I
United States Office of Air Quality EPA - 450/1 -89-004
Environmental Protection Planning and Standards July 1989
Agency Research Triangle Park NC 27711
Air/Superfund
«rEPA AIR / SUPERFUND
I NATIONAL TECHNICAL
1 GUIDANCE STUDY SERIES
I
| Volume IV - Procedures
for Dispersion Modeling
1 and Air Monitoring for
Superfund Air Pathway
Analysis
Interim
I
I
I
-------
1
I
I
1
•
I
I
•
1
I
I
I
I
I
PROCEDURES FOR CONDUCTING AIR PATHWAY
ANALYSES FOR SUPERFUND APPLICATIONS
VOLUME IV
Procedures for Dispersion Modeling
and Air Monitoring for
Superfund Air Pathway Analysis
• Interim Final
I
I
I Mr. Mark E. Garrison, Work Assignment Manager
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF AIR QUALITY PLANNING AND STANDARDS
RESEARCH TRIANGLE PARK, NORTH CAROLINA 27711
July 1989
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
PREFACE
This Is one in a series of manuals dealing with air pathway analysis at
hazardous waste sites. This document was developed for the Office of Air
Quality Planning and Standards in cooperation with the Office of Emergency
and Remedial Response (Superfund). It has been reviewed by the National
Technical Guidance Study Technical Advisory Committee and an expanded review
group consisting of State agencies, various groups within the U.S. Environ-
mental Protection Agency, and the private sector. This document is an
interim final manual offering technical guidance for use by a diverse
audience including EPA Air and Superfund Regional and Headquarters staff,
State Air and Superfund program staff, Federal and State remedial and removal
contractors, and potentially responsible parties in analyzing air pathways at
hazardous waste sites. This manual is written to serve the needs of in-
dividuals having different levels of scientific training and experience in
designing, conducting, and reviewing air pathway analyses. Because assump-
tions and judgments are required in many parts of the analysis, the in-
dividuals conducting air pathway analyses need a strong technical background
in air emission measurements, modeling, and monitoring. Remedial Project
Managers, On Scene Coordinators, and the Regional Air program staff,
supported by the technical expertise of their contractors, will use this
guide when establishing data quality objectives and the appropriate
scientific approach to air pathway analysis. This manual provides for flexi-
bility in tailoring the air pathway analysis to the specific conditions of
each site, the relative risk posed by this and other pathways, and the pro-
gram resource constraints.
Air pathway analyses cannot be reduced to simple "cookbook" procedures.
Therefore, the manual is designed to be flexible, allowing use of profes-
sional judgment. The procedures set out in this manual are intended solely
for technical guidance. These procedures are not intended, nor can they be
relied upon, to create rights substantive or procedural, enforceable by any
party in litigation with the United States.
It is envisioned that this manual will be periodically updated to incor-
porate new data and information on air pathway analysis procedures. The
Agency reserves the right to act at variance with these procedures and to
change them as new information and technical tools become available on air
pathway analyses without formal public notice. The Agency will, however,
attempt to make any revised or updated manual available to those who
currently have a copy through the registration form included with the manual.
Copies of this report are available, as supplies permit, through the
Library Services Office (MD-35), U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina 27711 or from the National Technical
Information Services, 5285 Port Royal Road, Springfield, Virginia 22161.
iii
-------
DISCLAIMER
Mention of trade names or commercial products does not constitute
endorsement or recommendation for use by the Air Management Division, U.S.
Environmental Protection Agency.
IV
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
1
I
I
I
I
TABLE OF CONTENTS
Page
DISCLAIMER i i
ACKNOWLEDGEMENT i i i
ACRONYMS iv
1.0 INTRODUCTION 1-1
2.0 ATMOSPHERIC DISPERSION MODELING PROCEDURE 2-1
2.1 Overview 2-1
2.2 Step 1 - Collect and Review Input Information 2-13
2.2.1 Overview 2-13
2.2.2 Source Data 2-17
2.2.3 Receptor Data 2-19
2.2.4 Environmental Characteristics 2-21
2.2.5 Previous APA Data 2-27
2.3 Step 2 - Select Modeling Sophistication Level 2-28
2.3.1 Overview 2-28
2.3.2 Selection of Models as a Function of
Sophistication Levels 2-29
2.4 Step 3 - Develop Modeling Plan 2-37
2.4.1 Overview 2-37
2.4.2 Dispersion Modeling Data Quality Objectives... 2-40
2.4.3 Select Modeling Constituents 2-40
2.4.4 Define Emission Inventory Methodology 2-46
2.4.5 Define Meteorological DataBase 2-49
2.4.6 Design Receptor Grid 2-53
2.4.7 Detailed Modeling Methodology 2-56
2.4.8 Estimated Background Concentrations 2-58
2.4.9 Define Dispersion Calculations to be Performed 2-59
2.4.10 Document the Modeling Plan 2-60
2.5 Step 4 - Conduct Modeling 2-60
2.5.1 Overview 2-60
2.5.2 Staff Qualifications and Training 2-60
2.5.3 Performance of Modeling 2-61
2.6 Step 5 - Summarize and Evaluate Results 2-67
2.6.1 Overview 2-67
2.6.2 Summarize Data 2-68
2.6.3 Evaluate Modeling Results 2-72
2.6.4 Prepare a Report 2-81
-------
TABLE OF CONTENTS (Continued)
Page
3.0 AIR MONITORING PROCEDURES. 3-1
3.1 Overview 3-1
3.2 Step 1 - Collect and Review Input Information 3-7
3.2.1 Overview 3-7
3.2.2 Source Data.... 3-8
3.2.3 Receptor Data.. 3-11
3.2.4 Environmental Characteristics 3-12
3.2.5 Previous APA Data 3-13
3.3 Step 2 - Select Monitoring Sophistication Level 3-16
3.3.1 Overview 3-16
3.3.2 Definition of Monitoring Sophistication Levels 3-20
3.4 Step 3 - Develop Monitoring Plan 3-25
3.4.1 Overview 3-25
3.4.2 Select Monitoring constituents 3-25
3.4.3 Specify Meteorological Program 3-35
3.4.4 Design Monitoring Network 3-41
3.4.5 Document Air Monitoring Plan 3-63
3.5 Step 4 - Conduct Monitoring 3-91
3.5.1 Overview 3-91
3.5.2 Field Staff Qualifications and Training 3-91
3.5.3 Quality Assurance/Quality Control 3-94
3.6 Step 5 - Summarize and Evaluate Results 3-98
3.6.1 Overview 3-98
3.6.2 Validate Data 3-103
3.6.3 Summarize Data 3-108
3.6.4 Perform Dispersion Modeling 3-116
4.0 CASE EXAMPLES 4-1
4.1 Overview 4-1
4.2 Example 1 - Dispersion Modeling/Air Monitoring
Appl ications 4-2
4.2.1 Site Description 4-3
4.2.2 Example 1 - Dispersion Modeling Study 4-4
4.2.3 Example 1 - Air Monitoring Study 4-11
4.3 Example 2 - Air Monitoring Application 4-16
4.4 Example 3 - Air Monitoring Application 4-20
4.5 Example 4 - Air Monitoring Application 4-24
-------
I
I
• TABLE OF CONTENTS (Continued)
• Page
A 5.0 REFERENCES 5-1
• APPENDIX A: BIBLIOGRAPHY OF AIR MONITORING METHODS
APPENDIX B: EXCERPT FROM TECHNICAL ASSISTANCE DOCUMENT FOR SAMPLING
_ AND ANALYSIS OF TOXIC ORGANIC COMPOUNDS IN AMBIENT AIR
• (U.S. EPA, JUNE 1983)
APPENDIX C: BACKGROUND INFORMATION
I
I
I
I
I
I
I
1
I
I
I
I
I
-------
-------
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
ACGIH
ACL
AO
APA
APCD
ARAR
ATSDR
CAA
CAS
CD
CERCLA
CERCLIS
CERI
CFR
CR
CRF
CWA
DQO
ORE
EDO
ERT
ESP
FIFRA
FP
SUPERFUND ABBREVIATIONS/ACRONYMS
American Conference of Government Industrial Hygienists
Alternate Concentration Limit
Administrative Order on Consent
Air Pathway Analysis
Air Pollution Control Device
Applicable or Relevant and Appropriate Requirement (Cleanup
Standard)
Agency for Toxic Substances and Disease Registry
Clean Air Act
Carbon Adsorption System
Consent Decree
Comprehensive Environmental Response, Compensation, and Liability
Act
Comprehensive Environmental Response, Compensation, and Liability
Information System
Center for Environmental Research Information
Code of Federal Regulations
Community Relations
Combustion Research Facility -- Pine Bluff, Arkansas
Clean Water Act
Data Quality Objective
Destruction and Removal Efficiency
Enforcement Decision Document
Environmental Response Team
Electrostatic Precipitator
Federal Insecticide, Fungicide, and Rodenticide Act
Fine Particualte
ix
-------
FS Feasibility Study
HRS Hazard Ranking System
HSWA Hazardous Waste Engineering Amendments to RCRA, 1984
HWERL Hazardous Waste Engineering Research Laboratory
IDLH Immediately Dangerous to Life or Health
MCL Maximum Contaminant Level
MCLG Maximum Contaminant Level Goal
NBAR Non-binding Preliminary Allocation of Responsibility
NCP National Contingency Plan
NEIC National Enforcement Investigations Center
CFPA National Fire Protection Association
NIOSH National Institute of Occupational Safety and Health
NPL National Priorities List
NRC National Response Center
NRT National Response Team
NTIS National Technical Information Service
OERR Office of Emergency and Remedial Response
O&M Operation and Maintenance
ORD Office of Research and Development
OSC On-Scene Coordinator
OSH Act Occupational Safety and Health Act
OSHA Occupational Safety and Health Administration
OSWER Office of Solid Waste and Emergency Repsonse
OTA Office of Technology Assessment
PA Preliminary Assessment
PEL Permissible Exposure Limits
-------
I
I
PIC Products of Incomplete Combustion
PM-20 Particualte Matter with Physical Diameter <20 urn
• PRP Potentially Responsible Party
QA/QC Quality Assurance/Quality Control
I QAPP Quality Assurance Project Plan
M RA Remedial Action
RCRA Resource Conversation and Recovery Act
• RD Remedial Design
REL Recommended Exposure Limit
£ RI Remedial Investigation
— RI/FS Remedial Investigation/Feasibility Study
™ ROD Record of Decision
• RPM Remedial Project Manager
RRT Regional Response Team
I RQ Reportable Quantity
SAB Science Advisory Board
I SARA Superfund Amendments and Reauthorization Act
• SCAP Superfund Comprehensive Accomplishments Plan
SI Site Inspection
• SITE Superfund Innovative Technology Evaluation
SWDA Solid Waste Disposal Act (RCRA predecessor)
I TLV Threshold Limit Value
g TLV-C Threshold Limit Value - Ceiling
TLV-STEL Threshold Limit Value - Short-Term Exposure Limit
• TLV-TWA Threshold Limit Value - Time-Weighted Average
TSDF Treatment Storage and Disposal Facility
| TSCA Toxic Substances Control Act
I
XI
-------
TSP Total Suspended Particulate
Title III Emergency Planning and Community Right-To-Know Act (SARA)
T&E Testing and Evaluation
UST Underground Storage Tank
VO Volatile Organics
VOC Volatile Organic Compound
xn
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
ACKNOWLEDGMENT
This document was prepared for the U.S. Environmental Protection Agency
(EPA) by NUS Corporation and Radian 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. Amiram
Roffman and Mr. Ronald Stoner of NUS. The authors would like to thank Mr.
Jim Vickery 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. James Durham of the EPA Office of Air Quality Planning and
Standards, and Mr. Al Cimorelli of EPA, Region III for their guidance and
direction. The authors would also like to acknowledge Mr. Robert Jubach, Mr.
Thomas laccarino, Mr. Hank Firstenberg, Mr. Jeffrey Panek, and Ms. Elizabeth
Butler for their overall contribution to this document. Mr. Bart Eklund of
Radian Corporation provided the final editing of the material and portions of
Section 4.
xiii
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
SECTION 1
INTRODUCTION
The multivolume set of Procedures for Conducting Air Pathway
Analyses for Superfund Applications has been developed 1n response to
increased concern by the U.S. Environmental Protection Agency (EPA) regarding
the potential for 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 Reauthorization Act (SARA), EPA has the responsibility for
assessment and cleanup of these Superfund sites. Although air emissions pose
a potential human health risk from air emissions at these sites, comprehensive
national guidance did not exist for determining the magnitude and impact of
these emissions. Therefore, the goal of these Procedures is 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 are also generally
applicable to hazardous waste sites not included on the NPL.
The Procedures for Conducting Air Pathway Analyses for Superfund
Applications consists of four volumes:
• Volume I - Application of Air Pathway Analyses for Superfund
Activities
• Volume II - Estimation of Baseline Emissions at Superfund Sites
1-1
-------
t Volume III - Estimation of Air Emissions from Cleanup
Activities at Suoerfund Sites
• Volume IV - Procedures for Dispersion Modeling and Air
Monitoring for Superfund Air 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 in 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 is on providing technical procedures for
dispersion modeling and air monitoring. Volume IV provides the procedures for
implementing activity-specific and source-specific dispersion modeling/air
monitoring recommendations provided in 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 procedures frequently requires source
emission rate inputs that can be developed through application of Volumes II
and III.
1-2
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
Section 2 of this volume 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 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 conducting
Superfund APAs. Therefore, available standard procedures for conducting 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 in Volumes II-IV are based on the
general format illustrated in Figure 1 and discussed in Volume I. The major
elements of these procedures are as follows:
• Collect and review APA input information
t Select APA sophistication level
• Develop APA plan
• Conduct APA
t Summarize/evaluate results
t Evaluate need for additional analyses.
Data quality objectives (DQOs) should be considered during each
step. The following is a brief discussion of each of these procedural steps.
1-3
-------
APA RECOMMENDATIONS (Volume I)
Activity-specific recommendations
Source-specific recommendations
Modeling/monitoring recommendations
1
COLLECT AND REVIEW APA INPUT INFORMATION
• Source Data
• Environmental Data
• Receptor/Population Data
EPA TECHNICAL
GUIDELINES
SELECT APA SOPHISTICATION LEVEL
• Screening
• Refined
DEVELOP APA PLAN
• Technical Approach
• Evaluate APA Uncertainty
Peer Review/
RPM Approval
JL
CONDUCT APA
• Quality Control
• Documentation
SUMMARIZE/EVALUATE RESULTS
• Data Review
• Data Format
• Comparison to Health Criteria
• Consider APA Uncertainty
Yes
No
ADDITIONAL ANALYSES NEEDED?
Input to EPA
Remedial/
Removal
Decision
Making
Figure 1. Superfund Air Pathway Analyses Technical Procedures -
General Format.
1-4
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
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 can
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 PI an--This step involves preparation of an APA
plan. The APA should include documentation of the selected technical approach
(e.g., nonrepresentative 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.
Step 4 - Conduct APA--This step involves the implementation of the
APA plan developed during Step 3. The emphasis during Step 4 is on conducting
the APA commensurate with appropriate QC measures and DQO 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).
1-5
-------
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, 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. 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 in
Sections 2-3, this general approach has been adapted for each of the technical
procedures presented in Volume IV.
1-6
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
SECTION 2
ATMOSPHERIC DISPERSION MODELING PROCEDURE
2.1 OVERVIEW
Atmospheric dispersion modeling is an air pathway analysis (APA)
approach that can provide calculated contaminant concentrations at receptor
locations of interest based on emission rate and meteorological data.
Atmospheric dispersion modeling for Superfund activities is an integral part
of the planning and decision-making process for the protection of public
health and the environment. Dispersion modeling results may be useful at all
stages of the Superfund process and are especially necessary for predicting
impacts from proposed remedial actions. This section provides procedures for
the selection and application of dispersion modeling approaches for Superfund
APAs.
The two major dispersion modeling applications for Superfund are:
• To estimate concentrations at receptors of interest using input
emission rate data based on field measurements or emission
model predictions; and
t To design an air monitoring program (i.e. selecting monitoring
locations and periods) as well as in interpreting and
extrapolating monitoring results.
Atmospheric dispersion models can be used when designing an air
monitoring program to see how offsite areas of high concentration relate to
actual receptor locations. Places where high-concentration areas correspond
to actual receptors are priority locations for air monitoring stations.
2-1
-------
Dispersion models can also be used to provide seasonal dispersion
concentration patterns based on available representative historical
meteorological data (either onsite or offsite). These dispersion patterns can
be used to evaluate the representativeness of any air monitoring data
collection period. Data representativeness is determined by comparing the
dispersion concentration patterns for the air monitoring period with
historical seasonal dispersion concentration patterns.
It is often not practical to place air monitoring stations at actual
offsite receptor locations of interest. It will be necessary, however, 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 offsite receptor locations.
A summary of Superfund APA dispersion modeling recommendations and
objectives is presented in Table 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 in Volumes II and III. Meteorological modeling input
data should preferably be based on an onsite monitoring program. (See
Sections 2.2. and 3.4.3 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 dispersion model selection are
included in Sections 2.3 and 2.4. It is also recommended that near real-time
concentration estimates associated with nonroutine air releases be developed,
as necessary. A combination of monitoring/modeling approaches is recommended
to provide this capability. An example of this approach is provided in
Appendix C.
2-2
-------
TABLE 1. SUMMARY OF DISPERSION MODELING RECOMMENDATIONS AND OBJECTIVES
Source
Classification
Dispersion Modeling Objectives
APA Recommendations
Superfund Activities
Pre-Remediation
Source
ro
i
<*>
Provide sufficient data
base on concentrations of
air toxic contaminants for
performing a detailed risk
assessment of public health
and the environment for on-
site, perimeter and off-
site 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 on-
site, perimeter and off-
site 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 on-site
monitoring program pursuant
to recommendations
presented in Volume IV -
Section 3.4.3.
- Conduct dispersion modeling
based on considering ISC as
the preferred model for
Superfund APA applications.
RI/FS - Screening/
refined APA.
(Continued)
-------
TABLE 1. (Continued)
Source
Classification
Dispersion Modeling Objectives
APA Recommendations
Superfund
Activities
Remediation
source
Provide air quality data to
assess the affects of the
remedial action evaluated.
Provide input to the design
of air monitoring program
for this step.
IN*
Characterize air
concentrations during
remedial/removal activities:
- Obtain emission rate
estimates based on
procedures presented in
Volumes II and III.
- Obtain meteorological Input
data based on an on-site
monitoring program pursuant
to recommendations
presented in Volume IV -
Section 3.4.3.
- Conduct dispersion modeling
based on considering ISC as
the preferred model for
Superfund APA applications.
Remedial design
(pilot field
studies)
(Continued)
-------
TABLE 1. (Continued)
Source
Classification
Dispersion Modeling Objectives
APA Recommendations
Superfund
Activities
Remediation
source
ro
i
en
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 response
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 III.
- Obtain meteorological input
data based on an on-site
monitoring program pursuant
to recommendations
presented in Volume IV -
Section 3.4.3.
- 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 on a
combined monitoring/
modeling approach to obtain
near realtime dispersion
estimates (see example in
Appendix C).
Remedial actions
(full-scale
operations)
(Continued)
-------
TABLE 1. (Continued)
Source
Classification
Post-
Remediation
Source
ro
Dispersion Modeling Objectives
APA Recommendations
Superfund
Activities
Provide air quality data
base at the site perimeter
and off-site as a part of
assessing the effectiveness
of the remedial action
implemented.
Provide air quality data
base at the site perimeter
and off-site to demonstrate
the protection of public
health and the environment.
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 on-site
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)
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
Atmospheric dispersion modeling for Superfund activities includes a
mix of sources that, in general, are different in configuration and
characteristics from the sources traditionally modeled for air permitting
applications. The traditional sources modeled for air permitting applications
are usually elevated, buoyant, 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 list of the types of sources associated with the various Superfund
activities is presented in Table 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 paved and unpaved roads, and point sources
include air strippers, incinerators, and in situ venting operations. Most
Superfund sources are considered ground-level or near-ground-level, nonbuoyant
releases.
Superfund activity emissions exhibit more involved and complex
processes that govern the rate and type of air emissions compared with air
emissions from traditionally modeled sources. Air emissions from Superfund
activities can be continuous or intermittent releases, or a one-time release
over a defined period of time. The releases can be routine or unforeseen.
Both gaseous and particulate matter emissions must be considered. The gaseous
emissions include volatile and semi volatile compounds, and particulate matter
emissions include semivolatile, base neutrals, metals and other inorganic
compounds. Table 1 lists the general type of gaseous and particulate matter
emissions associated with various Superfund activity sources as well as the
anticipated nature of the release.
