA
objectives:
• Providing concentration estimates which can be used as Input to the
Superfund risk assessment process and to compare to ARARs
Providing technically sound spatial distribution of receptors to
account for areas exhibiting large concentration gradients over
short distances, by Increasing the density of receptors at these
locations and ensuring that locations of high concentrations are
not missed
It 1s therefore Important to establish a receptor grid that will address
both the locations of anticipated maximum air toxics concentration and the
air toxic concentrations at environmentally sensitive receptors such as
residences, work areas, schools, hospitals, parks, and monuments.
Concentration averaging times should be a factor in setting the receptor
grid based on the APA objectives. For short-term averaging times (up to 24
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hours), the selection of receptors should be based on the objective of
protecting public health and the environment at all publicly accessible areas
around the Superfund site. In this respect the receptor should Include
locations of anticipated maximum air toxics concentration offsite. With
respect to long averaging times (monthly, seasonal, annual, 70 years, or
others) air toxics concentrations should be evaluated at actual receptor
locations (I.e., 1n areas surrounding residences, work places, and at
locations with environmentally sensitive species).
From a practical viewpoint, most of the Superfund release sources can be
regarded as ground-level sources. Only a few of them are elevated, and even
they are classified as low-level elevated sources. Examples Include onslte
structures and onsite treatment facilities (e.g.. Incinerators, air
strippers). This Implies that, for most releases from Superfund sources,
high-ground-level concentrations of air toxics will occur at short distances
from the source. Depending on the source configuration and the release
height, such concentrations will occur less than 1 to 2 kilometers from the
source
For Superfund APA modeling applications to Identify high concentration
areas (I.e., generally for modeling planning purposes) 1t 1s recommended that
the receptor grid spacing for the area within 2 kilometers of the source be
approximately 200 meters, depending on the number of sources and their
configuration. The receptor grid spacing for areas more than 2 kilometers
from the source could be 1 to 2 kilometers up to 10 kilometers from the
source; for areas than 10 kilometers from the source. It could be 5
kilometers. This basic grid network should be supplemented by receptor
points of Interest (e.g., houses, schools, etc.) on a site-specific basis. A
polar or rectangular grid could be used for these applications based on these
receptor grid criteria.
The receptor grid system for Superfund APAs should be developed on a
case-by-case basis and should consider:
• Results of the receptor data evaluation performed under Section
2.2.3
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Results of screening and refined screening dispersion modeling
estimates of locations of high concentrations may be useful to
reduce the receptor grid size for refined analyses
• Prevailing wind direction
• Meteorological conditions conducive to high concentrations
Population distribution In the site vicinity (Section 2.2.3)
Sensitive receptor locations
The number and configuration of sources
Release characteristics such as height, dimensions, and proximity
to the site perimeter
• Work areas on the site
• Locations of air monitoring stations
• Screening analyses, especially for short-term exposure evaluations
may be based on worst-case meteorological scenarios which -assume
Invariant wind conditions. Therefore, for a single source
evaluation based on these conservative assumptions, the screening
analysis calculatlonal grid points may be limited to the plume
centerline for the downwind sector of Interest.
These factors should be considered in selecting onsite, perimeter, and
offsite receptors. The rationale for the selection of the number and
locations of each type of receptor should be stated. Depending on the
specific application, the number of receptors could range from 200 to 400.
2.4.7 Detailed Modeling Methodology
The modeling methodology 1s based on the objectives outlined in Table
2-6 for dispersion modeling as a function of the Superfund activity, and it
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1s consistent with the OQOs for the project. As discussed 1n Section 2.4.2,
1t 1s necessary to determine the level of sophistication of the dispersion
modeling, the Input data requirements, and the quality of data. This
determination will permit assessment of the costs and benefits of the
modeling methodology and the effects of the uncertainties Involved on the
Superfund APA.
Screening modeling 1s desirable for
Obtaining rough estimates of the levels of air "contaminant
concentrations and the approximate locations of high concentrations
Providing Information on the need for refined dispersion modeling
Techniques for performing screening dispersion calculations are provided
1n Table 2-6.
The selected methodology should take Into account the following:
• Screening versus refined modeling applications
• Formulation to be used
Applicability of the approach to the Superfund activity and source
under consideration
Concentration averaging time
Special considerations such as heav1er-than-a1r gas
• Dispersion parameters
Plume rise considerations
• Quality and quantity of meteorological data available (e.g., the
availability of representative data recommended to support refined
dispersion modeling analyses)
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For refined dispersion modeling, the model to be used should be selected
from Table 2-7. The ISC dispersion model 1s the preferred model for most
Superfund APAs. When there 1s a need for characterizing Instantaneous
releases, the INPUFF model should be utilized, and when heav1er-than-a1r gas
1s considered, OEGAOIS should be employed. Other models listed 1n Table 2-7
could also be used on a case-by-case basis.
The dispersion modeling plan should address the following for refined
modeling:
• Selected model and rationale.
Model applicability, as determined by the Superfund activity
Involved and source characteristics. For example, nonroutlne
releases during the remedial action step should be considered when
the model 1s selected.
• The rural or urban character of the area, based on demographic
data.
Wake and/or downwash effects, Including those attributable to
onslte obstructions.
• Particle deposition taking Into consideration the particle mass-
size distribution.
Plume rise and dispersion parameters, Including Initial dilution
parameters.
• Model switches (tabulation).
In addition, a brief synopsis of the model formulation should be
discussed.
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2.4.8 Estimated Background Concentrations
Background air concentrations are an Integral part of many air quality
studies that Involve dispersion modeling. Such Information 1s useful In
estimating the cumulative Impact of air toxic contaminants as well as the
Incremental Impact of the Superfund site activities. The major application
for background concentration estimates Is to assess conformance with ambient
air quality criteria for ARARs.
Measurement of air quality 1n the vicinity of a Superfund site could
provide the necessary Information on existing background air quality levels,
providing the following are met:
• The air monitoring network was designed and Implemented following
procedures similar to the guidelines provided 1n Section 3.0.
• The network monitored several of the site-specific target
compounds.
Background air quality data could be obtained from previous air
monitoring programs conducted 1n the site vicinity, as discussed in Section
2.2.5. It also could be obtained through the Implementation of an air
monitoring program 1n the vicinity of the site as a part of the Superfund
site activity.
The modeling plan should address the subject of background air quality
for the Superfund project and delineate the process for estimating background
levels based on existing data or proposed air monitoring. The project
objectives and OQOs should serve as a key factor In assessing the background
levels 1n the vicinity of the site.
2.4.9 Define Dispersion Calculations To Be Performed
Once the overall scheme for dispersion modeling has been outlined, the
dispersion calculations to be performed must be defined. -This Includes the
following:
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• Averaging times for calculating concentrations.
Short term: hourly and 3-, 8-, and 24-hours.
Long term: monthly, seasonal, annual, or other.
Dispersion modeling scenarios as a function of the Superfund
activity under consideration. For example, the RI/FS activity inay
require modeling the no-action scenario or scenarios associated
with the alternative remedial actions. The remedial design
activity may require modeling a few scenarios associated with a
specific onslte technology.
• The results of calculation.
Tables summarizing receptors that exhibit high concentrations
and sensitive receptors with associated concentrations, for
various averaging times.
Isopleths of concentrations for the site area.
The modeling plan should outline the type of dispersion calculations to
be performed and present results of the calculations.
2.4.10 Document the Modeling Plan
The modeling plan should be documented according to the discussion
provided in Sections 2.4.2 through 2.4.8, utilizing the outline suggested in
Table 2-9.
2.5 STEP 4 - CONDUCT MODELING
2.5.1 Overview
Dispersion modeling for Superfund APA applications should be conducted
consistent with the modeling plan developed during Step 3. However,
successful Implementation of the modeling plan requires qualified modelers
and attention to QA/QC factors. Therefore, the modeling approach illustrated
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1n Figure 2-9 should be applied to Superfund APAs. This also Involves the
application of A Workbook of Screening Techniques for Assessing Impacts of
Toxic A1r Pollutants (U.S. EPA, 1988) and Guidelines on A1r Quality Models
(U.S. EPA, 1988), for refined assessments. Dispersion modeling
recommendations presented 1n other technical references may also be
applicable 1f specified 1n the site-specific modeling plan.
2.5.2 Staff Qualifications and Training
Dispersion modeling 1s a complex process that requires specialized
qualifications and training. This aspect of modeling has been frequently
neglected as personal computer (PC) versions, which are easy to use, have
become prevalent. However, 1t 1s also easy for the novice to select
Inappropriate modeling options and/or enter data Incorrectly. These errors
can be subtle 1n nature and difficult to detect, and they can significantly
affect the validity of the modeling output. Also, Interpretation of modeling
data requires a thorough understanding of the theory on which the model 1s
based and on Input data/model limitations. Therefore, 1t 1s Imperative that
a qualified dispersion modeler thoroughly familiar with the modeling process
and the required QC documentation be assigned to provide dispersion modeling
support for Superfund APA applications.
2.5.3 Quality Control
This section addresses the process of performing dispersion modeling for
a Superfund APA with emphasis on quality control. The modeling can be
executed by hand calculation or computer models when screening dispersion
modeling (depending on which of the alternative approaches listed 1n Table 2-
6 1s selected) 1s considered. It 1s Implemented with a computer when refined
dispersion modeling 1s performed.
The screening dispersion modeling process Includes the following steps:
• Calculate the emission release rate or total release
Derive the source parameters required as additional Input
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MODELING
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MODELING
STAFF
QUALIFICATIONS/
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2-66
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• Define the special parameters required to estimate wake effects or
negative plume buoyancy
• Select the meteorological data set or scenario to be modeled
Define the receptors for which calculations will be performed
• Perform the calculations (generally using computer models)
• Obtain conservative concentration estimates
The refined dispersion modeling process Includes the following basic
tasks:
Develop the emission Inventory
• Preprocess the meteorological data
• Develop the receptor grid (this generally Involves refined
screening modeling as previously discussed)
• Run bench mark test cases
Verify the Input files
• Perform model calculations
• Obtain more realistic concentration estimates
The modeling process 1s delineated 1n Figure 2-10. The tasks Involved
1n these steps must be executed carefully to minimize the likelihood of
errors. A small error 1n one of the Input data files will require rerunning
the model, thus Increasing the expenses of the project. Subsequent sections
address the refined dispersion modeling process. A similar but simpler
discussion applies to the screening modeling.
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Develop
Receptor
Grid (Sections
2.2.3 and 2.4.6)
Preproeess
Meteorological
Data (Sections
2.2.4 and 2.4.5)
Develop Emission
Inventory
(Sections 2.2.2,
2.4.3, and 2.4.4)
I
Input Into
Computer
Files
Set Up Model
Switches
JL
Run Benchmark
Teat Cases
Verify Input
Filea
Perform
Modal
Calculations
a-1O. TH» Ol«p*r«ion Modeling Proe*a«.
2-68
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Develop Emission Inventory
This task calls for utilizing Input data collected under Step 1 (Collect
and review Input Information) (see Section 2.2) and developing an emission
Inventory and other source data required as Input to the dispersion model.
The overall process of developing this data base was outlined 1n Sections
2.4.3 and 2.4.4. The emission Inventory 1s developed using source-specific
formulas, factors, and procedures described in Volumes II and III of this
Guideline. Calculated emissions and related parameters should be verified
and tabulated 1n a format similar to that presented 1n Table 2-3.
Preorocess Meteorological Data
In most cases, meteorological data compiled under Step 1 (Collect and
review Input Information) (see Section 2.2.4) must be processed (e.g., using
MPRM or RAMMET) prior to their use in the dispersion calculations, to make
them compatible with model Input requirements. Model-specific meteorological
preprocessing requirements are defined 1n the user's guide for each EPA
dispersion model.
Preprocessing generally involves a large volume of data (e.g., 1 year of
data Includes 8760 hourly va.lues for each meteorological parameter under
consideration). In refined, modeling, the preprocessing is done with a
computerized preprocessor that accepts NWS data and generates a processed
data base compatible with the dispersion modeling code.
The meteorological data should be handled as outlined In Sections 2.2.4
and 2.4.5 and as discussed 1n reference material associated with each
modeling technique (see Tables 2-7 and 2-8). The preprocessed data should be
rigorously checked for validity before their use. Recommendations for
meteorological data validity checks are provided 1n Table 2-10 and 1n Section
3.0.
Develop Receptor Grid
A receptor grid should be developed based on data collected under Step 1
(Collect and review Input Information) (see Section 2.2.3) and the process
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TABLE 2-10
SUGGESTED METEOROLOGICAL DATA SCREENING CRITERIA*
(U.S. EPA. JUNE 1987)
Meteorological
Variable
Screening Criteria*
Wind Speed
Flag the data If the value:
• 1s less than zero or greater than 25 m/s
• does not vary by more than 0.1 m/s for 3
consecutive hours
• does not vary by more than 0.5 m/s for 12
consecutive hours
Wind Direction
1s less than zero or greater than 360 degrees
does not vary by more than 1 degree for more than
3 consecutive hours
does not vary by more than 10 degrees for 18
consecutive hours
Temperature
1s greater than the local record high
1s less than the local record low
(The above limits could be applied on a monthly
basis.)
1s greater than a 5°C change from the previous
hour
does not vary by more than 0.5°C for 12
consecutive hours
Temperature
Difference
1s greater than 0.1°C/m during the daytime
1s less than -0.1°C/m during the nighttime
1s greater than 5.0°C/m or less than -3.0°C/m
a Some criteria may have to be changed for a given location.
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outlined 1n Section 2.4.6. The grid can be rectangular or circular, or 1t
can consist of a selected number of receptors located at special locations.
In general, all three forms are utilized by most of the refined models
Included 1n Table 2-8. The spatial distribution of receptors should be
determined based on factors discussed 1n Section 2.2.3 and on site-specific
considerations. Once the grid has been established and coordinates assigned
using U.S. Geologic Survey (USGS) maps, the data base can be put into a
receptor file 1n a format compatible for use by a refined dispersion model.
The number of receptors may be limited for screening modeling based on
conservative Input assumptions (e.g., worst-case, short-term meteorological
scenarios based on Invariant wind conditions). However, as previously
discussed, a more comprehensive receptor grid network 1s generally warranted
for refined screening modeling analyses to identify high concentration areas.
The results from the refined screening analyses may be used to limit the
calculatlonal grid network to significant receptor locations for refined
modeling APAs.
The coordinate of each receptor point should be verified as a routine QC
measure.
Run Benchmark Test Cases
Two additional activities have to be performed prior to the execution
actual dispersion model runs 1n the case of refined modeling.
The first Involves model runs with benchmark test cases to ensure that
the model performs as specified. It is recommended that benchmark cases
accompanying the dispersion model be utilized and results be checked against
these cases.
The second activity Involves the setting of model switches 1n accordance
with the case under consideration. Switches provide the user with the
program setting options pertaining to input, dispersion model, and output.
Examples Include receptor grid (rectangular or polar), rural or urban mode,
building wake and stack tip downwash effects, printout of the 50 maximum
concentration values, and annual average concentrations. It 1s Important in
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this case to consider the type of model output, based on the options
available, to avoid excessive printout without any use for most of 1t. From
a practical viewpoint, dally and annual concentrations are the most useful 1n
assessing air release effects through the APA. Once 1t has been determined
that the model performs properly and the appropriate switches have been set,
the model 1s ready for execution.
Perform Model Calculations
Once the Input data files have been prepared and verified, the model
tested, and the switches set properly, the actual dispersion model
calculations are performed 1n accordance with the modeling plan.
2.6 STEP 5 - SUMMARIZE AND EVALUATE RESULTS
2.6.1. Overview
Modeling results available from Step 4 should be summarized and
evaluated to provide Input to site-specific APA and the Superfund decision-
making process. The recommended approach (see Figure 2-11) for this step 1s
as follows:
• Summarize data.
Evaluate modeling results.
Prepare a report.
Output of the dispersion modeling should be summarized together with
pertinent source and meteorological data to serve as a basis for data
evaluation. Calculated high concentrations and their locations, coupled with
applicable air toxics guidelines, should be used to evaluate the results of
the dispersion calculations. The performance of the dispersion modeling for
existing sources could be assessed by comparing calculated and measured air
concentrations. The measured air concentrations are obtained and evaluated
through the process outlined 1n Section 2.2.5.
Results of the dispersion modeling, together with Information on the
methodology employed, should be summarized 1n a modeling report.
2-72
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INPUT DATA
FROM
STEP 4
SUMMARIZE DATA
o Tabular Data
o Graphical Data
METEOROLOGICAL
SUMMARIES
AIR CONCENTRATION
SUMMARIES
EVALUATE
DISPERSION
MODELING
DATA
o Dtaperalon
Qradlente/Patterna
o Modeling
Concentrations
o Supplemental
Analyses
i
INPUT TO
SUPERFUND
RISK ASSESSMENT/
DECISION MAKING
PROCESS
Figure a-11. Step • - Summarize and Evaluate Reaulta.
2-73
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2.6,2 Summarize Data
In general, the output of computer model calculations 1s given 1n a
tabular form. These data have to be summarized 1n a form that 1s useful for
the specific APA application. Examples of recommended tabular data summaries
for air toxics Indicator constituents Include
• Daily concentrations at sensitive receptor locations Included 1n
the dispersion calculations
• Maximum long-term (monthly, seasonal, annual, or other) calculated
concentrations
• Daytime and nighttime maximum and average concentration estimates
(for complex terrain and coastal sites only)
• Calculated long-term concentrations at sensitive receptors
• Applicable ambient air toxics guidelines
• Summaries of calculated versus measured (as available)
concentrations for short- and long-term averaging times
• Source-specific summaries for Superfund sites with multiple air
release sources.
A useful presentation of the results 1n graphic form Is accomplished by
plotting dispersion factors or concentrations for Indicator constituents.
These Isopleth summaries depict the areas affected by Superfund air release
sources. Figure 2-12 1s an example of a computer-generated, ground-level
Isopleth plot.
Frequently, It may not be practical to place air monitoring stations at
offslte receptor locations of Interest. However, It may be necessary to
characterize concentrations at these locations as Input to site-specific risk
assessments. In these cases, dispersion patterns based on modeling results
2-74
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ESTIMATED ANNUAL CONC.. UG/M3 (RURAL)
29.00
80.00 61.00 62.00 83. OO 84.00 85.00 86.00 87.00
FIGURE 2-12 EXAMPLE OF A COMPUTER GENERATED GROUND LEVEL ISOPLETH PLOT
2-75
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can be used to extrapolate concentrations monitored onslte to offslte
locations. An Illustration of modeling results for this application is
provided 1n Figure 2-13.
Meteorological data summaries should Include the following at a minimum:
Daytime wind rose (only for coastal or complex terrain areas)
Nighttime wind rose (only for coastal or complex terrain areas)
• Summary wind rose
Summary of dispersion conditions for the sampling period (Joint
frequency distributions of wind direction versus wind speed
category and stability class frequencies based on guidance
presented 1n Guidelines on Air Quality Models (Revised) (U.S. EPA,
July 1986)
Tabular summaries of means and extremes for temperature and other
pertinent meteorological parameters
• Data recovery summaries for all parameters
Statistical summaries for the meteorological data should be presented on
a monthly, seasonal, and annual basis as well as for the entire modeling
period. For sites with diurnal wind patterns (e.g., complex terrain or
coastal areas), the modeling should Include separate wind roses for daytime
and nighttime conditions and a summary wind rose (for all wind observations
during the monitoring period).
Data recovery Information should also be presented to evaluate data
representativeness. A minimum data recovery target should be 90 percent.
2-76
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CO
ro
t-I
S
g
t-i
i
I
i
ATMOSPHERIC DILUTION PATTERN
NEAREST RECEPTORS
MONITORING STATIONS
DILUTION FACTOR ISOPLETHS
(RATIO OF DOWNWIND CONCENTRATION/FACILITY PROPERTY BOUNDARY CONCENTRATION)
-------
2.6.3 Evaluate Modeling Results
Modeling results should be carefully evaluated and Interpreted to
provide Input to the Superfund risk assessment process. Factors that should
be considered during this data evaluation phase Include the following:
• Modeling concentrations
• Source receptor relationship
Need for supplemental analyses
Modeling results should also be compared to ARARs considering the above
data Interpretation factors. In addition, Interpretation of dispersion
modeling results should account for additional factors such as complex
terrain, variable winds, multiple contaminant sources, and Intermittent or
Irregular releases.
Modeling Uncertainties
The uncertainties associated with dispersion modeling results should be
quantified, If feasible, and evaluated. Uncertainty factors have been
defined and discussed 1n Section 2.3. The UP values associated with air
concentration estimates should be based on uncertainties associated with
input emission rate values and meteorological data as well as the accuracy of
the dispersion model. This can be accomplished as follows:
UFTQT= (UFER)Z+(UFMET)Z + (UFDM)Z ( 2-1)
where
UFiOT a Uncertainty Factor for air concentration estimate, which
accounts for the accuracy of the Input data as well as
limitations of the dispersion model.
UFER • Uncertainty Factor associated with emission rate estimates
UFMET ° Uncertainty Factor associated with meteorological data
2-78
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UFQM = Uncertainty Factor associated with the dispersion model
The UFER values for emission rate estimates should be based on
Information presented 1n Volumes II and III. Meteorological monitoring
accuracies presented 1n Section 3.0 of this volume should be used to
determine UFMET values. Model-specific UFQM values should be based on
Information presented in the Individual user's manuals and in model
performance studies that have been conducted by the EPA and other
organizations. In general, dispersion estimates are associated with
accuracies of plus or minus a factor of 2 to 3 for flat terrain
applications. However, for complex terrain applications, modeling estimates
can be inaccurate by more than an order of magnitude for some situations.
The UF values account for the accuracy of modeling predictions of
maximum concentrations. However, field validation studies have demonstrated
that the predicted locations of maximum concentrations based on modeling
results may not correspond with the location of the maximum value based on
field measurements. Therefore, for Superfund APA applications 1t 1s
necessary to define a geographic area of applicability for dispersion
modeling results.
The geographic area of applicability 1s defined as the area in which the
receptor of Interest 1s located. It accounts for limitations of the
dispersion model to predict the exact location of maximum concentrations.
Therefore, the maximum concentrations that occur within the geographic area
of applicability could potentially occur at the receptor of Interest.
Example criteria for Identifying the geographic area of applicability
for dispersion modeling results relevant to receptors of Interest are
presented 1n Table 2-11. The geographic area of applicability can be
specified 1n terms of a sector width and a range of downwind distances. The
criteria for the geographic area of applicability are a function of the
modeling time frame (long term versus short term), site terrain (flat versus
complex), and -the representativeness of the meteorological data (onsite
versus offsite). The criteria presented In Table 2-11 are least restrictive
(I.e., smallest geographic area of applicability) for long-term modeling
2-79
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Table 2-11.
Example Criteria for Identifying the Geographic Area of Applicability for
Dispersing Modeling Results Relevant to Receptors of Interest*
Based On Ons1te
Meteorological Data
Based on Offsite
Meteorological Data
Lona Term fz 24 hrs)
• Flat Terrain
• Complex Terrain/
Coastal Locations
ShorMTerni f<24 hrs)
• Flat Terrain
• Complex Terrain/
Impact
Sectors**
R
R ± 22.50
R ± 22.50
R ± 22.50
Downwind
Impact
X
X
X
X ± 0.1X
Impact
Sectors**
R ± 22.50
R ± 22.50
R ± 22.50
R ± 22.50
Downwi nd
Impact
X
X ± 0.
X
X ± 0
X ± 0
1 X
.IX
.2X
Coastal Regions
* The geographic area of applicability 1s defined as the area 1n which the
receptor of Interest 1s located which accounts for conditions of the
dispersion model to predict the exact location of maximum
concentrations. Therefore, the maximum concentration which occurs
within Its geographic area of applicability could potentially occur at
the receptor of interest.
** Sector R 1s defined as the 22.5 degree sector 1n which the receptor of
Interest is located
*** X Is defined as the downwind distance from the source to the receptor
of Interest.
2-80
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results at flat terrain sites with onsite meteorological data. The criteria
are most restrictive (i.e., greatest geographic area of applicability) for
short-term modeling results at complex terrain/control sites with only
offsite meteorological data available. Site-specific modeling factors may
warrant modifications to the criteria presented in Table 2-11.
Source/Receptor Relationship
Source/receptor relationships should be evaluated based on dispersion
patterns and gradients. Isopleth plots and tabular summaries should be
evaluated to Identify the most restrictive exposure conditions. For short-
term modeling results (i.e., less than 24 hours) the maximum offsite
concentration values should be selected considering all publicly accessible
locations. The most restrictive exposure conditions based on short-term
modeling results should be characterized by the actual receptor locations
with the maximum predicted concentration. These maximum short- and long-term
concentration events should be evaluated by calculating HI values.
Procedures for the calculation of the HI values have been presented in
Section 2.3
An example format is presented in Table 2-12 for evaluation of HI values
for toxicants and carcinogens at receptor locations associated with maximum
concentrations. As indicated in Table 2-12, 1t is Important to determine the
relative impacts for each source type. This source-specific impact
information Is useful for the RPM/EPM to develop a cost-effective strategy
(which may Involve technical and/or administrative measures) to mitigate
potential exceedances of health criteria. For example, remediation sources
may Involve soil handling activities and an air stripper. Evaluation of HI
values by source type may indicate that the greatest impacts are associated
with soil handling operations. Based on the Insight, the RPM may decide to
limit certain soil handling operations during adverse meteorological
conditions. However, 1t may be useful to Identify the relative Impacts of
each of the subclasses (e.g., excavations, haul roads, storage piles, etc.)
associated with soil handling air emission sources.
Table 2-12 also facilitates the evaluations of modeling results relevant
to constituent-specific health criteria. At a minimum, the modeling
2-81
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Table 2-12.
Example Format for Evaluation of Hazard Index for Toxicants and Carcinogens at
Receptor Locations Associated with the Maximum Concentrations
Toxicants
Carcinogens
Controlled Sources
• Landfills
• Lagoons
• Contaminated Soil
Surfaces
• Containers
(above-ground)
SUBTOTAL
• Background
TOTAL
Remediation Sources
• Soil Handling
• A1r Stripper
• Incinerator
• In-S1tu Venting
• Solidification/
Stabilization
SUBTOTAL
• Background
TOTAL
Constituent-Specific Hazard Index
Values
A B C D E Etc.
•
Hazard
Index
for Mix
Constituent-Specific Hazard Index
Values
A B C D E Etc.
,
Hazard
Index
for Mix
IN)
00
IN)
-------
Table 2-12.
Exanple Format for Evaluation of Hazard Index for Toxicants and Carcinogens at
Receptor Locations Associated with the Maxima Concentrations
Toxicants
Carcinogens
Controlled Sources
• Landfills
• Lagoons
• Soil Surfaces
• Containers
(above-ground)
SUBTOTAL
• Background
TOTAL
Constituent-Specific Hazard Index
Values
A B C 0 E Etc.
Hazard
Index
for Mix
Constituent-Specific Hazard Index
Values
A B C 0 E Etc.
Hazard
Index
for Mix
00
-------
constituents selected based on the procedure discussed 1n Section 2.3.2 and
Illustrated 1n Figure 2-6 should be Included 1n this evaluation.
Constituent-specific as well as total-mix HI values should be computed for
each source and for all sources combined. A realistic assessment of
potential Impacts should also Include combinations due to background
concentrations from offslte sources. The HI values should be computed
separately for toxicants and carcinogens. These evaluations can be used as
Input to the Superfund risk assessment process.
An example format for evaluation of HI values relevant to ARARs Is
presented 1n Table 2-13. It 1s recommended that source-specific HI values as
well as a total-site HI value be computed for each ARAR.
Supplemental Analyses
Supplemental analyses may be warranted at complex terrain or coastal
locations 1n order to apply dispersion modeling results to Superfund APA
applications. These supplemental analyses may Involve additional modeling
(e.g., wind flow field models, physical models, specialized mesoscale models)
to characterize local transport and/or diffusion conditions. Frequently 1t
may be necessary to conduct specialized field studies that may Involve
Intensive meteorological monitoring materials and/or tracer studies.
Figures 2-14 and 2-15 Illustrate an example application of supplemental
analyses. This Superfund site 1s located on the sloping terrain of a valley
wall. Available dispersion models could not adequately characterize the very
localized dispersion conditions. However, receptors were located at the site
perimeter, and 1t was necessary to characterize potential Impacts associated
with soil handling operations at the onslte landfill. Smoke and SFe tracer
studies were used to define transport paths for typical drainage flow
conditions. These results are summarized 1n Figure 2-14. Results from the
tracer studies were also used to develop a site-specific dispersion model.
These results are summarized in Figure 2-15.
Supplemental analyses can be expensive and result 1n project schedule
delays. Therefore, these analyses are generally only warranted 1f
2-84
-------
TABLE 2-13
EXAMPLE FORMAT FOR EVALUATION OF HAZARD INDEX VALUES RELEVANT TO ARARs AT
LOCATIONS ASSOCIATED WITH MAXIMUM CONCENTRATIONS
Uncontrolled Sources
• Landfills
• Lagoons
• Contaminated Soil
Surfaces
• Containers (above-
ground)
SUBTOTAL
• Background
TOTAL
Remediation Sources
• Soil Handling
• A1r Stripper
• Incinerator
• In-SItu Venting
• Solidification/
Stabl1zat1on
SUBTOTAL
• Background
TOTAL
Controlled Sources
• Landfills
• Lagoons
• Soil Surfaces
• Containers (above-
ground)
SUBTOTAL
• Background
TOTAL
ARAR-Spec1f1c Hazard Index Values
a
b
c
d
e
etc.
•
2-85
-------
Wm '*
g
CD
Drainage MUM Saokc Test Results
-------
ro
CD
7*
H*
Ul
S
>—i
*
SPiOHC ATMOSPHERIC DISPERSION
FACTOR
DILUTION
FACTOR
DILUTIO
ON FACT
-------
unacceptable offsite air pathway Impacts have been predicted based on
application of standard dispersion models and modeling procedures.
2.6.4 Prepare A Report
A report summarizing the results of the dispersion calculations should
be prepared. It should Include the elements of the modeling plan discussed
In Section 2.4. These elements basically outline the overall methodology for
the modeling. The following Is a recommended outline for the report:
I Introduction
II Methodology
Constituents To Be Modeled
Emission Inventory
Receptor Grid
Detailed Modeling Methodology
Estimated Background Concentrations
III Modeling Results
Short- and Long-Term Concentrations
Areas of Potential Impact
Comparison with Applicable A1r Toxics Guidelines
IV References
V Appendices
Meteorological Data
Emission Inventory
Model Testing
Detailed Modeling Printout
2-88
-------
The report should Include a sufficient amount of explanation of the
methodology and results. Figures such as Isopleths of concentrations are
highly recommended.
2.7 EXAMPLE APPLICATION
A screening assessment (based on emission/dispersion modeling)
commensurate with Volume I recommendations was conducted to characterize
hazardous air constituents being released from an Inactive wood treatment
facility that had been placed on the NPL. Evaluation of these screening
results Indicated that 1t was necessary to conduct a dispersion modeling to
more accurately quantify air emissions from the site to support preparation
of an RI/FS.
Collect and Review Information
The site 1s an Inactive 12-acre wood treatment facility located 1n a
flat Inland area of the southeast. At one time, creosote and
pentachlorophenol were used as wood preservatives; heavy metal salts were
also used. The creosote and pentachlorophenol were disposed of 1n a surface
Impoundment. Past waste disposal practices Included treatment and disposal
of the metal salts 1n a surface Impoundment and disposal of contaminated wood
shavings 1n waste piles. The constituents of concern 1n the facility's waste
stream Include phenols, cresols, and polycycllc aromatic hydrocarbons (PAHs)
1n the creosote; d1benzod1ox1ns and dlbenzofurans as contaminants 1n
pentachlorophenol; and partlculate heavy metals. The potential emission
sources (Figure 2-16) Include the container storage facility for creosote and
pentachlorophenol, the wood treatment and product storage areas, the surface
Impoundment for the creosote and pentachlorophenol wastes, and the
contaminated soil area, which previously contained both the surface
Impoundment for treating the metal salts and the wood shavings storage area.
Seepage from these waste management units has resulted 1n documented ground-
water and surface water contamination.
The area surrounding the facility has experienced substantial
development over the years. A shopping center 1s now adjacent to the eastern
2-89
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INACTIVE SURFACE
IMPOUNDMENT ANQ
CONTAMINATED
WOOD SHAVINGS
STORAGE APEA
AERATED
SURFACE
IMPOUNDMENT
OFFICE Q
TREATMENT
AND PRODUCT
STORAGE AREAS
CONTAINER
STORAGE
FACILITY
•4 h-
GATE
PREVAILING
WIND
OIPECTON
FIGURE 2-16
EXAMPLE SITE PLAN FOR AIR DISPERSION MODELING
2-90
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site perimeter. This development has significantly Increased the number of
potential receptors of air releases of hazardous constituents.
To perform an adequate air dispersion modeling, the composition of
wastes handled 1n each waste management unit was first determined to Identify
which constituents were likely to be present 1n the air releases. Existing
water quality data Indicated contamination of groundwater with cresols,
phenol, and PAHs, and of surface water with phenols, benzene, chlorobenzene,
and ethylbenzene. A field sampling program was developed to further
characterize the facility's waste stream. Wastewater samples were collected
from the aerated surface Impoundment, and soil samples were collected from
the heavy metal salt waste treatment/disposal area. Analytical data from
this sampling effort confirmed the presence of the constituents previously
Identified. Additional constituents detected Included toluene and xylenes 1n
surface Impoundment wastes, and arsenic, copper, chromium, and zinc 1n the
treatment/disposal area.
Select Modeling Sophistication Level
A screening air dispersion modeling was performed as a part of the
planning stage for the project. It addressed a few receptors at the site
perimeter. The increase 1n development 1n the vicinity of the site and the
associated Increase in the number of potential receptors that could be
exposed to air toxics releases from the site required the use of refined
dispersion modeling 1n support of the RI/FS activities.
It was determined that the ISC dispersion model 1s the preferred model
for this applications because
• The sources Involved resemble Industrial sources similar to the
ones the model was developed for.
The topography 1s gently rolling and no major topographical
obstruction exist.
The ISC dispersion model was employed successfully for a Superfund
site similar to the one under consideration.
2-91
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Develop Modeling Plan
Based on their Individual emission potentials (as determined from waste
analyses and confirmatory emission rate modeling) and potential for
presenting health and environmental hazards, the following target
constituents were selected for use 1n the dispersion modeling:
• Volat1le/sem1volat1le constituents
Toluene
Benzene
Total phenols
Pentachlorophenol
Polycyclic aromatic hydrocarbons
Cresols
• Part1culate constituents
Arsenic
Copper
Chromium
Z1nc
The target constituents list was then evaluated 1n terms of prevalence
of constituents' 1n each of the four sources and the Information available
about the activities Involved with each source (see Table 2-14).
Emission predictive equations were Identified using Volume II Technical
Protocol and- Procedures for Developing Baseline A1r Emission Estimates, of
the Procedures for Conducting A1r Pathway Analysis for Suoerfund Application.
for the sources Involved. This Included
Predictive lagoon equations for the Inactive surface Impoundment
and the aerated surface Impoundment for organic*, and predictive
fugitive dust equations for Inorganics
2-92
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TABLE 2-14
TARGET CONSTITUENTS MODELED FOR EACH OF THE SOURCES AT THE SITE
Indicator
Constituents
Organ 1cs - gases
Toluene
Benzene
Total phenols
Pentaoch 1 orophenol
PAHs
Cresols
Inorganics -
part 1cu late
Arsenic
Copper
Chromium
Z1nc
Source
Inactive
Surface
Impoudnment
X
X
X
X
X
X
X
X
X
X
Aerated
Surface
Impoundment
X
X
X
X
X
X
Treatment
and Product
Storage
Areas
X
X
X
X
X
X
X
X
X
X
Container
Storage
Facility
X
X
X
2-93
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• Predictive closed landfill equations for the treatment and product
storage areas and the container storage facility, and predictive
fugitive dust equations for Inorganics
Onslte meteorological monitoring from a 10-meter tower provided 3 months
of data. These data were used to evaluate the applicability of
meteorological data available from an NWS station located about 25 kilometers
southeast of the site. The evaluation of wind data showed that
Offsite meteorological data correlate reasonably with the onslte
data for the same time period. Wind direction data for off site
areas show the same pattern as those for onslte areas: an apparent
small shift of about 10 to 15 degrees. The frequency distribution
of wind speed and direction by stability 1s within about 20-30
percent.
• No major topographical features.or water bodies exist between the
NWS station and the site.
It was decided to use 5 years of meteorological data from the NWS
station. This Included both surface and upper air data.
Considering prevailing wind directions, source characteristics (ground
level releases), population distribution 1n the site vicinity, and other
sensitive receptor locations, 1t was decided to set up a grid as follows:
Program adjust all stack heights for downwash • No. (=1)
For modeling purposes, concentrations were averaged every 24 hours and
annually.
Background concentrations for the Indicator compounds were obtained from
a 1-month perimeter monitoring program conducted at the site. The background
concentrations were obtained from upwind stations utilizing the onslte data.
2-94
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Conduct Modeling
The emission Inventory for the Indicator compounds was developed based
on the methodology outlined 1n the modeling plan. Data were Input Into the
ISC dispersion model. Meteorological data from the NWS station were
preprocessed to generate hourly data used by the ISC dispersion model.
Receptor coordinates based on the receptor developed were Input Into the
model.
All Input data wwere checked and verified before the files were linked
to the model. A test run was performed to verify that the model performed as
specified.
Dispersion calculations were performed for each of the Indicator
constituents, and computer printout were obtained. Individual runs were made
for the various Indicator constituents.
Summarize and Evaluate Results
Results of the calculations were checked to ensure that no errors were
made with the Input data. Three hand calculations were made to determine the
arsenic concentration at a selected receptor to verify that the model
calculations are correct. Ground-level concentrations were summarized for
each Indicator constituent by considering the highest and second highest 24-
hour concentrations and 24-hour concentrations at sensitive receptors.
Isopleths of annual concentrations were plotted for the Indicator
compounds 1n a format similar to the one shown 1n Figure 2-10.
Prepare a Report
A report summarizing the results of the dispersion calculations and the
detailed methodology was prepared. The calculations were based on readings
obtained at receptors arranged 1n a rectangular grid (see Figure 2-17) with
Intervals of 100 meters for the area close to the site and on the site
perimeter; 200 meters for the area from the site perimeter to about 1
kilometer from the center of the site; 500-meters for the,area between 1 and
2-95
-------
N
i1
• •
• • • • • •
• • • • • •
• •
prevailing
Mind
direction
• •
site
area
• •
FIGURE 2-17 RECEPTOR GRID CLOSE THE SITE
2-96
-------
2 kilometers from the center of the site; and 1 kilometer for the area
between 2 and 5 kilometers from the center of the site.
This receptor distribution was considered adequate to cover offsite
publicly accessible locations and sensitive environmental receptors.
In the latter case, 1t was determined that most of the development took
place up to about 2 kilometers from of the site and mainly to the east.
The model selected was the ISC dispersion model. It was considered most
suitable for this application. Both the short- and long-term calculations
were performed. Key model switches Included
• Calculate concentration (=1)
• Discrete receptor system - rectangular (=1)
• Terrain elevations are read - no (=0)
• Compute average concentrations for 24 hours - yes (=1); for other
averaging times - no (=0)
• Print highest second highest tables - yes (=1); maximum 50 tables -
yes (=1)
• Rural-urban option - rural (=1)
• Wind profile exponent values - default (-1)
• Vertical potential temperature gradient values - default (=1)
• Program calculates final plume rise only - no (=2)
2-97
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SECTION 3
AIR CONCENTRATION MONITORING PROCEDURES
3.1 OVERVIEW
A1r concentration monitoring is an air pathway analysis (APA)
approach that provides direct measurements of air contamination levels for
receptor locations of interest. However, this approach is limited to
existing sources. Also, monitoring methods with detection levels
commensurate with health criteria may not be available for all
contaminants of interest. This section provides procedures for the
selection and application of air monitoring approaches for Superfund APAs.
Superfund activity and source-specific recommendations concerning air
monitoring applications have been presented in Volume I. A cross-
reference to these recommendations and a summary of potential Superfund
air monitoring applications are presented in Table 3-1. A review of Table
3-1 indicates that air monitoring applications are directly related to
specific Superfund activities. Therefore, the technical information and
recommendations 1n this section are frequently presented on a Superfund
activity-specific basis.
The procedures for air monitoring APAs presented in this section are
based on a five-step process (illustrated in Figure 3-1):
Step 1 - Collect and review input Information
Step 2 - Select monitoring sophistication level
3-1
-------
TABLE 3-1
SUMMARY OF AIR MONITORING APPLICATIONS
Source Classification
APA Recommendations
Superfund Activities
Atr Monitoring Applications
Uncontrolled source
Characterize baseline air
concentrations
RI/FS - Screening/Refined
Screening APA
Preliminary baseline air
quality data and Information on
emissions
Atr quality data In support of
the design of a refined air
monitoring program to support
the RI/FS (I.e.. preparation of
site-specific Mork Plan and
Field Sampling and Analysis
Plan)
Uncontrolled source
Characterize baseline air
concentration
RI/FS - Refined APA
i
IN)
Comprehensive baseline air
quality for onslte. perimeter.
and offslte.
Data are used as risk
assessment Input for the no-
action alternative
Data are used In evaluating
remedial alternative actions
Remediation source
Characterize air concentration
during remedial/removal activities
Remedial design (pilot field
studies)
Mork area, perimeter, and
offstte air monitoring program
In support of pilot field
studies
Data are used to assess worker
exposures and estimate the
effect on the public and the
environment during the remedial
action
-------
TABLE 3-1
SUMMARY OF AIR MONITORIMG APPLICATIONS (Continued)
Source Classification
APA Recommendations
Superfund Activities
Air Monitoring Applications
Remediation source
Characterize air concentrations
during rewdlal/removal activities
Remedial actions I fun-scale
operations)
worn area, perimeter, ana
offsite air Monitoring program
In support of cleanup
activities
Data are used to protect
workers, the public, and the
environment under routine and
nonrouttne air releases
Controlled source
Confirm controlled source air
concentrations
Operation and maintenance
(post-remedial activities)
Perimeter and offslte program
to evaluate the performance of
the remedial action
Data are used to verify the
effectiveness of the remedial
action In protecting public
health and the environment
-------
•f»Xat*0«l A«t.M
A^A QuMfMifle>o)
V0l«. Ill * IV
COLLECT AND REVIEW
INFORMATION
o Source Data
o Receptor Data
o Environmental
Characteristics
Available
Monitoring/
Modeling
Data
SELECT MONITORING
SOPHISTICATION LEVEL
o Screening
o Refined
EPAXNIOSM
Monitoring
Guidelines
1
MevlowXNPM
Approval
CONDUCT MONITORING
e Routine Operation
o Quality Control
o Reid Documentation
INPUT TO
PA MMBDUU
MMOVAI.
Figure 3-1. auperfund Air Pathway Analysea Air Monitoring Protocol.
3-4
-------
• Step 3 - Develop monitoring plan
• Step 4 - Conduct monitoring
• Step 5 - Summarize and evaluate results
The following 1s a brief discussion of each of these steps.
Step 1 - Collect and Review Input Information—This initial step
addresses the process of collecting and compiling existing. Information
pertinent to the air monitoring program based on a literature survey. It
includes obtaining available source, receptor, and environmental data.
Once the existing data have been collected, compi.led, and evaluated, data
gaps can be defined and a coherent air monitoring plan developed based on
the site-specific requirements.
Step 2 - Select Monitoring Sophistication Level—This step Involves
the selection of the air monitoring sophistication level considering
screening, refined screening, and refined monitoring techniques. This
selection process depends on program objectives as well as available
resource and technical constraints. Technical aspects that should be
considered include the availability of appropriate monitoring and analysis
techniques for the Superfund 11st of toxic constituents. Monitoring
approaches should be evaluated considering constituent-specific factors,
Including detection limits, performance criteria (e.g., precision,
accuracy), and advantages and disadvantages of alternative methods.
Step 3 - Develop Monitoring Plan—This step involves preparation of
an air monitoring plan. Elements that should be addressed in the plan
Include (a) selection of monitoring constituents, (b) specification of the
meteorological monitoring program, (c) specification of the monitoring
network design (I.e., number and location of monitoring sites, probe
siting criteria, sampling and analysis methods, and program duration and
frequency of monitoring), (d) development of project data quality
objectives (DQOs) and sampling and analysis quality assurance (QA) and
quality control (QC) procedures, and (e) documentation of the air
monitoring plan.
3-5
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Step 4 - Conduct Monitoring—This step Involves the day-to-day
activities of conducting an air monitoring program at a Superfund site.
It Includes the following: (a) routine equipment operation and
maintenance, (b) sampling calibrations and checks, (c) audits, (d)
handling of samples, (e) field documentation, (f) maintenance of
laboratory data and records (including chain-of-custody forms), and (g)
other QA/QC procedures necessary to ensure a successful monitoring
program.
Step 5 - Summarize and Evaluate Results—This step Involves reviewing
data and evaluating air monitoring results for validity. Additional
components of this step should include (a) data processing,
(b) preparation of statistical summaries, (c) comparison of upwind and
downwind concentration results, and (d) concentration mapping, if
possible. Estimates of data uncertainties based on Instrument limitations
and analytical technique Inaccuracies should also be obtained and used to
qualify air monitoring results.
The following subsections present an expanded discussion of each of
these steps.
3.2 STEP 1 - COLLECT AND REVIEW INPUT INFORMATION
3.2.1 Overview
The first step 1n the design and Implementation of an effective air
quality monitoring program 1s the compilation and evaluation of available
Information via a literature search. A summary of this process is
presented In Figure 3-2.
3-6
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SOURCE DATA
o Sit* Layout Map
o Sourea Specifications
o Contaminants List
o Toxlclty Factors
o Offslta Sources
RECEPTOR DATA
o Population Distribution
o Sanaltlva Racaptors
o Slta Work Zonaa
o Local Land Uaa
ENVIRONMENTAL DATA
o Dlaparslon Data
o Climatology
o Topography
o Soil and Vagatatlon
PREVIOUS APA DATA
o Motoorologleol
Monitoring Dots
o Bmloolon Rato Modallngx
Monitoring
o Dlaporslon Modeling
o Air Monitoring
o ARAR Summary
COLLECT
AVAILABLE
INFORMATION
COMPILE
AND
EVALUATE
INFORMATION
(TABLE 3-2)
INPUT
TO
STEP 2 - Salaot Monitoring
Sophlatlcatlon Laval
AND
STEP 3 - Davalop Monitoring
Plan
nguro 3-a. Stop 1 - Colloot and Rovtow Input Information.
3-7
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The following information, at a minimum, should be collected and
reviewed to support air monitoring program design:
• Source data
• Receptor data
• Environmental data
Previous APA data
Most of the site-specific information required for Step 1 is
available from the Superfund remedial project manager/enforcement project
manager (RPM/EPM). The quality of available Information will depend on
the nature and extent of the previously performed studies. For example,
information available at the initiation of the Remedial
Investigation/Feasibility Study (RI/FS) may be limited in nature.
However, information available for the implementation of remedial actions
could be very thorough depending on the level of effort and extent of the
RI/FS. In any event, available information and data should be evaluated
for the following factors:
Technical soundness of methodologies employed
Completeness and quality of the data, Including detection
limits, precision, and accuracy
• Quality assurance/quality control 1n support of the information
gathered
Compatibility and applicability of the data
Data gaps
3-8
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Supplemental information gathered through a literature search is
available from records and documents from sources such as the following:
U.S. Environmental Protection Agency (EPA)
• State and local agencies
• Contractor studies
National Weather Service (NWS)
• Other Federal Government offices
The information collected during Step 1 should be documented using a
form similar to the example presented in Table 3-2. This form should be
used to identify and evaluate available data. In addition, copies of data
summaries should be attached to the form to provide a convenient, complete
documentation package.
The following subsections provide a further discussion of the various
types of data that should be collected during Step 1.
3.2.2 Source Data
Site-specific information on the nature and extent of the
contamination is useful 1n estimating the magnitude of air emissions from
each of the source areas and in defining the primary emission
constituents. The data should be available from the Superfund RPM/EPM.
Specific information that should be collected and evaluated Includes the
following:
Specific source areas at the site and their estimated locations,
configuration, and dimensions based on Information about past
contamination. (Example source areas are lagoons, drainage
ditches, landfills, contaminated soil surfaces, drums, tank and
container areas, and structures within processing facilities.)
Constituents associated with each source area, grouped as
organ1cs (volatiles, semlvolatlles, base neutrals, pesticides.
3-9
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TABLE 3-2. EXAMPLE - SUPERFUND AIR MONITORING PROGRAM INPUT INFORMATION FORM
Data Type
Source Data
• Site Layout Map
• Source Specifications
• Conttalnants List
• Contaminant Toxlclty
Factors
• Offslte Sources
Receptor Data
• Population Distribution
Map
• Identification of
Sensitive Receptors
• Site Work Zones Map
• Local Land Use
Environmental Data
• Dispersion Data
- Mind Direct Ion/Mind
Speed
- Atmospheric Stability
Data Obtained
(Yes or No)
(Attachment
No.)
Evaluation Factors
Technical
Methods
Employed
Acceptable
(Ves or No)
Completeness
and Quality
of Data
Acceptable
(Ves or No)
QA/QC
Appropriate
(Ves or No)
Data
Relevant for
this
Application
(Ves or Ho)
Data Gaps
Significant
(Ves or No)
Comments
I
t—•
o
-------
TABLE 3-2. EXAMPLE - SUPERFUND AIR MONITORING PROGRAM INPUT INFORMATION FORM (Continued)
Data Type
Lnvlroranenta.1 Data (Cont'd)
• Climatology
- Temperature
- Humidity
- Precipitation
• Topographic Maps
- Site
- Local Area
• Soil and Vegetation
Previous APA Data
• Emission Rate Modeling
• Emission Rate Monitoring
• Dispersion Modeling
• Air Monitoring
• ARAR Summary
Data Obtained
(Yes or No)
(Attachment
No.)
Evaluation Factors
Technical
Methods
Employed
Acceptable
(Ves or No)
Completeness
and Quality
of Data
Acceptable
(Ves or No)
QA/QC
Appropriate
(Yes or No)
Data
Relevant for
this
Application
(Yes or No)
Data Gaps
Significant
(Yes or No)
Comments
-------
PCBs) and Inorganics (metals and other toxic compounds [e.g.,
H2S, HCN1).
Toxldty factors Important in evaluating the potential risk to
human health and the environment and accounted for 1n the design
and Implementation of air monitoring programs.
• Identification and description of offsite air emission sources.
3.2.3 Receptor Data
Receptor data, when coupled with source data, can provide the basis
for a cost-effective air monitoring program design for a Superfund
project. Receptor information that should be collected and evaluated
includes the following:
• Results of air dispersion modeling showing locations of
calculated high-ground-level concentrations of air toxics
constituents emitted from the site and from other nearby sources
• Upwind and downwind receptor locations based on prevailing wind
conditions at the site
• Population distribution by 22.5-degree sectors 1n 1- to 2-
kllometer increments for a distance of 10 kilometers from the
site
• Sensitive receptors within 10 kilometers of the site and
Individual residences and buildings within 1 to 2 kilometers of
the site
Site work zones as identified in the Health and Safety Plan
Local land use characterization (e.g., residential, commercial)
within 10 kilometers of the site
3-12
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Sensitive receptor locations Include schools and hospitals associated
with sensitive population segments, as well as locations where sensitive
environmental flora and fauna exist, Including parks, monuments, and
forests.