2-7
-------
TABLE 2. SOURCES ASSOCIATED WITH SUPERFUND ACTIVITIES AND THEIR CHARACTERISTICS
Important
Air Emission Mechanisms
Superfund Source
P re-remediation
Sources:
• Landfills
• Lagoons
• Contaminated
soil surfaces
rO
i • Containers
00
• Process
Facilities
• Storage Tanks
Remediation Sources:
• Soil Handling
• Air Stripperb
• Incinerator
Source"
Configuration
Fugitive Area
Fugitive Area
Fugitive Area
Fugitive Area
volume
Fugitive Area
volume line,
point
Fugitive Area
Fugitive Area,
volume
Point, Volume
Point, Volume
Gas Phase
Volatilization,
biodegradation
Volatilization,
biodegradation
Volatilization,
biodegradation
Volatilization.
biodegradation
Volatilization,
combustion
Volatilization
Volatilization
Volatilization
Combustion
Particulate
Phase
Wind Erosion,
mechanical
disturbances
Wind Erosion,
mechanical
disturbances
Wind Erosion
mechanical
disturbances
Mechanical
diturbances
Wind Erosion,
mechanical
disturbances
—
Wind Erosion,
mechanical
disturbances
Combustion
Combustion
Emission
Gas Phase
Continuous
Continuous
Continuous
Continuous
Continuous
Continuous
Continuous,
Intermittent
Continuous,
Intermittent
Continuous,
Intermittent
Mode
Particulate
Phase
Intermittent
Intermittent
Intermittent
Intermittent
Intermittent
—
Intermittent
Continuous
Continuous
Routine/
Non-Routine
Release
Routine
Routine
Routine
Routine
Routine
Routine
Routine/
Non-Routine
Routine/
Non-Rout ine
Routine/
Non-Routine
(Continued)
-------
TABLE 2. (Continued)
rv>
i
vo
Superfund Source
Remediation Sources:
• In-s1tu Venting
• Solidification/
Stabilization
Source*
Configuration
(Continued)
Fugitive Area
Fugitive Area,
volume
Important
Air Emission Mechanisms
Gas Phase
Volatilization
Volatilization
Particulate
Phase
—
Wind Erosion,
mechanical
disturbances
Emission Mode
Particulate
Gas Phase Phase
Continuous
Intermittent
Continuous, Intermittent
Intermittent
Routine/
Non-Routine
Release
Routine/
Non-Routine
Routine/
Non-Routine
Post-remediation Sources:
• Landfills
• Lagoons
•Soil Surfaces
• Containers
Fugitive Area
Fugitive Area
Fugitive Area
Fugitive Area
volume
Volatilization,
biodegradatlon
Volatilization,
biodegradation
Volatilization,
biodegradation
Volatilization,
biodegradation
Wind Erosion,
mechanical
disturbances
Wind Erosion,
mechanical
disturbances
Wind Erosion,
mechanical
disturbances
Mechanical
disturbances
Continuous Intermittent
Continuous Intermittent
Continuous Intermittent
Continuous Intermittent
Routine
Routine
Routine
Routine
a Most Superfund sources are ground level or near ground level non-buoyant releases.
Small stacks where plume 1s frequently in the downwash cavity.
-------
The factors discussed above clearly imply that many of the currently
employed air dispersion models for traditional sources, as outlined in the
U.S. Environmental Protection Agency'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 in the EPA Guidelines are
applicable to Superfund applications. It is therefore important to define the
sources involved, their configuration, and their characteristics before a
suitable model is selected.
It can also be concluded that the added complexity of air dispersion
modeling for Superfund activities is mainly associated with estimating
emission rates for the specific source under consideration. It is therefore
vital to develop emission inventory data for the sources involved based on the
procedures outlined in Volumes II and III of this series for pre-remediation
sources, remediation sources, and post-remediation sources. It is also
critical to subdivide large-area sources to smaller sources in accordance with
the guidelines provided in 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 in this section as passive constituents. This is 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 in Sections 2.2 through 2.6.
The procedures for atmospheric dispersion modeling presented in this
section are based on a five-step process (illustrated in Figure 2):
t Step 1 - Collect and review input information;
• Step 2 - Select modeling sophistication level;
t Step 3 - Develop modeling plan;
• Step 4 - Conduct modeling; and
• Step 5 - Summarize and evaluate results.
2-10
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
Emission Rates
APA Guidelines
Vols. II & III
COLLECT AND REVIEW INFORMATION
• Source data
• Urban/rural classification
data and receptor data
• Environmental characteristics
Available
Monitoring
Data
SELECT MODEL CLASS AND
SOPHISTICATION LEVEL
• Screened
• Refined
EPA
Modeling
Guidelines
DEVELOP MODELING PLAN
• Select model
• Select constituents to be
modeled
• Define model input require-
ments (emissions, meteorol-
ogy, receptors)
• Select receptors
• Select modeling period
• Evaluate modeling
uncertainty
EPA
Review/
Approval
CONDUCT MODELING
Develop emission inventory
Process meteorological data
Develop receptor grid
Run model test cases
Verify input files
Perform calculation for averaging times
under consideration
I
SUMMARIZE/EVALUATE RESULTS
• Determine concentrations
• Prepare meteorological summaries
• Consider modeling uncertainty
Yes
ADDITIONAL ANALYSES NEEDED?
No
Input to EPA
Remedial/
Removal
Decision
Making
Figure 2. Superfund Air Pathway Analyses Dispersion Modeling Protocol
2-11
-------
Additional technical discussion on dispersion modeling is found in
the EPA's Guidelines on Air Quality Models.
The following is a brief discussion of each of these steps. An
expanded discussion is presented in the"subsequent subsections.
Step 1 - Collect and Review Input 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 warranted, 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 list 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.
2-12
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
Step 3 - Develop Modeling PI an--This step involves preparation of a
dispersion modeling plan. Elements that should be addressed in 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 - Conduct Model ing--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 following information, at a minimum, should be collected and
reviewed to support the air modeling program design:
t Source data;
• Receptor data; and
• Environmental data.
2-13
-------
This type of information serves a dual purpose: 1) it provides an
overall understanding of site-specific features that can affect dispersion
modeling, and 2) it provides the necessary input to drive the dispersion
model. The accuracy of the model predictions depends, of course, on the
accuracy and representativeness of the input 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, but it should generally
improve as the Superfund process progresses. In any event, available
information and data should be evaluated for the following factors:
t Data quality objectives (DQO);
• Technical soundness of methodologies employed;
• Completeness and quality of the data;
• Quality assurance/quality control (QA/QC);
t Compatibility, representativeness, and applicability of the
data; and
• Data gaps.
Supplemental information can be gathered through a literature search
of records and documents from sources such as the following:
• National Weather Service;
• U.S. Environmental Protection Agency;
• State and local agencies;
• Contractor studies; and
• Other Federal government offices.
The information collected during Step 1 should be evaluated and the
results documented using a form similar to the example presented in Table 3.
In addition, copies of data summaries should be attached to the form to
provide a convenient, complete documentation package for the project files.
2-14
-------
TABLE 3. EXAMPLE - SUPERFUND AIR DISPERSION MODELING INPUT INFORMATION FORM
Data Tvoe
Source Data
• Site Layout Map
• Contaminants List
• Emission Inventory
• Contaminant Toxicity
Factors
• Off -Site Sources
Receptor Data:
• Population Distribution
Hap
• Identification of
Sensitive Receptors
•Site Work Zones Hap
• Local Land Use
Environmental Data:
• Dispersion Data
- Wind Direction/
Wind Speed
- Atmospheric Stability
• Climatology
- Temperature
- Humidity
- Precipitation
• Topographic Haps
- Site
- Local Area
•Soil and Vegetation
Data
(Yes or No
or N/A)
pbtained
(Attachment 1)
Technical
Methods
Employed
Acceptable
(Yes or No)
Completeness
and Quality
of Data
Acceptable
(Yes or No)
valuation Fac
QA/QC
Appropriate
(Yes or No)
ors
Data
Relevant
for this
Application
(Yes or No)
Data Gaps
Significant
(Yes or No)
Comments
ro
(Continued)
-------
TABLE 3. (Continued)
Data Type
Previous APA Data:
• Emission Rate Modeling
• Emission Rate Monitoring
• Dispersion Modeling
• Air Monitoring
• ARAR Summary
Data
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
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 is critical for estimating the magnitude of air emissions from
each of the sources and in defining the primary emitted species. In addition,
information on source configuration is vital. As discussed in Section 2.1 and
summarized in Table 1, area sources constitute the majority of sources at 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 can 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:
• 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 is
an extremely important consideration for Superfund APAs. In
particular, emission/source conditions during remediation can
vary significantly.
t Configuration and classification (based on information
presented in Table 2 and site-specific considerations) of
sources as area, volume, line, or point sources.
2-17
-------
Dimensions t)f each area, volume, and line source, including the
shape of sources (e.g., is 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 in the dispersion model. If
the square covers a large area, it may be advisable to
subdivide it into smaller squares if calculated concentrations
are required at short distances from the source. Similarly
nonregular-volume sources have to be approximated by a cube and
nonregular-shaped-line 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.
Contaminants associated with each source area. It will be
useful to subdivide the contaminants into groups and subgroups
with similar chemical or physical characteristics: organics
(volatiles, semivolatiles, base neutrals, pesticides,
polychlorinated biphenyls (PCBs)), and inorganics (metals and
other toxic compounds [H2S, HCN, etc]).
Physical and chemical characteristics of the contaminants
involved, including density relative to air (for gaseous
emissions) and particle size distribution (for particulate
matter emissions).
Estimated typical long-term emission rates and typical as well
as maximum short-term emission rates for each source under
consideration. The emphasis for Superfund APAs is 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 dispersion model are considered during the data
2-18
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
evaluation 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 in
Volume II and III, repectively, of this document.
Table 4 represents an example of input requirements for various
source categories. As noted in Section 2.1, in 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 is 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 calculational (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 in 2-kilometer
increments for a distance of 10 kilometers from the site if
total risk is to be considered;
• Sensitive receptors within 10 kilometers of the site and
individual residences and buildings within 1 kilometer of the
site;
2-19
-------
TABLE 4. EXAMPLE OF INPUT REQUIREMENTS FOR VARIOUS SOURCE CATEGORIES
Input
Parameter
Source
Location
Source Cateaorv
Point Line Area
Coordinates Coordinates Coordinates
of the point of the center of the sciuth-
(m). of the line west corner
(m). of the area
approximated
by a square
(m).
Vol ume
Coordinates
of the center
of the source
(m).
Source
Dimension
Source
Emission Rate
for each
constituent
under con-
sideration.
Adjacent
Obstructions
Initial
Dilution
Particle mass-
size distri-
bution and
deposition
velocity.
Stack height
(m), exit
diameter (m),
exit velocity
(m/sec), exit
temperature
CK)
Mass per unit
time.
Length (m),
Width (m),
Height (m).
Width of the
square area
source (m).
Mass per unit
time per unit
length, or
mass per unit
time if sim-
ulated by an
array of vol-
ume sources.
Mass per unit
time per unit
area.
Height of the
volume source
(m), width
(m).
Mass per unit
time.
Height (m),
Width (m),
Length (m).
Initial
horizontal
and vertical
dimensions
(m).
Initial
horizontal
and vertical
dimensions
(m).
Initial
horizontal
and vertical
dimensions
Fraction of mass in each size group. Average deposition
velocity for each mass size group (m/sec).
2-20
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
0 Site work zones as identified in the Health and Safety Plan;
and
t 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 is a necessary component for defining air pathway exposure
potential. In the case of dispersion modeling, the environmental charac-
teristics serve as key input to the modeling calculations. Environmental
characteristics that should be evaluated prior to the implementation of air
dispersion modeling may include:
• Climate (historical summaries from available onsite and offsite
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;
t Meteorological survey results
Hourly listing of all meteorological parameters for the
entire monitoring period,
Daytime wind rose (at coastal or complex terrain sites),
Nightime wind rose (at coastal or complex terrain sites),
Summary wind rose for all hours,
2-21
-------
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.,
in waste piles);
• 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-minute quadrangle sheets
are acceptable),
Maps that indicate the location of the nearest residence
for each of the sixteen 22.5-degree sectors that
correspond major compass points (e.g., north, north-
northwest), nearest population centers, and sensitive
receptors 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; and
• Sensitive environmental areas (e.g., wildlife preserves, parks,
etc.).
2-22
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
In searching for meteorological data, it is important to consider
the following factors:
t Meteorological data drive the dispersion model and govern the
advection and dispersion of contaminants released from a
source. It is 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 in 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 is the issue a meterological data period longer than 5
years may be desireable to characterize the expected exposure
period.
Onsite meteorological monitoring is recommended as a part of the
Superfund project planning phase. Although data collected from an onsite
meteorological station may not have the long record required for their direct
use in dispersion calculation, their benefits are substantial because they
contain site-specific data:
• To assess the correlation with offsite meteorological data and
the applicability of the offsite data to the site under
consideration;
• To show the diurnal variation of the meteorological parameters
affecting plume advection and dispersion; and
t To indicate any topography-induced flow, including drainage and
valley flows and the effect of water bodies on wind flow,
including coastal zone flow.
2-23
-------
Therefore, It Is recommended that an onsite meteorological
monitoring program be initiated immediately after a site is included on the
National Priorities List (NPL) if 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 onsite meteorological program (e.g., recommendations
on the number and siting of meteorological stations) for a Superfund site are
discussed in Section 3.4.3 of this volume, along with references for siting
guidelines.
Meteorological and climatological data available from a National
Weather Service (NWS) station or other suitable offsite source should be
utilized (e.g. stability array [STAR] meteorological summaries). From a
practical viewpoint, NWS data should be considered in most applications, since
such data are subject to reasonable QA/QC programs and are processed by the
National Climatic Center for use in 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 associated QA/QC programs. In any event, meteorological
and climatological data should be obtained from a station that is 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 in 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 5 provides a summary of meteorological data for use in
dispersion modeling for Superfund APAs.
2-24
-------
1
1
1
1
1
1
1
1
TABLE 5. A SUMMARY OF INPUT METEOROLOGICAL DATA FOR USE IN DISPERSION
MODELING FOR SUPERFUND
Input Meteorolooical Data
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 daily
mixing heights;
• Hourly ambient temperature.
II. Superfund Step: Remedial Action
A. Routine Releases
• Hourly average wind speed;
• Hourly average wind
direction;
• Hourly average atmospheric
stability;
• Hourly ambient temperature;
• Estimated mixing height.
B. Non-Routine Releases
• 15-min. average wind speed;
• 15-min. average wind
direction;
• 15-min. average atmospheric
stability;
• 15-min ambient temperature;
• Estimated mixing height.
APAs
Source
•
• NWS
• State
• Industrial
Facilities
(on-site)
On-Site
Meteorological
Program
On-Site
Meteorological
Program
2-25
Lenath of Record
• One year minimum.
• Five years
preferred, (a
longer data set may
be appropriate
depending on the
potential exposure
period).
N/A
N/A
-------
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 downs!ope 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 in 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 in 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, onsite
meteorological data can be used to identify and characterize these local wind
patterns.
Soil characteristics and conditions can influence emission rates of
volatile species from Superfund sites and have a large impact on the wind
erosion of contaminated surface soils. It is important when considering
particulate matter emissions 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 is therefore important to obtain
pertinent information for use in the dispersion modeling.
2-26
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
2.2.5 Previous APA Data
Previous air quality data that address calculated air concentrations
of contaminants known to exist at the site can provide insight into existing
levels of air toxic compounds of interest. Compound-specific information will
be useful in assessing what indicator compounds should be modeled and what
modeling methodologies should be employed. Site-specific Superfund documents
(e.g., site investigations (Sis), RI/FSs, records of decision (RODs), 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 in 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.
t The assessed quality of the dispersion modeling analysis.
Existing air monitoring data for the site area can be used in
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.
2-27
-------
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. Coupled with the
sophistication level is the applicability of the model to the site and
activity involved and the model's 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:
t Source-specific APA recommendations presented in Volume I;
t 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; and
t 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 emissions models to adequately simulate
emission rates and variability,
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,
2-28
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
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.
These recommendations are based on a standard sequence of APAs. The APA
strategy is 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 and modeling inaccuracies.
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 in Table 1. Input from the RPM/EPM should be obtained to confirm
site-specific dispersion modeling objectives and to ensure that the dispersion
modeling level selected is consistent with these objectives.
The availability of appropriate meteorological data is probably the
most significant factor when selecting the modeling sophistication level.
Synthesized meterological data are generally limited to screening modeling
while actual meterological data are appropriate for screening applications.
2.3.2 Selection of Models as a Function of Sophistication Levels
Air dispersion models are employed in 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 in the regulatory development process.
2-29
-------
The air dispersion models utilized in 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 in air quality studies are point source models.
They are the dominant tools in all air regulatory applications, as noted in
the EPAs Guidelines on Air Quality Models. The bases of the four classes of
models are:
t Gaussian models are based on the assumption that plume
dispersion in the crosswind and vertical directions follows a
Gaussian distribution in a uniform wind field. They are
analytical solutions to the continuity equation.
t Numerical models include the continuity, momentum, and energy
conservation equations that are solved numerically using
various techniques. Plume transport can be in a uniform or
nonuniform wind field. These models require extensive input
and substantial computer and manpower resources, but may be
helpful in the presence of obstructions in the wind field.
• 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.
t 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.
2-30
-------
I
I
I
I
I
I
I
I
i
I
I
I
I
I
I
I
I
I
I
Of these four classes of models, Gaussian dispersion models are by
far the most commonly used in air quality assessments. As discussed in
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.
Gaussian dispersion models can and have been successfully applied to the types
of sources encountered at Superfund sites; but the number of applicable models
is limited.
Alternative modeling sophistication levels for Superfund APA
applications can be classified as either:
• Screening models; or
• 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 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 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 is warranted.
Table 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 in
Table 6. From Table 6, it is 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
2-31
-------
TABLE 6. A SUMMARY OF DISPERSION MODELING SCREENING TECHNIQUES FOR SUPERFUND APAs
Feature
1. Source Configuration:
Point
Line
Area
Volume
2. Release Mode:
Continuous
Instantaneous
3. Contaminant Physical State:
Gas
Part leu late
4. Wake Effect
5. Down wash
6. Heavier than Air Gas Module
7. Number of Sources Handled
8. Concentration Averaging Time
9. Gormen ts
Screening Modeling Technique
Screening Procedure
for Estimating
the Air Quality
Impact of
Stationary Sources,
(PA. August 1988)
Yes
No
Yes
No
Yes
No
Yes
Yes
Yes
No
No
Single
1, 3, and 24-hours,
annual
This document contains
formulas and a large
number of nomoqrams for
normalized concentra-
tions thai are useful
for simple screening
calculations. A
computerized version of
this technique is in the
form of the PTPLU-2
model.
A
Workbook of Screening
Techniques for
Assessing Impacts
Toxic A1r Pollutants
USEPA. March 1988
Yes
No
Yes
Yes
Yes-
Yes2
Yes
Yes
Yes
No
Yes2
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
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes
No
No
No
Single
Various Averaging
Times
This document
contains formulas
and a large number
of nomograms for
normalized concen-
trations that are
useful for simple
screening calcula-
tions. Also
included are
examples of
calculations.
Rapid Assessment of
Exposure to Particulate
Emissions From Surface
Contamination Sites,
USEPA. September 1984
No
No
Yes
No
Yes
No
No
Yes
No
No
No
Single
24-hour and annual
This document provides
a methodology for
screening estimates of
air concentrations
from surface releases
from Superfund Sites.
ISC
Dispersion Model
(screening mode)
Yes2
Yes2
Yes2
Yes2
Yes2
No
Yes2
Yes2
Yes2
Yes2
No
Multiple2
1, 3, 8, and 24-
hours and annual
The ISC dispersion
model combines
various dispersion
algorithms into 'a
set of two com-
puter programs
that can be used
to assess the air
quality Impacts of
emissions from a
wide variety of
sources .
OJ
ro
These guidelines Include a computerized model SCREEN which carries out the screening calculations.
O
Preferred technique when applicable.
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
the calculations involved become tedious and subject to calculational errors.
The preferred screening techniques, when applicable, for Superfund APA
applications are based on the use of ISC in a screening mode and supplemented,
as necessary by those stipulated in 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 a 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 by relying on fewer assumptions and providing a consistent means
of making repetitious and involved calculations without error. 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 is to identify locations of high concentration using a
relatively dense calculational grid network. Thus, the refined modeling
analysis can be conducted in a cost-effective manner by limiting the
calculational 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 is 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 7
provides a summary of refined dispersion models applicable for Superfund APAs.
2-33
-------
TABLE 7. A SUMMARY OF DISPERSION MODELING REFINED TECHNIQUES FOR
SUPERFUND APAs
Model inq Technique
1.
2.
3.
4.
5.
6.
7.
Feature
Source Configuration:
Point
Line
Area
Volume
Release Mode:
Continuous
Instantaneous
Contaminant Physical State:
Gas
Parti cul ate
Wake Effect
Downwash
Heavier than Air Gas Module
Number of Sources Handled
ISC
Dispersion
Model1*
Yes*
No
Yes*
Yes*
Yes*
No
Yes*
Yes*
Yes*
Yes*
No
Multiple
PAL DS Model1
Yes
Yes
Yes
No
Yes
No
Yes
Yes
No
No
No
Multiple
Inpuff2
Yes
No
No
No
Yes
Yes
Yes
No
No
Yes
No
Single
DEGADIS3
Yes
No
No
No
Yes
Yes
Yes
No
No
No
Yes*
Single
(Continued)
2-34
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
TABLE 7. (Continued)
Modeling Technique
Feature
ISC
Dispersion
Model1* PAL DS Model1 Inpuff2 DEGADIS3
8. Number of Meteorological
Towers
Single
9. Concentration Averaging Time 1,3,8, and
24-hour,
annual
10. Applicability to Superfund
Activities All steps
Single
1 through
24 hours
All steps
Multiple Multiple
Hourly
Remedial
Action
Step
Remedial
Action
Step and
selected
use for
other
steps.
1 Include in the EPA Guideline on Air Quality Models (Revised), July 1986;
ISC • Industrial Source Complex; PAL DS - Point, Area, and Line Source
Dispersion Deposition.
2 USEPA 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,
Volume 1 and 2, April, 1988; DEGADIS = Dense Gas Dispersion.
* Preferred technique when applicable.
2-35
-------
The Industrial Source Complex (ISC) dispersion model and the Point,
Area, and Line Dispersion Deposition (PAL DS) model are included in the EPAs
Guideline on Air Quality Models. The ISC dispersion and PAL DS models are
applicable to continuous sources with several configurations, while the
MESOPUFF model is applicable to instantaneous, continuous, and time-dependent
releases and can handle point and area sources generally on a larger scale
than most Superfund applications. Of these three, the ISC dispersion model is
the preferred model for most applications and should be given first
consideration as the model of choice for use in the Superfund APA for the
RI/FS, remedial design, and operation and maintenance activities. It can be
augmented as required under non-routine air releases by the use of the
MESOPUFF II, Integrated Puff (INPUFF), or Dense Gas Dispersion (DEGADIS)
models if special air release situations exist that could be simulated by any
of these models.
The ISC dispersion model should also be given first consideration as
the model of choice under the remedial action activities to simulate routine
air releases. A model like the INPUFF or the procedure outlined in Appendix C
should be utilized 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 in the EPAs Graphical Exposure Modeling System, which is
standard for use in conducting Superfund risk assessments.,)
The PAL DS model may also be useful for estimating short-term
impacts. It has a good area source treatment and it is expected to be more
accurate than the ISC model for receptors immediately downwind of an area
source. Furthermore, PAL DS has a more complete deposition algorithm than
ISC, but it contains no downwash algorithm.
2-36
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
The iNPUFF and the DEGADIS models were Included for handling
instantaneous releases, with the DEGADIS model having the capability to handle
heavier-than-air gases. These two models could be useful as a part of the
remedial action step on a case-by-case basis to augment EPA's A Workbook of
Screening Techniques for Assessing Impacts of Toxic Air Pollutants.
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 is 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.
Developing a modeling plan involves the following major elements:
t Select constituents to be modeled;
• Define emission inventory methodology;
• Define meteorological data base;
• Design receptor grid;
t Detail modeling methodology;
• Estimate background concentrations;
• Define dispersion calculations to be performed; and
• 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 8 provides an outline for the
modeling plan. Each of the major elements of the modeling plan is discussed
in the following subsections.
2-37
-------
TABLE 8. AN OUTLINE FOR THE DISPERSION MODELING PLAN I:OR A SUPERFUND APA
I. INTRODUCTION
t General site background (site location, topography, nearby water
bodies, demography, vegetation, general site activities).
II. DISPERSION MODELING DATA QUALITY OBJECTIVES
t Modeling objectives (consistent with the Superfund activity involved
and the overall project objective);
t Overall rationale for the modeling approach; and
• 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);
t 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; and
0 Dimensions of obstructions.
V. METEOROLOGICAL DATA
Source of meteorological data;
Length of record;
Parameters to be utilized in the dispersion modeling; and
Quality of the data.
Representativeness of data.
(Continued)
2-38
-------
I
I
• TABLE 8. (Continued)
• VI. RECEPTOR GRID
• On-site Receptors (number and locations);
• Perimeter Receptors (number and locations);
• • Off-site Receptors
Regular (number and locations);
| - Extra locations In potential high concentration areas (number
and locations); and
• - Environmentally sensitive locations (number and locations).
• VII. MODELING METHODOLOGY
• Selected model(s) and rationale;
I • Model application to the Superfund activity APA;
• Model features:
• - Rural/urban classification,
• - Wake and/or downwash effects,
Particle deposition,
I Plume rise,
Dispersion parameters;
_ • Setting of model switches; and
• • Testing the model against bench mark test cases.
I VIII. ESTIMATED BACKGROUND CONCENTRATIONS
| XI. DISPERSION CALCULATIONS
t Averaging times;
• • Data summaries (tabular, graphical);
• 0 Comparison with guideline values; and
t Input to the risk assessment.
X. REFERENCES
I
I
• 2-39
-------
2.4.2 Dispersion Modeling Data Quality Objectives
The purpose of this section is 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
is necessary to provide adequate input into the Superfund APA.
Elements included in this section should address:
t The overall rationale for the modeling approach;
t Model output and anticipated uncertainties,, considering input
data, model formulation and assumptions involved, and output;
and
• Implications of model uncertainties on the Superfund APA (e.g.,
are they acceptable).
In this respect, dispersion modeling DQOs provide consistency in
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 compounds for dispersion modeling is
generally less critical than for air monitoring. Selection of air monitoring
compounds is significantly limited by technical, budget, and schedule
constraints. However, dispersion modeling results from one target contaminant
for a particular source can generally be scaled to obtain, on a cost-effective
basis, concentrations for numerous other contaminants of interest.
2-40
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
A list of the compounds included in the Hazardous Substances List
(HSL) developed by EPA for the Superfund program is presented in Table 9.
This list is a composite of the Target Compound List (TCL) for organics and
Target Analyte List (TAL) for inorganics. Table 9 also includes examples for
additional potential Superfund air emission constituents (e.g., HCN, H2S,
HC1). Therefore, Table 9 represents a comprehensive initial list of target
compounds for air dispersion modeling.
Emission rates should be estimated prior to the conduct of
dispersion studies. These results, as well as dispersion modeling results (as
available), should be used to identify appropriate site and source-specific
modeling contaminants from Table 9. In addition, contaminants included in
ARARs identified during Step 1 should also be used to identify candidate
modeling contaminants.
Dispersion modeling for screening applications should include all
site/source-specific contaminants.
Dispersion modeling target compounds (i.e. indicator compounds) for
refined APAs should, at a minimum, include all contaminants with
concentrations greater than or equal to 10 percent of the appropriate health-
based action level. These contaminants 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 compounds (e.g., over one hundred) of which only a limited
subset significantly affect inhalation exposure estimates. However, it is
generally recommended, as practical, to also evaluate all appropriate
site/source-specific contaminants for refined modeling APAs (especially if the
cumulative effect due to exposure to a mixture of constituents is used for
comparison to health criteria).
The dispersion modeling target compounds list should be reevaluated,
and revised if warranted, based on monitoring results.
2-41
-------
TABLE 9. CLASSIFICATION OF ORGANIC AND INORGANIC COMPOUNDS FOR AMBIENT AIR
MODELING STUDIES
Contaminant Type
Compound Class
Representative Compounds
Volatile Orqanics Aromatics
Halogenated Species
Oxygenated Species
Sulfur-Containing Species
Nitrogen-Containing Species
benzene
toluene
ethyl benzene
total xylenes
styrene
chlorobenzene
carbon tetrachloride
chlorofrom
methylene chloride
chlorornethane
1,2-dichloropropane
trans-1,3-dichloropropene
cis-l,3-dichloropropene
bromoform
bromomethane
bromodichloromethane
di bromochloromethane
1,1,2,2-tetrachloroethane
,1,1-trichloroethane
,1,2-trichloroethane
,1-dichloroethane
1,2-dichloroethane
chlroethane
tetrachloroethene
trichloroethene
1,2-dichloroethene
1,1-dichloroethene
1,2-dichloroethene
vinyl chloride
actone
2-butanone
2-hexanone
4-methyl-2-pentanone
carbon disulfide
benzonltrile*
1,.
i,:
i,:
(Continued)
2-42
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
TABLE 9. (Continued)
Contaminant Type
Compound Class
Representative Compounds
Volatile Inorganics Acid Gases
Semi-Volatile
Orqanics
Phenols
Esters
Chlorinated Benzenes
Amines
hydrogen cyanide*
hydrochloric acid*
Sulfur-Containing Species hydrogen sulfide*
phenol
2-methyl phenol
4-methylphenol
2,4-dimethylphenol
2-chlorophenol
2,4-dichlorophenol
2,4,5-trichlorophenol
2,4,6-trichlorophenol
pentachlorophenol
4-chloro-3-methylphenol
2-nitrophenol
4-nitrophenol
2,4-dinitrophenol
4,6-dinitro-2-methylphenol
bis(2-ethylhexyl)phthalate
di-n-octyl phthalate
di-n-butyl phthalate
diethyl phthalate
butyl benzyl phthalate
dimethyl phthalate
vinyl acetate
1,2-dichlorobenzene
1,3-dichlorobenzene
1,4-dichlorobenzene
1,2,4-trichlorobenzene
hexachlorobenzene
nitrobenzene
2,6-dinitrotoluene
2,4-dinitrotoluene
3,3'-dichlorobenzidine
n-nitrosodimethylamine
n-nitrosodi-n-propylamine
n-nitrosodiphenylamine
aniline
2-nitroaniline
3-nitroaniline
4-nitroaniline
4-chloroaniline
(Continued)
2-43
-------
TABLE 9. (Continued)
Contaminant Type
Compound Class
Representative Compounds
Semi-Volatile
Organics (cont.)
Ethers
Alkadienes
Miscellaneous Aliphatics
and Aromatics
Polynuclear Aromatic
Hydrocarbons (PAHs)
Pesticides
bis(2-chloroethyl)ether
bi s(2-chloroi sopropyl)ether
bromophenyl-phenylether
4-chlorophenyl-phenylether
hexachlorobutadiene
hexachlorocyclopentad i ene
benzole acid
benzyl alcohol
bi s(2-chloroethoxy)methane
dibenzofuran
hexachloroethane
isophorone
acenaphthene
acenaphthylene
benzo(a)anthracene
benzo(b)fluoranthene
benzo (k.) f 1 uoranthene
benzo(g,h,i)perylene
benzo(a)pyrene
chrysene
dibenz(a,h)anthracene
fluoranthene
fluorene
indeno(l,2,3-cd)pyrene
naphthalene
2-methylnaphthal ene
2-chloronaphthalene
phenanthrene
pyrene
alpha-BHC
beta-BHC
delta-BHC
gamma-BHC
heptachlor
heptachlor epoxide
4,4'-DDT
4,4'-DDD
4,4'-DDE
(Continued)
2-44
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
1
I
TABLE 9. (Continued)
Contaminant Type
Compound Class
Representative Compounds
Semi-Volatile Pesticides (cont.)
Organics (cont.)
Polychlorinated Biphenyls
(PCBs)
Semi-Volatile Metals
Non-Volatiles
Inorganic Metals and
Non-metals
endrin
endrin ketone
endrin aldehyde
endosulfan I
endosulfan II
endosulfan sulfate
aldrin
dieldrin
chlordane
methoxychlor
toxaphene
Arochlor 1016
Arochlor 1221
Arochlor 1232
Arochlor 1242
Arochlor 1248
Arochlor 1254
Arochlor 1260
Mercury
aluminum
antimony
arsenic
barium
beryl1i urn
cadmium
calcium
chromium
cobalt
copper
iron
lead magnesium
manganese
nickel
potassium
selenium
silver
sodium
thallium
tine
vanadium
zinc
NOTE: Compounds identified by an asterisk (*) are not contained on the US EPA
Hazardous Substance List (HSL).
2-45
-------
It is recommended that dispersion modeling results initially be
obtained in 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 compound-specific concentration equals the dispersion factor of the
receptor location of interest times the compound-specific emission rate).
2.4.4 Define Emission Inventory Methodology
An emission inventory is a key input to the Superfund air dispersion
modeling. Data obtained from Step 1 (Collect and review Input information)
should be utilized in 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.
t Defining the constituents involved with each source based on
the output of Section 2.4.3.
• Defining the parameters required for estimating emissions that
are identified in Volumes II and III, and the rationale for
their selection.
• Calculating emissions based on methods outlined in Volumes II
and III.
• Estimating particle size distribution for calculating
particulate deposition.
2-46
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
• Accounting for downwash from nearby structures. This
phenomenon is particularly important for onsite 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 DQOs should be an integral part of the
methodology outlined.
The emissions inventory should be tabulated in a format suitable for
use in dispersion modeling. This table should include physical and chemical
characteristics of the constituents to be modeled.
As previously discussed, 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, it may be necessary to subdivide a Superfund area source
into a number of smaller area sources, square in shape. Source subdividing
into small, square area sources has the following two major benefits:
t The areas and shapes of irregular sources can be approximated
in most cases by a number of small squares, as illustrated in
Figure 3.
• Receptors at or near the source can also be included in the
dispersion modeling, as often required for the Superfund APA.
This includes receptors at onsite work areas, at the site
perimeter, and immediately offsite.
2-47
-------
•1
•9
•2
•3
•4
•5
•6
•7
•8
•10
•11
Figure 3. Representation of an Irregularly Shaped Area Source,
2-48
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
A specialized modeling approach is generally needed for standard
Gaussian dispersion models such as the ISC, in order to obtain concentration
estimates near the boundary of a large area source. For example, the
nested-area subdivision approach illustrated in Figure 4 can be used. By
subdividing the area source such that the square nearest the receptor is less
than 10 meters on a side, it is possible for the ISC dispersion model to
provide estimates of concentration within 1 meter of the source boundary.
Flux models, which simulate the microscale physics immediately above
a ground-level emission surface, can also be used to estimate concentration at
and in 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 is 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 onsite data, data applicable for
use in 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 is
desirable to have five or more years of meteorological data to support
long-term exposure assessments for refined APAs.
As discussed in Section 2.2.4, onsite meteorological data should be
used:
2-49
-------
Wind Direction
Receptor at
site boundary
Nested subdivisions, as
necessary to yield areas
of <100m2
Figure 4. Example of Nested Subdivision of Area Source,
2-50
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
t To evaluate (correlate) offsite data;
t 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; and
• Define worst-case emission/dispersion scenarios to
conservatively evaluate short-term exposure conditions to
support screening APAs. Worst-case scenarios should represent
the highest impact resulting from the combination of
meteorological conditions giving high emissions and low
dilution.
The data base selected should meet program and DQO objectives, have
a record of sufficient length, and include data representative of the site
area. Some guidance on the determination of representativeness of
meteorological data can be found in the "On-Site Meteorological Program
Guidance" document referenced below. Due to uncertainties associated with the
use of off-site data, it is often advisable to establish an on-site
measurement program as early in the site remediation process as possible.
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:
2-51
-------
t U.S. EPA. June 1987. On-Slte 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.
t 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 Air 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 is
required, with 5 years of data being preferred.
t Parameters to be utilized in the dispersion model, including
wind speed, wind direction, atmospheric stability, ambient
temperature, and mixing height.
An onsite meteorological program is recommended in the case of the
remedial action step. Section 3.0 addresses the requirements of onsite
2-52
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
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 in making the dispersion calculations and in assessing routine air
releases, or as near real time data in estimating the impact of nonroutine air
releases. The modeling plan for the remedial action step should address the
use of onsite meteorology in dispersion modeling for both routine and
nonroutine 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 is
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:
2-53
-------
• Provide concentration estimates which can be used as input to
the Superfund risk assessment process and to compare to ARARs;
and
• Provide 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 is 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 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., in 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
onsite 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.
2-54
-------
I
I
• The receptor grid system for Superfund APAs should be developed on a
case-by-case basis. The basic objective is to resolve concentration gradients
I
I
in the vicinity of the site and to identify maximum concentrations. Receptor
grid design should also consider the following:
• Results of the receptor data evaluation performed under Section
2.2.3;
• Results of screening and refined screening dispersion modeling
that can be invaluable in terms of identifying gradients and
potential locations of high concentrations;
I
I
I
I • 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;
I
• Release characteristics such as height, dimensions, and
• proximity to the site perimeter;
• • Work areas on the site; and
• • 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
I conservative assumptions, the screening analysis calculational grid points may
be limited to the plume centerline for the downwind sector of interest.
I
I
2-55
-------
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 in a refined analysis could
range from 200 to 400.
2.4.7 Detailed Modeling Methodology
The modeling methodology is based on the objectives outlined in
Table 1 for dispersion modeling as a function of the Superfund activity, and
it is consistent with the DQOs for the project. As discussed in Section
2.4.2, it is 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 is useful for obtaining rough upper-bound
estimates of the levels of air contaminant concentrations and the approximate
locations of high concentrations and providing information on the need for
refined dispersion modeling. Screening models are presented in Table 6. The
selected methodology should take into account the following:
• Screening versus refined modeling applications;
t Formulation to be used;
• Applicability of the approach to the Superfund activity and
source under consideration;
• Concentration averaging time;
• Special considerations such as downwash;
2-56
-------
I
I
I t Dispersion parameters;
• Plume rise considerations; and
• Quality and quantity of meteorological data available (e.g.,
the availability of representative data recommended to support
refined dispersion modeling analyses).
For refined dispersion modeling, the model to be used should be
selected from Table 7. The ISC dispersion model is the preferred model for
most Superfund APAs. When there is a need for characterizing time-dependent
releases, the INPUFF model should be utilized. Other models listed in Table 7
could also be used on a case-by-case basis.
The dispersion modeling plan should address the following for
refined modeling:
t Selected model and rationale;
I
I
I
I
I
I
I
t Model applicability, as determined by the Superfund activity
•involved and source characteristics. For example, nonroutine
releases during the remedial action step should be considered
when the model is selected;
• The rural or urban character of the area, based on demographic
I data;
• t Wake and/or downwash effects, including those attributable to
onsite obstructions;
I • Particle deposition, taking into consideration the particle
mass-size distribution;
I
I
2-57
-------
• Plume rise and dispersion parameters, including initial
dilution parameters; and
• Model switches (tabulation).
In addition, a brief synopsis of the model formulation should be
discussed.
2.4.8 Estimated Background Concentrations
Background air concentrations are an integral part of many air
quality studies that involve dispersion modeling. Such information is 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 conformity with ambient
air quality criteria for ARARs.
Measurement of air quality in the vicinity of a Superfund site could
provide the necessary information on existing background air quality levels,
providing the following are met:
t The air monitoring network was designed and implemented
following procedures similar to the guidelines provided in
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 in the site vicinity, as discussed in Section
2.2.5. It also could be obtained through the implementation of an air
monitoring program in the vicinity of the site as a part of the Superfund site
activity. In areas where there are large sources of toxic air pollutants
close to the Superfund site, modeling these sources can be performed in order
to determine background concentrations.
2-58
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
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, proposed air monitoring, or
additional modeling. The project objectives and DQOs should serve as a key
factor in assessing the background levels in 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:
t Averaging times for calculating concentrations,
Short term: hourly and 3-, 8-, and 24-hours.
Long term: monthly, seasonal, annual, or other;
t Dispersion modeling scenarios as a function of the Superfund
activity under consideration. For example, the RI/FS activity
may 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 onsite technology; and
• The reporting format for calculated results,
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.
2-59
-------
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 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 such as verifying all model input files.
2.5.2 Staff Qualifications and Training
Dispersion modeling is a complex process that requires specialized
qualifications and training. This aspect of modeling has been frequently
overlooked as personal computer (PC) versions, which are easy to use, have
become prevalent. However, it is also easy for the novice to select
inappropriate modeling options and/or enter data incorrectly. These errors
can be subtle in 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 is
based and on input data/model limitations. Therefore, it is 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.
2-60
-------
I
I
• 2.5.3 Performance of Modeling
_ 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 in Table 6
is selected) is considered. It is implemented with a computer when refined
• dispersion modeling is performed.
The screening dispersion modeling process includes the following
steps:
I
I • Calculate the emission release rate or total release;
I • Derive the source parameters required as additional input;
• • Define the special parameters required to estimate wake effects
• or negative plume buoyancy;
I 0 Select the meteorological data set or scenario to be modeled;
I 0 Define the receptors for which calculations will be performed;
I 0 Perform the calculations (generally using computer models); and
• 0 Obtain conservative concentration estimates.
_ The benefits of simplicity in screening techniques can be easily
| lost if repeated calculations introduce a higher probability of computational
errors. Screening calculations should always be accompanied by adequate
I documentation to permit QC checks on the simulations.
I
I
. 2-61
-------
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;
t Perform model calculations; and
• Obtain more realistic concentration estimates;
The modeling process is delineated in Figure 5. The tasks involved
in these steps must be executed carefully to minimize the likelihood of
errors. A small error in 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.
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 in
Sections 2.4.3 and 2.4.4. The emission inventory is 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 in a format similar to that presented in Table 3.
2-62
-------
1
1
Develop Preprocess
Receptor Meteorological
•Grid (Sections Data (Sections
2.2.3 and 2.4.6) 2.2.4 and 2.4.5)
\r
I^___
Input into
Computer
_ Files
1
\ '
• Set Up Model
™ Switches
1
Run Benchmark
• Test Cases
1"
Verify Input
Files
1...
V
•Perform
Model
Calculations
1
1
Figure 5. The Dispersion Model
1
1
1
- 2-63
Develop Emission
Inventory
(Sections 2.2.2,
2.4.3, and 2.4.4)
ing Process.
-------
Preprocess 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 in 'the users guide for
each EPA dispersion model.
Preprocessing generally involves a large volume of data (e.g., 1
year of data includes 8760 hourly values for each meteorological parameter
under consideration). In refined modeling, the preprocessing is done with a
computerized preprocessor that accepts on-site or 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 in reference material associated with each
modeling technique (see Tables 7 and 8). The preprocessed data should be
checked for validity before their use. Recommendations for meteorological
data validity checks are provided in Table 10 and in Section 3.6.2.
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 outlined in Section 2.4.6. The grid can be rectangular or circular,
or it 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 in Table 7. The spatial distribution of receptors should be
determined based on factors discussed in 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 in a format compatible for use by a refined dispersion model.