3.2.4 Environmental Characteristics
Existing Information on environmental characteristics pertinent to a
Superfund site 1s a necessary component for defining air pathway exposure
potential. Environmental characteristics data that should be considered
Include the following:
Dispersion characterization data Including wind direction/speed
and atmospheric stability summaries
CUmatologlcal data- representative of the site area. Including
wind, precipitation, temperature, and humidity conditions
Topographic features and water bodies at the site and vicinity
Soil and vegetation characteristics of the site and vicinity
Other environmental settings that could affect the number,
location, and type of air monitoring stations, Including
sensitive environmental species
Existing representative dispersion and c11matolog1cal data will be
useful 1n evaluating the numbers and locations of air monitoring stations.
Wind data can be used for evaluating candidate upwind and downwind
locations for air monitoring. Wind data, atmospheric stability, ambient
temperature, and mixing height data can be used, coupled with one of the
air dispersion models described In Section 2, to provide estimated
calculated concentrations for the constituents of Interest at locations of
maximum Impact. Temperature and humidity data could provide some
3-13
-------
information on the potential for volatilization. Precipitation data
provide some Insight on the potential for wind erosion of participates.
Topographic features and water bodies could affect the dispersion and
transport of airborne air toxic constituents. It is therefore Important
to understand local wind flows and to identify areas with topography
and/or water bodies that could influence the dispersion and transport of
constituents released from the site. For example, a site located
downslope of an elevated terrain feature could be affected by nighttime
downslope drainage flows. Topographic features should also be considered
in siting air monitoring stations to avoid natural obstructions.
Large water bodies could affect atmospheric stability conditions and
the dispersion of air contaminants. In general, large water bodies tend
to increase the stability of the atmosphere 1n the air layer adjacent to
the water, thus reducing the dispersion of air contaminants.
Soil characteristics and conditions can affect air emissions from
Superfund sites and the wind erosion of contaminated surface soils. It is
therefore important to understand soil conditions such as porosity,
particle size distribution, soil type, and source data.
Vegetation, Including shrubs and trees, can be a factor 1n siting an
air monitoring station due to flow obstructions and accessibility. In
addition, vegetation could affect air releases because of the Increase in
soil coverage and air flow because of the Increase 1n surface roughness.
It is therefore Important to obtain pertinent Information for use in the
design of the air monitoring network.
Similarly. 1t 1s Important to obtain and evaluate data on other
environmental settings to ensure that a balance 1s maintained 1n selecting
the numbers and locations of air monitoring stations.
3-14
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3.2.5 Previous APA Data
The Superfund APA recommendations presented 1n Volume I specify the
conduct of emission rate modeling/monitoring and dispersion modeling as a
prerequisite to an air monitoring study. Therefore, the following data
should be available from previous APAs and should be collected and
reviewed:
• Onsite meteorological monitoring data
• Emission rate modeling data
• Emission rate monitoring data
• Dispersion modeling data
• A1r monitoring data
• Applicable or relevant and appropriate requirements (ARAR)
summaries that Identify air toxic exposure criteria
These APA data are significant Input to development of a site-
specific air monitoring program. Therefore, site- and source-specific
APAs to estimate emission rates and air concentrations (via dispersion
modeling) should be conducted to provide these Inputs pursuant to
recommendations specified 1n Volume I. Procedures for characterizing
baseline air emissions from Superfund sources are presented in Volume II,
and procedures for characterizing air emissions from remedial actions are
available 1n Volume III. Procedures for the conduct of dispersion
modeling studies to support Superfund APAs are presented in Volume IV,
Section 2. A discussion of Federal ARARs and sources of Information on
state ARARs 1s provided in Volume I.
Previous air quality data available for the site area that address
air concentrations of constituents known to exist at the site can provide
3-15
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Insight on the existing levels of air toxic constituents of Interest.
Compound-specific Information will be useful in assessing what Indicator
compounds should be monitored and what monitoring and analysis
methodologies should be employed.
Existing air quality data should be evaluated for acceptable
quantity, quality, and representativeness before use. Factors to be
accounted for 1n these evaluations include
Monitoring and analysis techniques employed during the air
monitoring program. These include the type of techniques
(screening, refined screening, or refined monitoring),
associated detection limits, accuracy, and precision for the
constituents monitored.
Mix and number of compounds monitored and analyzed for. This
information 1s Important to determine the degree of Interference
between the compounds Involved. Such a matter often limits the
usefulness of nonspecific compound screening analysis
procedures, since the response from background compounds may
overwhelm any response because of small levels of the compounds
of Interest.
• Records about equipment performance, maintenance, and
calibration.
Records of audits performed to evaluate program quality.
• Detailed description of the monitoring station setting to allow
for an evaluation of the station siting. Consideration is given
to siting criteria such as proper sample Intake exposure, proper
height above ground, and avoidance of man-made and natural
obstructions that could affect or alter the air flow near the
sampler Intake.
3-16
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Existing air dispersion modeling for the site area could be useful in
evaluating locations for ambient air monitoring stations. The objective
of the dispersion modeling, together with the input data, the modeling
technique, and assumptions about the source air releases, should be
evaluated to determine the applicability and utility of the results of the
dispersion calculations. Coupled with measured air quality data, results
of air dispersion modeling offer an objective means for siting air quality
monitoring stations at locations of maximum impact. Data available from
air dispersion calculations could be used as input into the risk
assessment, which could in turn be used in selecting locations of
sensitive receptors. Procedures for the conduct of dispersion modeling
are presented in Section 2.
3.3 STEP 2 - SELECT MONITORING SOPHISTICATION LEVEL
3.3.1 Overview
The selection of air monitoring sophistication levels, including
associated sampling and analytical methods, is the cornerstone of a
successful air monitoring program. A summary of this process is presented
in Figure 3-3. The appropriate monitoring sophistication level for each
Superfund project application depends on the following factors:
• Source-specific APA recommendations (presented 1n Volume I)
Input data from Step 1 (Table 3-2)
Technical air monitoring objectives (Table 3-3)
• Overall project objectives and activity-specific air monitoring
applications (Table 3-3)
Legal and liability aspects of the Superfund project
• Pragmatic aspects of the program
3-17
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SOURCE-SPECIFIC
APA
RECOMMENDATIONS
(Volume I)
STEP 1 • INPUT
DATA
(Table 3-2)
AIR MONITORING
OBJECTIVES
(Table 3-3)
AVAILABILITY
OF APPROPRIATE
MONITORING
TECHNIQUES
(Tables 3-4 and 3-5)
MONITORING
SOPHISTICATION
LEVEL
(Figure 3-4)
STEP 3 -
INPUT
TO
Dovolop Monitoring
Plan
Rguro 3-3. Stop Z - Soloot Monitoring Sophistication Lovol.
3-18
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TABLE 3-3
SUMMARY OF TECHNICAL AIR MONITORING OBJECTIVES
Superfund Activity
Technical A1r Monitoring Objective
RI/FS-Screening APA
Provide preliminary insight about the
existence of air emissions and their
characteristics (magnitude of air
concentrations, constituents Involved and
their distribution) by performing onsite
measurements
Provide preliminary air quality baseline
(onsite and perimeter)
Provide preliminary information for onsite
exposure (workers), perimeter and offsite
exposure (population and the environment)
under existing conditions
Provide air quality data in support of the
design of a good air monitoring program
under the RI/FS step, Including components
of the Health and Safety Plan.
RI/FS-Refined APA
Provide detailed insight about the
existence of air emissions and their
characteristics (magnitude of emissions,
constituents involved and their
distribution) by performing onsite
measurements
Provide onsite air quality data during the
field investigations in support of the Work
Plan, Field Sampling and Analyses Plan and
Health and Safety Plan to protect the field
team
Provide sufficient database for performing
a detailed risk assessment of the public
and the environment based on onsite,
perimeter, and offsite air quality data
under the baseline conditions (no-action
alternative)
Provide sufficient database for performing
the evaluation of remedial alternatives
Provide ground truth to dispersion modeling
calculations.
Remedial Design (field
demonstration)
Provide onsite air quality data during the
implementation of field pilot studies in
support of the Health and Safety Plan for
this step to protect onsite workers
Provide perimeter air quality data for
preliminary assessment of the effects of
the remedial action evaluated.
3-19
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TABLE 3-3 (Continued)
SUMMARY OF TECHNICAL AIR MONITORING OBJECTIVES
Superfund Activity
Technical A1r Monitoring Objective
Remedial Action
Provide work area air quality data for
routine and nonroutlne air releases to
protect workers and to provide a guidance
for anticipated air concentration at site
perimeter and offslte
Provide work area air quality data in
support of an emergency response air
dispersion model and APA emergency field
guide (see Appendix C)
Provide perimeter and offslte air quality
data to protect public health and the
environment under routine and nonroutlne
air releases
Provide perimeter and offslte air quality
data in support of an emergency response
air dispersion model
Provide work area, perimeter, and offsite
air quality data in support of protective
actions during the remedial action
activities.
Operation and
Maintenance
Provide a long-term air quality database at
the site perimeter and offslte as a part of
assessing the effectiveness of the remedial
action Implemented
Provide a long-term air quality database at
the site perimeter and offslte to
demonstrate the protection of public health
and the environment.
3-20
-------
Duration of the monitoring program
Time to obtain results
Technical expertise of field personnel
Ability to accomplish the air monitoring program objectives
by obtaining good quality data with modest uncertainties
Source-specific APA recommendations have been presented in Volume I,
as referenced 1n Figure 3-3. These recommendations are based on a
standard sequence of APAs, as illustrated in Figure 3-4. The APA strategy
presented in Figure 3-4 is based on the premise that Initially a screening
APA should be conducted. The need for a refined APA 1s then determined
based on evaluating screening results, considering the potential to exceed
health criteria (as indicated by the Hazard Index) and monitoring
inaccuracies (as indicated by the Uncertainty Factor).
The Hazard Index (HI) for systemic toxicants 1s determined as
follows:
(3-D
AL1
where
E1 « exposure level of the 1th toxicant
A11 » maximum acceptable level for the 1th toxicant
n - total number of toxicants
3-21
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CONDUCT
SCREENING
APA
EVALUATE
HAZARD INDEX
AND MONITORING
UNCERTAINTY FACTORS
(•oo Rguro 3-6)
CONSIDER
MONITORING
DETECTION
LIMITS
INPUT TO
•PA Ml
CONDUCT
REFINED
APA
EVALUATE
HAZARD INDEX AND
MONITORING)
UNCERTAINTY FACTORS
Fl«ur» 3-4. 3*l«e«len of
Air Menlter1n0.
3-22
-------
The HI for carcinogens (hlc) 1s similar:
(3-2)
where
Ej = exposure level of the jth carcinogen
DRj = dose at a set level of risk for the jth carcinogen
m » total number of carcinogens
If any calculated HI exceeds unity (I.e., 1), then health criteria
may be exceeded. However, 1t 1s also necessary to consider the
uncertainty of modeling results. Because of these uncertainties, the air
concentrations and associated HI values could represent underestimates or
overestimates of the true HI value. Therefore, as Indicated 1n Figure
3-5, it 1s necessary to compare HI and Uncertainty Factor (UF) values to
determine the adequacy of APA results to provide exposure Input data to
characterize the potential health Impact of Superfund air emission
sources.
Based on Figure 3-5, it may be appropriate to conduct refined
monitoring as a follow-up to screening monitoring 1f Information 1s not
sufficient to definitively characterize the results. Consider the
following example:
• HI - 2 based on screening monitoring results (i.e.,
measurements Indicate that health criteria will
be exceeded by a factor of 2)
• UF = ±5 for screening monitoring results considering the
uncertainty of the monitoring/analytical method
(I.e., monitoring results may overestimate or
underestimate air concentrations by up to a
factor of 5)
3-23
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AIR PATHWAY ANALYSES
MODELING/MONITORING
RESULTS
1
COMPUTE
HAZARD INOBX
(HI)
MI1
UNOBMTAINTV FAOTOM*
HI > UF
UP > HI > 1/UP
HI < 1/UF
Information !•
Sufficient To
Choroetefize
ROlO«OO> A«
Slonlfleant
Information !•
Not Sufflolont
To Definitively
Choraotorlzo
> Roloaao
Inffermatlen !•
Suffloi«nt To
(*•!•••• As
Inslonlfleant
T
INPUT TO
EPA RBMBOIALX
REMOVAL
DECISION
MAKING
ADDITIONAL
AIM PATHWAY
ANALYSES SHOULD
BE CONSIOBREO
INPUT TO
EPA REMEDIAL/
REMOVAL
DECISION
MAKING
APA
3-Z4
-------
For this case, the HI value can be characterized as follows:
UF > HI > 1/UF (3-3)
which 1s equivalent to:
5.0 > 2.0 > 0.2 (3-4)
Therefore, for this example, based on the evaluation criteria
presented 1n Figure 3-5, 1t 1s warranted to consider the conduct of
refined air monitoring to confirm screening results.
Sophistication level recommendations presented 1n Table 3-1 should be
evaluated based on site-specific factors. For example, Input data
collected during Step 1 may Include previous air monitoring results.
Therefore, these data may provide sufficient Information to preclude the
need for screening monitoring, although refined monitoring may still be
warranted. Again the strategy Illustrated 1n Figure 3-4 and the HI/UF
evaluation criteria presented in Figure 3-5 should be used for monitoring
sophistication level selection.
The air monitoring objectives for specific Superfund activities
(e.g., RI/FS, remedial action) are also Important Input for the selection
of monitoring sophistication levels. These activity-specific objectives
are summarized 1n Table 3-3. Input from the RPM/EPM should be obtained to
confirm site-specific air monitoring objectives and to ensure that the air
monitoring level selected 1s consistent with these objectives.
The availability of appropriate monitoring methods 1s another
significant factor for monitoring sophistication level decision-making.
Certain constituents, polychlorlnated blphenyls (PCBs) for example, are
not conducive to screening monitoring. A further discussion of available
monitoring methods 1s presented 1n Section 3.4.
3-25
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3.3.2 Definition of Monitoring Sophistication Levels
Alternative monitoring sophistication levels for Superfund APA
applications can be classified as follows:
• Screening level
Screening techniques
Refined screening techniques
• Refined level
Refined techniques
Screening air monitoring techniques are generally associated with
relatively high detection levels (I.e., 1n the range of parts per million
for gaseous contaminants and milligrams per cubic meter for participates
commensurate with Industrial hygiene measurements) and frequently provide
near-real-time results 1n the field. Quite often, these detection levels
exceed health criteria and ARARs. Screening techniques are also quite
limited regarding the number of constituents that can be evaluated
concurrently. Therefore, screening techniques are most effective for air
monitoring near the source to confirm the presence of an air release and
to provide input information to support the development of specifications
for a more refined monitoring program.
Candidate screening air monitoring techniques are summarized in
Table 3-4. The screening techniques for gaseous constituents presented in
Table 3-4 Include total hydrocarbon (THC) analyzers, colorlmetrlc gas
detection tubes, electrochemical alarm cells, and screening portable gas
chromatograph (GC) analyzers. Screening portable GC analyzers have been
developed to provide only gross information on the concentration of an
Individual air toxic constituent calculated as an equivalent to a selected
single chemical constituent (methane, for example). Screening techniques
3-26
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TABLE 3-4
AN OVERVIEW OF SCREENING AIR MONITORING/SAMPLING TECHNIQUES
Program
Sophistication
Level
Screening
Screening
Screening
Screening
Screening
Screening
Refined screening
Refined screening
Category of
Monitoring/Sampling
Method
Gas Phase:
• Total hydrocarbon
(THC) Analyzers
• Colorimetric gas
detection tubes and
monitors
• Electrochemical
alarm cells
• Screening portable
GC analyzer
Participate Phase:
• Portable pumps with
filters
• Portable pumps with
filters and special
plugs
Gas Phase:
• Portable field GC
analyzers with
constant-
temperature oven
• Field GC laboratory
Detection
Limit
• ppm
• ppm
• ppm
• PPb
• mg/m3
• mg/m3
• PPb
• PPb
Compounds Detected
• Most organics but
not by chemical
species
• Various organics
and inorganics for
a specific chemical
species
• Various organics
for a specific
chemical species
• Species expressed
as equivalent to a
selected single
species
• Most Inorganic
compounds
• Semi volatile
chemical species
• Limited list of
organic compounds
by chemical species
• Limited list of
organic compounds
by chemical species
Monitoring/
Sampling Mode
• Realtime-
continuous
• Historical-
integrated
• Realtime-
continuous
• Realtime -
continuous
• Historical-
integrated
• Historical-
integrated
• Realtime-
continuous
• Historical-
integrated
Typical
Uncertainty
Factors
±1.5 to
±3.0
±1.5 to
±3.0
±1.5 to
±3.0
±1.5 to
±3.0
±1.5 to
±2.0
±1.5 to
±2.0
±1.3 to
±1.5
±1.3 to
±1.5
a An Uncertainty Factor of ±1.0 indicates a perfect method (i.e., zero uncertainty)
-------
applicable to participates include portable pumps with special filters or
plugs.
Table 3-4 Includes uncertainty values that typify the deviation from
the UF yielded by a perfect method where a perfect method will yield an
uncertainty factor of ± 1.0. Uncertainty of ± 3.0 means a deviation of ±
200 percent from the perfect method or value.
The typical uncertainty values are based on a qualitative assessment
of the various screening methods, experience, and field applications. The
uncertainty values depend on the number of the air toxic compounds
involved, the concentration of the individual compounds, and the
interferences introduced.
Refined screening air monitoring techniques can provide reasonably
accurate information on ambient air quality of organic compounds 1n the
gas phase at the ppb level. These refined screening techniques utilize a
combination of air sampling and a near-real-time analytical analysis
without the use of offsite laboratory facilities. Refined screening air
monitoring techniques listed in Table 3-4 Include field portable GC
systems.
Although similar to refined methods, refined screening air monitoring
techniques have the following limitations:
The 11st of chemical species that can be accommodated 1s shorter
than the one handled by a fully equipped offsite laboratory.
Only an uncomplicated matrix of chemical species can be
analyzed.
As field techniques, these techniques lack the ability to
implement the comprehensive QA/QC procedures used by a certified
offsite laboratory.
3-28
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Refined air monitoring is applicable to situations when high-quality
data are required and the response time for obtaining air quality results
is not near real time. It also is applicable as a supplement to the near-
real-time air monitoring data obtained through the use of a refined
screening technique during the implementation of remedial actions. In
such a case, the refined air monitoring technique provides high-quality
results to supplement and verify results of the refined screening
monitoring. Of course, the comparison between the two is based on
historical data.
A listing of typical refined air monitoring techniques is presented
in Table 3-5. Although a myriad of refined air monitoring techniques is
available, the process of selecting the most suitable one 1s difficult.
This is because of the technical limitations of available monitoring
methods and the large number of target compounds that may be Involved.
Furthermore, the field of air toxics monitoring for protecting public
health and the environment is 1n the developing stages compared with the
field of air monitoring for criteria pollutants, which is considered
mature.
In spite of the high quality of the chemical analysis involved with
refined air monitoring techniques, it 1s possible that the data obtained
will be useful only 1n a qualitative rather than a quantitative way. The
reasons for this could be many. Several factors that could affect the
quality of the data Include the following:
• Large number of compounds Involved
• Variability 1n the concentrations of Individual compounds and
the need for low detection limits
Potential for the formation of artifacts during sampling
• Interference between compounds during analysis
3-29
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TABLE 3-5
AN OVERVIEW OF REFINED AIR MONITORING/SAMPLING TECHNIQUES
Program
Sophistication
Level
Refined
Refined
Category of
Mon 1 tor i ng /Samp 1 1 ng
Method
Gas Phase:
• Traps (sorbents and
cryogenics) and
laboratory analysis
• Whole air samplers
(bags and
canisters) and
laboratory analysis
• Liquid impingers
Part icu late Phase:
• High-volume
samplers with glass
fiber filter.
membrane filter or
teflon filter
• High-volume
samplers with a
glass fiber filter
and polyurethane
foam*
Detection
Limit
• Fraction
of a ppb
to ppb
• Fraction
of a ppb
to ppb
• Fraction
of a ppb
to ppb
• pg/m3
• ug/m3
Compounds Detected
• Many organic
compounds by
chemical species
• Many organic
compounds by
chemical species
• Aldehydes, ketones,
phosgene,
cresol/phenols
• Inorganics
• PCBs and other
semi volatile
organic species
Monitoring/
Sampling Mode
• Historical-
integrated
• Historical-
integrated
• Historical-
integrated
• Historical-
integrated
• Historical-
integrated
Typical
Uncertainty
Factors
±2.0
±1.1
±1.2
±1.3
±2.0
I
u*
O
*Polyurethane foam (PUF) plug is designed to collect semivolatile organic gases.
-------
Variable response of the analytical system as a function of the
specific compound
This Implies that a cost-benefit assessment may be useful. This
assessment may, based on the factors involved, show that a refined
screening methodology utilizing a portable field GC analyzer is more
beneficial for the application involved than is a refined methodology.
Therefore, the UFs for candidate monitoring approaches should be
considered as discussed in Section 3.3.1. This approach 1s also included
in the discussion on the application of monitoring sophistication levels.
An expanded discussion of alternative screening and refined air
monitoring methods/equipment 1s presented in Section 3.4.
3.4 STEP 3 - DEVELOP MONITORING PLAN
3.4.1 Overview
An air monitoring plan should be developed for each Superfund APA
application. The objective of the plan is to document the Technical
Specifications for a site/source-specific monitoring program. The plan
also provides an opportunity for peer review and RPM/EPM approval of the
monitoring program. Developing a site/source-specific monitoring plan
involves the following major elements, as illustrated 1n Figure 3-6:
• Select monitoring constituents
Specify meteorological monitoring program
• Design air monitoring network
• Document air monitoring plan
Major Input to the development of an air monitoring plan should
include the Information collected during Step 1 (e.g., identification of
previous APAs, ARARs), the monitoring constituent target 11st developed
during Step 2, and available EPA technical guidance.
3-31
-------
INPUT DATA
(STEP 1)
EPA
GUIDANCE
MONITORING
CONSTITUENT
TARGET LIST
(STEP 2)
OTHER
TECHNICAL
GUIDANCE
SELECT MONITORING
CONSTITUENTS
(Flgur* 3-7)
SPECIFY
MBTBOROLOOICAL
MONITORING PROGRAM
(Figure 3-8)
DESIGN AIR
MONITORING NETWORK
(Flgur* 3-9)
DOCUMENT AIR
MONITORING PLAN
(Figure 3-1O)
INPUT TO
STEP 4 - CONDUCT
MONITORINQ
»-•. 9t*p a - O*v*lop Menlterlna Plan.
3-32
-------
Procedures for the development of an air monitoring plan are provided
in the subsections that follow.
3.4.2 Select Monitoring Constituents
The selection of air monitoring constituents is frequently a
challenging task for Superfund applications because of the extensive
number of potential release constituents. Sampling/analytical technical
factors and project budget limitations generally necessitate the selection
of a limited subset of target constituents.
The selection of target air monitoring constituents involves the
following key factors:
Physical and chemical properties of the constituents
Physical phase (gas, particulate)
Volatility
Thermal stability
Polarity
Ion character
Toxlcity and health effects (risk assessment) of the chemicals
involved
Estimated concentration of a constituent relative to other
constituents and potential interference
Availability of standard sampling and analysis methods and their
performance
Overall and technical project objectives
• Data quality objectives and resource constraints
3-33
-------
A summary of the recommended procedure for the selection of air
monitoring constituents is presented in Figure 3-7.
A list of the compounds included in the Hazardous Substances List
(HSL) developed by EPA for the Superfund program is presented in Table
3-6. This list is a composite of the Target Compound List (TCL) for
organics and the Target Analyte List (TAL) for inorganics. Table 3-6 also
includes examples for additional potential Superfund air emission
constituents (e.g., HCN, H2$, HC1). Therefore, Table 3-6 represents a
comprehensive list of compounds from which a list of target air toxics
compounds can be selected.
Emission rate APA results should be obtained prior to the conduct of
air monitoring studies based on Volume I recommendations. These results
as well as air monitoring data (as available) should be used to identify
appropriate site- and source-specific monitoring constituents from Table
3-6. Constituents included in ARARs Identified during Step 1 should also
be used to identify candidate monitoring constituents.
The limited set of candidate monitoring constituents based on
previous APAs and ARAR considerations should be used to compute
constituent-specific HI values, as previously discussed.
The HI values computed should then be ranked from highest to lowest
1n order to develop a priority list of candidate monitoring constituents.
The final constituents selected for air monitoring should be a function of
the APA sophistication level (as indicated in Figure 3-7).
Monitoring Indicators for screening applications should be selected
for one to five constituents with the highest HI values for which
appropriate monitoring methods are available. Monitoring Indicators could
include total hydrocarbons for organics and compound class Indicators
(e.g., ethers, aromatics) for organics and inorganics. Specific
constituents could also be selected as monitoring targets for organics and
inorganics.
3-34
-------
AIR CONCENTRATION
BASED ON
DATA •
3TEP 1 INPUT
(T«b« 3-2)
PREVIOUS AIR
MONITORING DATA -
STEP 1 INPUT
POM t-» CON»TmjBMT«
WITH MIOMaVr M VALUM
POM WMMM APPttOPRIATI
MONfTOMMa MKTMOO*
REPINED I3CREENINO
siuer s-ie MONITOBINO
coMarrruiNTa WITH
HIOMK9T Ml VALUB8 PON
WMION APPMOPMATE
MONITOMIMO METMOOa
AM AVAItABLl
9BLBOT
FV.I ^^p^vvwv • • • ^^mm^m • w ^
O.1 Ml (TOTA*. MIXT
POM WMIOM APPMOPMIATV
MOMITOMIMO MCTHOOa
ARE AVAIiAMJB
INPUT TO
AIR MONITORING
PLAN
RBBVALUATB TARGET
UST BA3ED ON
CURRENT MONITOR-
INO RESULTS
Flgur* 3-7.