2-64
-------
1
1
1
•
1
1
1
1
•
1
1
1
1
1
1
TABLE 10. SUGGESTED METEOROLOGICAL DATA SCREENING CRITERIA8
(U.S. EPA, JUNE 1987)
Meteorological Variable
Screening Criteria8
Wind Speed Flag data if the value:
0
0
0
Wind Direction o
0
0
Temperature o
0
0
0
Temperature Difference o
0
0
8 Some criteria may have to
Is less than zero or greater than 25 m/s;
Does not vary by more than 0.1 m/s for 3
consecutive hours; and
Does not vary by more than 0.5 m/s for 12
consecutive hours.
Is less than zero or greater than 360 degrees;
Does not vary by more than one degree for more
than three consecutive hours; and
Does not vary by more than ten degrees for 18
consecutive hours.
Is greater than the local record high;
Is less than the local record low; (The above
limits could be applied on a monthly basis.)
Is greater than a 5* change from the previous
hour; and
Does not vary by more than 0.5'C for 12
consecutive hours.
Is greater than 0.1*C/m during the daytime;
Is less than -0.1°C/m during the nighttime; and
Is greater than 5.0'C/m or less than -3.0eC/m.
be changed for a given location.
2-65
-------
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 is 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
calculational 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 of actual dispersion model runs in 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 in
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 is important in
this case to consider the type of model output, based on the options
available, to avoid excessive printout without any use for most of it. From
a practical viewpoint, daily and annual concentrations are the most useful in
assessing air release effects through the APA. Once it has been determined
that the model performs properly and the appropriate switches have been set,
the model is ready for execution.
2-66
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
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 in 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 for this step is as
fol1ows:
t Summarize data;
• Evaluate modeling results; and
• 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 concentrations and their location can be used to
compare with ARARs or as part of the exposure assessment input to a risk
assessment. The performance of the dispersion modeling for existing sources
could be assessed by comparing calculated and measured air concentrations.
Results of the dispersion modeling, together with information on the
methodology employed, should be summarized in a modeling report.
2.6.2 Summarize Data
In general, the output of computer model calculations is given in a
tabular form. These data have to be summarized in a form that is useful for
the specific APA application. Examples of recommended tabular data summaries
for air toxics indicator constituents include:
2-67
-------
• Daily concentrations at sensitive receptor locations included
in the dispersion calculations;
• Maximum long-term (monthly, seasonal, annual, or other)
calculated concentrations;
t Daytime and nighttime maximum and average concentration
estimates (for complex terrain and coastal sites only);
• Calculated long-term concentrations at sensitive receptors;
• ARARs;
• Summaries of calculated versus measured (as available)
concentrations for short- and long-term averaging times; and
• Source-specific summaries for Superfund sites with multiple air
release sources.
A useful presentation of the results in graphic form is accomplished
by plotting concentration isopleths for indicator constituents. These
isopleth summaries depict the areas affected by Superfund air release sources.
Plots can be generated using specialized software (e.g. SURFER) or using an
integrated modeling/plotting software package. Figure 6 is an example of a
computer-generated, ground-level isopleth plot.
Frequently, it may not be practical to place air monitoring stations
at offsite 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, concentration patterns based on modeling results
can be used to extrapolate concentrations monitored onsite to offsite
locations. An illustration of modeling results for this application is
provided in Figure 7.
2-68
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
ESTIMATED ANNUAL CONC.. UG/M3 (RURAL)
29.00
28.00
80.00 81.00 82.00 83.00 84.00 85.00 86.00 87.00
Figure 6. Example of a Computer Generated Ground Level Isopleth Plot.
2-69
-------
ATMOSPHERIC DILUTION PATTERN
• = NEAREST RECEPTORS
+ = MONITORING STATIONS
0.1
•—"
Figure 7. Example Atmospheric Dispersion (Dilution) Pattern.
2-70
-------
I
I
I
I
•
•
•
I
I
I
I
Meteorological data summaries should include the following at a
minimum:
• Daytime wind rose (only for coastal or complex terrain areas);
t 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, or Stability Array
(STAR) summaries;
• Tabular summaries of means and extremes for temperature and
other pertinent meteorological parameters; and
• Data recovery summaries for all parameters.
Statistical summaries for the meteorological data should be
I 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
I 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.
2.6.3 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:
2-71
-------
t Modeling concentrations;
• Source receptor relationship; and
• The 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.
In situations where multiple sources are being modeled, it is
important to consider source-specific contributions to predicted
concentrations. For example, remediation sources may involve soil handling
activities and an air stripper. Maximum impacts may be dominated by soil
handling operations, and this information is important to determining what
emission controls are effective in reducing maximum concentrations to
acceptable levels.
Model Uncertainty/Receptor Applicability
Field validation studies of Gaussian models have consistently
demonstrated that estimates of model uncertainty are largely inadequate,
particularly in their quantification of the representativeness of data and the
non-homogeneous and stochastic nature of atmospheric dispersion which are not
handled in models. These studies have shown 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, the
recommended approach is to consider maximum concentrations predicted off site
as controlling concentrations irrespective of whether the maximum receptor
coincides with a residence. This is particularly important for short-term
(i.e., 24-hours or less) concentrations. For long-term concentrations, the
location of maximum receptors in relation to residences can be considered on a
case-by-case basis as a factor in evaluating model results.
2-72
-------
I
I
I
I
I
I
1
I
I
I
I
I
I
I
I
I
I
I
I
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 it
may be necessary to conduct specialized field studies that may involve
intensive meteorological monitoring materials and/or tracer studies.
Figures 8 and 9 illustrate an example application of supplemental
analyses. This Superfund site is 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 it was necessary to characterize potential impacts associated
with soil handling operations at the onsite landfill. Smoke and SF6 tracer
studies were used to define transport paths for typical drainage flow
conditions. These results are summarized in Figure 8. Results from the
tracer studies were also used to develop a site-specific dispersion model.
These results are summarized in Figure 9.
2-73
-------
ro
i
(D
CO
C3
-t
fa
tu
to
O
(O
ut
to
C
Drainage I:!OM Sw»li« Test lesults
-------
I
1
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
SPECIFIC ATMOSPHERIC DISPERSION MODEL
DILUTION
FACTOR
DILUTION
FACTOR
FACTOR
S
«^TTt7« •
FACTOR
DILUTION
FACTOR
AREA AND DILUTION FACTORS
f •:
Figure 9. Drainage Flow Impact Area and Dilution Factors.
2-75
-------
Supplemental analyses can be expensive and result In project
schedule delays. Therefore, these analyses are generally only warranted if
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 Air Toxics Guidelines
IV References
V Appendices
Meteorological Data
Emission Inventory
Model Testing
Detailed Modeling Printout
2-76
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
The report should Include a sufficient amount of explanation of the
" methodology and results. Figures such as isopleths of concentrations are
highly recommended. Voluminous data printouts are often not necessary If the
data are carefully summarized and the full set of data provided on a floppy
disk.
2-77
-------
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
SECTION 3
AIR MONITORING PROCEDURES
3.1 OVERVIEW
Air monitoring is an air pathway analysis (APA) approach that can
provide direct measurements of air contamination levels at receptor locations
of interest. This approach is useful for checking modeling predictions and as
part of the overall health and safety monitoring at Superfund sites. Air
monitoring, however, 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. The procedures are
necessarily general so as to apply to any generic site, and they are as
complete as possible so that potentially important considerations will not be
overlooked for any specific site. Each consideration of the procedures will
not be applicable for every site, nor will it always have an equal relative
importance.
Recommendations concerning air monitoring applications for specific
Superfund activities and sources have been presented in Volume I. These
recommendations are cross-referenced and potential Superfund air monitoring
applications are summarized in Table 11. A review of this information
indicates that air monitoring applications are directly related to specific
Superfund activities. Therefore, the technical information and
recommendations in this section are frequently presented on a Superfund
activity-specific basis.
3-1
-------
TABLE 11. SUMMARY OF AIR MONITORING APPLICATIONS
Source Classification APA Recommendations Superfund Activities
Air Monitoring Applications
Pre-Remediation
Source
Characterize baseline RI/FS -
air concentrations Screening/Refined
Screening APA
Pre-Remediation
Source
Characterize baseline
air concentrations
RI/FS - Refined APA
• Preliminary baseline air
quality data and
information on emissions.
t Air Quality Data in support
of the design of a refined
air monitoring program to
support the RI/FS (i.e.,
preparation of site-
specific Work Plan and
Field Sampling and Analysis
Plan).
• Comprehensive baseline air
quality for on-site,
perimeter, and off-site.
t Data are used as risk
assessment input for the
no-action alternative.
t Data are used in evaluating
remedial alternative
actions.
(Continued)
-------
TABLE 11. (Continued)
Source Classification APA Recommendations Superfund Activities
Air Monitoring Applications
Remediation Source
Remediation Source
CO
I
CO
Post-Remediation
Source
Characterize air
concentration during
remedial/removal
activities.
Remedial design
(pilot field studies)
Characterize air
concentrations during
remedial/removal
activities.
Remedial actions
(full-scale
operations).
Confirm controlled
source air
concentrations.
Operation and
Maintenance (post-
remedial activities)
• Work area, perimeter, and
off-site 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.
t Work area, perimeter, and
off-site air monitoring
program in support of
clean-up activities.
• Data are used to protect
workers, the public, and
the environment under
routine and non-routine air
releases.
• Perimeter and off-site
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.
-------
The procedures for air monitoring presented in this section are
based on a five-step process (illustrated in Figure 10):
• Step 1 - Collect and review input information;
• Step 2 - Select monitoring sophistication level;
• Step 3 - Develop monitoring plan;
• Step 4 - Conduct monitoring; and
• Step 5 - Summarize and evaluate results.
Each of these steps is briefly described below and discussed in more detail in
subsequent subsections.
Step 1 - Collect and Review Input Information—Existing information
pertinent to the air monitoring program should be collected. Possible sources
of information include site files, EPA guidance documents, local
meteorological stations, and the open literature. Available information
should be obtained for emission sources, receptors, and historical
meteorological trends. Once the existing data have been collected, compiled,
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--The air monitoring
sophistication level should be selected from among 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 toxic and hazardous
compounds present at the site. Monitoring approaches should be evaluated
considering compound-specific factors, including detection limits, performance
criteria (e.g., precision, accuracy), and advantages and disadvantages of
alternative methods.
3-4
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
Emission Rates
APA Guidelines
Vols. Ill & IV
EPA/NIOSH
Monitoring
Guidelines
COLLECT AND REVIEW
INFORMATION
• Source data
• Receptor data
• Environmental
characteristics
Available
Monitoring/
Modeling
Data
SELECT MONITORING
SOPHISTICATION LEVEL
• Screening
• Refined
DEVELOP MONITORING PLAN
• Select monitoring
constituents
• Specify meteorological
monitoring
• Design network
• Select monitoring
me thods/equipment
• Develop sampling and
analysis QA/QC
Peer
Review/RPM
Approval
CONDUCT MONITORING
• Routine operation
• Quality control
• Field documentation
SUMMARIZE/EVALUATE
RESULTS
• Data review and validation
• Data summaries
• Consider monitoring uncertainties
• Dispersion modeling applications
Yes
No
ADDITIONAL MONITORING NEEDED
Input to EPA
Remedial/
Removal
Decision
Making
Figure 10. Superfund Air Pathway Analyses Air Monitoring Protocol.
3-5
-------
Step 3 - Develop Monitoring Plan—An air monitoring plan should be
developed. Elements that should be addressed in the plan include (a)
selection of monitoring compounds, (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. The plan will require review,
revision, and approval prior to starting monitoring.
Step 4 - Conduct Monitoring—This step involves the day-to-day
activities of initiating and conducting an air monitoring program at a
Superfund site. It includes the following: (a) final selection of air
monitoring sites, (b) installation and check-out of monitoring equipment, (c)
routine equipment operation and maintenance, (d) sampling calibrations and
checks, (e) audits, (f) handling of samples, (g) field documentation, (h)
sample analysis, (i) maintenance of laboratory data and records (including
chain-of-custody forms), (j) corrective action, and (k) other QA/QC procedures
necessary to ensure a successful monitoring program.
Step 5 - Summarize and Evaluate Results--Data should be reviewed and
air monitoring results validated. 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.
3-6
-------
I
I
• 3.2 STEP 1 - COLLECT AND REVIEW INPUT INFORMATION
• 3.2.1 Overview
The first step in the design and implementation of an effective air
| quality monitoring program is the compilation and evaluation of available
information. The following information, at a minimum, should be considered
I when developing an air monitoring program design:
• Source data;
• Receptor data;
I
•• Environmental data; and
t Previous APA data.
I 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. In general, the
•quality of information should improve as the Superfund process progresses
since each step can build on the results of previous work.
| Available information and data should be evaluated for the following
factors:
I
t Technical soundness of methodologies employed;
|
• Completeness and quality of the data, including detection
• limits, precision, and accuracy;
• Quality assurance/quality control results;
t Compatibility and applicability of the data; and
I
• Existence of data gaps.
I
I
3-7
-------
The results of the evaluation should be documented using a form similar to the
example presented in Table 12. In addition, copies of data summaries should
be attached to the form to provide a convenient, complete documentation
package for the project files.
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 in-situ
contamination is essential for estimating the magnitude of air emissions from
each of the source areas and in defining the primary airborne contaminants of
interest. The data should be available from the Superfund RPM/EPM, though the
data will be relatively incomplete or uncertain until the RI/FS work has been
completed. Specific information that should be collected and evaluated
includes:
• 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.);
0 Contaminants associated with each source area. It will be
useful to subdivide the contaminants into groups and subgroups
with similar chemical or physical characteristics: organics
(volatiles, semivolatiles, base neutrals, jpesticides, PCBs) and
inorganics (metals and other toxic compounds [e.g., H2S, HCN]);
• Toxicity factors important in evaluating the potential risk to
human health and the environment; and
t Identification and description of offsite air emission sources.
3-8
-------
TABLE 12. EXAMPLE - SUPERFUND AIR MONITRING PROGRAM INPUT INFORMATION FORM
Data Tvoe
Source Data
• Site Layout Map
• Contaminants List
• Emission Inventory
• Contaminant Toxic ity
Factors
• Off -Site Sources
Receptor Data:
• Population Distribution
Map
• Identification of
Sensitive Receptors
•Site Work Zones Map
• Local Land Use
Environmental Data:
• Dispersion Data
- Wind Direction/
Wind Speed
- Atmospheric Stability
• Climatology
- Temperature
- Humidity
- Precipitation
• Topographic Maps
- Site
- Local Area
•Soil and Vegetation
Data C
(Yes or No
or N/A)
Obtained
(Attachment f)
Technical
Methods
Employed
Acceptable
(Yes or No)
E
Completeness
and Quality
of Data
Acceptable
(Yes or No)
valuation Facl
QA/QC
Appropriate
(Yes or No)
ors
Data
Relevant
for this
Application
(Yes or No)
Data Gaps
Significant
(Yes or No)
Conmsnts
I
vo
(Continued)
-------
t*>
t
%—*
o
TABLE 12. (Continued)
Data Tvoe
Previous APA Data:
• Emission Rate Modeling
• Emission Rate Monitoring
• Dispersion Modeling
• Air Monitoring
• ARAR Summary
Data C
(Yes or No
or N/A)
total ned
(Attachment f)
Technical
Methods
Employed
Acceptable
(Yes or No)
Completeness
and Quality
of Data
Acceptable
(Yes or No)
valuation Facl
QA/QC
Appropriate
(Yes or No)
ors
Data
Relevant
for this
Application
(Yes or No)
Data Gaps
Significant
(Yes or No)
Comments
-------
I
I
I 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.
I
I
I
I
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
I contaminants 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 in 1- to 2-
• kilometer 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;
t Site work zones as identified in the Health and Safety Plan;
and
I
t Local land use characterization (e.g., residential, commercial)
within 10 kilometers of the site.
Sensitive receptor locations include schools, nursing homes,
hospitals and other places associated with sensitive population segments, as
well as locations with sensitive non-human receptors.
I
-------
3.2.4 Environmental Characteristics
Existing information on the environmental characteristics pertinent
to a Superfund site should be considered when defining air pathway exposure
potential. Environmental characteristics data that may be relevant to the
design of an air monitoring program include:
• Dispersion characterization data including wind direction/speed
and atmospheric stability summaries;
• Climatological data representative of the site area, including
wind, precipitation, temperature, and humidity conditions;
t Topographic features and water bodies at the site and vicinity;
t Soil and vegetation characteristics of the site and vicinity;
and
• Any other environmental factors that could affect the number,
location, and type of air monitoring stations.
Existing representative dispersion and Climatological data will be
useful in 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 with an air dispersion model (see Section
2) to provide estimated calculated concentrations for the contaminants of
interest at locations of maximum impact. Temperature, precipitation, and
humidity data can influence the selection of monitoring and analysis methods.
3-12
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
Topographic features and water bodies can 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 can 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 can affect atmospheric stability conditions and
the dispersion of air contaminants. In general, large water bodies tend to
increase the stability of the atmosphere in the air layer adjacent to the
water, thus reducing the dispersion of air contaminants.
Soil characteristics and conditions can influence emission rates of
volatile species from Superfund sites and have a large impact on the wind
erosion of contaminated surface soils. It is important when considering
particulate matter emissions to understand soil conditions such as porosity,
particle size distribution, soil type, and source data.
Vegetation, including shrubs and trees, can be a factor in siting an
air monitoring station due to flow obstructions and accessibility. In
addition, vegetation can retard emissions of subsurface contaminants and can
affect air flow because of the increase in surface roughness.
3.2.5 Previous APA Data
The Superfund APA recommendations presented in Volume I specify
conducting 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;
3-13
-------
t Emission rate monitoring data;
• Dispersion modeling data;
t Air monitoring data; and
• 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. If these types of data are not available or
do not meet completeness or QA/QC specifications, then it is recommended that
site-specific and source-specific APAs be conducted to estimate emission rates
and air concentrations (via dispersion modeling) to provide these inputs.
Overall recommendations on developing APA data are specified in 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 in Volume III. Procedures for the conduct
of dispersion modeling studies to support Superfund APAs are presented in
Section 2 of this document. ARARs are discussed in Volume I.
Previous air quality data available for the site area that address
air concentrations of contaminants known to exist at the site can provide
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 in these evaluations include:
3-14
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
t 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.
t Number and types of compounds that were monitored and analyzed.
This information is important to determine the degree of
interference between the compounds involved; this 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.
t Detailed description of the monitoring station setting to allow
for an evaluation of the station siting. Consideration should
be 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.
Existing air dispersion modeling for the site area can be useful in
evaluating locations for ambient air monitoring stations. 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 can be used
as input into the risk assessment, which can in turn be used in selecting
locations of sensitive receptors. Procedures for the conduct of dispersion
modeling were presented in Section 2.
3-15
-------
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. The three levels of sophistication described in this
section are screening, refined screening, and refined monitoring. The
appropriate monitoring sophistication level for each Superfund project
application depends on the following factors:
• Source-specific APA recommendations (presented in Volume I);
• Input data from Step 1 (Table 12);
• Technical air monitoring objectives (Table 13);
t Overall project objectives and activity-specific air monitoring
applications (Table 13);
• Legal and liability aspects of the Superfund project; and
• Pragmatic aspects of the program
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.
Of these factors, the time to obtain results (analytical turnaround time)
dictated by the program objectives is often the single most important criteria
when selecting from among air monitoring approaches.
3-16
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
TABLE 13. SUMMARY OF TECHNICAL AIR MONITORING OBJECTIVES
Superfund Activity
Technical Air Monitoring Objective
RI/FS - Screening APA
RI/FS - Refined APA
t Provide preliminary insight about the existence
of air emissions and their characteristics
(magnitude of air concentraitons, constituents
involved and their distribution) by performing
on-site measurements.
• Provide preliminary air quality baseline (on-
site and perimeter).
t Provide preliminary information for on-site
exposure (workers), perimeter and off-site
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.
• Provide detailed insight about the existence of
air emissions and their characteristics
(magnitude of emissions, constituents involved
and their distribution) by perfoming on-site
measurements.
• Provide on-site 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 data base for perfroming a
detailed risk assessment of the public and the
environment based on on-site pereimter, and off-
site air quality data under the baseline
conditions (no-action alternative).
• Provide sufficient data base for performing the
evaluation of remedial alternatives.
t Provide ground truth to dispersion modeling
calculations.
(Continued)
3-17
-------
TABLE 13. (Continued)
Superfund Activity
Technical Air Monitoring Objective
Remedial Design
(field demonstration)
• Provide on-site air quality data during the
implementation of field pilot studies in support
of the Health and Safety Plan for this step to
protect on-site workers.
• Provide perimeter air quality data for
preliminary assessment of the effects of the
remedial action evaluated.
Remedial Action
Provide work area air quality data for routine
and non-routine air releases to protect workers
and to provide a guidance for anticipated air
concentration at site perimeter and off-site.
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 off-site air quality data
in support of an emergency response air
dispersion model.
Provide work area, perimeter, and off-site 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 off-site as a part of
assessing the effectiveness of the remedial
action implemented.
• Provide a long-term air quality database at the
site perimeter and off-site to demonstrate the
protection of public health and the environment.
3-18
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
Source-specific APA recommendations have been presented in Volume I.
The APA strategy assumes that an initial screening APA should be conducted.
This screening work serves as one input for deciding when more refined air
monitoring work will be required. The dominant considerations, however, for
selecting the monitoring sophistication level are the ambient levels of
specific contaminants expected at the site. These data can be generated by
applying emission rate models to the known site and waste characteristics.
These emission rates are then used as input to dispersion models to predict
the concentration levels at receptor locations of concern, and these levels
are in turn compared to health-based action levels. The greater the liklihood
for exceedances of the action levels, the greater the need for more refined
air monitoring data.
Sophistication level recommendations presented in Table 11 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.
The air monitoring objectives for specific Superfund activities
(e.g., RI/FS, remedial action) are the single important input for the
selection of monitoring sophistication levels. These activity-specific
objectives are summarized in Table 16. Input from the RPM/EPM should be
obtained to confirm site-specific air monitoring objectives and to ensure that
the air monitoring level selected is consistent with these objectives.
The availability of appropriate monitoring methods is another
significant factor for monitoring sophistication level decision-making.
Certain compounds, polychlorinated biphenyls (PCBs) for example, are not
conducive to screening monitoring. A further discussion of available
monitoring methods is presented in Section 3.4. It is also necessary to
consider the uncertainty associated with the monitoring results.
3-19
-------
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; and
• Refined level
Refined techniques.
Screening techniques are generally associated with relatively high
detection levels (i.e., in the range of parts per million for gaseous
contaminants and milligrams per cubic meter for particulate matter
commensurate with industrial hygiene measurements) and frequently are used to
provide real-time results in 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 monitoring near the
source to confirm the presence of an air release and for providing input
information to support the development of specifications for a more refined
monitoring program. It is important to recognize that monitoring screening
techniques are not inherently conservative; therefore, the absence of air
concentrations measured in a screening mode does not mean that air impacts
are entirely absent.
Candidate screening techniques are summarized in Table 14. The
screening techniques for gaseous constituents presented in Table 14 include
total hydrocarbon (THC) analyzers, colorimetric gas detection tubes,
electrochemical alarm cells, and screening portable gas chromatograph (GC)
analyzers. Screening portable GC analyzers are available that provide gross
information on the concentration of an individual air toxic constituent.
3-20
-------
TABLE 14. AN OVERVIEW OF SCREENING AIR MONITORING/SAMPLING TECHNIQUES
to
I
ro
Program
Sophistication
Level
Screening
Screening
Screening
Screening
Screening
Screening
Screening
Refined
screening
Refined
Screening
Category of Detection
Monitoring/Sampling Method Limit
Gas Phase:
• Total hydrocarbon • ppm
(THC) analyzers.
• Colorimetric gas • ppm
detection tubes and
monitors.
• Electrochemical alarm • ppm
cells
• Screening portable GC • ppb
analyzer
Part icu late Phase:
• Portable pumps with • mg/m
filters.
• Portable pumps with • mg/m3
filters and special
plugs.
• Portable aerosol • mg/m
monitor.
Gas Phase:
• Portable field GC • ppb
analyzers with
constant-temperature
oven.
• Field GC laboratory • ppb
Compounds Detected
• Most organ ics but
not by chemical
species.
• Various organ 1cs and
in-orgam'cs for a
specific chemical
species.
• Various organ Ics for
a specific chemical
species.
• Species expressed as
equivalent to a
selected single
species.
• Most inorganic
compounds
• Semi-volatile
chemical species.
• Total suspended
part icu lates (TSP).
• Limited list of
organic compounds by
chemical species.
• Limited list of
organic compounds by
Monitoring/Sampling Mode
• Realtime-continuous
• Historical-integrated
• Realtime-continuous
• Realtime-continuous
• Historical-integrated
• Historical-integrated
• Realtime-continuous
• Realtime-continuous
• Historical- Integrated
Typical
Uncertainty
Factors
±50-200%
±50-200%
±50-200%
±50-200%
±50-100%
±50-100%
±50-100%
±100%
±100%
chemical species.
-------
Screening techniques applicable to particulate matter include portable pumps
with special filters or plugs and portable monitors that detect changes in
light absorbance.
Table 14 includes uncertainty values (UF) that typify the deviation
from a perfect method (i.e. a method with an uncertainty factor of ±1.0). An
uncertainty of ±3.0 means a deviation of ±200 percent from the "true" value
can be expected.
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 techniques can provide reasonably accurate
information on ambient air quality of organic compounds iin 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 14 include field portable GC systems.
Although similar to the refined methods discussed below, refined
screening techniques have the following relative limitations as compared to
the more sophisticated refined methods:
t The target analyte list is more limited;
• Only uncomplicated matrices of chemical species can be
analyzed; and
• QA/QC procedures are less comprehensive than those used by a
certified offsite laboratory.
3-22
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
Refined air monitoring is applicable to situations where high-
quality data are required and immediate response time for obtaining air
quality results is not required. 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 15. A myriad of refined air monitoring techniques is available, and
the process of selecting the most suitable one can be 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 is still undergoing rapid development.
In spite of the high quality of the chemical analyses involved with
refined air monitoring techniques, it is possible that the data obtained will
be useful only in 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;
t Variability in 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; and
• Variable response of the analytical system as a function of the
specific compound.
3-23
-------
TABLE 15. AN OVERVIEW OF REFINED AIR MONITORING/SAMPLING TECHNIQUES
Program
Sophistication
Level
Refined
Category of
Monitoring/Sampling Method
Gas Phase:
• Traps (sorbents and
cryogenics) and
laboratory analysis.
• Whole air samplers
(bags and canisters)
and laboratory
analysis.
• Liquid Impingers
Detection
Limit
• Fraction
of a ppb
to ppb.
• Fraction
of a ppb
to ppb.
• Fraction
of a ppb
to ppb.
Compounds Detected
• Many organic compounds
by chemical species.
• Many organic compounds
by chemical species.
• Aldehydes, ketones,
phosgene, cresol/
phenols.
Monitoring/Sampling Mode
• Historical-Integrated
• Historical-integrated
• Historical-Integrated
Typical
Uncertainty
Factors
±100%
±50%
±100%
Refined
i
ro
Participate Phase:
High-Volume samplers • ngfm
with glass fiber
filter, membrane
filter or teflon
filter.
High-volume samplers ng/m
with glass fiber
filter and
polyurethane foama
Inorganics
PCBs and other semi-
volatile organic
species.
• Historical-Integrated
• Historical-integrated
±50%
±100%
9 Polyurethane foam (PUF) plug is designed to collect semi-volatile organic gases.
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
This implies that a cost-benefit assessment may be useful. In many
cases, a combination of sophistication levels will be appropriate.
An expanded discussion of alternative screening and refined air
monitoring methods/equipment is 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 in Figure 11:
• Select monitoring constituents;
• Specify meteorological monitoring program;
• Design air monitoring network; and
• 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 target compound list for monitoring developed
during Step 2, and available EPA technical guidance.
Procedures for the development of an air monitoring plan are
provided in the subsections that follow.
3-25
-------
Input Data
(Step 1)
EPA
Guidance
Monitoring
Constituents
Target List
(Step 2)
Other
Technical
Guidance
SELECT MONITORING
CONSTITUENTS
(Figure 12)
SPECIFY
METEOROLOGICAL
MONITORING PROGRAM
(Figure 13)
DESIGN AIR
MONITORING NETWORK
(Figure 14)
DOCUMENT AIR
MONITORING PLAN
(Figure 15)
INPUT TO
STEP 4 - CONDUCT
MONITORING
Figure 11. Step 3 - Develop Monitoring Plan,
3-26
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
3.4.2 Select Monitoring Constituents
The selection of compounds to be addressed in the monitoring program
is a challenging task for Superfund applications because of the extensive
number of potential release contaminants. Sampling/analytical technical
factors and project budget limitations generally necessitate the selection of
a limited subset of target compounds. The selection of target air monitoring
contaminants involves the following key factors:
• Physical and chemical properties of the constituents
Physical phase (gas, particulate)
- Volatility
Water solubility
Etcetera
• Toxicity and health effects (risk assessment) of the chemicals
involved;
• Estimated concentration of a constituent relative to other
constituents and potential interference;
t Availability of standard sampling and analysis methods and
their performance;
• Overall and technical project objectives; and
t Data quality objectives and resource constraints.
A list of the compounds included in the Hazardous Substances List
(HSL) developed by EPA for the Superfund program was presented in Table 9.
This list is a composite of the Target Compound List (TCL) for organics and
the Target Analyte List (TAL) for inorganics. Table 9 also includes examples
for additional potential Superfund air emission constituents (e.g., HCN, H2S,
HC1). Therefore, Table 9 represents a comprehensive list of compounds from
which a list of target air toxics compounds can be selected.
3-27
-------
Emission rate measurement or modeling 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
compounds from Table 9. Contaminants included in ARARs identified during Step
1 should also be used to identify target (i.e. indicator) compounds for air
monitoring.
The limited set of target compounds based on previous APAs and ARAR
considerations should be ratioed to the appropriate health-based action level
to derive a hazard index (HI). The HI values computed should then be ranked
from highest to lowest in order to develop a priority list of candidate target
compounds. The final compounds selected for air monitoring should be a
function of the APA sophistication level and the technical feasability of
collecting and analyzing the various compounds. A flowchart to assist in
selection is given as Figure 12.
For screening applications, one to five target compounds with the
highest HI values for which appropriate monitoring methods are available
should be selected. Target compounds could include total hydrocarbons for
organics and compound class indicators (e.g., ethers, aromatics) for organics
and inorganics. Specific organic and inorganic contanrinantss could also be
selected.
Refined screening monitoring applications should include the
selection of 5 to 10 target compounds with the highest HI values. This
approach should facilitate the preliminary characterization of air releases at
Superfund sites. Again, the selection process should consider the
availability of appropriate monitoring methods commensurate with health and
safety criteria.
3-28
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
Figure 12. Flowchart for Defining a Target List of Compounds
for Air Monitoring.
3-29
-------
CO
I
CO
o
any compound(»
regulated by •
Retain compound)*) on
In* general list
Would
omitting the compound(
sacrifice any project
objectives
significant •
compound!*)
Do
sampling and
nalytlcal methods •«
lor In* compound(i) (In proper
physical slat*) that satlsly
the project ob|«ctlv*s
7
Miy
any compund(s)
rtbule to communll
Consider compound(s)
for target list
Can
trw project
objectives be re-
defined with approval
all Interested
parties
Redefine project objectives
to disregard compound(s)
defined
target
list
Management and technical
review of the target 1st
Include methods development
task to establish satisfactory
sampling/analytical methods
Redefine project objectives
to establish a target tsl
that can be studied within
the resources ol the project
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
Target compounds for refined APA monitoring should include all
contaminants with an HI value greater than or equal to 10 percent of the
composite HI value for the total mix. These contaminants are expected to
represent the greatest contributors to potential health impacts.
The target compound 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 list of compounds to confirm the representativeness of the
routine target compound list.
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 is presented in Figure 13.
The number and location of meteorological stations needed for a
site-specific application depend on local terrain conditions. One
meteorological station is generally sufficient for flat-terrain sites.
However, for complex-terrain sites it may be necessary to have multiple
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 away
from any nearby obstruction at a distance equal to at least 10 times the
height of the obstruction.
3-31
-------
DETERMINE NUMBER
AND LOCATION OF
METEOROLOGICAL
STATIONS
FLAT TERRAIN
1 STATION
COMPLEX TERRAIN
1-3 STATIONS
DETERMINE
EXPOSURE
HEIGHT
SCREENING/
REFINED SCREENING
2-3 m
REFINED
• 10 m - Primary parameters
•2m- Secondary parameters
DETERMINE
MONITORING
PARAMETERS
SCREENING/
REFINED SCREENING
• Wind direction
• Wind speed
• Sigma theta
REFINED
Primary
- Wind direction
- Wind speed
- Sigma Theta
Secondary
- Temperature
- Precipitation
- Humidity
- Pressure
DETERMINE DATA
RECORDING
APPROACH
CONDUCT METEOROLOGICAL
SURVEY TO SUPPORT AIR
MONITORING NETWORK DESIGN
(As Necessary)
SCREENING/
REFINED SCREENING
1 week
REFINED
4 weeks
INPUT TO AIR MONITORING PLAN
Figure 13. Specify Meterological Monitoring Program.
3-32
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
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:
t 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
Humidity
Atmospheric pressure
Primary parameters are representative of site dispersion conditions
and should be included in all meteorological monitoring programs. Secondary
parameters are representative of emission conditions and are generally only
recommended for refined air monitoring activities.
3-33
-------
Recommended meteorological monitoring system accuracies/resolutions
and sensor response characteristics are summarized in Tables 16 and 17,
respectively. Field equipment used to collect meteorological data can range
in 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 onsite 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 on-site 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 offsite data to estimate seasonal effects for
planning purposes if the air monitoring program is scheduled to last for more
than a few months.
Additional recommendations on meteorological measurements can be
obtained from the following sources:
t 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.
3-34
-------
I
I
I
I
I
I
1
I
I
I
I
I
I
I
I
I
I
I
I
TABLE 16. RECOMMENDED SYSTEM ACCURACIES AND RESOLUTIONS
Meteorological Variable
System Accuracy
Measurement Resolution
Wind Speed
Wind Direction
Ambient Temperature
Dew Point Temperature
Precipitation
Pressure
Time
±(0.2 m/s + 5% of observed
±5 degrees
±0.5'C
±1.5'C
±10% of observed
±3 mb (0.3 kPa)
±5 minutes
0.1 m/s
1 degree
o.rc
o.rc
0.3 mm
0.5 mb
3-35
-------
TABLE 17. RECOMMENDED RESPONSE CHARACTERISTICS FOR METEOROLOGICAL SENSORS
Meteorological Variable Sensor Specification(s)a
Wind Speed Starting speed <0.5 m/s; Distance constant <5 m.
Wind Direction Starting speed <0.5 m/s at 10° deflection;
Damping Ratio 0.4 to 0.7; Delay distance <5 m.
Temperature Time Constant <1 minute.
Dew Point Temperature Time Constant <30 minutes; operating temperature
range -30*C to +30*C.
a From Table 5-2. On-Site Meteorological Program Guidance for Regulatory
Modeling Applications, U.S. EPA, Office of Air Quality Planning and
Standards, Research Triangle Park, NC 27711. June 1987.
3-36
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
• 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 Significant Deterioration (PSD).
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 18). 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 14. Key components
of the monitoring network design include:
• Number of locations of monitoring stations;
• Probe siting criteria;
• Program duration and frequency of monitoring;
t Sampling and analysis methods; and
• Air monitoring equipment.
Each of these components is discussed below.
3-37
-------
TABLE 18. 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 Characteristic
Data Quality Objectives
See Table 12
t 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.
t Historical air quality data for the site area
representing on-site, perimeter, and off-site
measurements and the quality of the data.
• Results of air dispersion modeling and
locations of high calculated air toxics
concentrations.
t Number and locations of sensitive receptors
(population; sensitive population locations-
schools, hospitals, etc.; sensitive
environmental species and settings such as
flora and auna, state parks, and monuments,
national parks and monuments, etc.) and
distance to these locations.
t 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 ara and its potential
effect on local dispersion conditions, and
its proximity to the site.
t 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.
Laboratory turn-around time.
Detection limit for constituents involved.
Precision and accuracy of monitoring and
analyses methodologies.
(Continued)
3-38
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
TABLE 18. (Continued)
Factor
Elements
Data Quality Objectives
(Continued)
Source Characteristics
Constraints
Receptor Constraints
Environmental Constraints
Data Quality Objective
Constraints
Resource Constraints
Data representativeness.
Data completeness.
Data comparability.
Data use for Superfund APA application.
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.
t Limited budget
• Limited Time.
3-39
-------
CONSIDER DESIGN
FACTORS
(Table 18)
METEOROLOGICAL
SURVEY
DATA
DETERMINE NUMBER
AND LOCATIONS OF
AIR MONITORING
STATIONS
DETERMINE PROBE
EXPOSURE HEIGHT
(Table 19)
DETERMINE PROGRAM
DURATION/SAMPLING
FREQUENCY
(Table 20)
EPA
GUIDANCE
(Table 21)
SELECT MONITORING
METHODS
(Table 21)
SELECT MONITORING
EQUIPMENT
(Table 30, 31)
DISPERSION
MODELING
RESULTS
OTHER
TECHNICAL
GUIDANCE
(Appendix A)
INPUT TO
AIR MONITORING
PLAN
Figure 14. Design Air Monitoring Network.
3-40
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
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.);
t Siting constraints; and
f 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 patterns and
3-41
-------
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.
Many 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, as discussed in the following paragraphs.
1. 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.
2. 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.
3. 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. It is extremely important to consider concentration
gradients revealed by plotting model results as isolpeths of
concentration. Steep gradients suggest that a greater number of
monitoring locations would be required than for broad gradients. In
general, the impacts of elevated point sources display steep
3-42
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
concentration gradients and the impacts of low-level, area sources
display broad concetration gradients.
4. Source size and configuration. It is preferable 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.
5. Locations of sensitive receptors at the site perimeter and offsite.
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:
5A. 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.
5B. Population and environmentally sensitive locations. In
evaluating locations, it is 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. This factor will
dictate the selection of a monitoring station representing
small but highly sensitive or large but less sensitive
population and environmental species.
3-43
-------
6. Meteorological conditions
6A. 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.
6B. Local day/night wind flow and stability conditions for the area
and monitoring period under consideration.
6C. 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.
6D. Results of previous air quality monitoring programs in the
vicinity of the site that could be considered applicable to the
case in question.
6E. Results of previous air dispersion calculations for similar
sources with meteorological data considered representative of
the site conditions.
7. Topographical features that would influence the advection and
transport of air toxic constituents. Examples include land surface
elevations, valley channels, and the land-water interface.
3-44
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
Air monitoring station numbers and locations are highly site-
specific, and therefore no specific recommendations are being made.
Generally, however, a single downwind stationary monitor is not adequate to
monitor for maximum concentrations. The examples presented in Section 4, as
well as, the factors listed above, should be examined before deciding on a
network design.
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 (PSDK
EPA-450/4-87/007, Office of Air Quality Planning and Standards.
Research Triangle Park, NC 27711.
A summary of key factors that should be considered as a part of the
placement of an air quality monitoring station is given below. The reader is
referred for more details to the above-referenced document.
Key siting factors include:
• Vertical-placement above ground;
• Horizontal spacing from obstructions and obstacles;
t Unrestricted air flow; and
• Spacing from roads.
3-45
-------
A summary of the key criteria associated with these siting factors
for air monitoring stations is included in Table 19. The information included
in 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 it 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 in Table 19, 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 greater than 5 meters from the edge of the nearest
traffic lane and at a height of 2-15 meters aboveground.
3-46
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
TABLE 19. A SUMMARY OF KEY PROBE SITING CRITERIA FOR AIR MONITORING STATIONS
Factor
Criteria
Vertical spacing above
ground
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 i in general, 2-3 m above ground
and 2-15 m above ground in the case of nearby
roadways.
t About 1 m or more above the structure where
the sampler is located.
• Minimum horizontal separation from
obstructions such as trees is >20 m form the
dripline and 10 m from the dripline 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 in the 270
degree arc.
t A sufficient separation must exist between
the sampler and nearby roadways to avoid the
effect of dust re-entrainment and vehicular
emissions on the measured air concentrations.
• Sampler should be placed at a distance of 5-
25 m from the edge of the nearest traffic
lane on the roadway depending on the vertical
placement of the sampler inlet which could be
2-15 m above ground.
3-47
-------
Determine Program Duration and Sampling Frequency
The recommendations for program duration and frequency of monitoring
are summarized in Table 20. Actual monitoring duration and frequency,
however, will depend on the specific project objectives and resources. It is
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 20 are based on the following factors:
• 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; and
• 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.
The information presented in Table 20 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:
3-48
-------
TABLE 20. PROGRAM DURATION AND FREQUENCY OF MONITORING AS A FUNCTION OF THE SUPERFUND PROJECT STEP
Superfund Step
Monitoring
Program Duration
Frequency
Sampling Duration
Number of Samples
10
RI/FS - Screening APA
• Screening Monitoring
• Refined screening
monitoring
RI/FS - Refined APA
0 Refined Monitoring
•1-2 days
• 15-30 minutes at each
sampling location.
same as above • 24-hour integrated.
• 4-6 weeks
• 24-hour integrated.
• 20-30 readings using THC
analyzers.
• 10-20 samples using
colorimetric gas detection
tubes or equivalent.
• 5-10 samples for organics in
gas phase.
• Limited QA/QC samples.
• 10 at each monitoring
location for organics in gas
phase, semi-volatile
organics and in-orgnaics in
particulate phase.
• 10 at the collocated
monitoring location for the
same constituents as above.
• Field and trip blanks,
spiked, spilt and surrogate
samples on a case-by-case
basis.
(Continued)
-------
TABLE 20. (Continued)
Superfund Step
Monitoring
Program Duration
Frequency
Sampling Duration
Number of Samples
Remedial Design
• Refined Monitoring
•3-12 months
depending on
the length of
the pilot
treatability
study.
i
en
o
• Refined Screening
Monitoring
same as above
• 24-hour integrated
• 24-hour continuous
• 10-30 at each monitoring
location for organics in gas
phase, semi-volatile
organics and inorganics in
particulate 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 organics only.
(Continued)
-------
TABLE 20. (Continued)
Superfund Step
Monitoring
Program Duration
Frequency
Sampling Duration
Number of Samples
Remedial Action
t Refined Monitoring
10
in
• Refined screening
monitoring
t Several
months to
more than a
year,
depending on
the length of
the site
clean-up.
Same as above
• 24-hour integrated
• 24-hour continuous
• Screening Monitoring Same as above • 24-hour continuous
• One sample every day" at
each sampling location for
organics in gas phase, semi-
volatile organics and
inorganics in particulate
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.
• Continuous at each of the
designated monitoring
locations for organics only.
• Continuous at each of the
designated monitoring
locations for inorganics and
total hydrocarbons.