Cen«tHumit«.
3-35
-------
TABLE 3-6 (PAGE 1 OF 4)
CLASSIFICATION OF ORGANIC AND INORGANIC COMPOUNDS
FOR AMBIENT AIR MONITORING STUDIES
Broad Band
Volatile Organics
Compound Class
Aliphatics
aromatlcs
Halogenated Species
Oxygenated Species
Sulfur-Containing
Species
N1 trogen-Contai ni ng
Species
Representative Compounds
vinyl acetate
benzene
toluene
ethylbenzene
total xylenes
styrene
chlorobenzene
carbon tetrachloride
chloroform
methylene chloride
chlorome thane
1 , 2-d i ch 1 oropropane
trans-l,3-dichloropropene
cis-l,3-dichloropropene
bromoform
bromomethane
bromod i ch 1 oromethane
di bromoch 1 oromethane
1 , 1 ,2, 2-tetrachloroethane
1 , 1, 1-trichloroethane
1,1,2-trlchloroethane
1,1-dichloroethane
1 , 2-d i ch 1 oroethane
chloroethane
tetrachloroethene
trichloroethene
1,2-dichloroethene
1,1-dichloroethene
vinyl chloride
acetone
2-butanone
2-hexanone
4-methyl -2-pentanone
carbon disulfide
benzonitrlle*
3-36
-------
TABLE 3-6 (PAGE 2 OF 4)
CLASSIFICATION OF ORGANIC AND INORGANIC COMPOUNDS
FOR AMBIENT AIR MONITORING STUDIES
Broad Band
Volatile Inorganics
Semi-Volatile
Organics
Compound Class
Acid Gases
Sulfur Containing
Species
Phenols
Esters
Chlorinated Benzenes
Amines
Representative Compounds
cyanide*
hydrochloric acid*
hydrogen sulfide*
phenol
2-methyl phenol
4-methyl phenol
2,4-d1methylphenol
2-chlorophenol
2,4-dichlorophenol
2,4,5-trichlorophenol
2,4,6-trichlorophenol
pentach 1 oropheno 1
4-chloro-3-methy 1 phenol
2-nitrophenol
4-nitrophenol
2f4-d1nitrophenol
4, 6-d1n1tro-2-methyl phenol
bis(2-ethylhexyl)phthalate
di-n-octyl phthalate
d1-n-butyl phthalate
diethyl phthalate
butylbenzyl phthalate
dimethyl phthalate
1,2-dichlorobenzene
1,3-dichlorobenzene
l,4-d1chlorobenzene
1,2,4-trichlorobenzene
hexachlorobenzene
nitrobenzene
2,6-d1nitrotoluene
2,4-d1n1trotoluene
3,3'-d1ch1orobenz1d1ne
n-ni trosodimethy 1 ami ne
n-n1 trosodi -n-propy 1 ami ne
n-nitrosod1phenylamine
aniline
2-n1troan1l1ne
3-n1troaniline
4-nitroan1l1ne
4-chloroanil1ne
3-37
-------
TABLE 3-6 (PAGE 3 OF 4}
CLASSIFICATION OF ORGANIC AND INORGANIC COMPOUNDS
FOR AMBIENT AIR MONITORING STUDIES
Broad Band
Compound Class
Representative Compounds
Ethers
jis(2-chloroethy1)ether
3is(2-chloroisopropyl)ether
bromophenyl-phenylether
4-chlorophenyl-phenylether
Alkadienes
hexachlorobutadlene
hexach1orocyc1opentad iene
Miscellaneous
Aliphatics and
Aromatics
ienzoic acid
aenzyl alcohol
bis(2-chloroethoxy)methane
dibenzofuran
hexachloroethane
isophorone
Polynuclear Aromatic
Hydrocarbons (PAHs)
acenaphthene
acenaphthylene
anthracene
benzo(a)anthracene
benzo(b)fluoranthene
benzo(k)fluoranthene
benzo(g,h,1)perylene
benzo(a)pyrene
chrysene
d1benz(a,h)anthracene
fluoranthene
fluorene
1ndeno(l,2,3-cd)pyrene
naphthalene
2-methylnaphthalene
2-ch1oronaphthalene
phenanthrene
pyrene
Pesticides
alpha-BHC
beta-BHC
delta-BHC
gamma-BHC
heptachlor
heptachlor epoxide
4,4'-DDT
4,4'-DDD
4(4'-ODE
endrin
endrin ketone
endrin aldehyde
3-38
-------
TABLE 3-6 (PAGE 4 OF 4)
CLASSIFICATION OF ORGANIC AND INORGANIC COMPOUNDS
FOR AMBIENT AIR MONITORING STUDIES
Broad Band
Compound Class
Representative Compounds
Pesticides
endosulfan I
endosulfan II
endosulfan sulfate
aldrin
dleldrin
chlordane
methoxychior
toxaphene
Polychlorinated
Biphenyls (PCBs)
Arochlor
Arochlor
Arochlor
Arochlor
Arochlor
Arochlor
Arochlor
1016
1221
1232
1242
1248
1254
1260
Non-Volatiles
Inorganic Metals and
Non-Metals
aluminum
antimony
arsenic
barium
beryllium
cadmium
calcium
chromium
cobalt
copper
iron
lead
magnesium
manganese
mercury
nickel
potassium
selenium
silver
sodium
thallium
tin
vanadium
zinc
Note: Compounds identified by an asterisk (*) are not contained on the USEPA
Hazardous Substance List (HSL).
3-39
-------
Refined screening monitoring applications should Include the
selection of 5 to 10 monitoring constituents with the highest HI values.
This approach should facilitate the preliminary characterization of air
releases at Superfund sites. Again, the monitoring list selection process
should consider the availability of appropriate monitoring methods
commensurate with health and safety criteria.
Target monitoring constituents for refined APAs should include all
constituents with an HI value greater than or equal to 10 percent of the
composite HI value for the total mix. These constituents are expected to
represent the greatest contributors to potential health impacts.
The target monitoring list should be periodically reevaluated, and
revised if warranted, as monitoring results become available. This is
particularly useful for refined monitoring studies that are long term in
nature (e.g., during remedial actions). For these applications it may
also be effective to periodically (e.g., monthly) sample and analyze for a
more comprehensive 11st of compounds to confirm the representativeness of
the routine-monitoring target 11st.
3.4.3 Specify Meteorological Program
A meteorological monitoring program should be an integral part of
Superfund air monitoring activities. A meteorological survey can be used
to design the air monitoring network based on local wind patterns.
Meteorological and air quality data collected can be used for the
interpretation of air concentration data considering upwind/downwind
exposure conditions. A recommended procedure for the development of a
site-specific meteorological program design 1s presented in Figure 3-8.
The number and location of meteorological stations needed for a site-
specific application depend on local terrain conditions. One
meteorological station 1s generally sufficient for flat-terrain sites.
However, for complex-terrain sites it may be necessary to have multiple
3-40
-------
DETERMINE NUMBER
AND LOCATION OF
METEOROLOGICAL
STATIONS
FLAT TERRAIN
1 STATION
t
COMPLEX TERRAIN
1-3 STATIONS
_L
DETERMINE
EXPOSURE
HEIGHT
SCREENINGS'
REPINED SCREENING
2-3 m
REFINED
DETERMINE
MONITORING
PARAMETERS
SCREENING/
REPINED SCREBNINO
e Wtnd Dlraatton
e Wind Spaad
e Sigma Thata
REFINED
a Primary
Sigma Thata
T«mparatura
Praelpitatten
Humidity
Praaaur*
DETERMINE DATA
• RECORDING
APPROACH
CONDUCT M«TBO«O-
LOQICAk 9UMVKV TO
SUPPORT AIR MONITOR*
I NO NBTWORK OBSIttN
(A* N*o«««aryl
SCREENINax
REPINED SCREENING
REFINED
INPUT TO
AIR MONITORING
PLAN
3-41
-------
stations to represent major onsite/local air flow paths. Generally one to
three stations will be sufficient for these sites. To ensure a
representative exposure, it is recommended that the meteorological
stations be located at a distance of at least 10 times the height of any
nearby obstruction.
Meteorological sensor exposure height should be 2-3 meters above the
ground surface for screening and refined screening applications. This
approach facilitates the use of portable stations, which can be rapidly
deployed. For refined analyses the primary exposure height should be 10
meters (for wind and stability data) and 2 meters for parameters that do
not directly affect atmospheric dispersion. For elevated releases such as
those from incinerators, primary meteorological parameters should also be
measured at stack height to the extent practicable.
Meteorological monitoring parameters for Superfund applications can
be classified as follows:
• Primary parameters
Wind direction
Wind speed
Sigma theta (I.e., the horizontal wind direction standard
deviation, which is an indicator of atmospheric stability)
• Secondary parameters
Temperature
Precipitation
3-42
-------
Humidity
Atmospheric pressure
Primary parameters are representative of site dispersion conditions
and should be included 1n all meteorological monitoring programs.
Secondary parameters are representative of emission conditions and are
generally only recommended for refined air monitoring activities.
Recommended meteorological monitoring system accuracies/resolutions
and sensor response characteristics are summarized in Tables 3-7 and 3-8,
respectively. Field equipment used to collect meteorological data can
range 1n complexity from very simple analog or mechanical pulse counter
systems to microprocessor-based systems. A combination of these
approaches is recommended for Superfund applications. This approach is
generally not expensive but it facilitates the convenient collection of
meteorological data that can be processed onslte at a field office using
personal computers (PCs). The chart recorders provide a low-cost backup
system if the digital data are not available.
A meteorological survey should also be conducted to support air
monitoring network design. Exceptions would include sites that have
historical onsite meteorological data that are consistent with the DQOs or
flat-terrain sites for which representative offsite data are available.
The duration of the meteorological survey should range from 1 week for
screening/refined screening applications to 4 or more weeks for the
conduct of a refined air monitoring program. The survey should be
conducted during a period (season and time of day) representative of the
planned air monitoring program and air emission source operational
schedules. However, it may be necessary to use historical offslte data to
estimate seasonal effects for planning purposes if the air monitoring
program 1s scheduled to last for more than a few months.
Additional recommendations on meteorological measurements can be
obtained from the following sources:
3-43
-------
TABLE 3-7
RECOMMENDED SYSTEM ACCURACIES AND RESOLUTIONS
Meteorological Variable
System Accuracy
Measurement Resolution
Wind Speed
Wind Direction
Ambient Temperature
Oew Point Temperature
Precipitation
Pressure
Time
±(0.2 m/s + 556 of
observed)
±5 degrees
±0.50C
±1.50C
±10% of observed
±3 mb (0.3 kPa)
±5 minutes
0.1 m/s
1 degree
O.loc
0.3 mm
0.5 mb
3-44
-------
TABLE 3-8
RECOMMENDED RESPONSE CHARACTERISTICS FOR METEOROLOGICAL SENSORS
Meteorological Variable
Sensor Specif1cat1on(s)*
Wind Speed
Wind Direction
Temperature
Dew Point Temperature
Starting Speed <0.5 m/s; Distance Constant <5m
Starting Speed <0.5 m/s 9 10o Deflection;
Damping Ratio 0.4 to 0.7; Delay Distance <5m
Time Constant <1 minute
Time Constant <30 minutes; Operating
Temperature Range -30QC to +30°C
*From Table 5-2. On-Site Meterological Program Guidance for Regulatory
Modeling Applications, U.S. EPA, Office of Air Quality Planning and
Standards, Research Triangle Park, N.C., 27711. June 1987.
3-45
-------
U.S. EPA. June 1987. On-Site Meteorological Program Guidance for
Regulatory Modeling Applications. EPA-450/4-87-013. Office of Air
Quality Planning and Standards. Research Triangle Park, NC 27711.
U.S. EPA. February 1983. Quality Assurance Handbook for Air
Pollution Measurements Systems: Volume IV. Meteorological
Measurements. EPA-600/4-82-060. Office of Research and Development.
Research Triangle Park, NC 27711.
U.S. EPA. July 1986. Guidelines on Air Quality Models (Revised).
EPA-405/2-78-027R. NTIS PB 86-245248. Office of Air Quality
Planning and Standards. Research Triangle Park, NC 27711.
U.S. EPA. May 1987. Ambient Monitoring Guidelines for Prevention of
Sionifleant Deterioration fPSDU EPA-450/4-87/007. Office of Air
Quality Planning and Standards. Research Triangle Park, NC 27711.
3.4.4 Design Monitoring Network
The air monitoring network design will be affected by factors such as
site-specific source, receptor, and environmental characteristics (see
Table 3-9). Therefore, the design of an air monitoring network for a
Superfund APA must be decided on a case-by-case basis. A recommended
procedure for designing an air monitoring network is presented in
Figure 3-9. Key components of the monitoring network design include:
Number of locations of monitoring stations
Probe siting criteria
Program duration and frequency of monitoring
Sampling and analysis methods
Air monitoring equipment
The following is a discussion of each of these components.
3-46
-------
TABLE 3-9
FACTORS AND ASSOCIATED ELEMENTS THAT AFFECT THE DESIGN OF AIR
MONITORING PROGRAMS FOR SUPERFUND APAs
Factor
Elements
Technical air
monitoring objectives
Source Characteristics
Receptor data
Environmental
characteristics
Data Quality
Objectives
see Table 3-2
• Nature and extent of site sources (lagoon,
landfarm, land disposal, processing
facility, tank farm, etc) and their size
• Constituents involved and their physical
state (gas, particle, total)
• Estimated emission rates (measured or
calculated)
• Site source grouping
• Historical air quality data for the site
area representing onsite, perimeter, and
offsite measurements and the quality of the
data
• Results of air dispersion modeling and
locations of high calculated air toxics
concentrations
• Number and locations of sensitive receptors
(population; sensitive population
locations-schools, hospitals, etc;
sensitive environmental species and
settings such as flora and fauna, state
parks and monuments, national parks and
monuments, etc.) and distance to these
locations
• Historical records of meteorological data
representing the site area including
diffusion climatology and special
conditions conducive to high concentration
of airborne contaminants
• Topography in the site area and its
potential effect on local dispersion
conditions, and its proximity to the site.
• Water bodies in the site area, number, size
and proximity to the site.
• Database for worker protection only
• Database for worker, public and
environmental protection
3-47
-------
TABLE 3-9 (Continued)
FACTORS AND ASSOCIATED ELEMENTS THAT AFFECT THE DESIGN OF AIR
MONITORING PROGRAMS FOR SUPERFUND APAs
Factor
Elements
Data Quality
Objectives
Detection limit for constituents involved
Precision and accuracy of monitoring and
analyses methodologies
Data representativeness
Data completeness
Data comparability
Data use for Superfund APA application
Data Quality
Objectives (continued)
Source Characteristics
Constraints
Receptor Constraints
Environmental
Constraints
Data Quality Objective
Constraints
Resource Constraints
Frequency of monitoring and program
duration (short - few days to weeks;
intermediate - few weeks to few months;
long- a year or more)
Monitoring mode (real time - instantaneous,
continuous historical - integrated)
QA/QC requirements (data validation.
equipment calibration, equipment and
documentation, data handling, chain of
custody, audits)
Large number of air toxics compounds with
high level of air emissions (volatile;
semi-volatile, base/neutral, pesticides,
PCBs, inorganic)
Mixed physical state (gas, particulates)
non homogeneous source
Incomplete source characterization and data
gaps
Large number of receptors are Identified
for the specific application
Large number of obstructions close to the
receptors identified (trees, bushes,
structures, etc.)
Accessibility to receptors
Availability of utilities
Security
complex topography
large water body(ies)
Limited or no applicable monitoring and
analysis methodologies
Limited budget
Limited time
3-48
-------
METEORO-
LOGICAL
SURVEY
DATA
CONSIDER DESIGN
FACTORS
(Table 3-9)
DETERMINE NUMBER
AND LOCATIONS OF
AIR MONITORING
STATIONS
(Table 3-10)
DISPERSION
MODELING
RESULTS
DETERMINE PROBE
EXPOSURE HEIGHT
(Table 3-11)
JL
DETERMINE PROGRAM
DURATION/SAMPLING
FREQUENCY
(Table 3-12)
EPA
GUIDANCE
(Tabl* 3-13)
SELECT MONITORING
METHODS
(Table 3-13)
OTHER
TECHNICAL
GUIDANCE
(Appendix A)
SELECT MONITORING
EQUIPMENT
(Table 3-22. 3-23)
INPUT TO
AIR MONITORING
PLAN
O««l«n Air Monltorln* Network
3-49
-------
Determine Number and Locations of Monitoring Stations
The number and location of monitoring stations for an air monitoring
network depend on the site-specific characteristics listed below.
• Results of air dispersion modeling for the site area utilizing
an atmospheric dispersion model applicable to the source and
site (see Section 2.0 in this volume)
• Environmental characteristics (meteorology, topography, soil
characteristics, etc.)
Receptor characteristics (population centers, sensitive
population and environmental locations, locations of calculated
high concentrations of air toxics)
Source characteristics (type and extent of contamination,
locations of hot spots, etc.)
Siting constraints
Duration of the monitoring program
Meteorological variables affecting monitoring network design include
wind direction, wind speed, and atmospheric stability. These parameters
can be used to define prevailing wind patterns and characterize local
dispersion conditions.
Air monitoring programs that last for only 2 weeks or less (e.g.,
screening APAs) require some judgment about the placement of monitoring
stations and their numbers. This is because the use of historical
meteorological data would generally not provide accurate information on
the meteorological conditions for the few days of sampling and analysis.
However, the results of a meteorological survey onsite (see Section 3.4.2)
conducted just prior to screening can help to identify expected wind
3-50
-------
patterns and downwind sampling sectors, and to characterize temporal wind
direction variability. Meteorological forecast information can also be
used to deploy screening air sampling equipment. Therefore, it is
recommended that air screening samples be taken with portable sampling
equipment.
The following factors should be considered in selecting locations and
the number of monitoring stations for air monitoring programs with the
duration of several weeks to several months:
• Predominant wind directions, based on historical records, for
the monitoring period under consideration. This may involve the
review of daily, weekly, and monthly meteorological records.
Time of the year the monitoring program is scheduled, to
account, to the extent possible, for seasonal effects that could
cause either high or low ambient air concentrations. Seasons
that in general do not exhibit high-ground-level concentrations
of the constituents Involved should not be considered as
candidate periods for air monitoring, to the extent possible.
• Use of a dispersion model (screening or refined) to calculate
ground-level concentrations in the site vicinity and to
determine locations of maximum calculated concentrations for
short-term (up to 24 hours) averages and long-term (monthly,
seasonal, and annual) averages. Input into the dispersion
model, including source data, meteorology, topography,
population centers, sensitive population, and environmental
setting locations, should be defined for the time averages under
consideration in order to obtain model output showing the
receptors of maximum impact on the population and the
environment. For example, meteorological conditions conducive
to high-ground-level concentrations of air toxic constituents
such as nighttime drainage flows are quite important for
consideration in selecting the locations of air monitoring
3-51
-------
stations for the implementation of the remedial action step
under the Superfund project.
Source size and configuration. It is preferred to locate an air
monitoring station downwind from a source so that it will be
exposed to a large fetch of the source area for a long period.
considering the frequency of occurrence of wind direction. This
will ensure that source emissions are transported toward the
monitoring station from a large portion of the source area for
an extended period. In this respect, the fetch should cover an
area that 1s exposed to high concentrations for an extended
period.
Locations of sensitive receptors at the site perimeter and
offslte. The locations and number of monitoring stations at
sensitive receptors should be evaluated considering
meteorological conditions conducive to high-ground-level
concentrations of airborne air toxic constituents and their
frequency of occurrence. From a practical viewpoint, it is
important to consider the following:
Locations of anticipated high-ambient-ground-level
concentrations of air toxic constituents and the frequency
of occurrence of the meteorological conditions that are
conducive to these levels. Depending on the monitoring
objective, the first priority should be to select locations
that will most frequently be exposed to high concentrations
of such constituents.
Population and environmentally sensitive locations. In
evaluating locations, it 1s Important to consider the
objectives of the monitoring program: to provide
Information on possible high impact at sensitive receptors,
specifically, a high dose to an Individual person or
species or a high Integrated dose to the nearby population.
3-52
-------
This factor will dictate the selection of a monitoring
station representing small but highly sensitive or large
but less sensitive population and environmental species.
Meteorological conditions
Wind directions and speeds and atmospheric stabilities
conducive to high-ground-level concentrations of air
toxic constituents for both short- and long-term
averaging periods.
Local day/night wind flow and stability conditions for
the area and monitoring period under consideration.
Characteristics of the regional flow regime for the
area and the monitoring period under consideration.
For example, it may occur that the regional flow for
this site for the monitoring period of Interest is
generally southwesterly, and that the local night
drainage flow under stable conditions is
northeasterly. Accordingly, a monitoring location
southwest of the site would be the upwind location for
the regional flow and the downwind location for the
more limiting local flow.
Results of previous air quality monitoring programs in
the vicinity of the site that could be considered
applicable to the case in question.
Results of previous air dispersion calculations for
similar sources with meteorological data considered
representative of the site conditions.
Topographical features that would influence the advection
and transport of air toxic constituents. Examples Include
3-53
-------
land surface elevations, valley channels, and the land-
water interface.
A1r monitoring station number and location recommendations are
summarized 1n Table 3-10 based on consideration of the above factors.
These recommendations address the identification of air monitoring target
sectors based on the following analysis for the planned monitoring period:
• Historical prevailing wind direction
• Maximum short-term (24-hour) dispersion modeling predictions
Maximum long-term (monthly, seasonal, or annual, commensurate
with the planned monitoring duration) dispersion modeling
predictions
Sectors associated with sensitive offsite receptors
• Most recent 24-hour wind forecast Information
Portable air monitoring stations are recommended for use at locations
Identified based on the most recent 24-hour wind forecast information.
This approach provides maximum flexibility; that 1s, 1t permits variation
of the sampling network design to accommodate changes in day-to-day wind
conditions. •
The air monitoring siting recommendations presented 1n Table 3-10
Include the following zones for each of the APA sophistication levels:
• Source boundary
Upwind
Downwind
Site boundary
3-54
-------
TABLE 3-10
AIR MONITORING STATION NUMBER AND LOCATION RECOMMENDATIONSa.b.c
• Screening APA
- Source Boundary
Upwind
Downwind
- Site Boundary
Upwind
Downwind
• Refined Screening APA
- Source Boundary
Upwind
Downwind
- Site Boundary
Upwind
Downwind
Based on
Historical
Prevailing
Wind
Direction
NA
NA
NA
NA
1- Stationary
1 -Stationary
1- Stationary
1-Stationary
Based on Maximum
Short-Term
Dispersion Modeling
Concentration
Sector
NA
NA
NA
NA
NA
NA
Based on Maximum
Long-Term
Dispersion Modeling
Concentration
Sector
NA
NA
NA
NA
NA
NA
Based on Sectors
Associated with
Sensitive
Offslte
Receptors
NA
NA
NA
NA
NA
NA
Based on
Most Recent
24-hour Wind
Forecast
Sector(s)d
1 Portable
3 Portable
1 Portable
3 Portable
1 Portable
3 Portable
1 Portable
3 Portable
at
ui
-------
TABLE 3-10
AIR MONITORING STATION NUMBER AND LOCATION RECOMMENDATIONS*,b,c (Continued)
• Refined APA
- Source Boundary
Upwind
Downwind
- Site Boundary
Upwind
Downwind
Based on
Historical
Prevailing
Wind
Direction
1-Statlonary
1 -Stationary
1-Stationary
1-Stationary
Based on Maximum
Short-Term
Dispersion Modeling
Concentration
Sector
NA
NA
1-Stationary
1-Stationary
Based on Maximum
Long -Term
Dispersion Modeling
Concentration
Sector
NA
NA
1-Stationary
1-Stationary
Based on Sectors
Associated with
Sensitive
Offslte
Receptors
NA
NA
Ad
Ad
Based on
Most Recent
24-hour Wind
Forecast
Sector(s)d
1 Portable
3 Portable
1 Portable
3 Portable
I
01
0»
NA = Not applicable
a = Upwind stations based on historical wind data and dispersion modeling results can frequently be
consolidated to one location
b = Additional monitoring stations may be required for complex-terrain sites
c = Offslte monitoring should be conducted on an ad hoc basis commensurate with site-specific project needs
d = If Invariant wind directions are predicted, one station should be located downwind based on this prediction
plus one station In each adjoining 22.5-degree sector
-------
Upwind
Downwind
Upwind stations will provide background air concentration data.
Frequently, upwind stations can be consolidated into one location based on
historical wind data and dispersion modeling results. Downwind stations
can be used to characterize source impacts. Locating downwind monitoring
locations at the source boundary Increases the potential for release
detection and the characterization of onsite exposure levels. Downwind
locations at the site boundary can be used to estimate offsite air
concentration levels. Offsite air monitoring 1s frequently not practical
and should be conducted on an ad hoc basis commensurate with site-specific
project needs.
Determine Probe Exposure Height
The placement of air monitoring and meteorological stations must
conform to a consistent set of criteria and guidance to ensure data
comparability and compatibility. A detailed set of probe siting criteria
for ambient air monitoring and meteorological programs is given in the
following EPA document:
U.S. EPA, May 1987. Ambient Monitoring Guidelines for Prevention of
Significant Deterioration (PSD). EPA-450/4-87/007, Office of A1r
Quality Planning and Standards. Research Triangle Park, NC 27711.
This document provides detailed discussions and guidance on probe
siting criteria. This section provides a summary of key factors that
should bev considered as a part of the placement of an air quality
monitoring station. The reader 1s referred for more details to the above-
referenced document.