(Continued)
-------
TABLE 20. (Continued)
Superfund Step
Monitoring
Program Duration
Frequency
Sampling Duration
Number of Samples
Operation and Maintenance
• Refined Monitoring
Phase I - one
year
• 24-hour integrated
to
I
en
ro
t Refined Monitoring
• Phase II -
two to five
years
t 24-hour integrated
t One sample every 12th day at
each sampling location for
organics in gas phase, semi-
volatile organics, and
inorganics in particulate
phase.
• Same frequency as above for
the collocated monitoring &
for the same constituents as
above.
t Field and trip blanks,
spiked, split and surrogate
samples, on a case-by-case
basis.
t Twleve 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.
Frequency should be adjusted based on results of first 1 to 2 weeks of sampling.
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
• Physical and chemical properties of compounds;
t Relative and absolute concentrations of compounds;
• Relative importance of various compounds in program objective;
t Method performance characteristics;
• Potential interferences present at site;
• Time resolution requirements; and
• Cost restraints.
Various classes of contaminants must usually be monitored by
different methods, depending on the compounds and their physical/chemical
properties. Another condition that affects the choice of monitoring technique
is whether the compound is primarily in the gaseous phase or is 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. Air 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
compounds is 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 in higher concentrations.
Detection limits are ususally much higher for screening devices than for
quantitative methods.
Laboratory analytical techniques are used to provide positive
identification of the components and the accurate and precise measurement of
concentrations. This generally means that the preconcentration 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. Turnaround time for data is a key
factor to evaluate when considering offsite analyses.
3-53
-------
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
Air. 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 in Ambient Air.
EPA-600/4-84-041. Office of Research and Development.
Research Triangle Park, NC 27711.
t U.S. EPA. September 1986. Compendium of Methods for the
Determination of Toxic Organic Compounds in Ambient Air.
EPA/600/4-87-006. NTIS PB87-168696. Office of Research and
Development. Research Triangle Park, NC 27711.
t U.S. EPA. June 1987. Compendium Method TO-12: Method for
Determination of Non-Methane Organic Compounds (NMOC) in
Ambient Air Using Cryogenic Preconcentration and Direct Flame
lonization Detection (PDFID). Research Triangle Park, NC
27711.
• U.S. EPA. May 1988. Compendium Method TO-14: The
Determination of Volatile Organic Compounds (VOCs) in Ambient
Air Using SUMMAT Passivated Canister Sampling and Gas
Chromatoqraphic Analysis. Quality Assurance Division.
Research Triangle Park, NC 27711.
• NIOSH. February 1984. NIOSH Manual of Analytical Methods.
NTIS PB 85-179018. National Institute for Occupational Safety
and Health. Cincinnati, OH 45226.
3-54
-------
I
I
I* 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
I
I
Analytical Methods. EPA-600/4-83-040. NTIS PB 84-126929.
Office of Solid Waste. Washington, DC 20460.
I • U.S. EPA. 1986. Test Methods for Evaluating Solid Waste. 3rd
Edition. EPA SW-846. GPO No. 955-001-00000-1. Office of
I Solid Waste. Washington, DC 20460.
• • ASTM. 1982. Toxic Materials in the Atmosphere. ASTM, STP
" 786. Philadelphia, PA 19103.
• • ASTM. 1980. Sampling and Analysis of Toxic Oraanics in the
Atmosphere. ASTM, STP 721. Philadelphia, PA 19103.
t ASTM. 1974. Instrumentation for Monitoring Air Quality.
• ASTM, SP 555. Philadelphia, PA 19103.
• • APHA. 1977. Methods of Air Sampling and Analysis. American
™ Public Health Association. Washington, DC 20005.
ACGIH. 1983. Air Sampling Instruments for Evaluation of
Atmospheric Contaminants. American Conference of Governmental
Industrial Hygienists. Cincinnati, OH 45211.
I
I
I
3-55
-------
Recommended air monitoring methods are given in Table 21. These
recommendations are based on typical Superfund site conditions and are a
function of APA sophistication level and Superfund activity. Therefore,
alternative methods should be carefully considered and selected on a case-by-
case basis. A summary of screening methods and their applicability to various
compound classes is presented in Table 22. A listing of refined air
monitoring methods is included in Table 23. Additional summaries of these
refined methods and associated equipment are presented in Tables 24 through
30. A brief overview of emerging technologies (e.g., mobile mass spectrometry
and laser/infrared spectrometry) is presented in Table 31. Until these
technologies are further developed, however, it is recommended that standard
air monitoring methods be selected for Superfund APA applications.
A bibliography of air monitoring methods for sampling and analysis
is presented in Appendix A. A list of commercially available equipment for
screening and refined screening monitoring is presented in Tables 32 and 33.
Refined monitoring systems generally require the purchase of many individual
components. Therefore, a convenient summary of the numerous vendor
alternatives is 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 is presented in Figure 15.
Required Documentation: Quality Assurance Project Plan
The EPA requires any project involving environmental measurement,
such as the air monitoring for toxic substances of Superfund sites, to prepare
a Quality Assurance Project Plan (QAPP). The QAPP, which is distinct from 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 DQOs. A detailed description of the QAPP is given in the
following document:
3-56
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
TABLE 21. SUMMARY OF AIR MONITORING METHOD RECOMMENDATIONS
Activity Monitoring Recommendations
Objectives
RI/FS
• Screening
- THC analyzers
- Colorimetric gas
detection tubes
• Refined Screening
- Portable field GC
Analyzer
• Refined
- whole air samplers
with GC/MS analysis
for indicator
compounds and for an
expended list
(samples split) of
compounds (TO-14).
- whole air samplers
for volatile
organics (TO-14).
- impingers if
necessary (TO-5,
TO-6, TO-8).
- PUF sampling as
necessary (TO-9).
- Hi-Vol (PM-10) for
particulate 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 on-site and
off-site air toxic
concentration for defining a
more refined monitoring.
• Support refined monitoring
and provide near realOtime
data for site monitoring.
t Determine refined levels of
air toxic concentrations on-
site and at the site
perimeter.
i Utilize these data to define
air monitoring plan for the
next Superfund step (if
necessary).
• Assist in air quality data
interpretation.
• Determine refined levels of
toxic air contaminants on-
site, at the site perimter,
and off-site.
• 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.
(Continued)
3-57
-------
TABLE 21. (Continued)
Activity Monitoring Recommendations
Objectives
Remedial
Design
Remedial
Action
• Refined
- Whole air samplers
for volatile organic
(TO-14).
- impingers if
necessary (TO-5,
TO-6, TO-8).
- PUF sampling as
necessary for semi-
volatile organics
(TO-9).
- Hi-Vols (PM-10) for
particulate matter
as necessary (40 CFR
50, Part J).
• Refined Screening
- Portable field GC
analyzer.
t Refined
- Whole air samplers
for volatile organic
(TO-14).
- impingers if
necessary (TO-5,
TO-6, TO-8).
- PUF sampling as
necessary for semi-
volatile organics
(TO-9).
- Hi-Vols (PM-10) for
particulate matter
as necessary (40 CFR
50, Part J).
• Determine the effects of
pilot treatability study and
ambient air quality and make
use of the data in the
design of the Implementation
of remedial action step.
• Support refined monitoring
and provide near-realtime
data for site monitoring.
• Provide data in support of
protecting public health and
the environment as well as
on-site workers under
routine and non-routine
releases.
(Continued)
3-58
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
TABLE 21. (Continued)
Activity Monitoring Recommendations
Objectives
Remedial
Action
(Continued)
Operation
and
Maintenance
• Refined screening
- portable field GC
analyzer.
• Screening
- Electrochemical
alarm cells.
• Refined
- whole air samplers
for volatile
organics (TO-14).
- impingers as
necessary (TO-5,
TO-6, TO-8).
- PUF samplers as
necessary for semi-
volatile organics
(TO-9).
- Hi-Vol (PM-10) for
particulate matter
as necessary (40 CFR
50, Part J).
• Provide near-realtime data
1n support of protecting
public health and the
environment as well as on-
site workers under routine
and non-routine releases.
t Provide near-realtime data
in support of protecting on-
site workers and sufficient
information for protecting
public health and the
environment in case of non-
routine release.
t Assess the long-term effect
of the remedial action on
public health and
environment.
3-59
-------
TABLE 22. SUMMARY OF SCREENING TECHNIQUES FOR DETECTION OF ORGANIC
AND INORGANIC COMPOUNDS IN AMBIENT AIR
OJ
I
Compound Class (Ref. Table 9)
A. Volatile Orqanlcs
1. Allphatics
2. Aromatics
3. Halogenated Species
4. Oxygenated species
5. Sulfur-containing species
6. Nitrogen-containing species
B. Volatile Inorganics
1. Acid gases
2. Sulfur-Containing species
C. Semi-Volatile Orqanics
1. Phenols
2. Esters
3. Chlorinated benzenes
4. Amines
5. Pesticides Ethers
6. Alkadienes
7. Miscellaneous alphatics
and aromatics
8. Polynuclear aromatic
hydrocarbons
9. Pesticides
lO.Polychlorinated byphenyls
(PCBs)
Aoolicable Methods (Reference Table 3)
Total Hydrocarbon
Analyzers Colorimetric Methods Electrochemical Portable GC Analyzers Portable
Detectors and Pumps &
Gas Continuous Alarms Filters
. Detection Flow Tape PID &
Fid1 Infrared Tubes Colorimeter Monitor GC/FID GC/PID GC/ECD GC/FPD
x x
x x x£ x xx1*
x x xx4
XXX X
XX XX
XXX XX
x x xHCH x5
xxx
XX XX
XX XX
x x' xx
XX XXX
XX XX
X XX
x x
xx xx
x xx
x x
(Continued)
-------
TABLE 22. (Continued)
Applicable Methods (Reference Table 3)
Total Hydrocarbon
Analyzers
Colorimetric Methods
Gas Continuous
. Detection Flow Tape
Compound Class (Ref. Table 9) Fid Infrared Tubes Colorimeter Monitor
Electrochemical
Detectors and
Alarms
Portable 6C Analyzers
PID &
GC/FID GC/PID GC/ECD GC/FPD
Portable
Pumps &
Filters
0. Non-Volatiles
1. Inorganics metals
and nonmetals
Abbreviations: FID = Flame ionization detector
PID = Photoionization detector
FPD = Flame photometric detector
GC = Gas chromatograph
ECD= Electron capture detector
OJ
en
FID alone will not distinguish between categories of compounds. An "x" in this column means that the category is measured along with all
other categories.
p
Colorimetric gas detection tubes may not be applicable to every compound in a given category. COnsult manufacturer's information for
specific applicability.
Where more than one GC or total hydrocarbon detector method is listed, "xx" indicates a preferred method.
As an option for halogenated species, the ECD may be used in conjunction with a Hall detector or PID for more accurate identification of
compounds.
Pump/filter methods are applicable to parttculate species in the indicated categories.
Mercaptans may be detected using FID or infrared methods.
For chlorobenzenes, if a PID is used, it should be used In conjunction with an ECD.
-------
TABLE 23. A SUMMARY OF REFINED SAMPLING AND ANALYSIS TECHNIQUES FOR
ORGANICS AND INORGANICS IN AIR
Technique
Method No.
Type of Compounds
I. Organic Compounds:
Traps
• Sorption onto Tenax GC
packed cartridges using low
volume pump and GC/MS
analysis.
• Sorption onto carbon
molecular sieve packed
cartridge using low volume
pump and GC/MS analyses
• Cryogenic trapping of
analytes in the field and
GC/FID or ECD analyses.
• Sorption onto polyurethane
(PUF) using low volume or
high volume pump and GC/ECD
analysis.
• Sorption onto Thermosorb/N
packed cartridges using low
volume pump GC/MS analysis.
• Sorption onto PUF using low
volume or high volume pump
and high resolution Gas
Chromatography/High
Resolution Mass Spectrometry
(HRGC/HRMS).
TO-1
TO-2
TO-3
TO-4
TO-7
TO-9
• Volatile, nonpolar organic
(e.g., aromatic hydro-
carbons, chlorinated hydro-
carbons) having boiling
points in the range of 80°
to 200eC, in gas or vapor
phase.
• Highly volatile, nonpolar
organics (e.g., vinyl
chloride, vinylidene
chloride, benzene, toluene)
having boiling points in the
range of -15* to +120*C, in
gas or vapor phase.
• Volatile, nonpolar organics
having boiling points in the
range of -10° to +200°C, in
gas or vapor phase.
t Organochlorine pesticides
and PCBs, in particulate
phase.
• N-Nitrosodimethylamine in
gas phase.
t Dioxin
(Continued)
3-62
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
TABLE 23. (Continued)
Technique
Method No.
Type of Compounds
Whole Air Samplers
• Whole air samples are TO-14
collected in a SUMMA®
passivated stainless steel
canister and high resolution
GC coupled with mass
specified spectrometer (GC
MS-SIM or GC-MS-Scan).
• Whole air samples extracted TO-12
directly from ambient air
and analyzed using cryogenic
preconcentration and direct
flame ionization detector
(PDFID), or air samples are
collected in a canister and
analyzed by PDFID.
• Whole air samples are Modified
collected in Tedlar® bags TO-3 or
and subject to GC/FID or BCD TO-14
analysis or high resolution
GC compiled with MS-SIM or
MS-SCAN.
• Liquid Impingers
t Dinitrophenylhydrazine TO-5
Liquid Impinger sampling
using a low volume pump and
High Performance Liquid
Chromatography/UV analysis.
• Aniline liquid impinger TO-6
sampling using a low volume
pump and HPLC analysis.
• Sodium Hydroxide Liquid TO-8
impinger sampling using a
low volume pump and HPLC
analysis.
• 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
• Cresol/phenol
(Continued)
3-63
-------
TABLE 23. (Continued)
Technique
Method No.
Type of Compounds
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
t PM-10 high-volume sampler
40 CFR Part
50.7
Appendix B.
40 CFR part
50. Appendix
J (for
sampling
Methodology
only).
40 CFR Part
50.11
40 CFR Part
50.
Appendix J
• Metals in particulate phase.
• Inhalable metals in
particulate phase (up to 10
microns in diameter).
Total suspended particulate
(TSP)
• Inhalable particulate up to
10 microns in diameter.
3-64
-------
TABLE 24. SUMMARY OF SAMPLING AND ANALYTICAL METHODS FOR REFINED MONITORING FOR ORGANIC
AND INORGANIC COMPOUNDS IN AMBIENT AIR VOLATILE AROMATICS1
Sampling and Analysis Approach
Method
Designation
Detection
Limit Accuracy Precision3
Advantages
Disadvantages
CRYOGENIC PRECONCENTRATION/GC/FID/EC -
Vapor phase organics are condensed in a
cryogenic trap. Carrier gas transfers
the condensed sample to a GC column.
Adosrbed compounds are eluted from the GC
column and measured by FID or EC
detectors.
TO-3 0.1 ppbv 90-110% ±15% • Collects wide variety
(100 ml of volatile organic
sample) compounds.
• Standard procedures
are available.
• Contaminants common to
adsorbent materials
are avoided.
• Low blanks
Moisture levels In air
can cause freezing
problems.
Difficult to use in
field.
Expensive.
CO
i
en
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
GC/MS techniques.
TO-2 1-200 70-95% ±10-40% • Trace levels of
pptv (biased volatile organic
(20 ml low) compounds are
sample) collected and
concentrated on
sorbent material.
• Atmospheric moisture
not collected.
Some trace levels of
organic species are
difficult to recover
from the sorbent.
TENAX GC ADSORPTION AND GC/KS 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.
TO-1
.01-1
ppbv
(20 ml
sample)
80-100%
±20%
Good volume of air can
be sampled.
Water vapor Is not
collected.
Wide variety of
compounds collected.
Standard procedures
available.
Highly volatile
compounds and certain
polar compounds are not
collected.
Rigorous clean-up
required.
No possibility of
multiple analysis.
Low breakthrough
volumes for some
compounds.
(Continued)
-------
TABLE 24. (Continued)
Method
Sampling and Analysis Approach Designation
SUHHA* PASSIVATED CANISTER AND 6C/FID/ECD TO-14
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
revolatllized, separated on a GC column,
and passed to one or more detectors for
Identification and quantitation.
Detection
Limit
0.5-4
ppb
Accuracy2 Precision3 Advantages
90-100X ±10% • Best method for broad
spec iat Ion of unknown
trace volatile
organ Ics.
• Simple sampling
approach.
Disadvantages
• Sample components may
be adsorbed or
decompose through
interaction with
container walls.
• Condensation may be a
problem at high
concentrations (ppm).
Copmlex equipment
preparation required.
CO
i
cr>
1 See Table 3-6 for listing of analytes.
2 Accuracy - The agreement of an analytical measurement with a true or accepted value. Values int his table are expressed as Percent Recovery
(%R = Measured Value/True Value x 100).
3 Precision - The reproduclbllity of repeated measurement of the same property usually made under prescribed conditions. Values In this table are
expressed as Relative Percent Difference (RPD = Range/Mean x 100).
-------
TABLE 25. SUMMARY OF SAMPLING AND ANALYTICAL METHODS FOR REFINED MONITORING FOR ORGANIC
AND INORGANIC COMPOUNDS IN AMBIENT AIR VOLATILE HALOGENATED HYDROCARBONS1
CO
I
CT>
Method
Sampling and Analysis Approach Designation
TENAX GC ADSORPTION AND GC/NS OR GC/ECD - TO-1
Ambient air is drawn through a cartridge
containing Tenax where certain volatile
organic compounds are adsorbed.
Compounds are transferred by programmed
thermal desorption into a GC and detected
by MS or ECD.
Detection
Limit Accuracy Precision Advantages
.01-1 80-100% ±20% • Moisture is not
ppb collected
• Large sample volume
can be concentrated.
• Documented standard
procedures available
with extensive QA/QC
database
• Practical for field
use
• Low detection limits
Disadvantages
• Contamination problems
possible.
• Artifact formation
problems.
• Rigorous clean-up
requ 1 red .
• No possibility of
multiple analyses
CARBON MOLECULAR SIEVE ADSORPTION AND TO-2 1-200 70-95% ±10-40%
GC/MS OR GC/ECD - Ambient air is drawn pptv
through a cartridge containing carbon (20 ml
molecular sieve where highly volatile sample)
compounds are adsorbed. Compounds are
thermally desorbed to a GC where they are
quantitatively measured using MS or EC
detectors.
CRYOGENIC TRAPPING AND GC/ECD - Vapor TO-3 0.1 ppbv 90-110% ±10%
phase organics are condensed in a (100 ml
cryogenic trap. Carrier gas transfers sample)
the condensed sample to a GC column.
Adsorbed compounds are eluted from the GC
column and determined by MS or EC
detectors.
Efficient collection
of polar compounds.
Wide range of
application
Highly volatile
compounds are adsorbed
Easy to use In field.
Large database
Excellent long-term
storage
Wide applicability
Allows multiple
analyses
Best method for broad
special ion of unknown
VOCs
Easy sample collection
Consistent recoveries
Low breakthrough
volumes for some
compounds.
Water collected and can
de-activate adsorption
sites.
Thermal desorption of
compounds may be
difficult.
• Moisture condensation
• Integrated sampling is
difficult
1 See Table 3-6 for listing of analytes.
y
Accuracy - The agreement of an analytical measurement with a true or accepted value. Values in this table are expressed as Percent Recovery
(%R * Measured Value/True Value x 100).
Precision - The reproducibillty of repeated measurement of the same property usually made under prescribed conditions. Values In this table are
expressed as Relative Percent Difference (RPO = Range/Mean x 100).
-------
OO
TABLE 26. SUMMARY OF SAMPLING AND ANALYTICAL METHODS FOR REFINED MONITORING FOR ORGANIC
AND INORGANIC COMPOUNDS IN AMBIENT AIR VOLATILE OXYGENATES1
Sampling and Analysis Approach
SUHMA PASSIVATED CANISTER AND GC/FID/EC
OR GC/PID/EC 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 revolatized, separated on a GC column
and passed to one or more detectors for
identification and quantification.
Method
Designation
TO- 14
TO-3
Detection
Limit
0.5-20
ppb
0.5-20
ppb
? o
Accuracy Precision Advantages
90-110% ±10% • Low cost
• High sensitivity
90-110% ±20% • Positive compound ID
Disadvantages
• Calibration time
consuming
• Compound Identification
is not absolute
• Low sensitivity
• Expensive
Air sample Is drawn through TO-5
dinitrophenylhydrazine impinger solution
using a low volume pump. The solution is
analyzed using HPLC with a UV detector.
Air stream is drawn through a Tenax TO-1
cartridge and adsorbed to it. Desorption
from Tenax is by thermal desorption to
GC/MS or GC/FID.
1-5 ppbv 80-120%
1-5 ppbv 75-125%
±10% • Specific for aldehydes
and ketones
• Good stability for
derivative compounds
formed
• Low detection limits
±15-20% • Collect and
concentrate large
volume sample with
trace concentration.
• Moisture Is not a
problem.
• Broad use-reference
methods
* Low detection limit
• Easy to use in field
Sensitivity limited by
reagent priority.
Potential for
evaporation of liquid
over long term.
Blank contaminants may
be a problem
Single analysis per
sample
Artifact formations
with time
(Continued)
-------
TABLE 26. (Continued)
Sampling and Analysis Approach
Method
Designation
Detection
Limit
Accuracy
Precision3
Advantages
Disadvantages
Collection of whole air samples in SUMMA*
passivated stainless steel canisters.
VOCs are separated by GC methods and
measured by MS or multi-detector
techniques
TO-14
1 ppbv
Must calibrate
separate detectors
Compound ident-
ification not
positive. Lengthy
data interpretation.
Does not differentiate
targeted compounds
from interfering
compounds.
• Equipment expensive
• Operator skill level
important.
oo
i
10
1
See Table 3-6 for listing of analytes.
Accuracy - The agreement of an analytical measurement with a true or accepted value. Values int his table are expressed as Percent Recovery
(%R = Measured Value/True Value x 100).
Precision - The reproduclbllity of repeated measurement of the same property usually made under prescribed conditions. Values In this table are
expressed as Relative Percent Difference (RPD = Range/Mean x 100).
-------
CO
i
—i
o
TABLE 27. SUMMARY OF SAMPLING AND ANALYTICAL METHODS FOR REFINED MONITORING FOR ORGANIC
AND INORGANIC COMPOUNDS IN AMBIENT AIR SEMI-VOLATILE PHENOLICS1
Sampling and Analysis Approach
SODIUM HYDROXIDE LIQUID IMPINGER AND
HPLC/UV - Ambient air is drawn through
Method
Designation
TO-8
Detection
Limit
1 ppb
p
Accuracy
75-125%
Precision3
±20%
Advantages
• 4.6-din1tro-2-
methylphenol (50/1600)
Disadvantages
• Subject to
Interferences
two midget impingers. Phenols are
trapped as phenolates in NaOH solution
and analyzed by HPLC.
ADSORPTION OF TENAX AND 6C/FID OR GC/MS -
Ambient air is drawn through organic
polymer 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 - Sorption onto PUF.
TO-1
1-200
ppt
70-95%
±10-40%
TO-4
0.2-2
ng/nr
60-100%
±20%
specific to class of
compounds.
• Good stability.
• Detect non-volatile as
well as volatile
compounds.
• Good QA/QC database
• Wide range of
application
• Easy to use in field.
Wide range of
application
Easy to use - low
blanks
Excellent collection
and retention
efficiencies
• Limited sensitivity
• Desorption of some
compounds difficult
• Blank contamination
possible
* Artifact formation on
adsorbent
• High humldy reduces
collection efficiency
• Possibility of
contamination.
1 See Table 3-6 for listing of analytes.
p
Accuracy - The agreement of an analytical measurement with a true or accepted value. Values int his table are expressed as Percent Recovery
(%R = Measured Value/True Value x 100).
Precision - The reproduclbillty of repeated measurement of the same property usually made under prescribed conditions. Values in this table are
expressed as Relative Percent Difference (RPD = Range/Mean x 100).
-------
TABLE 28. SUMMARY OF SAMPLING AND ANALYTICAL METHODS FOR REFINED MONITORING FOR ORGANIC
AND INORGANIC COMPOUNDS IN AMBIENT AIR SEMI-VOLATILE BASE/NEUTRAL EXTRACTS1
Sampling and Analysis Approach
Method Detection
Designation Limit Accuracy Precision Advantages
Disadvantages
HIGH VOL GFF AND PUF FILTERS AND TO-4
6C/FID/ECD OR GC/MS - Participates
filtered in field and solvent extracted
In lab. Analyzed by GC/MS.
0.2-200 28-85% ±15%
ng/m
• Effective for broad
range of compounds
• Easy to preclean and
• Possible contamination
• Loss of volatile
organ Ics during storage
HIGH VOL. XAD-2 RESIN - Particulates TO-4 0.2-200
filtered from ambient air with low or hi (modifi- ng/m
vol filter. Filters solvent extracted cation)
and analses completed using GC/MS.
extract
• Low blanks
80-120% ±15% • Effective for broad
range of compounds.
• Easy to clean
• Broad database
• Good retention of
compounds
CO
1 See Table 3-6 for listing of analytes.
Accuracy - The agreement of an analytical measurement with a true or accepted value. Values int his table are expressed as Percent Recovery
(%R = Measured Value/True Value x 100).
Precision - The reproduclbllity of repeated measurement of the same property usually made under prescribed conditions. Values in this table are
expressed as Relative Percent Difference (RPD = Range/Mean x 100).
-------
TABLE 29. SUMMARY OF SAMPLING AND ANALYTICAL METHODS FOR REFINED MONITORING FOR ORGANIC
AND INORGANIC COMPOUNDS IN AMBIENT AIR SEMI-VOLATILE PESTICIDES/PCBs1
Sampling and Analysis Approach
HIGH VOL GLASS FIBER AND PUF FILTERS AND
GC/ECD -Particulates collected on
filters. Compounds solvent extracted and
analyzed using GC/ECD.
Method
Designation
TO-4
Detection
Limit
0.2-200
ng/mj
o
Accuracy
28 to
B5-100X
Precision Advantages
±15% • Broad range of
application
• Low blanks
Disadvantages
• Can lose volatile
compounds in storage
• Possibility of
contamination
HIGH VOL GLASS FIBER FILTER AND XAD-2
RESIN TO FILTER AND ADSORB PARTICULATES
TO-4
(modifi-
cation)
0.2-200
ng/mj
80-120%
±20%
Easy to use
Reusable
High sensitivity
Can analyze broad
range of compounds
(more efficient than
PUF).
to See Table 3-6 for listing of analytes.
ro ' Accuracy - The agreement of an analytical measurement with a true or accepted value. Values int his table are expressed as Percent Recovery
(%R = Measured Value/True Value x 100).
Precision - The reproduclbility of repeated measurement of the same property usually made under prescribed conditions. Values in this table are
expressed as Relative Percent Difference (RPO * Range/Mean x 100).
-------
tO
I
--4
to
TABLE 30. SUMMARY OF SAMPLING AND ANALYTICAL METHODS FOR REFINED MONITORING FOR ORGANIC
AND INORGANIC COMPOUNDS IN AMBIENT AIR VOLATILE IN-ORGANICS1
Method
Sampling and Analysis Approach Designation
HIGH VOL GFF AND AA/ICP - Particulates TO-4
are removed from air stream with a GFF or
PDF filter, dissolved and analyzed by
spectrometric methods.
VAPOR PHASE METALS (Sb, As. Pb. N1. Se.
Ag. Hg) INPINGER AND AA/6FA - Collection
of vapor phase metals on sorbents and in
impinger solutions.
VAPOR PHASE CN - HCEF and Sodium TO-8/
Hydroxide Liquid Impinger ISP/EP
A 335.1
or .3
Detection
Limit
1-5,
ng/nr
1-5
ng/m
1-5
ng/mj
2 Q
Accuracy Precision Advantages
±25% ±10% • Wide range of
applications
• Standard methods
• Low detection limits
• Standard methods
• High sensitivity
• QA/QC database
available
• Spediflc method for
each metal
• Standard methods for
each metal
Disadvantages
• Possible breakthrough
• High blanks
• Interferences
• Potential interferences
See Table 3-6 for listing of analytes.
y
Accuracy - The agreement of an analytical measurement with a true or accepted value. Values int his table are expressed as Percent Recovery
(%R = Measured Value/True Value x 100).
Precision - The reproduclblllty of repeated measurement of the same property usually made under prescribed conditions. Values In this table are
expressed as Relative Percent Difference (RPD = Range/Mean x 100).
-------
TABLE 31. SUMMARY OF SAMPLING AND ANALYTICAL METHODS FOR REFINED MONITORING FOR ORGANIC
AND INORGANIC COMPOUNDS IN AMBIENT AIR DEVELOPING TECHNOLOGIES1
Sampling and Analysis Approach
Method Detection
Designation Limit Accuracy Precision Advantages
Disadvantages
CO
i
MOBILE MASS SPECTROMETER (MS/MS.
MS/MS/MS) OR (6C/MS)
LONG PATH OPTICAL ABSORPTION - B1-static
open air transmission of broadband
radiation is used to obtain spectra of
trace gases in ambient air. Specialized
systems are available for both the
infrared and ultraviolet spectral
regions. Laser-based systems also are
available for more restricted
applications.
None
1 ppb
None
2 ppb
• Compound identi-
fication in complex
mixtures.
• Direct sampling
• Field operation
• Direct Field
measurements
• Minimum time
requ1rement
• No sampling required
• Llne-of-sight
coverage.
• Expensive
• Skilled operators
• Low sensitivity
1 See Table 3-6 for listing of analytes.
Accuracy - The agreement of an analytical measurement with a true or accepted value. Values int his table are expressed as Percent Recovery
(%fi = Measured Value/True Value x 100).
3 Precision - The reproducibillty of repeated measurement of the same property usually made under prescribed conditions. Values In this table are
expressed as Relative Percent Difference (RPD = Range/Mean x 100).
-------
TABLE 32. TYPICAL COMMERCIALLY AVAILABLE SCREENING MONITORING AND ANALYSIS EQUIPMENT
FOR ORGANICS AND INORGANICS IN AIR*
Technique
Approximate
Manufacturers Compounds Detected Detection Limit
Comments
co
i
1. THC Analyzers
FID (Total
Hydrocarbon
Analyzer)
Infrared
Analysis
2. Col orimetric
Gas Detection
Tubes and
Monitors
Gas Detection
Tubes
Continuous Flow
Colorimeter
Beckman MSA, Inc.
Thermo Electron,
Inc.
Foxboro/Wilkes
Draeger, Matheson,
Kitagawa
CEA Instruments,
Inc.
Most organics
Most organics
Varous organics
and inorganics
Acrylonitrile,
formaldehyde,
phosgene, and
various organics
0.5 ppmv
1-10 ppmv
0.1 to 1 ppmv
0.05 to 0.5 ppmv
Does not repond
uniformly to most
organic compounds
on carbon basis.
Some inorganic
gases (HJD, CO)
will be detected
and tehrefore are
potential inter-
ferences.
Highly subject to
interference,
sensitivity and
selectivity highly
dependent on
compound of
interest.
Sensitivity and
selectivity
similar to
detector tubes.
(Continued)
-------
TABLE 32. (Continued)
Technique
Manufacturers
Approximate
Compounds Detected Detection Limit
Comments
CO
I
en
Colorimetric
Tape Monitor
3. Electrochemical
alarm cells
4. Portable GC**
Analyzers
GC/FID
(portable)
KHDA Scientific
Foxboro, MSA, CEA
Instruments,
Sensidyne
Foxboro/Century,
Thermo Electron,
Inc.
Toluene, di-
isocyanate,
dinitro toluene,
phosgene, and
various inorganics
Wide range of
inorganics, also
combustion gases
Most organics
except that polar
compounds may not
elute from the
column.
0.05-0.5 ppmv
ppmv
0.5 ppbv
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.
(Continued)
-------
TABLE 32. (Continued)
Technique
Manufacturers
Approximate
Compounds Detected Detection Limit
Comments
CO
I
PID and GC/PID
(portable)
GC/ECD
(portable)
GC/FPD
(portable)
5. Portable pumps
and filters
HNU, Inc.
Photovac, Inc.
Thermo
Environmental
Instruments, Inc.
Thermo Electron,
Inc.
Thermo Electron,
Inc.
Gilian Instrument
Corporation, SKC,
Inc., Millipore,
Inc.
Most organic
compounds can be
detected with the
exception of
methane
Halogenated and
nitro-substituted
compounds.
Sulfur or
phosphorus-
containing
compounds
Inorganics
particulates and
semi-volatile
particulates
0.1 to 100 ppbv
0.1 to 100 ppbv
10-100 ppbv
100 ppbv-1 ppmv
Selectivity can be
adjusted by
selection of lamp
energy. Aromatics
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-volatiles.
* based on Riggins, 1983.
GC = Gas Chromatograph
PID = Photoionization Detector
FPD = Flame Photometric Detector
**Classified as a refined screening technique,
FID » Flame lonization Detector
ECD « Electron Capture Detector
-------
TABLE 33. SUMMARY OF REFINED SCREENING MONITORING EQUIPMENT FOR ORGANIC COMPOUNDS IN AMBIENT AIR
Sampling and
Analysis Approach
Manufacturer
Detection Limit
Precision
Mode of
Operation
Advantages and Disadvantages
oo
i
00
Scentoqraph PC operated
portable GC analyzer
utilizing Argon
ionizatIon/electron
capture detector (ECD)
with optional photo-
ionization detector.
preconcentrator and a
heated column with
temperature adjustable to
140'C. Up to 16 different
compounds can be
processed at any time.
Library is up to 100
compounds. On-going
calibration Is by
injecting standard
calibration gas.
Sentex Sensing
Technology
Low ppb range
when operated as
ambient air
monitor.
About 5-10% high
reproducibllity.
Realtime
Intermittent.
Automatic
sampling at 5-15
minute Intervals
depending on
operating
parameters.
Advantages:
• Near real time continuous
concentrations of air
toxic constituents.
• Good accuracy and low
detection limit for a
field technique.
• Eliminates in-accuracies
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.
(Continued)
-------
TABLE 33. (Continued)
Sampling and
Analysis Approach
Manufacturer
Detection Limit
Precision
Mode of
Operation
Advantages and Dlsadvantaaes
Photovac Model 10S70
portable GC analyzer
utilizing photo1onizatIon
detector (PIO) with a
range of 5 different
energy lamps to provide
selectivity for different
chemical groups,
isothermal oven control
for the multi capilarry
column. Up to 25
compounds can be
processed at any time.
Includes 4 libraries of
25 compounds each.
Calibration is by
injecting standard
calibration gas.
HNU Model 301DP or 311
portable GC analyzer.
The 301PD model can
utilize either a PID or
FID and the 311 model can
utilize a PID only.
Includes isothermal
temperature control of up
to 300'C for the 301PD
model and up to about
200'C for the 311 model.
Calibrate with either the
compounds of Interest or
with a reference
compound. Up to 20
compounds can be
processed at any time.
Photovac, Inc.
HNU Systems,
Inc.
0.1 to several
ppb for sub-
stituted
benzenes and
haloethylenes.
1 ppm for
saturated
haloalkanes.
About 5-10% high
reproducibility.
Realtime
intermittent.
Automatic
sampling is 5-15
minute Intervals
depending on
operating
parameters.
0.1 to several
ppb depending on
the number of
compounds
Involved and the
mix.
Not readily
available but
expected to be
in the same
range as above.
real time
continuous
Advantages:
• Similar to the ones
mentioned above with the
exception that It uses
only one detector.
Disadvantages:
• Similar to the ones
mentioned above with the
addition of:
—Isothermal oven control
Is up to 50*C. This GC
cannot operate at higher
temperatures. This
reduces the range of
volatile organics that can
be analyzed. Useful
mainly for high volatile
organics.
—Cannot use detectors
other than the PID.
Advantages:
• Similar to the ones above
for the 301PD model.
• Similar to the ones above
for the 311 model with the
exception that It uses
only one detector.
Disadvantages:
• Similar to ones listed for
the Scentograph GC.
With the addition of:
• No temperature
adjustments.
• No library for retention
times.
-------
MONITORING
CONSTITUENTS
TARGET LIST
METEOROLOGICAL
MONITORING
PROGRAM DESIGN
i
AIR MONITORING
NETWORK DESIGN
MONITORING
SOPHISTICATION
LEVEL
(STEP 2)
PREPARE AIR
MONITORING PLAN
Project description
Project organization
Facilities/equipment
Data quality objectives
Sample collection
Sample custody
Calibration
Sample analysis
Documentation
Data management
Internal QC checks
External QA audits
Preventative maintenance
Routine procedures
Corrective action
QA reports
PEER
REVIEW
RPM/EPM
APPROVAL
INPUT TO
STEP 4 - CONDUCT
MONITORING
Figure 15. Document Air Monitoring Plan.
3-80
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
• U.S. EPA, 1983. Interim Guidelines and Specifications for
Preparing of Quality Assurance Pro.iect Plans. QAMS-005/80
(EPA-600/4-83-004; NTIS PB83-170514)
Additional guidance Is available In the following:
• U.S. EPA. 1984. Guide to the Preparation of Quality Assurance
Pro.iect Plans. Office of Toxic Substances, Office of
Pesticides and Toxic Substances. Washington, DC 20460.
• U.S. EPA. 1977. Quality Assurance Handbook for Air 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
of Significant Deterioration (PSD). EPA-450/4-87-007.
Research Triangle Park, NC 27711.
• U.S. EPA. 1987. Onsite Meteorological Program Guidance for
Regulatory Modeling Applications. EPA-450/4-87-013. Research
Triangle Park, NC 27711.
Recommended EPA documents that provide detailed information on the calibration
process necessary for air monitoring QAPPs are:
• U.S. EPA, 1987. Quality Assurance Handbook for Air Pollution
Measurement Systems. Volumes I and II. EPA-60019-76-005.
Office of Research and Development. Research Triangle Park, NC
27711.
3-81
-------
• 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.
0 U.S. EPA, 1987. Onsite Meteorological Program Guidance for
Regulatory Modeling Applications. EPA-450/4-87-013. Office of
Air Quality Planning and Standards. Research Triangle Park, NC
27711.
Content of Quality Assurance Pro.iect Plan
The following is a breakdown and description of the contents of a
typical QAPP.
Pro.iect 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; and
t Intended use of the acquired data.
Pro.iect Organization and Responsibility. A list 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 is also recommended.
3-82
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
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 in sufficient quantities?
• Who maintains and calibrates the equipment required to make the
measurements?
• How frequently is the equipment calibrated and serviced?
• What standards are used to calibrate the equipment?
X
• Are special facilities needed to service or dispose of
supplies?
DQOs for Measurement Data. It is important to define the acceptance
limits for data generated for the project to ensure that it is complete and
representative of the site. An attempt should be made to discuss the
acceptance limits and control factors for sampling and analysis errors. This
includes means for determining if the data generated meet the requirements of
the monitoring objectives.
Sample Collection. EPA protocols for sample collection procedures
should be referenced and the procedures and equipment to be used in 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.
3-83
-------
Sample Custody. Procedures for field sampling operations as well as
laboratory operations are to be provided. It is 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 method used or through an ad hoc written description. The frequency
of calibration and the frequency with which continuing calibration is verified
also should be described. The standards for the calibration and the
acceptable sources should be documented. Calibration should address, when
applicable, instrument flow rate, electronic zero and span for analytical
instruments and meteorological equipment, calibration gas requirements, and
external 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 in 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.
Recordkeeoina/Documentation. 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.
Internal QC Checks. The internal QC methods for the air quality
monitoring project should be described. Items to be addressed include:
t Replicates;
• Spiked samples;
• Split samples;
t Control charts;
3-84
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
1
I
I
I
I
• Blanks;
t Internal standards;
• Zero and span gases;
• Quality control samples;
• Surrogate samples;
t Calibration standards and devices; and
t Reagent checks.
External QA 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 in 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 if the data
quality is not acceptable. The personnel responsible for reviewing the data
and for implementing correction action should also be identified.
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 in the final project report.
3-85
-------
Review and Approval of Quality Assurance Pro.iect 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 16 should be applied to Superfund air
monitoring programs.
3.5.2 Field Staff Qualifications and Training
The air monitoring program should be designed arid 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, it should be recognized that site health and safety
officers, as well as staff with similar backgrounds (e.g., industrial
hygienists), may not have experience in air toxics monitoring at the low
detection levels (parts per billion or micrograms per cubic meter) specified
in ARARs to protect offsite receptors. It is recommended, therefore, that
3-86
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
MONITORING
PLAN
(STEP 3)
MONITORING
STAFF
QUALIFICATIONS/
TRAINING
METHOD-SPECIFIC
QA/QC CRITERIA
(APPENDIX A)
SUPERFUND QA/
FIELD OPERATIONS
METHODS MANUAL
SAMPLING/ANALYSIS
INSTRUMENTATION
CALIBRATION
(Table 35)
QA/QC
IMPLEMENTATION
(Figure 17)
• QA Management
• Sampling QA
• Analytical QA
• Data Reduction QA
TECHNICAL
ASSISTANCE
DOCUMENT
(Appendix B)
OTHER
TECHNICAL
REFERENCES
QC SAMPLING/
ANALYSIS
FREQUENCIES
(Table 36)
INPUT TO
STEP 5 - SUMMARIZE
AND EVALUATE
RESULTS
Figure 16. Step 4 - Conduct Monitoring.
3-87
-------
Superfund air monitoring projects be designed and implemented by air quality
specialists with relevant ambient air toxics monitoring experience.
It is 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 the need for:
• In-depth understanding of the operating principles for 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.
t 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 in the future.
• 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 chain-of-custody.
• Maintenance of the program sampling and analysis schedule.
• Checks of regenerated equipment (traps, plugs, canisters, etc.)
that are returned by the laboratory.
3-i
-------
I
I
• • Consistent collection of QA/QC samples, including collocated
™ blanks.
•
—
I
g
I
|
• Communication with the site RPM/EPM to ensure that he is kept
apprised of any problem area and the means of mitigating it.
• Communication with the air toxics specialist assigned to the
8 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 designated contact at the off site laboratory to ensure that:
t The samples shipped are received on time.
t Analysis is performed on time.
• Any technical issues that develop are handled promptly to
• minimize loss of data.
Laboratory results are received in 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.
I 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 in
• 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
3-89
-------
monitoring program (see Table 34) include procedures to assess and control the
quality of the sampling, analytical, data reduction, and management
procedures.
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.
Generic air toxics monitoring QA/QC recommendations
t U.S. EPA. June 1983. Technical Assistance Document for
Sampling and Analysis of Toxic Organic Compounds in Ambient
Air. 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 in 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 in Ambient Air.
EPA/600/4-87-006. NTIS PB87-168696. Office of Research and
Development. Research Triangle Park, NC 27711.