3-57
-------
Key siting factors Include
• Vertical placement above ground
• Horizontal spacing from obstructions and obstacles
• Unrestricted air flow
• Spacing from roads
A summary of the key criteria associated with these siting factors
for air monitoring stations 1s included in Table 3-11. The information
Included 1n that table should be used to the extent possible as a part of
the monitoring network design to ensure that the monitoring program
provides representative and unbiased data. However, site-specific
constraints could make 1t very difficult to meet all criteria. For
example, the occurrence of wooded areas around a Superfund site would make
the perimeter siting very difficult, hence consideration should be given
to the placement of stations onsite and offsite to the extent possible.
Therefore, the use of the information 1n Table 3-11, coupled with a
balanced evaluation by an experienced air quality and meteorology
specialist is highly recommended.
Air emissions for most of the applications Involved with Superfund
sites are from ground level or near-ground-level releases. For a site
area with no major obstructions and obstacles, the air sampler intake
should be about 2-3 meters aboveground. For a site with nearby roadways,
however, Intake placement should take Into account the effects of road
dust reentrainment and vehicular emissions. In fact, a linear
relationship should be established between the horizontal distance of the
sampler Intake from the roadway and the aboveground elevation of that
Intake. For any roadway accommodating more than 3000 vehicles per day,
the Intake should be between 5 and 25 meters from the edge of the nearest
traffic lane. It should also be 15 meters aboveground for a distance of
5 meters from the nearest traffic lane and 2 meters aboveground for a
distance of 25 meters from the nearest lane. For a roadway supporting
less than 3000 vehicles per day, the intake should be placed at a distance
3-58
-------
TABLE 3-11
A SUMMARY OF KEY PROBE SITING CRITERIA FOR AIR MONITORING STATIONS
Factor
Criteria
Vertical spacing above
[round
Horizontal spacing
from obstruction and
obstacles
Unrestricted airflow
Spacing from roads
Representative of the breathing zone and
avoiding effects of obstruction, obstacles and
roadway traffic. Height of probe Intake above
ground Is In general, 2-3m above ground and 2-
15m above ground in the case of nearby
roadways.
About 1 m or more above the structure where
the sampler 1s located.
Minimum horizontal separation from
obstructions such as trees is > 20m from the
drlpHne and 10m from the drlpHne when the
trees act as an obstruction.
Distance from sampler Inlet to an obstacle
such as a building must be at least twice the
height the obstacle protrudes above the
sampler.
If a sampler Is located on a roof or other
structures, there must be a minimum of 2m
separation from walls, parapets, penthouses,
etc.
There must be sufficient separation between
the sampler and a furnace or Incinerator flue.
The separation distance depends on the height
and the nature of the emissions Involved.
Unrestricted airflow must exist In an arc of
at least 270 degrees around the sampler, and
the predominant wind direction for the
monitoring period must be Included 1n the 270
degree arc.
A sufficient separation must exist between the
sampler and nearby roadways to avoid the
effect of dust reentralnment and vehicular
emissions on the measured air concentrations.
Sampler should be placed at a distance of 5-
25m from the edge of the nearest traffic lane
on the roadway depending on the vertical
placement of the sampler inlet which could be
2-15m above ground.
3-59
-------
greater than 5 meters from the edge of the nearest traffic lane and at a
height of 2-15 meters aboveground.
Determine Program Duration and Sampling Frequency
The recommendations for program duration and frequency of monitoring
are summarized 1n Table 3-12. Actual monitoring duration and frequency,
however, will depend on the specific project objectives and resources. It
1s recommended that a representative number of air samples be collected
during each step of the project to ensure a reasonable data base. The
number of representative samples depends on many factors, and a simple
statistical analysis may not provide a good basis for this number. The
recommendations specified in Table 3-12 are based on the following
factors:
• Frequencies usually adopted in programs of criteria air
pollutant monitoring Involving the use of Integrated samplers (a
minimum of one sample every 6 days for most cases)
• Augmentation of integrated sampling with continuous monitoring
for steps that require more detailed data to enhance the data
base
• The resource requirements for laboratory analysis for organic
and Inorganic compounds
• Quality assurance/quality control requirements such as
collocated field and trip blank samples and spike samples
Samples taken over a very short period (a minute or so) are not
representative of average air concentrations of air toxic constituents
because of the high variability that could occur over short periods of
time. For screening monitoring, therefore, it is recommended that the
samples taken be averaged over at least 15 minutes and preferably over a
longer period.
3-60
-------
TABLE 3-12
PROGRAM DURATION AND FREQUENCY OF MONITORING AS A FUNCTION OF THE SUPERFUND PROJECT STEP (Page 1 of 4)
Superfund Step
RI/FS - Screening APA
screening monitoring
refined screening
monitoring
RI/FS - Refined APA
• refined monitoring
Monitoring
Program Duration
• 1-2 days
• same as above
• 4-6 weeks
Frequency
Sampling Duration
• 15-30 minutes at each
sampling location
• 24-hour Integrated
• 24-hour Integrated
No. of Samples
• 20-30 readings using THC
analyzers
• 10-20 samples- using
colorlnetrlc gas detection
tubes or equivalent
• 5-10 samples for organic s 1n
gas phase
• limited QA/QC samples
• 10 at each monitoring
location for organlcs In gas
phase, seal-volatile
organlcs and Inorganics 1n
partlculate phase
• 10 at the collocated
monitoring location for the
same constituents as above
• field and trip blanks*
spiked, split and surrogate
samples on a case-by-case
basis
I
at
-------
TABLE 3-1?
PROGRAM DURATION AND FREQUENCY OF MONITORING AS A FUNCTION OF THE SUPERFUNO PROJECT STEP (Page 2 of 4)
Superfund Step
Remedial Design
• refined monitoring
• refined screening
monitoring
Monitoring
Program Duration
• 3-12 months
depending on
the length of
the pilot
treat ability
study
• same as above
Frequency
Sampling Duration
• 24-hour Integrated
• 24-hour continuous
No. of Samples
• 10-30 at each monitoring
location for organlcs In gas
phase, semi-volatile
organlcs and Inorganics In
partial late phase
• 10-30 at the collocated
monitoring location for the
same constituents as above
• field and trip blanks,
spiked, split and surrogate
samples , on a case-by-case
basis
• continuous at each of the
designated monitoring
locations for organlcs only
-------
TABLE 3-12
PROGRAM DURATION AND FREQUENCY OF MONITORING AS A FUNCTION OF THE SUPERFUND PROJECT STEP (Page 3 of 4)
Superfund Step
Monitoring
Program Duration
Frequency
Sampling Duration
No. of Samples
Remedial Action
refined monitoring
several
months to
more than a
year
depending on
the length of
the site
cleanup
24-hour Integrated
one sample every sixth day
at each sampling location'
for organlcs In gas phase,
semi-volatile organlcs and
Inorganics In partial late
phase
same frequency as above for
the collocated monitoring
and for the same
constituents as above
field and trip blanks.
spikes, split and surrogate
samples, on a case-by-case
basis
refined screening
'monitoring
same as above
• 24-hour continuous
continuous at each of the
designated monitoring
locations for organlcs only
screening monitoring
same as above
24-hour continuous
continuous at each of the
designated monitoring
locations for Inorganics and
total hydrocarbons
-------
TABLE 3-12
PROGRAM DURATION AND FREQUENCY OF MONITORING AS A FUNCTION OF THE SUPERFUND PROJECT STEP (Page 4 of 4)
Superfund Step
Monitoring
Program Duration
Frequency
Sampling Duration
No. of Samples
Operation and Maintenance
refined monitoring
• Phase I -
1 year •
24-hour Integrated
2
one sample every 12th day at
each sampling location for
organlcs In gas phase, semi-
volatile organlcs and
Inorganics In participate
phase
same frequency as above for
the collocated monitoring
and for the same
constituents as above
field and trip blanks.
spiked, split and surrogate.
samples, on a case-by-case
basis
refined monitoring
Phase II 2-5
years
24-hour Integrated
twelve samples per year for
the same constituents as
above
same frequency as above for
the collocated monitoring
and for the same
constituents as above
field and trip blanks on a
case-by-case basis
-------
The Information presented 1n Table 3-12 provides general guidance and
should be tailored to the specific application.
Select Monitoring Methods and Equipment
The selection of air monitoring methods and equipment should be based
on the consideration of a number of factors. Including the following:
Physical and chemical properties of compounds
• Relative and absolute concentrations of compounds
• Relative Importance of various compounds 1n program objectives
• Method performance characteristics
Potential Interferences present at site
Time resolution requirements
• Cost restraints
Organic and Inorganic constituents must be monitored by different
methods. Within these two groups, different methods may also be required
depending on the constituent and Its physical/chemical properties.
Another condition that affects the choice of monitoring technique 1s
whether the compound 1s primarily 1n the gaseous phase or 1s found
adsorbed to solid particles or aerosols.
Screening for the presence of air constituents Involves techniques
and equipment that are rapid, are portable, and can provide real-time
monitoring data. A1r contamination screening will generally be used to
confirm the presence of a release or to establish the extent of
contamination during the screening phase of the Investigation.
Quantification of Individual components 1s not as Important during
screening as during Initial and additional air monitoring; however, the
technique must have sufficient specificity to differentiate hazardous
constituents of concern from potential Interferences, even when the latter
are present 1n higher concentrations. Detection limits are often higher
for screening devices than for quantitative methods.
3-65
-------
Laboratory analytical techniques oust provide for the positive
Identification of the components and the accurate and precise measurement
of concentrations. This generally means that the preconcentratlon and/or
storage of air samples will be required. Therefore, methods chosen for
refined monitoring usually Involve a longer analytical time period, more
sophisticated equipment, and more rigorous QA procedures.
The following list of references provides guidance on air monitoring
methodologies:
U.S. EPA. June 1983. Technical Assistance Document for Sampling and
Analysis of Toxic Organic Compounds In Ambient A1r. EPA-600/4-83-
027. NTIS PB 83-239020. Office of Research and Development.
Research Triangle Park. NC 27711.
U.S. EPA. April 1984. Compendium of Methods for the Determination
of Toxic Organic Compounds 1n Ambient Air. EPA-600/4-84-041. Office
of Research and Development. Research Triangle Park, NC 27711.
U.S. EPA. September 1986. Compendium of Methods for the
Determination of Toxic Organic Compounds 1n Ambient Air. EPA/600/4-
87-006. NTIS PB87-168696. Office of Research and Development.
Research Triangle Park, NC 27711.
U.S. EPA. June 1987. Compendium Method TO-12: Method for
Determination of Non-Methane Organic Compounds fHMOC) 1n Ambient A1r
Using Crvooenlc Preconcentratlon and Direct Flame Ion1zat1on
Detection fPDFIDl. Research Triangle Park, NC 27711.
U.S. EPA. May 1988. Compendium Method TO-14: The Determination of
Volatile Organic Compounds fVOCsl 1n Ambient A1r Uslno SUMMA*
Passlvated Canister Sampling and Gas Chromatograohlc Analysis.
Quality Assurance Division. Research Triangle Park, NC 27711.
3-66
-------
MIOSH. February 1984. NIOSH Manual of Analytical Methods. NTIS PB
85-179016. National Institute for Occupational Safety and Health.
Cincinnati. OH 45226.
U.S. EPA. September 1983. Characterization of Hazardous Waste Sites
- A Methods Manual! Volume II. Available Sampling Methods. EPA-
600/4-83-040. NTiS PB 84-126929. Office of Solid Waste.
Washington, DC 20460.
U.S. EPA. September 1983. Characterization of Hazardous Waste Sites
- A Methods Manual; Volume III. Available Laboratory Analytical
Methods. EPA-600/4-83-040. NTIS PB 84-126929. Office of Solid
Waste. Washington, DC 20460.
U.S. EPA. 1986. Test Methods for Evaluating Solid Waste. 3rd
Edition. EPA SW-846. GPO No. 955-001-00000-1. Office of Solid
Waste. Washington, DC 20460.
ASTM. 1982. Toxic Materials 1n the Atmosphere. ASTM, STP 786.
Philadelphia, PA 19103.
ASTM. 1980. Sampling and Analysis of Toxic Organ1cs 1n the
Atmosphere. ASTM, STP 721. Philadelphia. PA 19103.
ASTM. 1974. Instrumentation for Monitoring Air Quality. ASTM, SP
555. Philadelphia, PA 19103.
APHA. 1977. Methods of A1r Sampling and Analysis. American Public
Health Association. Washington. DC 20005.
AC6IH. 1983. A1r Sampling Instruments for Evaluation of Atmospheric
Contaminants. American Conference of Governmental Industrial
Hyg1en1sts. Cincinnati, OH 45211.
3-67
-------
A summary of air monitoring method recommendations as a function of
APA sophistication-level and Superfund activity application 1s presented
1n Table 3-13. These recommendations are based on typical Superfund site
conditions. Therefore, alternative methods should be carefully considered
and selected on a case-by-case basis. A summary of screening methods and
their compound class applicability 1s presented 1n Table 3-14. A listing
of refined air monitoring methods 1s Included 1n Table 3-15. Additional
summaries of these refined methods and associated equipment are presented
1n Tables 3-16 through 3-22. A brief overview of emerging technologies
(e.g., mobile mass spectrometry and laser/Infrared spectrometry) 1s
presented 1n Table 3-23. However, until these technologies are further
developed. 1t 1s recommended that standard air monitoring methods be
selected for Superfund APA applications.
A bibliography of standard operating procedures for air monitoring
applications 1s presented 1n Appendix A. A 11st of commercially available
equipment for screening and refined screening monitoring Is presented 1n
Tables 3-24 and 3-25. Refined monitoring systems generally require the
purchase of many Individual components. Therefore, a convenient summary
of the numerous vendor alternatives 1s not practical for this document.
3.4.5 Document Air Monitoring Plan
The site/source-specific air monitoring plan should be documented to
facilitate the Implementation of the selected monitoring strategy. A
recommended procedure for this phase 1s presented 1n Figure 3-10.
Required Documentation: Quality Assurance Project Plan
The EPA requires of any project Involving environmental measurement—
the monitoring for toxic substances of Superfund sites, for Instance—the
preparation of a Quality Assurance Project Plan (QAPP). The QAPP, which
1s distinct frora any general project plan, describes the organization of
the project and the assignment of responsibility for those specific QA/QC
activities required to meet the projet OQOs. A detailed description of
3-66
-------
TABLE 3-13
SUMMARY OF AIR MONITORING METHOD RECOMMENDATIONS
Superfund
Activity
Monitoring Recommendations
Objectives
II/FS
Screening
- THC analyzers
- colorlmetric gas
detection tubes
Refined Screening
- portable field GC
analyzer
Refined
- whole air samplers
with GC/MS analysis
for Indicator
compounds and for an
expended 11st (samples
split) of compounds
(TO-14)
- whole air samplers for
volatile organlcs {TO-
14)
- 1mp1ngers 1f necessary
(TO-5. TO-6, TO-8)
- PUT sampling as
necessary (TO-9)
- H1-Vol (PM-10) for
paniculate matter as
necessary (40 CFR 50,
Part J)
Determine whether or not
toxic air releases exist
at the site and Its
perimeter using gross
measurement techniques
Obtain qualitative
Information of onslte and
offslte air toxic
concentration for
defining a more refined
monitoring
Support refined
monitoring and provide
near real-time data for
site monitoring
Determine refined levels
of air toxic
concentrations onslte and
at the site perimeter
Utilize these data to
define air monitoring
plan for the next
Superfund step (1f
necessary)
Assist 1n air quality
data Interpretation
Determine refined levels
of toxic air contaminants
onslte. at the site
perimeter, and offslte
Utilize results of the
air monitoring In risk
assessment for the no-
action alternative and
evaluating remedial
alternatives
Provide sufficient
Information for the
design and Implementation
of remedial action-steps
3-69
-------
TABLE 3-13
SUMMARY OF AIR MONITORING METHOD RECOMMENDATIONS (Continued)
Superfund
Activity
Monitoring Recommendations
Objectives
Remedial
Design
Remedial
Action
Refined
- Whole air samplers for
volatile organic (TO-
14)
- 1mp1ngers 1f necessary
(TO-5, TO-6. TO-8)
. PUP sampling as
necessary for seml-
volatlle organlcs (TO-
9)
- H1-Vols (PM-10) for
participate matter as
necessary (40 CFR 50.
Part J)
Refined screening
- Portable field GC
analyzer
Refined
- whole air samplers for
volatile organlcs (TO-
14)
- Implngers as necessary
(TO-5. TO-6. TO-8)
- PUF samplers as
necessary for sernl-
volatlle organlcs (TO-
9)
- H1-Vol (PM-10) for
partleulate matter as
necessary (40 CFR 50.
Part J)
Refined screening
- portable field GC
analyzer
Determine the effects or
pilot treatablllty study
and ambient air quality
and make use of the data
1n the design of the
Implementation of
remedial action step
Support refined
monitoring and provide
near-realtime data for
site monitoring
Provide data 1n support
of protecting public
health and the
environment as well as
onslte workers under
routine and nonroutlne
releases
Provide near-realtime
data 1n support of
protecting public health
and the environment as
well as onslte workers
under routine and
nonroutlne releases
3-70
-------
TABLE 3-13
SUMMARY OF AIR MONITORING METHOD RECOMMENDATIONS (Continued)
Superfund
Activity
Monitoring Recommendations
Objectives
Remedial
Action
(continued)
Operation
and
Maintenance
Screening
- Electrochemical alarm
cells
• Refined
- whole air samplers for
volatile organlcs (TO-
14)
- 1mp1ngers as necessary
(TO-5. TO-6, TO-8)
- PUF samplers as
necessary for seml-
volatlle organlcs (TO-
9)
- H1-Vol (PM-10) for
part1culate matter as
necessary (40 CFR 50,
Part J)
Provide near-realtime
data 1n support of
protecting onslte workers
and sufficient
Information for
protecting public health
and the environment 1n
case of nonroutlne
release
Assess the long-term
effect of the remedial
action on public health
and environment.
3-71
-------
TABLE 3-14
SUNNMV OF SCREENING TECHNIQUES fOH DETECTION Of ORGANIC AND INORGANIC CONFOUNDS IN ANUEftT AIR
Compound dm (Ref.Table 3-6)
i. Vplatlle Qjaanlcs
1. Alfpnattcs
'. Aromatic*
1. Halogenated species
4. Oxygenated species
5. Sulfur-containing species
B. Volatile Inoratnlcs
1. Acid eases
2. Sulfur-contiln1«i
c. Sfal-Volatlle Qrqanlcs
1. Phenols
2. Esters
3. ChlortMted benzenes
4. talnes
S. Pesticides Ethers
6. Alkedlenes
7. NlscelUneous illptuttcs
•nd amities
8. Poljnwclear aroHtlc
hydrocarbons
9. PesttclOes
10. Pol/chlorinated blphenjrls
(Ptt's)
b. Non-Volatlles
1. Inoroanlc «eUl$ and non-
Applicable Methods (Ref. Table 3-4)
oiai njarourooii
Analyzers
FID(l)
X
•
«
R
H
II
K
•
M
X
Infrared
*
K
K
X
X
X
ColorlMtrlc Methods
€as
Detection
Tubes
x(?)
X
X
X
X
X
X
X
X
X
X
Continuous
Flow
Colorimeter
Ttpe
Monitor
X
Electrochemical
Detectors and
Alarm
x(HCN)
X
M«9)
Portable (C Analyzers
GC/FID
X
X
X
X
X
XX
X
X
PIO and
GC/PID
xxO)
X
nil)
X
GC/ECD
xx(4)
X
XX
X
X
X
X
GC/FPO
X
XX
X
X
Portable
ta*»
and
Filters
x(5)
X
*
X
X
I
••4
IM
-------
SUWARV'OF SCREENING TECHNIQUES FOR DETECTION OF ORGANIC AND INORGANIC COMPOUNDS IN AMBIENT AIR
PAG? 1X0
Abbreviations;
FIO
GC
PID
ECO
FPD
Fine Imitation detector
Gas chrautograph
Pnoto-lonlzatlon detector
Electron capture detector
FtaM photometric detector
Notes;
(I) FID alone Hill not distinguish between categories of oapounds. An •«• In this colon wans that the category «> mured along with all
other categories.
(*) Colorlaetrlc gas detection tubes «ay not be applicable to every coapound In a given category. Consult •enufecturer's Information for
specific applicability.
(1) Mhere wre than one GC or total hydrocarbon detector acthod Is listed. '«»• Indicates a preferred acthod.
(4) As an option for haloglnated species, the ECO aay be used In conjunction with a Hall detector or PID for anre accurate Identification of
compounds.
(5) Puap/f liter wthods are applicable to partlculate spectes In the Indicated categories.
(6) Nercaptans My be detected using FID or Infrared wthods.
(') For chlorobenzenes. If a PID Is used. It should be used In conjunction vlth an ECO.
-------
TABLE 3-15
A SUMMARY OF REFINED SAMPLING AND
ANALYSIS TECHNIQUES FOR ORGANICS AND INORGANICS IN AIR
Technique
I. Organic Compounds:
Traps
• Sorptlon onto Tenax GC
Packed Cartridges using
low volume pump and GC/MS
Analysis
• Sorptlon onto Carbon
Molecular Sieve packed
cartridge using low
volume pump and GC/MS
analyses
• Cryogenic trapping of
analytes 1n the field and
GC/FID or ECO analyses
• Sorptlon onto
polyurethane (PUF) using
low volume or high volume
pump and GC/ECD analysis
• Sorptlon onto
Thermosorb/N packed
cartridges using low
volume pump GC/MS
analysis
• Sorptlon onto PUF using
low volume or high volume
pump and high resolution
Gas Chromatography/H1gh
Resolution Mass
Spectrometry (HRGC/HRMS)
EPA
Method No.
TO-1
TO-2
TO-3
TO-4
TO-7
TO-9
Type of Compounds
• Volatile, nonpolar
organic (e.g., aromatic
hydrocarbons, chlorinated
hydrocarbons) having
boiling points In the
range of 80° to 200°C, 1n
gas or vapor phase.
• Highly volatile, nonpolar
organlcs (e.g., vinyl
chloride, vinyl Idene
chloride, benzene,
toluene) having boiling
points 1n the range of
1-15° to +120DC, In gas or
vapor phase.
• Volatile, nonpolar
organlcs having boiling
points In the range of
-10° to +200'C, In gas or
vapor phase.
• OrganochloHne pesticides
and PCBs, In participate
phase
• N-N1trosod1 methyl ami ne In
gas phase
• 01ox1n
3-74
-------
TABLE 3-15 (Continued)
A SUMMARY OF REPINED SAMPLING AND ANALYSIS
TECHNIQUES FOR ORGANICS AND INORGANICS IN AIR
Technique
Whole Air Samplers
• Whole air samples are
collected 1n a SUMMA
passlvated stainless
steel canister and high
resolution GC coupled
with mass specific
spectrometer (GC MS-SIM
or GC-MS-SCAN)
• Whole air samples
extracted directly from
ambient air and analyzed
using cryogenic
preconcentratlon and
direct flame 1on1zat1on
detector (PDFID), or air
samples are collected 1n
a canister and analyzed
by PDFID
• Whole air samples are
collected 1n Tedlar* bags
and subject to GC/FID or
ECD analysis or high
resolution GC compiled
with MS-SIM or MS-SCAN
• Liquid Implngers
• 01n1tropheny1hydraz1ne
Liquid Implnger sampling
using a low volume pump
and High Performance
Liquid Chromatography/UV
analysis
• Aniline liquid Implnger
sampling using a low
volume pump and HPLC
analysis
EPA
Method No.
TO- 14
TO- 12
Modified
TO-3 or
TO- 14
TO-5
TO-6
Type of Compounds
• Volatile, nonpolar
organic (e.g., aromatic
hydrocarbons) chlorinated
hydrocarbons having
boiling points of -30°C
to about 215°C.
• non methane organic
compounds (NMOC)
• TO-14 or TO-3 Compounds
• Aldehydes and Ketones
• Phosgene
3-75
-------
TABLE 3-15 (Continued)
A SUMMARY OF REFINED SAMPLING AND ANALYSIS
TECHNIQUES FOR ORGANICS AND INORGANICS IN AIR
Technique
• Sodium Hydroxide Liquid
Implnger sampling using a
low volume pump and HPLC
analysis
II. Inorganic Compounds:
Filter Samplers
• High-volume sampler and
atomic Absorption (AA) or
Inductive Coupled Plasma
(ICP)
• PM-10 high volume sampler
and AA or ICP
• High-volume sampler
• PM-10 high-volume sampler
EPA
Method No.
TO-8
40 CFR Part
50.11
Appendix B
40 CFR
Part 50
Appendix J
(for
sampling
methodology
only)
40 CFR
Part 50.11
40 CFR
Part 50
Appendix J
Type of Compounds
• Cresol /Phenol
Metals 1n part 1cu late phase
Inhalable metals 1n
part 1cu late phase (up to 10
microns 1n diameter)
Total suspended par tlcu late
(TSP)
Inhalable par tlcu late up to
10 microns 1n diameter
3-76
-------
TABLE 3-16
SUMURV OF SAMPLING AND ANALYTICAL METHODS FOR REFINED
MONITORING FOR ORGANIC AND INORGANIC COMPOUNDS IN AMBIENT AIR-
VOLATILE ARONATICSl
Sampling and Analysis Approach
CRYOGENIC PRCCONCENTRATION/GC/F ID/EC -
Vapor Phase organic* are condensed In a
cryogenic trap. Carrier gas transfers
the condensed sample to a GC column.
Adsorbed compounds are eluted from the
GC column and measured by FID or EC
detectors.
CARBON MOLECULAR SIEVE ADSORPTION AND
G/NS or GC/FID - Selected volatile
organic compounds are captured on carbon
molecular sieve adsorbents. Compounds
are thermally desorbed and analyzed by
TENU GC ADSORPTION AND GC/MS OR GC/FID
- Ambient air Is drawn through organic
polymer sorbent where certain compounds
are trapped. The cartridge Is
transferred to the laboratory for
analysis. Using GC/MS or GC/FID.
SUMNA PASSIVATED CANISTER AND GC/FIO/ECO
OR GC/MS - Whole air samples are
collected In an evacuated stainless
steel canister. VOCs are concentrated
In the laboratory with cryogen trap.
VOCs are revotattllzed, separated on a
GC column, and passed to one or mare
detectors for Identification and
Method
Designation
TO-3
TO-?
T0-t<
Detection
Limit
0.1 ppbv
(100 al
sample)
(20 ml
sample)
(20 ml
sample)
0.5-4 ppb
Accuracy'
90-1101
(biased
90-iW
Precisions
115S
tlOT
Advantages
volatile organic compounds
• Standard procedures are
available
• Contaminants common to
adsorbent materials are
avoided
• Low blanks
organic compounds are
collected and concentrated
on sorbent material
• Atmospheric moisture not
collected.
sampled
• Mater vapor Is not
'collected
• Hide variety of compounds
collected
• Standard procedures
available
speclatlon of unknown trace
volatile organtcs
• Staple sampling approach
Disadvantages
cause freezing problems
• Difficult to use In field
• Expensive
organic species are
difficult to recover from
the sorbent.
and certain polar compounds
are not collected.
•MSQTOCfl Q4T OQCQMpOSQ
through Interaction with
container malls
• Condensation may me a
problem at high
concentrations (ppa)
• Complex equipment
preparation required
2 Accuracy'. JTtar^reeMnt9ofTannanalytical measurement with a true or accepted value. Values In this table are expressed as Percent Recovery
3 Precision - The reproduclbimy of repeated measurements of the same property usually made under prescribed conditions. Values In this table are
expressed as Relative Percent Difference (RPD-Range/Nean • 100).
-------
TABLE 3-17
SUMMARY OF SAMPLING AND ANALYTICAL METHODS FOR REFINED
MONITORING FOR ORGANIC AND INORGANIC COMPOUNDS IN AMBIENT AIR-
VOLATILE HALOGENATED HVDROCARBONSl
Stapling and Analysts Approach
TENAX GC ADSORPTION AND GC/NS OR GC/ECO
- Aablent air Is dram through a
cartridge containing Tenax where certain
volatile organic coapounds are adsorbed.
Compounds are transferred by programed
thermal desorptlon Into a GC and
detected by MS or ECO.
CARBON MOLECULAR SIEVE ADSORPTION AND
GC/NS OR 6C/ECD - Art) lent air Is dram
through a cartridge containing carbon
•olecular sieve mere highly volatile
coapounds are adsorbed. Compounds are
thenMlly desorbed to a GC mere they
are quantitatively Measured using MS or
EC detectors.
CRYOGENIC TRAPPING AND GC/ECO - Vapor
phase organlcs are condensed In a
cryogenic trap. Carrier gas transfers
the condensed staple to a GC coluan.
Adsorbed coapounds are eluted fro» the
GC coluan and deteralned by MS or EC
detectors.
Method
Designation
TO-1
TO-2
TO-3
Detection
LlBlt
.01-1 ppb
1-200 pptv
(20*1
snple)
O.lppbv
(100 •!
sople)
Accuracy?
BO-100X
70-95*
90-1101
Precisions
120*
ilO-40X
tuts
Advantages
• Moisture Is not collected
• Large staple voluae can be
concentrated
• Docwented standard
procedures available with
extensive QA/QC data base
• Practical for field use
• Low detection Halts
• Efficient collection of
polar coapounds
• Hide range of application
• Highly volatile coapounds
arc adsorbed
• Easy to use In field
Large data base
Excellent long-tem storage
Hide applicability
Allows aultlple analyses
Best wthod for broad
speclatlon of unknown VOCs
Easy staple collection
Consistent recoveries
Disadvantages
possible
• Artifact formation probleas
• Rigorous cleanup required
• No possibility of aultlple
analyses
• Low breakthrough voluaes
• Mater collected and can
deactivate adsorption sites
• Theraal desorptlon of
coapounds aay be difficult
• Moisture condensation
• Integrated stapling Is
difficult
CO
1 See Table 3-6 for listing of analytes.
2 Accuracy - The Agreeaent of an analytical aeasureaent with a true or accepted value.
(W-Neasured Value/True Value x 100).
3 Precision - The reproduclblllty of repeated aeasureaents of the
expressed as Relative Percent Difference (RPD-Range/Nean x 100).
Values In this table are expressed as Percent Recovery
property usually aade under prescribed conditions. Values In this table are
-------
TABLE 3-18
SUMMARY OF SAMPLING AND ANALYTICAL METHODS FOR REFINED
MONITORING FOR ORGANIC AND INORGANIC COMPOUNDS IN AMBIENT AIR-VOLATILE OXYGENATES*
Sapling end Analysis Approach
OR GC/PID/EC OR GC/NS - Nhole air
snples ire collected In an evacuated
stainless steel canister. VOCs are
concentrated In the laboratory with
cryogen trap. VOCs are revolatlsed.
separated on a GC column and passed to
one or more detectors for Identification
and quantttatlon
Air sample is drawn through
Dlnltrophenylhydrailne Implnger solution
using a low volume pump. The solution
Is analyied using HPLC with a UV
detector.
Air stream Is drawn through a Tenax
cartridge and adsorbed to It.
Oesorptlon fm Tena« Is by thermal
desorptlon to GC/NS or GC/FID.
Collection of whole air sables In SUMMA
passlvated stainless steel canisters.
VOCs are separated by GC Methods and
•easured by MS or multi-detector
techniques .
See Table 3-6 for listing of analytei
Method
Designation
10- H
TO-3
TO- 5
TO-I
TO-I4
i.
Detection
Limit
U.9-
-------
TABLE 3-19
SUMMARY OF SAMPLING AND ANALYTICAL METHODS FOR REFINED
MONITORING FOR ORGANIC AND INORGANIC COMPOUNDS IN AMBIENT AIR-
SEMI -VOLATILE PMENOLICSl
Sapling and Analysts Approach
SODIUM HYDROXIDE LIQUID INPIN6ER AND
HPLC/UV - AwJent air It drawn through 2
•Idget taplngers. Phenols arc trapped
as phenolates In NaON solution and
analyzed by HPLC.
ADSORPTION ON TENAX AND GC/FIO OR GC/NS
- AwJent air Is dram organic polywr
sorbent where certain organic compounds
are trapped. The cartridge Is
transferred to the laboratory for
analysis. Compounds are desorbed by
heating.
HIGH VOLUME PUF/TENAX SAMPLER AND GC/ECD
- Sorptlon onto PUF.
Method
Designation
TO-8
TO-1
TO-4
Detection
L1>1t
1 PPb
1.200 ppt
0.2-2
ng/«3
Accuracy?
7S-125X
70-95*
60- lOOf
Precision!
1201
410-40*
t2M
Advantages
• 4.6-d1n1tro-2-wthytphefio1
(SO/1600) specific to class
_• «U^Mu|«
Of COMPOS
• Good stability
• Detect non-volatile as well
•s vo lilt lie CMtpoundt
• Good OA/QC data base
• Hide range of application
• Easy to use In field
• Hide range of application
• Easy to use - low blanks
• Excellent collection and
retention efficiencies
Disadvantages
• Subject to Interferences
• Ltalted sensitivity
• Oesorptlon of sow
cowounds difficult
• Blank contamination
possible
• Artifact formation on
-.-*-nrtia«it
MMII UCIIl
• Nigh hwridlty reduces
collection efficiency
• Possibility of
contamination
1 See Table 3-6 for listing of analytes.
2 Accuracy - The Agreement of an analytical wasurewnt with a true or accepted value. Values In this table are expressed as Percent Recovery
(tt-Neasured Value/True Value x 100).
3 Precision - The reproduclblllty of repeated wasurewnts of the saw property usually wde under prescribed conditions. Values In this table arc
expressed as Relative Percent Difference (RPO-Range/Nean x 100).
-------
TABLE 3-20
SUMMARY OF SAMPLING AND ANALYTICAL METHODS FOR REFINED
MONITORING FOR ORGANIC AND INORGANIC COMPOUNDS IN AMBIENT AIR-
SEMI-VOLATILE BASE/NEUTRAL EXTRACTS!
Sapling and Analysis Approach
HIGH VOL GFF AND PUF FILTERS AND
CC/f 10/tCD OR GC/NS - Partlculates
filtered In field and solvent extracted
In lab. Analyzed by GC/NS.
HIGH VOL. XAD-2 RESIN - Partlculates
filtered fro* art) lent air with low or hi
vol filter. Filters solvent extracted
and analyses completed using GC/NS.
Method
Designation
TO-4
TO-4
(Modifi-
cation)
Detection
Licit
0.2-200
ng/»3
0.2-200
ng/*3
Accuracy?
28-851
80-12M
Precisions
215X
ilSft
Advantages
• Effective for broad range
of compounds
• Easy to preclean and
extract
• Low blanks
• Effective for broad range
of compounds
• Easy to clean
• Broad data base
• Good retention of coapounds
Disadvantages
• Possible contamination
• Loss of volatile organic*
during storage
1 See Table 3-6 for listing of analytes.
V * Accuracy - The Agreement of an analytical Measurement with a true or accepted value. Values In this table are expressed as Percent Recovery
co (IR'Neasured Value/True Value x 100).
*~ 3 Precision - The reproduclblllty of repeated acasurewnts of the saw property usually Mde under prescribed conditions. Values In this table are
expressed as Relative Percent Difference (RPO-Range/Nean x 100).
-------
TABLE 3-21
SUMMARY OF SAMPLING AND ANALYTICAL METHODS FOR REFINED
MONITORING fOR ORGANIC AKD INORGANIC COMPOUNDS IN AMBIENT AIR-
SEMI-VOLATILE PESTlCIDES/PCBsl
Sampling and Analysis Approach
HIGH VOL GLASS FIBER AND PUF FILTERS AND
GC/ECD - Participates collected on
filters. Compounds solvent extracted
and analyzed using GC/ECD.
HIGH VOL GLASS FIBER FILTER AND XAD-2
RESIN TO FILTER AND ADSORB PARTICULATES
Method
Designation
TO-4
TO-4
(•Odlfl-
catton)
Detection
LlMlt
0.2-
200 ng/»3
0.2-
200 ng/»3
Accuracy?
28 to
85- 10W
80-12M
Precisions
tlSI
±201
Advantages
Broad range of application
Low blanks
Easy to use
Reusable
High sensitivity
• Can analyze broad range of
compounds (more efficient
than PUT)
Disadvantages
• Can lose volatile co^Kwnds
In storage
• Possibility of
contamination
1
w «
k J
Accuracy6- The Agreeocnt'of an analytical Masureaent with a true or accepted value. Values In this table are expressed as Percent Recovery
PrtcU1mT'T£'r^Sc1b!l1i; of°repMted msurements of the saM property usually Mde under prescribed conditions. Values In this table are
expressed as Relative Percent Difference (RPD-Range/Nean x 100).
-------
TABLE 3-22
SUMMARY OF SAMPLING AND ANALYTICAL METHODS FOR REFINED
MONITORING FOR ORGANIC AMD INORGANIC COMPOUNDS IN AMBIENT AIR-
VOLATILE INORGANICS*
CO
Sampling and Analysis Approach
HIGH VOL. GFF AND AA/ICP - Partlculates
are moved fro* air strew with a OFF
or PUT filter, dissolved and analyied by
spectraaetrlc •ettads.
VAPOR PHASE METALS (So. As. Pb. HI. Se.
». Hg) IMPINGCR AND AA/GFA - Collection
vapor phase Ktals on sorbents and In
linger solutions.
VAPOR PHASE CN - NCEF and Sodlui
Hydroxide Liquid liplnger
Method
Designation
TO-4
TO-8/ISP/F.P
A 335.1 or
.3
Detection
Llalt
l-5nq/«3
l-5ng/«3
l-5ng/*3
Accuracy2
IHB^BB^H
125»
Precision'
•••••••••
not
Advantages
Wide range of applications
Standard wthods
low detection 1 lilts
Standard Methods
High sensitivity
QA/QC data base available
Specific acthod for each
actal
• Standard wthods for each
a*tal
Disadvantages
• Possible breakthrough
• High blanks
• Interferences
• Potential Interferences
klcuI^^Xee^T'or.n^U.l a«.sure*nt with a true or accepted value. Values In this table are expressed ., Percent Recover,
Pr^lon'T'TK'rXroducSnit, ."repeated Masurewfts of the saw property usually «*de under prescribed conditions. Values In this table are
expressed as Relative Percent Difference (RPO-Range/Mean x 100).
-------
TMU 3-?l
SUMMARY OF SAMPLING MO AMU.YT1CM. KTMDS FOR RCFIMED
MONITORING FOR ORGANIC AND MMCANK COMPOUNDS « AMB1EN1 AIR-
DEVELOPING TfCHMUKIESl
Stapling and Analysis Approach
MOBILE MAS* SPECTROMTCR (MS/MS,
KS/NS/NS) OR {GC/MS}
LONG PATH FT/lit - RtMte Opt1«l
VoTdtlle [Klsslora Recorder. Uter
tource traftwUUd «cr«t contwfMtH
«rH. Omlte Fourier Trtrnfon nwlytt
of reflected later bew provides organic
contHilMMt uwlysli bj Infrared
fettad
Deilgiutlon
none
(torn
Detect ton
Malt
1 ppb
2«*
Accuracy*
PrecU1on3
Advantages
• Coepoumt tdewllflcattontR
coeylex •!«!*»«$
• Otrect sealing
• field operation
• Direct field MHumiMts
• NlnlM ttw revjulrewit
Oliatf«mta«es
• E>penl*e
• Skilled operator!
• LM sensitivity
u>
09
Z Acartcy - THe A^reeewrt of *n tralyttctl KMurctent wltfc o true «r tccealed vatue. «alu« tn IM« tab)* w» uqnr«ue4 as Percent fernery
3 pSc^^Tte'^SStat^Utll J?°reVeol«l «ea«re«nti of U» MM froBerty usually Hde wider prescribed conditions, tatas l« Mts table
expressed as Relative Percent Difference (RPO-ftcnee/MHn * 100).
-------
TABLE 3-24
TYPICAL COMMERCIALLY AVAILABLE SCREENING MONITORING AND ANALYSIS EQUIPMENT FOR ORGANICS AND
INORGANICS IN AIR*
Technique
1. THC Analyzers
FIO (Total Hydrocarbon
Analyzer)
Infrared Analysis
2. Colorlmetrlc Gas
detection tubes and
monitors
Gas Detection Tubes
Continuous Flow
Colorimeter
Manufacturers
Beckman
MSA, Inc.
Thermo Electron.
Inc.
Foxboro/W likes
Draeger
Matheson
Kltagawa
CEA Instruments,
Inc.
Compounds
Detected
Most organlcs
Most organlcs
Various organlcs
and Inorganics
Acrylonltrlle,
Formaldehyde,
Phosgene, and
various organlcs
Approximate
Detection Limit
0.5 ppmv
1-10 ppmv
0.1 to 1 ppmv
0.05 to 0.5 ppmv
Comments
Does not respond
uniformly to most
organic compounds on a
carbon basis
Some Inorganic gases
(HzO. CO) will be
detected and therefore
are potential
Interferences.
Highly subject to
Interfernece*
sensitivity and
selectivity highly
dependent on compound
of Interest.
Sensitivity and
selectivity similar to
detector tubes.
00
Ul
-------
TABLE 3-24 (Continued)
TYPICAL COMMERCIALLY AVAILABLE SCREENING MONITORING AND ANALYSIS EQUIPMENT FOR ORGANICS AND
INORGANICS IN AIR*
Technique
Colorimetrlc Tape
Monitor
3. Electrochemical
A Urn Cells
4. Portable GC**
Analyzers
GC/FID (portable)
Manufacturers
KHOA Scientific
Foxboro, MSA,
CEA Instruments,
Sensldyne
Foxboro/Century,
Thermo Electron,
Inc.
Compounds
Detected
Toluene.
dllscocyanate,
dlnltro toluene.
phosgene, and
various
Inorganics
Wide range of
Inorganics, also
combustion gases
Most organlcs
except that
polar compounds
may not elute
from the column
Approximate
Detection Limit
0.05-0.5 ppmv
ppmv
0.5 ppbv
Comments
Same as above.
Quantitative
Information for a
single compound by
each cell. Requires
an array of cells.
Qualitative as well as
quantitative
Information obtained,
does not respond
uniformly to organic
compounds.
00
01
* Based on Rlggln, 19B3.
** Classified as a refined screening technique
-------
TABLE 3-24 (Continued)
TYPICAL COMMERCIALLY AVAILABLE SCREENING MONITORING AND ANALYSIS EQUIPMENT FOR ORGANICS AND
INORGANICS IN AIR*
Technique
PIO and GC/PIO
(portable)
GC/ECD (portable)
GC/FPO (portable)
5. Portable pimps and
filters
Manufacturers
HNU, Inc.
Photo vac. Inc.
Therm
Environmental
Instruments Inc.
Thermo Electron.
Inc.
Thermo Electron.
Inc.
Gil Ian
Instrument
Corp., SKC,
Inc.. Mllllpore.
Inc.
Compounds
Detected
Most organic
compounds can be
detected with
the exception of
methane
Halogenated and
nltro-
substltuted
compounds
Sulfur or
phosphorus-
containing
compounds
Inorganics
parttculates and
semi volatile
partlculates
Approximate
Detection Limit
0.1 to 100 ppbv
0.1 to 100 ppbv
10-100 ppbv
100 ppbv-lppmv
Comments
Selectivity can be
adjusted by selection
of lamp energy.
Aromatlcs most readily
detected.
Response varies widely
from compound to
compound.
Both Inorganic and
organic sulfur or
phosphorus compounds
will be detected.
special sorbent plugs
have to be used to
collect semi volat lies
00
GC means Gas Chromatograph
FID means Flame Ion1zatIon Detector
PID means Photolonlzatlon Detector
ECD means Electron Capture Detector
FPD means Flame Photometric Detector
* Based on Rlgglns. 1983.
-------
TABLE 3-25
SUNMRV OF REFINED SCREENING MONITORING EQUIPMENT FOR ORGANIC COMPOUNDS IN AMBIENT AIR
Sampling and Analysis Approach
centooraoh PC operated portable
f Analyzer utilizing Argon
lottzat Ion/electron capture
detector (ECO) with optional
photolonlzatlon detector.
ireconcentrator and a heated
column with temperature adjustable
to 140'C. Up to 16 different
compounds can be processed at any
,1me. Library Is up to
100 compounds. Ongoing
calibration Is by Injecting
standard calibration gas.
Photovac Model 10S70 portable GC
analyzer utilizing photolonlzatlon
detector (PIO) with a range of
S different energy lamps to
provide selectivity for different
chemical groups. Isothermal oven
control for the multl capillary
colwn. Up to 25 compounds can be
processed at any time. Include
four libraries of 25 compounds
each. Calibration Is by Injecting
standard calibration gas
Manufacturer
Sentex Sensing
Technology, Inc.
Photovac, Inc.
Detection Limit
O.I to several
ppb depending on
the number of
compounds In-
volved and the
•1x
0.1 to several
ppb depending on
the number of
compounds In-
volved and the
•U
.
Precision
about 5- lot,
high
reproduclbllUy
about 5-10*
depending on
compound
Involved, high
reproduclblllty
Mode of
Operation
real tlM
continuous
real time
continuous
Advantages and Disadvantages
Advantages:
• near real time continuous
concentrations of air tonic
constituents
• good accuracy and low detection
limit for a field technique
• eliminates Inaccuracies
associated with the handling of
samples obtained by Integrator
samplers that have to be
shipped for laboratory analysis
• has an option for more than one
detector
Disadvantages:
• can analyze only a limited
number of air toxic
constituents at a time
• subject to Inaccuracies
Introduced by field conditions
and field operators
Advantages:
• Similar to the ones mentioned
above with the exception that
It uses only one detector
Disadvantages:
• Similar to tin ones mentioned
above with the addition of:
- Isothermal oven control Is
up to WC. This GC cannot
operate at higher
temperatures. This reduce
the range of volatile
organlcs that can be
analyzed. Useful mainly for
high volatile organic
- Cannot use detectors other
than the PIO
CO
CO
-------
TABLE 3-25(Cont1nued)
SUMMR* OF REFINED SCREW* MONITORING EQUIPMENT FOR ORGANIC COMPOUNDS IN AMBIENT AIR
Sampling and Analysis Approach
NMI Model 30IOP or 311 portable GC
analyzer. The 301PO aodel can
utilize either a PID or FID and
the 311 aodel can utilise a PIO
only. Includes Isotheraal
uaaerature control of up to JOO'C
for the 301PD aodel and up to
about ZOD'C for the 311 aodel.
Calibrate with either the
coapounds of Interest or with a
reference coapound. Up to
20 coapounds can be processed at
any tl*e.
Manufacturer
HNU Systeas.
Inc.
Detection Limit
0.1 to several
e ssn *
coapounds 1 n-
volved and the
Precision
not readily
available but
expected to be
In the saae
range as -above
Mode of
Operation
real tine
continuous
Advantages and Disadvantages
Advantages:
• Slatlar to the ones above for
the JOIPO aodel
• Slallar to the ones above for
the 311 aodel with the
exception that It uses only one
detector
Disadvantages:
• Slallar to ones listed for the
Scentograph GC
with the addition of
• no teaperature edjustaants
• no library for retention tlaes
co
«o
-------
MONITORING
CONSTITUENT
TARGET LIST
METEOROLOGICAL
MONITORING
PROGRAM DESIGN
AIR MONITORING
NETWORK DESIGN
MONITORING
SOPHISTICATION
LEVEL
(STEP 2)
PREPARE AIR
MONITORING PLAN
Project Description
Project Orcenlzetlon
Peellltlss/Bqulpmerrt
Data Quality Objectives
Sample Collection
Sample Cuetody
Calibration
Sample Analyala
Deeumentatlen
Data Management
Internal OO Oheeka
external QA Audits
Prevontatlve Malntena
Routine Procedures
Gorreottvo Action
QA Reports
JL
PEER
REVIEW
RPMXEPM
APPROVAL
INPUT TO ,
4 • CONDUCT
MONITORING
a-10.
Plan.
3-90
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the QAPP 1s given In the following document: activities to meet the data
quality objectives for the project. Detailed description of the QAPP 1s
given 1n the EPA document: U.S. EPA, September. 1981. Preparation of
Quality Assurance Prelect Plans. Office of Toxic Substances, Office of
Pesticides and Toxic Substances. Washington, DC. Additional guidance 1s
available 1n the following:
U.S. EPA. 1984. Guide to the Preparation of Quality Assurance
Prelect Plans. Office of Toxic Substances, Office of Pesticides
and Toxic Substances. Washington, DC 20460.
U.S. EPA. 1977. Quality Assurance Handbook for A1r Pollution
Measurement Systems. Volumes I and II. EPA-600/9-76-005.
Office of Research and Development. Research Triangle Park, NC
27711.
ASTM. 1988. Annual Book of Standards? Part 26. Gaseous Fuels;
Coal and Coke: Atmospheric Analysis. American Society for
Testing and Materials, Philadelphia, PA 19103.
U.S. EPA. 1987. Ambient Monitoring Guidelines for Prevention
Qf Significant n^rloratlon fPSDK EPA-450/4-87-007. Research
Triangle Park. NC 27711.
U.S. EPA. 1987. Qnslte Meteorological Program Guidance for
Reoulatorv Mo*»Hna Applications. EPA-450/4-87-013. Research
Triangle Park, NC 27711.
Content of Quality Assurance Prolect Plan
The following 1s a breakdown and description of the contents of a
typical QAPP.
3-91
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Project Description. A general description of the project, Including
the experimental design, must be provided. The description must be
complete enough to enable responsible parties to review and approve the
proposed plan. The plan shall Include the following Items:
• Statement of objectives
• Description of the air toxics monitoring program
Outline of the sampling method and frequency of sampling
• Outline of the method of data analysis to be used
• Anticipated duration of the project
• Intended use of the acquired data
Project Organization and Responsibility. A 11st of all personnel
assigned to data collection, measurement, and verification, Including
brief functional descriptions of their responsibilities, must be prepared.
An organization chart and description of the qualifications of all project
personnel 1s also recommended.
Facilities. Services. Equipment, and Supplies. The utilization of
the resources required for the project must be considered. Questions such
as the following should be addressed:
Can the plan be completed meeting all monitoring requirements In
a safe manner?
Are the equipment and supplies needed to complete the project
adequate and available 1n sufficient quantities?
Who maintains and calibrates the equipment required to make the
measurements?
How frequently 1s the equipment calibrated and serviced?
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What standards are used to calibrate the equipment?
Are special facilities needed to service or dispose of supplies?
nnn< for Measurement Data. It 1s Important to define the acceptance
limits for data generated for the project to ensure that 1t 1s complete
and representative of the site. An attempt should be made to discuss the
acceptance HmHs and control factors for sampling and analysis errors.
This Includes means for determining 1f the data generated meet the
requirements of the Intended use.
Collection. EPA protocols for sample collection procedures
should be referenced and the procedures and equipment to be used 1n the
project should be described. In addition, a description of equipment and
supplies used to collect and transport samples and of preservatives used
and holding-time limitations should be provided. Record-keeping
procedures must be Included to document pertinent detail.
Sample Custody. Procedures for field sampling operations as well as
laboratory operations are to be provided. It 1s critical to ensure that
records are adequate to support legal documentation of the collection,
preservation, transport, and transfer of samples for laboratory analysis.
calibration Procedures. The calibration procedure for each
measurement parameter should be described, either through reference to the
standard operating procedure (SOP) or through an vad hoc written
description. The frequency of calibration and the frequency with which
continuing calibration 1s verified also should be described. The
standards for the calibration and the acceptable sources should be
documented.
Recommended EPA documents that provide detailed Information on the
calibration process are
3-93
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U.S. EPA, 1987. Quality Assurance Handbook for A1r Pollution
Measurement Systems. Volumes I and II. EPA-60019-76-005. Office of
Research and Development. Research Triangle Park, NC 27711.
U.S. EPA, 1987. Ambient Monitoring Guidelines for Prevention of
Significant Deterioration (PSD). EPA-450/4-87-007. Office of Air
Quality Planning and Standards. Research Triangle Park. NC 27711.
U.S. EPA, 1987. OnsUe Meteorological Program Guidance for
Regulatory Modeling Applications. EPA-450/4-87-013. Office of A1r
Quality Planning and Standards. Research Triangle Park, NC 27711.
Calibration should address
• Instrument flow rate when 1t 1s an Important component In
determining the concentrations of air toxic constituents
Electronic zero and span for analytical Instruments such as
portable GC analyzers and meteorological equipment and known
calibration gas, zero, and span for analytical Instruments.
Laboratory Analysis Procedures. EPA-approved procedures for the
monitoring parameters should be discussed. Similarly, a written
description of the analytical procedures and SOPs that will be used 1n the
monitoring program should be addressed.
Data Management. Data management Includes the procedures established
to store and maintain both field and laboratory data collection and
analysis records.
Recordkeeo1na/Documentat1on. The QAPP should specify requirements
for field and laboratory documents. For example, the use of logbooks.
forms, and other records of monitoring/analytical operations should be
Identified.
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Internal PC Checks. The Internal QC methods for the air quality
monitoring project should be described. Items to be addressed Include
• Replicates
• Spiked samples
• Split samples
• Control charts
• Blanks
• Internal standards
• Zero and span gases
• Quality control samples
• Surrogate samples
• Calibration standards and devices
• Reagent checks
External OA Audits. Audits should be scheduled to verify that
components of the monitoring program are In place and operating as
described for both field and laboratory QC procedures.
Preventive Maintenance. Preventive maintenance, Including frequency
and methods of Implementation, should be addressed 1n the QA plan. A list
of the spare parts needed to ensure prompt equipment repair and thus to
minimize downtime should also be prepared.
Procedures to Assess Data Quality. Specific procedures to assess the
precision and accuracy of measurement data should be discussed In the
QAPP. This Includes standard statistical methods of evaluating data
quality. On completion of testing, the data can be reviewed by an
Independent reviewer to assess the quality of the reported values.
Feedback and Corrective Action. The criteria for acceptable data
should be described, as should the corrective action to be taken 1f the
data quality 1s not acceptable. The personnel responsible for reviewing
the data and for Implementing correction action should also be Identified.
3-95
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Quality Assurance Reports to Management. QAPPs should provide a
mechanism for the regular review of data quality. These periodic reports
Include data quality measurements, performance and system audits, and a
listing of measures taken to resolve problems noted. Each of these
elements should be Included 1n the final project report.
Review and Approval of Quality Assurance Project Plan
A draft of the QAPP should be reviewed by the EPA Project Officer and
the QA Officer to ensure that the plan contains the procedures necessary
to document the prevision, accuracy, and completeness of the data
generated.
The draft should also be subjected to a peer review—preferably
review by another air expert who was not a primary author of the plan. At
the discretion of the RPM/EPM, this review could be conducted within the
same organization that developed the plan.
Authority for final approval of the plan rests with the RPM/EPM. and
project cost and schedule are major considerations.
3.5 STEP 4 - CONDUCT MONITORING
3.5.1 Overview
Field and analytical operations of the air monitoring program should
be conducted commensurate with the monitoring plan developed during
Step 3. However, successful Implementation of the monitoring plan
requires adequate field staff and attention to QA/QC factors. Therefore,
the operational approach Illustrated In Figure 3-11 should be applied to
Superfund air monitoring programs.
3-96
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MONITORING
PLAN
(STEP 3)
MONITORING
STAFF
QUALIFICATIONS/
TRAINING
METHOD-SPECIFIC
QA/OO CRITERIA
CAopandlX A)
SUPIftPUND OAX
PIBLQ OPIRATlOMa
METHODS MANUAL
•AMPUNOX ANALYSIS
IMVmUMIMTATIOM
CALIBRATION
IMPLCMENTAT1ON
(Figure 3-11)
e OA M«n«g»m«iit
e Sampling OA
o Analytical OA
o Data Radueilon
OA
TECHNICAL
ASSISTANCE
OOOUMBNT
(Appandlx •)
OTHER
TECHNICAL
QC SAMPUNQ/
ANALYSIS
FREQUENCIES
(Tabla 3-28)
INPUT TO
STEP S - SUMMARIZE
AND EVALUATE
RESULTS
«-n. at«p * • oontftiot
3-97
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3.5.2 Field Staff Qualifications and Training
The air monitoring program should be designed and directed by staff
with air toxics monitoring experience. For many applications the site
health and safety officer will be qualified to direct the field monitoring
operations. However, 1t should be recognized that site health and safety
officers, as well as staff with similar backgrounds (e.g., Industrial
hyglenlsts), may not have experience 1n air toxics monitoring at the low
detection levels (parts per billion or mlcrograms per cubic meter)
specified 1n ARARs to protect offsite receptors. It Is recommended,
therefore, that Superfund air monitoring projects be designed and
Implemented by air quality specialists with relevant ambient air toxics
monitoring experience.
It 1s Imperative that the field staff who will be Involved with the
operation of the network be trained personnel with sufficient
understanding of, and hands-on experience with, air toxics monitoring
Instrumentation and laboratory analysis. The field operators must be
sensitive to the overall aspects of the program Including but not limited
to
In-depth understanding In operating the equipment Involved.
Consistent performance of the preventive maintenance actions
recommended by the manufacturer.
Consistent performance of the routine tests of the equipment
used to ensure It operates properly.
Timely Implementation of equipment checks and calibrations.
Maintenance of network logbook and monitoring station logbooks
to document pertinent field activities. These activities must
be documented In a clear manner to enable the use of the logs as
needed 1n the future.
3-98
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• Careful handling of samples collected to avoid the contamination
or loss of materials collected, and the documentation In detail
of every sample sent for laboratory analysis to maintain the
correct cha1n-of-custody.
• Careful maintenance of the program sampling and analysis
schedule.
»
Careful checks of regenerated equipment (traps, plugs,
canisters, etc.) that are returned by the laboratory.
Consistent collection of QA/QC samples, Including collocated
blanks.
Maintenance of open-channel communication with the site RPM/EPH
to ensure that he 1s kept apprised of any problem area and the
means of mitigating it.
• Maintenance of open-channel communication with the air toxics
specialist assigned to the project to expedite the exchange of
Information that Is essential to smooth network operation.
An Integral part of the network operation Is the close communication
with the laboratory that has been selected to perform the chemical
analysis on the samples collected In the field. It 1s critical to
maintain close communications with the designated contact at the
laboratory to ensure that
• The samples shipped are received on time.
• Analysis 1s performed on time.
Any technical Issues that develop are handled promptly to
minimize loss of data.
3-99
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• Laboratory results are received 1n time for an evaluation of the
performance of the monitoring program and a preliminary
assessment of, the Implications of the results to the Superfund
project.
It Is clear from this discussion that well-trained field personnel
are the key to a good air toxics monitoring program.
3.5.3 Quality Assurance/Quality Control
Quality assurance/quality control topics to be addressed In the QAPP,
required for Superfund monitoring activities, have been Identified 1n
Section 3.4.5. During the conduct of the air monitoring program, rigorous
conformance to the QAPP will be vital to meet project objectives. Major
QA/QC elements that should be Implemented during the operational phase of
an air monitoring program (see Table 3-26) Include
• QA management
• Sampling QA
Analytical QA
• Data reduction QA
QA management Involves Implementing project-specific administrative
procedures to control QA/QC functions. The potential for, and types of,
quality problems vary for the sampling, analytical, and data reduction
functions. Therefore, the QA/QC requirements must be developed
Individually for each of these functions. Comprehensive QA/QC
recommendations applicable to Superfund and air monitoring programs are
available. Key references Include the following:
Superfund program-specific QA/QC recommendations
U.S. EPA March 1986. Quality Assurance/Field Operations Methods
Manual. Draft.
3-100
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TABLE 3-26
QUALITY ASSURANCE (QA) ACTIVITIES TO BE SPECIFIED IN PROGRAM PLAN
QA Management
- QA System Design
- Document Control
- Data Evaluation
• Audit Procedures
- Corrective Action
- QA Reports to Program Management
- Training
Sampling QA
• Instrument Calibration and Maintenance
- Collection of Routine Quality Control Samples
- Data Recording
• Sample Labeling, Preservation, Storage and Transport
- Cha1n-of-Custody Procedures
Analytical QA
- Method Validation Requirements
- Instrument Calibration and Maintenance
- Quality Control Sample Analysis
- Data Recording
Data Reduction QA
- Merging Sampling and Analysis Data Files
- Storage of Raw and Intermediate Data
- Data Validation
3-101
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Generic air toxics monitoring QA/QC recommendations
U.S. EPA. June 1983. Technical Assistance Document for
Sampling and Analysis of Toxic Organic Compounds 1n Ambient A1r.
EPA-600/4-83-027. NTIS PB 83-239020. Office of Research and
Development. Research Triangle Park, NC 27711.
Monitoring method-specific QA/QC recommendations
U.S. EPA. April 1984. Compendium of Methods for the
Determination of Toxic Organic Compounds 1n Ambient A1r. EPA-
600/4-84-041. Office of Research and Development. Research
Triangle Park, NC 27711.
U.S. EPA. September 1986. Compendium of Methods for the
Determination of Toxic Organic Compounds In Ambient A1r.
EPA/600/4-87-006. NTIS PB87-168696. Office of Research and
Development. Research Triangle Park, NC 27711.
U.S. EPA. June 1987. Compendium Method TO-12: Method for the
Determination of Non-Methane Organic Compounds fNMOCl 1n Ambient
A1r Using Cryogenic Preconcentratlon and Direct Flame Inonzatlon
Detection (PDFIDK Research Triangle Park, NC 27711.
U.S. EPA. May 1988. Compendium Method TO-14: The
Determination of Volatile Organic Compounds fVOCsl 1n Ambient
A1r Using SUMMA* Pa«1vated Canister Sampling—find—Gas
Chromatooraphlc Analysis. Quality Assurance Division. Research
Triangle Park. NC 27711.
NIOSH. February 1984. NIOSH Manual of Analytical Methods.
NTIS PB 85-179018. National Institute of Occupational Safety
and Health. Cincinnati, OH.
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• Meteorological monitoring QA/QC recommendations
U.S. EPA. June 1987. On-S1te Meteorological Program Guidance
for Regulatory Modeling Applications. EPA-450/4-87-013. Office
of Air Quality Planning and Standards. Research Triangle Park,
NC 27711.
• A1r quality monitoring QA/QC recommendations
U.S. EPA. February 1983. Quality Assurance Handbook for A1r
Pollution Measurements Systems; Volume IV. Meteorological
Measurements. EPA-600/4-82-060. Office of Research and
Development. Research Triangle Park. NC 27711.
U.S. EPA. May 1987. Ambient Monitoring Guidelines for
Prevention of Significant Deterioration fPSDl. EPA-450/4-
87/007. NTIS PB81-153231. Office of A1r Quality Planning and
Standards. Research Triangle Park, NC 27711.
These references should be consulted to specify project-specific QA/QC
requirements based on the approach Illustrated 1n Figure 3-12. The
overall QA management system should be Implemented 1n conformance with the
standard Superfund program approach (U.S. EPA, March 1986).
The technical QA recommendations presented 1n On-SUe Meteorological
Program Guidance for Regulatory Modeling Applications (U.S. EPA, June
1987) and Technical Assistance Document fTADl for Sampling and Analysis of
Toxic Organic Compounds In Ambient A1r (U.S. EPA, June 1983) should also
be Implemented. The calibration requirements and QC sampling/analysis
frequency criteria presented 1n Tables 3-27 and 3-28, respectively, are
examples of the QA recommendations presented In the TAD.
The QA criteria presented 1n monitoring method-specific documents
(e.g.. Technical Assistance Document for Sampling and Analysis of Toxic
Organic Compounds In Ambient A1r. U.S. EPA, June 1983) Should also be
3-103
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IMPLEMENT
SUPERPUND FIELD
OPERATIONS METHODS
MANUAL - QA
MANAGEMENT
APPROACH
IMPLEMENT TECHNICAL
ASSISTANCE DOCUMENT
(TAD) - TECHNICAL,
QA RECOMMENDATIONS
FOR AIR TOXIC
MONITORING
(Appendix A)
IMPLEMENT ON-3ITB
METBOROLOQICAL
PROQRAM qUIDANCB
• TECHNICAL QA
RECOMMENDATIONS FOR
MBTSOROLOOICAL
MONITORINQ
IMPLEMENT METHOD-
SPECIFIC QA
CRITERIA IP MORE
STRINGENT THAN TAD
(Appendix B)
IMPLEMENT SUPPLEMENTAL
TECHNICAL QA RECOMMEND
ATIONS BASED ON OTHER
AVAILABE REFERENCES AS
WARRANTED IF NOT
ADDRESSED ABOVE
SITE-SPECIFIC
AIR MONITORING
QA/QC PROGRAM
3-12. a«jp«rfuod Air Monttortna QA/QC 8tr«t«ay.
3-104
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TABLE 3-27. CALIBRATION REQUIREMENTS FOR SAMPLING AND ANALYSIS INSTRUMENTATION
Device
Parameter
Calibrated
Method of
Calibration
Approximate
Frequency
Comments
o
Ul
Sampling Instrumentation
Sampling pump and
controller
Sample volume measurement
device (usually a dry
test meter)
Analytical Instruments
Continuous monitors
(e.g.. FID, P1D. FPD.
etc.)
Chromatographlc
Instruments
Chromatographic
Instruments
GC/HS
Flow rate
Total volume
Response
Column
performance and
retention time
for each analyte
Response for
each analyte
Response and
retention time
for each analyte
Mass spectral
resolution and
turning
parameters
Wet or dry test
meter or calibrated
rotameter
Wet test meter
Generation of test
atmosphere of known
concentrations
Injection of
standard using the
same process as for
sample Injection
Same as above
Same as for other
Chromatographlc
Instruments
(a) Introduction
of perfluoro-
compound directly
Into MS
(b) injection of
tuning standard
(e.g., brpmofluoro-
benzene) into GC
Meekly
Meekly
Dally or more
frequently if
required
Dally or more
frequently if
required
Same as above
Same as for other
Chromatographlc
Instruments
Dally
Must be determined at
known atmospheric pressure
and temperature. Flow
rate should be similar to
that used for sampling.
Test atmosphere should be
referenced to a primary
standard (e.g.. NBS
benzene In air).
Flow/pressure conditions
should duplicate sampling
process.
Standard composition
should be checked against
primary standards If
available.
Same as above
Same as for other
Chromatographlc
Instruments
Selection of tuning
standards will be
dependent on type of
analysis being performed.
-------
TABLE 3-28. TYPICAL SAMPLING/ANALYSIS FREQUENCIES FOR QC SAMPLES
Type of Sample
Typical Frequency
Field Blanks
Laboratory Blanks
Spiked Samples
Duplicate (parallel) Samples
Instrument Calibration Standards
Reference Samples
Series (Backup) Samples
Each Sample Set; at least 10* of
total number of samples.
Daily; at least 10* of total
number of samples. Each batch of
samples.
Each sample set; weekly.
10% of total number of samples;
each sample set.
Daily.
Weekly.
Each sample set.
3-106
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Implemented 1f these QA recommendations are more stringent than those
stipulated 1n the TAD.
Supplemented technical QA recommendations based on other available
references (e.g., Quality Assurance Handbook for Air Pollution Measurement
Systems. U.S. EPA, February 1983) should also be implemented as warranted
for factors not addressed in the previous documents.
3.6 STEP 5 - SUMMARIZE AND EVALUATE RESULTS
3.6.1 Overview
Monitoring data available from Step 4 should be summarized and
evaluated to provide input to site-specific risk assessments and the
Superfund decision-making process. The recommended data processing
approach 1s illustrated 1n Figure 3-13. This approach consists of the
following major elements:
Validate data
• Summarize data
Model dispersion to extrapolate monitoring data
Raw monitoring data should be checked for validity before they are
used as a part of the data base for site decision-making. These validity
checks are an integral part of the QA/QC program for monitoring
activities.
The validated data set should be further processed to provide
meteorological and air concentration summaries. Meteorological data are
also used to classify the upwind/downwind (relative to the Superfund air
emission source) exposure conditions associated with air monitoring
results. The validated data should be processed to obtain sequential data
listings as well as statistical summaries.
3-107
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INPUT DATA
FROM
STEP 4
1
VALIDATE DATA
o Mataorologloal Monitoring
o Air Monitoring
SUMMARIZE DATA
o Data Listings
o Statistical Summarise
METEOROLOQIOAL
SUMMARIES
AIR MONITORING
SUMMARIES
DISPERSION
MODELING TO
DATA
T
INPUT TO
SUPERFUND
RISK ASSESSMENT/
DECISION MAKING
Figure 3-13. Stop 8 - aummariza and Evaluate Neaulta.
3-108
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Dispersion modeling may be warranted for certain situations to
supplement air monitoring results. For example, 1t may be useful to
extrapolate site boundary.monitoring results to offslte receptor locations
of interest.
Each of these topics 1s discussed 1n greater detail 1n the following
subsections.
3.6.2 Validate Data
Data validation 1s an important QA/QC component of Superfund
monitoring programs. For Superfund APA applications, this usually
Involves a combination of automated checks during computer processing of
the raw data as well as manual review of the data by an air specialist.
Meteorological Data Validation
Raw meteorological data should be checked for validity using
equipment calibration, audit, and performance data. Comprehensive
technical recommendations for meteorological data validation presented in
the following reference should be adopted for Superfund APAs:
U.S. EPA, June 1987. Qn-Slte Meteorological Program Guidance
for Regulatory Modeling Applications. EPA-450/4-87-013.
Office of A1r Quality Planning and Standards. Research
Triangle Park, NC 27711.
Table 3-29 presents meteorological data screening criteria. It is an
example of the technical data validation recommendations presented in the
reference cited above.
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TABLE 3-29. SUGGESTED METEOROLOGICAL DATA SCREENING CRITERIA*
(U.S. EPA, JUNE 1987)
Meteorological
Variable
Screening Criteria*
Wind Speed
Flag the data 1f the value:
1s less than zero or greater than 25 m/s
does not vary by more than 0.1 m/s for 3
consecutive hours
does not vary by more than 0.5 m/s for 12
consecutive hours
Wind Direction
1s less than zero or greater than 360 degrees
does not vary by more than 1 degree for more than
3 consecutive hours
does not vary by more than 10 degrees for 18
consecutive hours
Temperature
1s greater than the local record high
1s less than the local record low
(The above limits could be applied on a monthly
basis.)
1s greater than a 5°C change from the previous
hour
does not vary by more than 0.5°C for 12
consecutive hours
Temperature
Difference
1s greater than 0.1°C/m during the daytime
1s less than -0.1°C/m during the nighttime
1s greater than 5.0°C/m or less than -3.0°C/m
Dew Point
Temperature
1s greater than the ambient temperature for the
given time period
1s greater than a 5°C change for the previous
hour
does not vary by more than 0.5°C for 12
consecutive hours
equals the ambient temperature for 12 consecutive
hours
Precipitation
1s greater than 25 mm in one hour
1s greater than 100 mm 1n 24 hours
1s less than 50 mm in three months
(The above values can be adjusted based on local
climate.)
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TABLE 3-29.
SUGGESTED METEOROLOGICAL DATA SCREENING CRITERIA*
(U.S. EPA. JUNE 1987) (Continued)
Meteorological
Variable
Pressure
Screening Criteria*
• Is greater than 1060 mb (sea level)
• 1s less than 940 mb (sea level)
(The above values should be adjusted for
elevations other than sea level.)
• changes by more than 6 mb 1n three hours
a Some criteria may have to be changed for a given location.
3-111
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Air Monitoring Data Validation
A1r monitoring data should also be validated utilizing equipment
calibration, audit, and performance data in a manner similar to% that
recommended for meteorological data.
Analytical results should be subject to a thorough validation
process. This process requires the use of a qualified chemist who is
familiar with the data validation requirements and process. Validation of
analytical results for one sample could take from 15 minutes to more than
an hour, depending on the type of analysis, the number of air toxic
constituents involved, Interference, contamination, and other factors.
Raw air quality data received from portable GC analyzers or other
continuous Instruments should also be checked for validity. The
performance of the analyzer, calibration, and QA results should be
considered.
Air monitoring data validation efforts should include evaluating
collocated station results and audit results to determine data precision
and accuracy, as follows:
The percent difference between the air concentrations measured
at coal located samplers is
di = Y1 " X1 x 100 (3-5)
where
the percent difference between the concentration of
air toxic constituents YI measured by the collocated
monitoring station and the concentration of air toxic
3-112
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constituent XL measured by the monitoring station
reporting the air quality
The average percent difference dj for the monitoring period Is
n
n
£
1=1
(3-6)
where
d-| = percent difference defined above
n = number of samples collected during the monitoring
period
The standard deviation Sj for the percent differences 1s
1
n-1
n
£
1/2
(3-7)
The 95-percent probability limits for precision are
Upper 95-Percent Probability Limit = dj+1.96 SJ//2 (3-8)
Lower 95-Percent Probability Limit = dj-1.96 SJ//2 (3-9)
The accuracy 1s calculated for the monitoring period by
calculating the percent difference di between the Indicated
parameter from the audit (concentration, flow rate, etc.) and
the known parameter, as follows:
3-113
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" x 100 (3-10)
X1
where
YI = monitor's Indicated parameter from the Hh audit check
Xi = known parameter used for the 1th audit check
These results should then be compared with the QA/QC criteria
stipulated 1n the monitoring plan to determine data validity.
3.6.3 Summarize Data
Monitoring data summaries should be prepared using the validated data
bases as Input. These meteorological and air monitoring data summaries
facilitate the characterization of exposure potential at various locations
and receptors of Interest.
Meteorological Data Summaries
Meteorological data summaries should Include the following at a
minimum:
Listing of all meteorological parameters for the air sampling
periods
Daytime wind rose (only for coastal or complex terrain areas)
Nighttime wind rose (only for coastal or complex terrain areas)
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• Summary wind rose
Summary of dispersion conditions for the sampling period (joint
frequency distributions of wind direction versus wind speed
category and stability class frequencies based on guidance
presented 1n Guidelines on A1r Quality Models (Revised) (U.S.
EPA, July 1986)
• Tabular summaries of means and extremes for temperature and
other meteorological parameters
Data recovery summaries for all parameters
Meteorological listings should generally be presented on a sequential
hourly basis. A 1-hour time frame is sufficient to account for any short-
term temporal variability of the data. The presentation of data for
periods of less than 1 hour would unduly complicate the data evaluation
process, and the listings would be voluminous. For those cases 1n which
multiple meteorological stations are used at a single site, it is
desirable to 11st the data in adjacent columns to facilitate data
comparisons.
Statistical summaries for the meteorological data should be presented
monthly, seasonally, and annually, and for the entire monitoring period.
For sites with diurnal wind patterns (e.g., at complex terrain or coastal
areas), separate wind roses should be prepared to characterize daytime
conditions and nighttime conditions, and a summary wind rose (based on all
wind observations during the monitoring period) should be developed. A
suggested format for wind rose data is illustrated in Figure 3-14.
Data recovery Information should also be presented to allow for an
evaluation of data representativeness. The minimum data recovery target
should be 75 percent.
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WIND OZRECTZON FREQUENCY (PERCENT)
MEAN WIND SPEED (MZ/HR )
Figure 3-14 Example Wind Rose Format
3-116
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A1r Monitoring Data Summaries
A1r monitoring data summaries should Include the following at a
minimum:
• A listing of concentrations measured by station and monitoring
period Indicating concentrations of all constituents for which
monitoring was conducted. The listings should Indicate
detection limits for those cases 1n which a constituent 1s not
detected, as well as upwind/downwind exposure classification and
monitoring station operational data (e.g., sampling flow rates,
station numbers, sampling start/end times);
• Summary tables of constituent-specific concentrations measured
for each monitoring station, Including the following:
Mean concentration
Minimum concentration
Maximum concentration
Detection limit
Frequency above and below detection limits
Number of samples
Number of occurrences of air concentrations exceeding
selected values (e.g., health and safety criteria, ARARs
and odor thresholds)
Upwind/downwind exposure summaries
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• A narrative discussion of sampling results, Indicating problems
encountered, the relationship of the sampling activity to unit
operating conditions and meteorological conditions, sampling
periods and times, background levels and other air emission
sources, and interferences that may complicate data
interpretation
• Data recovery parameters for all parameters
A1r monitoring listings should be sequential and consistent with the
sampling interval used (e.g., one 24-hour Integrated sample to represent a
1-day period 1s frequently used). The listings should include flags to
identify samples that exceed health/safety criteria, ARARs, and odor
thresholds. Monitoring station operational data (e.g., start and stop
times for sampling, sampling flow rates) should also be included with the
data listings. If practical, concurrent data for the monitoring network
(I.e.. all stations) should be listed 1n adjacent columns to facilitate
data comparisons.
The air monitoring data listings should also indicate the
upwind/downwind classification of the monitoring station during the
sampling period. Based on hourly meteorological data, the percentages of
the sampling time that a station 1s upwind and downwind should be
specified. Therefore, upwind and downwind sectors (I.e., a range of wind
directions) should be defined for each monitoring station to aid 1n data
Interpretation. Figure 3-15 exemplifies the range of wind directions over
which the air monitoring stations will be downwind of an air emission
source. Therefore, concentrations measured during upwind conditions can
be used to characterize background conditions, and concentrations measured
during downwind conditions can be used to evaluate the source-specific
contributions to downwind exposures.
Plotting Individual concentration points as a function of downwind
frequency can Improve the interpretation of data for certain situations.
Such analyses are generally beneficial for sites with significant diurnal
3-118
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UNIT SOURCE
MONITOR ING STATIONS
DOWNWIND SECTOR
Figure 3-15. Example of Downxlnd Exposures at A1r Monitoring Stations
3-119
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wind direction variability, especially those on complex terrain and in
coastal locations. An application of this downwind frequency analysis
approach 1s Illustrated in Figure 3-16. Examination of the data presented
in this figure Indicates that air concentrations at Station A are random
and not correlated with downwind frequency. However, the data for Station
B appear to be linearly related to downwind frequency. Therefore, it can
be concluded that the air emission source significantly affects Station B
but not Station A.
Statistical summaries of air monitoring data should be presented
monthly, seasonally, and annually, and for the entire monitoring period.
In addition to concentration means and extremes, these summaries should
present any other information deemed useful for the interpretation of
monitoring results. Of particular interest, for example, is the frequency
that sampling results are below (or above) analytical detection limits.
Samples that are below detection limits can greatly complicate the
computation of mean concentrations. Therefore, in the computation of mean
concentrations for a Superfund APA application, concentrations for any
sampling period that are less than the lower analytical detection limits
should arbitrarily be assumed to be one-half the lower detection limit.
In the same connection, concentrations that exceed the upper detection
limits should arbitrarily be assumed to be equal to the detection limit.
Air monitoring data summaries should also indicate the number of
occurrences of air concentrations that exceed health/safety criteria,
ARARs, and odor thresholds. Upwind/downwind exposure conditions should
also be addressed 1n these summaries. Therefore, concentration means and
extremes for each station should be presented for the following data sets:
All samples
Samples that are predominantly (i.e., greater than 75 percent)
downwind
3-120
-------
i
»-•
ro
i
•->
Ok
7
I
24-HOUR
CONCENTRATION (ppb)
100-r-
o
o
50 --
in
KEY:
A » STATION A
• = STATION B
60
DOWNWIND FREQUENCY
100
-------
• Samples which are predominantly (I.e., greater than 75 percent)
upwind
Data recovery Information should also be presented to evaluate data
representativeness. A minimum data recovery target should be 75 percent.
3.6.4 Perform Dispersion Modeling
Results of atmospheric dispersion modeling can be used to assist in
the interpretation of the air monitoring results. They also can be used
to augment the measured data.
Dispersion patterns derived by plotting isopleths of air
concentration divided by the source emission rate for the air monitoring
periods can provide Information on areas of high concentrations and zones
of concentration gradients. Comparison of these patterns with measured
concentrations can provide additional Information on areas of high
concentration and a qualitative Interpolation and extrapolation of the
pattern of the measured concentrations.
Frequently 1t may not be practical to place air monitoring stations
at offslte receptor locations of Interest. However, it may be necessary
to characterize concentrations at these locations as Input to site-
specific risk assessments. In these cases, dispersion patterns based on
modeling results can be used to extrapolate concentrations monitored
onsite to offslte locations. An example of this application 1s
Illustrated in Figure 3-17.
Technical recommendations regarding the conduct of dispersion
modeling studies (e.g., model selection) are provided 1n Section 2.
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ATMOSPHERIC DILUTION PATTERN
i
o
0
VI
•
ft
o
-o
n
NEAREST RECEPTORS
MONITORING STATIONS
JBA™^^ PBOPEBTY BOUNOABY CONCENTBATIOW)
-------
3.7 EXAMPLE APPLICATION
A screening assessment (based on emission/dispersion modeling) 1n
accordance with Volume I recommendations was conducted to characterize
hazardous air constituents being released from an inactive wood treatment
facility that had been placed on the NPL. Evaluation of these screening
results indicated that 1t was necessary to conduct a monitoring program to
more accurately quantify air emissions from the site to support
preparation of an RI/FS.
Collect and Review Information
~he site 1s an Inactive 12-acre wood treatment facility located in a
flat Inland area of the Southeast. Creosote and pentachlorophenol were
used as wood preservatives; heavy metal salts had also been used 1n the
past. Creosote and pentachlorophenol were disposed of 1n a surface
Impoundment. Past waste disposal practices Included the treatment and
disposal of the metal salts 1n a surface Impoundment, and the disposal of
contaminated wood shavings 1n waste piles. The constituents of concern 1n
the facility's waste stream Include phenols, cresols, and polycycllc
aromatic hydrocarbons (PAHs) 1n the creosote; d1benzod1ox1ns and
dlbenzofurans as contaminants 1n pentachlorophenol; and partlculate heavy
metals. The potential emission sources (Figure 3-18) Include the
container storage facility for creosote and pentachlorophenol; the wood
treatment and product storage areas; the surface impoundment for the
creosote and pentachlorophenol wastes; and the contaminated soil area,
which previously contained both the surface Impoundment for treating the
metal salts and the wood shavings storage area. Seepage from these waste
management units has resulted 1n documented groundwater and surface water
contamination.
The area surrounding the facility has experienced substantial
development over the years. A shopping center is now adjacent to the
eastern site perimeter. This development has significantly increased the
number of potential receptors of air releases of hazardous constituents.
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SURFACE
IMPOUNDMENT AND
CONTAMINATED
WOOO SHAVINQ9
STORAGE AREA
ACMTIO
SUflFACt
OFFICE Q
CONTAINER
STORAGE
FACILITY
-H—
GATE
PREVA1UNO
WIND
DIRECTION
ft
Figure 3-18 Example Site Plan and A1r Monitoring Network
3-125
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To develop an adequate monitoring program, the composition of wastes
handled 1n each waste management unit was first determined to identify
which constituents were likely to be present in the air releases.
Existing water quality data Indicated the contamination of groundwater
with cresols, phenol, and PAHs and of surface water with phenols, benzene,
chlorobenzene, and ethylbenzene. A field sampling program was developed
to further characterize the facility's waste stream. Wastewater samples
were collected from the aerated surface impoundment, and soil samples were
collected from the heavy metal salt waste treatment/disposal area.
Analytical data from this sampling effort confirmed the presence of the
constituents previously identified. Additional constituents detected
include toluene and xylenes in surface impoundment wastes, and arsenic,
copper, chromium, and zinc in the treatment/disposal area.
Select Monitoring Sophistication Level
A limited onsite air screening survey was first conducted to document
air releases of potentially hazardous constituents, to assign priorities
to air emission sources, and to verify screening assessment modeling
results and the need to conduct a monitoring program. Total hydrocarbon
(THC) levels were measured with a portable THC analyzer downwind of the
aerated surface Impoundment, wood treatment area, and product storage
area. Measurements were also made upwind of all units to provide
background concentrations. The THC levels detected downwind were
significantly higher than background levels. However, constituent-
specific results were not available from this screening approach to
quantify the potential health and safety impacts associated with air
emissions from the site. Therefore, a refined monitoring program to
characterize releases to the air was considered appropriate.
Develop Monitoring Plan
Based on their Individual emission potentials (as determined from
waste analyses and confirmatory emission rate modeling) and potentials for
3-126
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presenting health and environmental hazards, the following constituents
were selected for measurement In the air monitoring program:
• VolatHe/semlvolatile constituents
Toluene
Benzene
Total phenols
Pentachlorophenol
Polycycllc aromatic hydrocarbons
Cresols
• Participate constituents
Arsenic
Copper
Chromium
Zinc
Meteorological Information 1s critical for designing an air
monitoring program because stations must be located both upwind and
downwind of the contaminant sources. Therefore, a 1-month meteorological
monitoring survey was conducted at this flat-terrain site. The survey was
conducted under conditions considered representative of the summer months
during which air samples would be collected. Summer represented the
worst-case combination of emission and dispersion conditions (I.e., light,
steady winds and warm temperatures). The collected meteorological data
showed that the local wind direction was from the southwest. No well-
defined secondary wind flows were identified. The survey data also
confirmed that one 10-meter meteorological station would be sufficient to
support the air monitoring program.
The onslte meteorological survey data were used with the EPA's,
Industrial Source Complex (ISC) dispersion model to estimate the worst-
case air emission concentrations and to help determine the locations of
3-127
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the air sampling stations. The ISC dispersion model was used because of
its capability to simulate conditions of point and nonpoint source air
emissions and because of recommendations made in Chapter 2. Allowing for
the established southwest wind direction, maximum downwind concentrations
were predicted for different meteorological conditions (e.g., different
wind speeds). The selection of upwind background stations and downwind
monitoring stations was based on the predicted dispersion pathways.
Because the releases from the Individual source areas overlapped, the
model also provided a means of identifying the contamination from each
source.
Figure 3-18 shows the locations of the selected sampling stations.
Station 1 was selected as the upwind background station. Background
volatile organic concentrations, partlculate concentrations, and
meteorological conditions were monitored at this station. Stations 2 and
4 were located at points convenient for the monitoring of volatile
emissions from the surface impoundment and wood treatment/product storage
areas, respectively. Station 3 was located downwind of the Inactive
surface Impoundment/wood shavings disposal area. Releases from these
sources and worst-case concentrations of volatlles and partlculates at the
site property boundary were documented at this site. For this
application, the locations of Stations 2, 3, and 4 were adequate for
characterizing the air concentrations at both the source boundary and the
site property boundary (due to the proximity of these two boundaries in
the downwind direction of the units of concern for the site prevailing
wind direction). Three trailer-mounted air monitoring stations were used
to supplement the permanent stations and to account for any variability 1n
wind direction.
Several alternative methods were considered for air monitoring at
this site. It was decided to use EPA Method TO-14 (whole air sampling
using metal canisters) for benzene and toluene. A modified high-volume
sampler consisting of a glass fiber filter with a polyurethane foam backup
sorbent (EPA Method TO-4) was selected to sample for total phenols,
pentachlorophenol, and PAHs. NIOSH Method 2001, which involves use of
3-128
-------
silica gel cartridges, was selected for the collection and analysis of
cresol samples. Particulates were collected on glass fiber filters using
high-volume samplers.
Conduct Monitoring
The air quality monitoring was conducted over a 3-month period during
the summer. Meteorological variables were measured continuously
throughout the study. A1r samples were taken over a 24-hour period every
six days. A rigorous QA/QC program was Implemented commensurate with the
selected monitoring period and according to the method specified 1n EPA
technical reference documents. Field technicians assigned to conduct
multimedia environmental surveys for the RI/FS and to operate the air
monitoring network. These staff were trained by an air toxics specialist.
The air toxics specialist also routinely reviewed the monitoring results
to evaluate data validity, to Identify potential monitoring problems, and
to determine the need for corrective action. He was assisted by a
chemist, who performed the detailed data validation for the air toxics
under consideration.
Summarize and Evaluate Results
Standard sampling/analytical methods were available for all the
target monitoring constituents. However, analytical detection limits were
below specific health and environmental criteria for all constituents
except cresol. The high analytical detection limit for cresol—it
exceeded reference health criteria—complicated data analysis. This
difficulty was handled by the collection and analysis of additional waste
samples. The data obtained 1n these analyses were subjected to emission
rate modeling to determine the emission potential of cresol and thus to
develop an estimate of cresol levels 1n the air.
Analytical results obtained during this sampling program established
that fugitive air emissions significantly exceeded reference health
3-129
-------
criteria. Measures to reduce emission concentrations to a point below
health criteria levels were Identified.
3-130
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4.0 REFERENCES
ASTM. Annual Book of Standards (published annually). Part 26, Gaseous
Fuels; Coal and Coke; Atmospheric Analysis. American Society for Testing
and Materials, Philadelphia, PA.
U.S. EPA. March 1986. Quality Assurance/Field Operations Methods Manual.
Draft.
U.S. EPA. June 1983. Technical Assistance Document for Sampling and
Analysis of Toxic Organic Compounds 1n Ambient A1r. EPA-600/4-83-027.
NTIS PB 83-239020. Office of Research and Development. Research Triangle
Park, NC 27711.
U.S. EPA. April 1984. Compendium of Methods for the Determination of
Toxic Organic Compounds 1n Ambient A1r. EPA-600/4-84-041. Office of
Research and Development. Research Triangle Park, NC 27711.
NIOSH. February 1984. NIOSH Manual of Analytical Methods. NTIS PB 85-
179018. National Institute of Occupational Safety and Health.
Cincinnati, OH.
U.S. EPA. June 1987. On-S1te Meteorological Program Guidance for
Regulatory Modeling Applications. EPA-450/4-87-013. Office of A1r
Quality Planning and Standards. Research Triangle Park, NC 27711.
4-1
-------
U.S. EPA. February 1983.. Quality Assurance Handbook for Air Pollution
Measurements Systems: Volume IV. Meteorological Measurements. EPA-600/4-
82-060. Office of Research and Development. Research Triangle Park, NC
27711.
U.S. EPA. November 1980. Ambient Monitoring Guidelines for Prevention of
Significant Deterioration fPSDK EPA-450/4-80/012. NTIS PB 81-153231.
Office of A1r Quality Planning and Standards. Research Triangle Park, NC
27711.
U.S. EPA. July 1986. Guidelines on Air Quality Models (Revised!. EPA-
405/2-78-027R. NTIS PB 86-245248. Office of Air Quality Planning and
Standards. Research Triangle Park, NC 27711.
U.S. EPA. September 1983. Characterization of Hazardous Waste Sites - A
Methods Manual: Volume II. Available Sampling Methods. EPA-600/4-83-040.
NTIS PB 84-126929. Office of Solid Waste. Washington, DC 20460.
U.S. EPA. September 1983. Characterization of Hazardous Waste Sites - A
Methods Manual; Volume III. Available Laboratory Analytical Methods.
EPA-600/4-83-040. NTIS PB 84-126929. Office of Solid Waste. Washington,
DC 20460.
U.S. EPA. 1986. Test Methods for Evaluating Solid Waste. Third Edition.
EPA SW-846. GPO No. 955-001-00000-1. Office of Solid Waste. Washington,
DC 20460.
ASTM. 1982. Toxic Materials 1n the Atmosphere. STP 786. American
Society for Testing and Materials. Philadelphia, PA.
ASTM. 1980. Sampling and Analysis of Toxic Oroanics in the Atmosphere.
STP 721. American Society for Testing and Materials. Philadelphia, PA.
ASTM. 1974. Instrumentation for Monitoring Air Quality. STP 555.
American Society for Testing and Materials. Philadelphia, PA.
4-2
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APHA. 1977. Methods of Air Sampling and Analysis. American Public
Health Association. Cincinnati, OH.
ACGIH. 1983. A1r Sampling Instruments for Evaluation of Atmospheric
Contaminants. American Conference of Governmental Industrial Hyglenists.
Washington, DC.
U.S. EPA. 1984. Guide to the Preparation of Quality Assurance Project
Plans. Office of Toxic Substances. Office of Pesticides and Toxic
Substances. Washington, DC.
4-3
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APPENDIX A
BIBLIOGRAPHY
OF
AIR MONITORING
STANDARD OPERATING PROCEDURES
A-l
-------
APPENDIX A
BIBLIOGRAPHY
APCA. May 1987. Proceedings of the 1987 EPA/APCA Symposium on
Measurement of Toxic and Related A1r Pollutants. VIP-8. A1r Pollution
Control Association. Pittsburgh, PA 15230.
These proceedings cover a wide range of topics on recent advances In
measurement and monitoring procedures for toxic and related
pollutants found in ambient and source atmospheres.
APHA. 1977. Methods of Air Sampling and Analysis. American Public
Health Association. Cincinnati, OH.
This manual 1s a comprehensive compilation of standardized methods
for sampling and analysis of ambient and workplace air adopted by the
APHA Intersociety Committee on Methods of Air Sampling and Analysis.
ASTM. 1980. Sampling and Analysis of Toxic Organ1cs In the
Atmosphere. American Society for Testing and Materials. STP 721.
Philadelphia, PA.
This publication resulted from the fourth biennial Boulder Conference
on environmental monitoring of air quality sponsored by the ASTM.
The conference was structured to highlight several major areas of
concern to environmental scientists, namely, sampling for toxic
A-2
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organlcs 1n ambient, workplace, and source-related atmospheres;
analyzing for important classes of pollutants such as polychlorinated
biphenyls (PCBs), polynuclear aromatic hydrocarbons (PAHs), and
polycycllc organic matter (POM); and measuring exposure to toxic
organlcs 1n the workplace.
CARB. February 1985. Toxic Ambient A1r Monitoring Operation
Procedure. California Network. Aerometrlc Data Division. California Air
Resources Board. Sacramento, CA 95814.
CARB. December 1986. Testing Guidelines for Active Solid Waste
Disposal Sites. Stationary Source Division. Toxic Pollutants Branch.
California A1r Resources Board. Sacramento, CA 95814.
These guidelines present standard operating procedures for the
sampling and analysis of ambient air collected 1n Tedlar bags.
Analytical procedures are primarily for halogenated volatile organlcs
and benzene.
Drager. May 1985. Detector Tube Handbook. Dragerwerk AG Lubeck.
Federal Republic of Germany.
This handbook presents procedures for the use of colorlmetrlc
detector tubes for a wide range of organic and Inorganic compounds.
Data 1s provided on standard ranges of measurement, precision and
accuracy, measurement principles, and cross-sens1t1v1ty.
NIOSH. February 1984. NIOSH Manual of Analytical Methods. NTIS PB
85-179018. National Institute of Occupational Safety and Health.
Cincinnati, OH.
The NIOSH manuals contain a wealth of Information on sampling and
analytical procedures for a wide range of toxic organic and Inorganic
species. Although primarily directed at determination of worker
exposure levels, these methods can quite often be applied (with
A-3
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minimal modifications) to the measurement of ambient concentration
levels of concern 1n perimeter and offsite monitoring.
N.J. DEP. October 1987. Ambient A1r Monitoring at Hazardous Waste
and Superfund Sites. Division of Environmental Quality. A1r Quality
Management and Surveillance. New Jersey Department of Environmental
Protection. Trenton, NJ 08625.
This document contains a master table of sampling and analytical
methods for ambient air monitoring listed by compound name. Key
Information on species Includes recommended sampling and analytical
methods, the applicability of each method, performance data, and
reference Information.
SCAQMD. October 1985. Guidelines for Implementation of Rule 1150.1.
South Coast A1r Quality Management District. Engineering Division. El
Monte, CA 91731.
This document contains standard operating procedures for the
collection of ambient air samples at landfill perimeters and for
Instantaneous landfill surface monitoring, as well as analytical
procedures for a wide range of toxic volatile organic compounds.
U.S. EPA. April 1984. Compendium of Methods for the Determination
of Toxic Organic Compounds 1n Ambient Air. EPA-600/4-84-041. Office of
Research and Development. Research Triangle Park, NC 27711.
Specific Standard Operating Procedures (SOPs) contained 1n this
compendium are as follows:
Method TO-1 Method for the Determination of Volatile Organic
Compounds in Ambient A1r Using Tenax Adsorption and
Gas Chromatography/Mass Spectrometry (GC/MS)*
(Applicable to volatile, non-polar organic compounds.)
A-4
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Method TO-2
Method TO-3
Method TO-4
Method TO-5
Method TO-6
Method TO-7
Method TO-8
Method TO-9
Method for the Determination of Volatile Organic
Compounds In Ambient Air by Molecular Sieve Adsorption
and GC/MS. (Applicable to highly volatile, nonpolar
organic compounds.)
Method for the Determination of Volatile Organic
Compounds in Ambient A1r Using Cryogenic
Preconcentratlon Techniques and Gas Chromatography
with Flame lonization and Electron Capture Detection.
(Applicable to volatile, nonpolar organic compounds.)
Method for the Determination of Organochlorine
Pesticides and Polychlorlnated Biphenyls 1n Ambient
A1r.
Method for the Determination of Aldehydes and Ketones
1n Ambient A1r Using High Performance Liquid
Chromatography.
Method for the Determination of Phosgene 1n Ambient
A1r Using High Performance Liquid Chromatography.
Method for the Determination of N-N1trosod1methyl amine
1n Ambient A1r Using Gas Chromatography.
Method for the Determination of Phenol and
Methylphenols (Cresols) 1n Ambient A1r Using High
Performance Liquid Chromatography.
Method for the Determination of Polychlorlnated
D1benzo-p-diox1ns (PCDOs) in Ambient A1r Using High-
Resolution Gas Chromatography/High-Resolution Mass
Spectrometry (HRGC/HRMS).
A-5
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Method TO-12 (Draft) Method for the Determination of Non-Methane
Organic Compounds (NMOC) 1n Ambient Air Using
Cryogenic Preconcentratlon and Direct Flame lonization
Detection (PDFID).
Method TO-14 Determination of Volatile Organic Compounds (VOCs) In
Ambient Air Using SUMMA Passlvated Canister Sampling
and Gas Chromatographlc Analysis.
U.S. EPA. September 1983. Characterization of Hazardous Waste Sites
- A Methods Manual; Volume II. Available Sampling Methods. EPA-600/4-83-
040. NTIS PB 84-126929. Office of Solid Waste. Washington, DC 20460.
This volume 1s a compilation of sampling methods suitable to address
most needs that arise during routine waste site and spill
Investigations. Twelve methods are presented for ambient air, soil
gases and vapors, and headspace gases.
U.S. EPA. September 1983. Characterization of Hazardous Waste Sites
- A Methods Manual: Volume III. Available Laboratory Analytical Methods.
EPA-600/4-83-040. NTIS PB 84-126929. Office of Solid Waste. Washington,
DC 20460.
This volume provides bench-level guidance for the preparation of
hazardous waste, water, soil/sediment, biological tissue, and air
samples, and methods that can be used to analyze the resultant
digests/extracts of 244 of the substances listed 1n the RCRA permit
regulations.
U.S. EPA. February 1986. Measurement of Gaseous Emission Rates from
Land Surfaces Using an Emission Isolation Flux Chamber: User's Guide.
EPA-600/8-86-008. Environmental Monitoring Systems Laboratory. Las
Vegas, NV 89114.
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U.S. EPA. December 1987. Development of Collection Methods for
Semivolatile Organic Compounds 1n Ambient A1r. EPA-600/4-87-042.
Environmental Monitoring .Systems Laboratory. Research Triangle Park, NC
27711.
U.S. EPA. July 1983. Standard Operating Procedures for the
Preparation of Standard Organic Gas Mixtures 1n a Static Dilution Bottle.
RTP-SOP-EMD-012. Environmental Monitoring Systems Laboratory. Research
Triangle Park, NC 27711.
U.S. EPA. November 1981. Standard Operating Procedures for the
Preparation of Tenax Cartridges Containing Known Quantities of Orqanlcs
Using Flash Vaporization. RTP-SOP-EMD-011. Environmental Monitoring
Systems Laboratory. Research Triangle Park, NC 27711.
U.S. EPA. November 1981. Standard Operating Procedures for the
Preparation of Clean Tenax Cartridges. RTP-SOP-EMD-013. Environmental
Monitoring Systems Laboratory. Research Triangle Park, NC 27711.
U.S. EPA. January 1984. Standard Operating Procedures for Sampling
Gaseous Organic Air Pollutants for Quantitative Analysis Using Solid
Adsorbents. RTP-SOP-EMD-018. Environmental Monitoring Systems
Laboratory. Research Triangle Park, NC 27711.
U.S. EPA. July 1985. Draft Standard Operating Procedures No. FA112A
- Monitoring for Gaseous Air Pollutants Using the Gilian LFS Model 113
Dual Mode Air Sampling Pumps. Environmental Monitoring and Compliance
Branch, Environmental Services Division, Region VII. Kansas City, KS
66115.
U.S. EPA. June 1984. Standard Operating Procedures for the GC/MS
Determination of Volatile Organic Compounds Collected on Tenax. RTP-SOP-
EMD-021. Environmental Monitoring Systems Laboratory. Research Triangle
Park, NC 27711.
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U.S. EPA. August 1983. Development of Protocols for Ambient Air
Sampling and Monitoring at Hazardous Waste Facilities: Methods Summary
Report. Office of Solid Waste. Land Disposal Branch. Washington, DC,
20460.
U.S. EPA. 1984. Field Standard Operating Procedures for Air
Surveillance. FSOP #8. Office of Emergency and Remedial Response.
Washington, DC 20460.
U.S. EPA. 1983. A1r Pollution Training Institute Course 435;
Atmospheric Sampling. EPA-450/2-80-004. Environmental Research Center.
Research Triangle Park. NC 27711.
U.S. EPA. November 1980. Ambient Monitoring Guidelines for
Prevention of Significant Deterioration fPSDK EPA-450/4-80/012. NTIS PB
81-153231. Office of A1r Quality Planning and Standards. Research
Triangle Park, NC 27711.
U.S. EPA. June 1983. Technical Assistance Document for Sampling and
Analysis of Toxic Organic Compounds 1n Ambient A1r. EPA-600/4-83-027.
NTIS PB 83-239020. Office of Research and Development. Research Triangle
Park, NC 27711.
U.S. EPA. 1977. Quality Assurance Handbook for A1r Pollution
Measurement Systems: Volume II. Ambient Air Specific Methods. EPA-600/4-
27-027a. Environmental Monitoring Systems Laboratory. Research Triangle
Park, NC 27711.
U.S. GSA. 1987. Code of Federal Regulations. Title 40. Part 50.
Appendices A-G and J. Office of the Federal Register. Washington, DC
20402.
The listed appendices to 40 CFR 50 contain EPA Reference Methods for
the sampling and analysis of SOz, TSP, CO, 03, NOs. Pb, and PM-10 1n
ambient air.
A-8
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APPENDIX B
EXCERPT
FROM
TECHNICAL ASSISTANCE DOCUMENT
FOR
SAMPLING AND ANALYSIS
OF
TOXIC ORGANIC COMPOUNDS
IN AMBIENT AIR
(U.S. EPA. JUNE 1983)
B-l
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