3-90
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
TABLE 39. QUALITY ASSURANCE (QA) ACTIVITIES TO BE SPECIFIED IN PROGRAM PLAN
QA Management
QA System Design
Design 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
Chain-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.
3-91
-------
t U.S. EPA. June 1987. Compendium Method TO-12: Method for the
Determination of Non-Methane Organic Compounds fNMOCl in
Ambient Air Using Cryogenic Preconcentration and Direct Flame
Inonzation Detection (PDFIDK Research Triangle Park, NC
27711.
§ U.S. EPA. May 1988. Compendium Method TO-14: The
Determination of Volatile Organic Compounds (VOCs) in Ambient
Air Using SUMMA® Passivated Canister Sampling and Gas
Chromatoqraphic 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.
Meteorological monitoring QA/QC recommendations
• 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.
Air quality monitoring QA/QC recommendations
• 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. May 1987. Ambient Monitoring Guidelines for
Prevention of Significant Deterioration fPSDK
EPA-450/4-87/007. NTIS PB81-153231. Office of Air Quality
Planning and Standards. Research Triangle Park, NC 27711.
3-92
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
These references should be consulted to specify project-specific QA/QC
requirements based on the approach illustrated in Figure 17.
The technical QA recommendations presented in On-Site Meteorological
Program Guidance for Regulatory Modeling Applications (U.S. EPA, June 1987)
and Technical Assistance Document (TAD) for Sampling and Analysis of Toxic
Organic Compounds in Ambient Air (U.S. EPA, June 1983) should also be
implemented. The calibration requirements and QC sampling/analysis frequency
criteria presented in Tables 35 and 36, respectively, are examples of the QA
recommendations presented in the TAD.
The QA criteria presented in monitoring method-specific documents
(e.g., Technical Assistance Document for Sampling and Analysis of Toxic
Organic Compounds in Ambient Air. U.S. EPA, June 1983) should also be
implemented if these QA recommendations are more stringent than those
stipulated in 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 is
illustrated in Figure 18. This approach consists of the following major
elements:
• Validate data;
• Summarize data; and
• Model dispersion to extrapolate monitoring data.
3-93
-------
IMPLEMENT
SUPERFUND FIELD
OPERATIONS METHODS
MANUAL - QA
MANAGEMENT
APPROACH
IMPLEMENT TECHNICAL
ASSISTANCE DOCUMENT
(TAD) - TECHNICAL
QA RECOMMENDATIONS
FOR AIR TOXIC
MONITORING
(APPENDIX A)
IMPLEMENT METHOD-
SPECIFIC QA
CRITERIA IF MORE
STRINGENT THAN TAD
(APPENDIX B)
IMPLEMENT ON-SITE
METEOROLOGICAL
PROGRAM GUIDANCE
- TECHNICAL QA
RECOMMENDATIONS FOR
METEOROLOGICAL
MONITORING
IMPLEMENT SUPPLEMENTAL
TECHNICAL QA RECOMMENDATIONS
BASED ON OTHER AVAILABLE
REFERENCES AS WARRANTED
IF NOT ADDRESSED ABOVE
SITE-SPECIFIC
AIR MONITORING
QA/QC PROGRAM
Figure 17. Superfund Air Monitoring QA/QC Strategy.
3-94
-------
TABLE 35. CALIBRATION REQUIREMENTS FOR SAMPLING AND ANALYSIS INSTRUMENTATION
Parameter
Device Calibrated
Method of
Calibration
Approximate
Frequency
Garments
Sampling Instrumentation
Sampling pump and controller
CO
i
tn
Analytical Instruments
Continuous monitors (e.g., FID,
PID, FPD. etc.)
Chromatographic istruments
GC/MS
6C/MS
Flow rate
Sample volume measurement device Total volume
(usually a dry test meter)
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
Chromatographic
instruments
a) Introduction or
perfluoro-compound
directly into MS.
b) Injection of
tuning standard
(e.g., bromofluoro-
benzene) into GC.
Weekly
Weekly
Dally or more
frequently if
required.
Dally or more
frequently if
required.
Same as above
Same as for
other Chromato-
graphic
instruments
Daily
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 chromatorgaphlc
instruments.
Selection of tuning standards
will be dependent on type of
analysis being performed.
-------
TABLE 36. TYPICAL SAMPLING/ANALYSIS FREQUENCIES FOR QC SAMPLES
Type of Sample Typical Frequency
Field Blanks Each sample set; at least 10% of total
number of samples.
Laboratory Blanks Daily; at least 10% of total number of
samples. Each batch of samples.
Spiked Samples Each sample set; weekly.
Duplicate (parallel) Samples 10% of total number of samples; each
sample set.
Instrument Calibration Standards Daily.
Reference Samples Weekly.
Series (backup) samples3 Each Sample set.
a Duplicates of each sample that are archived.
3-96
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
INPUT DATA
FROM STEP 4
VALIDATE DATA
• Meteorological monitoring
• Air monitoring
SUMMARIZE DATA
• Data listings
• Statistical summaries
METEOROLOGICAL
SUMMARIES
AIR MONITORING
SUMMARIES
DISPERSION
MODELING TO
EXTRAPOLATE
DATA
D T C1? A C Cl?C CMt
MAFTraP
Figure 18. Step 5 - Summarize and Evaluate Results.
3-97
-------
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.
Dispersion modeling may be warranted for certain situations to
supplement air monitoring results. For example, it may be useful to
extrapolate site boundary monitoring results to offsite receptor locations of
interest.
Each of these topics is discussed in greater detail in the following
subsections.
3.6.2 Validate Data
Data validation is 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:
3-98
-------
I
I
I
I
I
I
I
I
I
I
I
I
I
t 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.
Table 37 presents meteorological data screening criteria. It is an example of
the technical data validation recommendations presented in the reference cited
above.
Air Monitoring Data Validation
Air 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:
3-99
-------
TABLE 37. SUGGESTED METEOROLOGICAL DATA SCREENING CRITERIA8
(U.S. EPA, JUNE 1987)
Meteorological Variable Screening Criteria8
Wind Speed Flag data if the value:
t Is less than zero or greater than 25 m/s;
• Does not vary by more than 0.1 m/s for 3
consecutive hours; and
t Does not vary by more than 0.5 m/s for 12
consecutive hours.
Wind Direction • Is less than zero or greater than 360 degrees;
• Does not vary by more than one degree for more than
three consecutive hours; and
• Does not vary by more than ten degrees for 18
consecutive hours.
Temperature t Is greater than the local record high;
• Is less than the local record low; (The above
limits could be applied on a monthly basis.)
• Is greater than a 5s change from the previous hour;
and
t Does not vary by more than 0.5°C for 12 consecutive
hours.
Temperature Difference • Is greater than O.TC/m during the daytime;
• Is less than -0.1'C/m during the nighttime; and
• Is greater than 5.0*C/m or less than -3.0'C/m.
Dew Point Temperature • Is greater than the ambient temperature for the
given time period.
• Is greater than a 5°C change for the previous hour
t Does not vary by more than 0.5*C for 12 consecutive
hours
• Equals the ambient temperature for 12 consecutive
hours.
(Continued)
3-100
-------
Meteorological Variable Screening Criteria"
Precipitation • Is greater than 25 mm in one hour.
t Is greater than 100 mm in 24-hours.
• Is less than 50 mm in three months.
I
I
• TABLE 37. (Continued)
I
I
_ (The above values can be adjusted base on local
• climate.)
Pressure • Is greater than 1,060 mb (sea level)
• • Is less than 940 mb (sea level)
I (The above values can be adjusted for elevations other
than sea level).
• Changes by more than 6 mb in three hours.
a Some criteria may have to be changed for a given location.
I
3-101
-------
t The percent difference between the air concentrations measured
at coal located samplers is:
d, - Yi " Xi x 100 (Eq. 2)
1 (Yi - X.)/2
where:
d1 - the percent difference between the concentration of air
toxic constituents Yi measured by the collocated
monitoring station and the concentration of air toxic
constituent Xi, measured by the monitoring station
reporting the air quality.
t The average percent difference dj for the monitoring period is:
n
2 d. (Eq. 3)
1-1
where:
d, = percent difference defined above, and
n = number of samples collected during the monitoring period.
The standard deviation Sj for the percent differences is:
1/2 (Eq. 4)
1
n-1
^w
[
n ,
2 d.^
i=l
1
n
n
(2
i=l
d,)2]"
The 95-percent probability limits for precision are:
Upper 95-Percent Probability Limit - d.,+1.96 SyVZ ~ (Eq. 4)
Lower 95-Percent Probability Limit - dj-1.96 S.//2 " (Eq. 5)
3-102
-------
I
I
I
• The accuracy is calculated for the monitoring period by
calculating the percent difference d1 between the indicated
parameter from the audit (concentration, flow rate, etc.) and
I the known parameter, as follows:
Id. - Yi ' Xi x 100 (Eq. 6)
Xi
where:
Y, « monitor's indicated parameter from the ith audit check,
I and
Xi = known parameter used for the ith audit check.
g These results should then be compared with the QA/QC criteria
stipulated in 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 at least the following:
t Listing of all meteorological parameters for the air sampling
periods;
• Daytime wind rose (only for coastal or complex terrain areas);
t Nighttime wind rose (only for coastal or complex terrain
areas);
t Summary wind rose;
3-103
-------
• 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 in Guidelines on Air Quality Models (Revised) (U.S.
EPA, July 1986);
f Tabular summaries of means and extremes for temperature and
other meteorological parameters; and
• 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 in which
multiple meteorological stations are used at a single site, it is desirable to
list 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 19.
Data recovery information should also be presented to allow for an
evaluation of data representativeness. The minimum data recovery target
should be 75 percent.
3-104
-------
I
I
April
720 083
Wind Direction Frequency (Percent)
////// Mean Wind Speed (Mi/Hr)
Figure 19. Example Wind Rose Format.
3-105
-------
Air Monitoring Data Summaries
Air monitoring data summaries should include at: least the following:
• 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 in which a constituent is not
detected, as well as upwind/downwind exposiure 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;
• 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
3-106
-------
I
I
Air 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 is 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 in 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 is 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 in data interpretation. Figure 20
illustrates 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 wind
direction variability, especially those on complex terrain and in coastal
locations. An application of this downwind frequency analysis approach is
illustrated in Figure 21. 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.
3-107
-------
'.VA
:•'£•:
MONITORING STATIONS
DOWNWIND SfCTOR
UNIT SOURCE
Figure 20. Example of Downwind Exposures at Air Monitoring Stations.
3-108
-------
I
I
24-HOUR
CONCENTRATION (ppb)
100-r-
50 --
KEY:
STATION A
STATION B
60
DOWNWIND FREQUENCY
100
Figure 21. Example Application of Downwind Frequency Analysis,
3-109
-------
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. Similarly, 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 in 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; and
• 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.
3-110
-------
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 it may not be practical to place air monitoring stations
at offsite 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 offsite
locations. An example of this application is illustrated in Figure 22.
Technical recommendations regarding the conduct of dispersion
modeling studies (e.g., model selection) are provided in Section 2.
3-111
-------
ATMOSPHERIC DILUTION PATTERN
• = NEAREST RECEPTORS
+ = MONITORING STATIONS
= DILUTION FACTOR ISOPLETHS
(RATIO OF DOWNWIND
CONC^TWN/FACIUTV PROPERTY 1OUNDARY CONCENTRATION,
Figure 22. Example Atmospheric Dispersion (Dilution) Pattern.
3-112
-------
SECTION 4
CASE EXAMPLES
4.1 OVERVIEW
Several case examples are presented in this section to demonstrate
the atmospheric dispersion modeling and air monitoring procedures given in
Sections 2 and 3. Example 1 illustrates a combined modeling and monitoring
study in support of an RI/FS at a hypothetical wood treatment facility. The
site is first described, then the five-step procedure for designing and
conducting a dispersion modeling study is shown, followed by the five-step
procedure for designing and conducting an air monitoring study.
Air monitoring programs are generally more dificult to design than
dispersion modeling studies, so three additional case examples are shown for
Superfund sites that present elements of complexity in the monitoring
situations representative of actual conditions at many sites. The discussion
for examples 2, 3, and 4 focuses on the design of an air monitoring network of
refined monitoring techniques; it is assumed that real-time monitoring is also
conducted at each site as part of the health and safety plan.
Example 2 is somewhat more complicated than the ideal monitoring
scenario with a wider wind arc, fugitive sources distributed over a wider area
and two other nearby emission sources, both downwind. Example 3 is
characterized by an even wider wind arc, two other nearby emission sources
both upwind of the Superfund site, two nearby receptors and restricted access
to some potential sampling sites. Example 4 has both complex meteorology and
complex terrain because of weak seasonal air patterns and the location of the
site in a river valley in a heavily industrialized region.
4-1
-------
4.2 EXAMPLE 1 - DISPERSION MODELING/AIR MONITORING APPLICATION
A screening assessment (based on emission/dispersion modeling)
commensurate with Volume I recommendations was conducted to characterize
hazardous air contaminants being released from an inactive wood treatment
facility that had been placed on the NPL. Evaluation of these screening
results indicated that it was necessary to conduct a combined dispersion
modeling/air monitoring program to more accurately quantify air emissions from
the site to support preparation of an RI/FS. The site is described in Section
4.2.1. The air dispersion modeling study is presented in Section 4.2.2 and
the air monitoring study is presented in Section 4.2.3.
4.2.1 Site Description
The site is an inactive 12-acre wood treatment facility located in 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 in a surface
impoundment. Past waste disposal practices included treatment and disposal of
the metal salts in a surface impoundment and disposal of contaminated wood
shavings in waste piles. The constituents of concern in the facility's waste
stream include phenols, cresols, and polycyclic aromatic hydrocarbons (PAHs)
in the creosote; dibenzodioxins and dibenzofurans as contaminants in
pentachlorophenol; and particulate heavy metals. The potential emission
sources (Figure 23) 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 in documented ground-
water and surface water contamination.
4-2
-------
INACTIVE SURFACE
IMPOUNDMENT ANO
CONTAMINATED
WOOD SHAVINGS
STORAGE AREA
SURFACE
IMPOUNDMENT
OFFICE
TREATMENT
ANO PRODUCT
STORAGE AREAS
I
CONTAINER
STORAGE
FACILITY
GATE
PREVAILING
WIND
DIRECTION
Figure 23. Example 1 Site Plan for Air Dispersion Modeling,
4-3
-------
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.
The first step in developing the modeling/monitoring program was to
examine the composition of wastes handled in each waste management unit were
determined to identify which contaminants were likely to be present in 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 ethyl benzene. 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 contaminants
previously identified. Additional contaminants detected included toluene and
xylenes in surface impoundment wastes, and arsenic, copper, chromium, and zinc
in the treatment/disposal area.
4.2.2 Example 1 - Dispersion Modeling Study
The dispersion modeling study is presented below. The discussion
follows the format given in Section 2 for conducting a modeling study.
Collect and Review Information
The results of the information review are summarized in the site
description in Section 4.2.1.
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 in development in the vicinity of the site and the
associated increase in the number of potential receptors that could be exposed
4-4
-------
to air toxics releases from the site required the use of refined dispersion
modeling in support of the RI/FS activities.
It was determined that the ISC dispersion model is the preferred
model for this applications because:
• The sources involved resemble the types of industrial sources
for which the model was developed;
• The topography is gently rolling and no major topographical
obstruction exist; and
• The ISC dispersion model was employed successfully for a
Superfund site similar to the one under consideration.
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 compounds
were selected for use in the dispersion modeling (and air monitoring):
t Volatile/semivolatile constituents
Toluene
Benzene
Total phenols
Pentachlorophenol
Polycyclic aromatic hydrocarbons
Cresols
t Particulate constituents
Arsenic
Copper
Chromium
- Zinc
4-5
-------
The target compound list was then evaluated in terms of prevalence
of contaminants In each of the four sources and the Information available
about the activities involved with each source (see Table 38).
Emission predictive equations were identified using Volume II,
Estimation of Baseline Air Emissions at Superfund Sites, for the sources
involved. This included:
t Predictive lagoon equations for the inactive surface
impoundment and the aerated surface impoundment for organics,
and predictive fugitive dust equations for inorganics; and
• Predictive closed landfill equations for the treatment and
product storage areas and the container storage facility, and
predictive fugitive dust equations for inorganics.
Onsite 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
onsite data for the same time period. Wind direction data for
offsite areas show the same pattern as those for onsite areas,
i.e. an apparent small shift of about 10 to 15 degrees. The
frequency distribution of wind speed and direction by stability
is within about 20-30 percent.
t 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.
4-6
-------
TABLE 38. TARGET CONSTITUENTS MODELED FOR EACH OF THE SOURCES AT THE SITE
Source
Target Compounds
In-active
Surface
Impoundment
Aerated
Surface
Impoundment
Treatment
and Product
Storage Areas
Container
Storage
Facility
Organics - gases
Toluene XXX
Benzene 'X X X
Total Phenols XXX
Pentaochlorophenol X X X X
PAHs XXX
Cresols XX XX
Inorganics-Particulate
Arsenic X XX
Copper X X
Chromium X X
Zinc X X
4-7
-------
Considering prevailing wind directions, source characteristics
(ground level releases), population distribution in the site vicinity, and
other sensitive receptor locations, it was decided to set up a grid with
closely spaced receptors adjacent to the site. For modeling purposes,
concentrations were averaged every 24 hours and annually.
Background concentrations for the target (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
onsite data.
Conduct Modeling
The emission inventory for the target compounds was developed based
on the methodology outlined in 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 grid developed were input into the
model.
All input data were 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 target
compounds, and computer printout were obtained. Individual runs were made for
the various target compounds.
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
4-8
-------
each target compound 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 target
compounds in a format similar to the one shown in Figure 6.
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 in a rectangular grid (see Figure 24)
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
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, it was determined that most of the development
took place up to about 2 kilometers from 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);
4-9
-------
• fl
prevailing
wind
direction
• •
site
area
Figure 24. Receptor Grid Close the Site.
4-10
-------
t Print highest second highest tables - yes (-1); maximum 50
tables - yes (=1);
t Rural-urban option - rural (=1);
• Wind profile exponent values - default (-1);
• Vertical potential temperature gradient values - default (=1);
and
• Program calculates final plume rise only - no (=2).
4.2.3 Example 1 - Air Monitoring Study
Collect and Review Information
The results of the information review are summarized in the site
description in Section 4.2.1.
Select Monitoring Sophistication Level
A limited onsite air screening survey was first conducted to
document air releases of potentially hazardous contaminants, 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, compound-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.
4-11
-------
Develop Monitoring Plan
The target analytes for the air monitoring were selected on the same
basis as the target compounds for the dispersion modeling. The lists are
identical since no logistical considerations precluded collecting and
analyzing each of the compounds. They were:
• Volatile/semi volatile constituents
Toluene
Benzene
Total phenols
Pentachlorophenol
Polycyclic aromatic hydrocarbons
Cresols
t Particulate constituents
Arsenic
Copper
Chromium
Zinc
Meteorological information is 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 onsite meteorological survey data were used with the EPA's,
Industrial Source Complex (ISC) dispersion model to estimate the worst-case
4-12
-------
air emission concentrations and to help determine the locations of the air
sampling stations. The ISC dispersion model was used because of its
capability to simulate conditions of point and nonpoint source air emissions.
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 estimating the contamination from each source.
Figure 25 shows the locations of the selected sampling stations.
Station 1 was selected as the upwind background station. Background volatile
organic concentrations, particulate 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
volatiles and particulates 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 in 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 silica gel cartridges, was
selected for the collection and analysis of cresol samples. Particulates were
collected on glass fiber filters using high-volume samplers.
4-13
-------
©
INACTIVE SURFACE
IMPOUNDMENT ANO
CONTAMINATED
WOOD SHAVINGS
STORAGE AREA
SURFACE
IMPOUNDMENT
OFFICEQ
TRCATM6NT {
ANO PWOOUCT
STORAGS AAEA3
I
CONTAINER
STORAGE
FACILITY
PREVAILING
WIND
DIRECTION
GATE
Monitoring Location
Figure 25. Example Site Plan and Air Monitoring Network.
4-14
-------
Conduct Monitoring
The air quality monitoring was conducted over a 3-month period
during the summer. Meteorological variables were measured continuously
throughout the study. Air 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 in 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 compounds. However, analytical detection limits were below
specific health and environmental criteria for all compounds 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 in
these analyses were subjected to emission rate modeling to determine the
emission potential of cresol and thus to develop an estimate of cresol levels
in the air.
Analytical results obtained during this sampling program established
that fugitive air emissions significantly exceeded reference health criteria.
Measures to reduce emission concentrations to a point below health criteria
levels were identified.
4-15
-------
4.3 ' EXAMPLE 2 - AIR MONITORING APPLICATION
This example scenario presents a monitoring situation with minimum
levels of complication. The presentation primarily deals with one step of the
five-step process given in Section 3 - the design of the air monitoring
network. The key parameters for example 2 are listed in Table 39. The site
is assumed to be in the remediation phase, with emissions arising from
excavation of contaminated soils and nearby on-site stabilization. Two views
of the Superfund site are given in Figure 26.
With strong seasonal winds and a small wind arc, only one 100%
upwind location (#1) is necessary. Seven downwind locations (#2-#8) are in an
array between the Superfund site and the adjacent wastewater treatment
facility and the interstate freeway. These downwind sites are located at
three radial distances from the site: 1000, 2000, and 3000 feet from the
center of the remediation area. Note that the site fenceline in the downwind
direction is only 1200-1300 feet from the center of the processing area.
Thus, some of the downwind sites will have to be placed off the property.
The downwind monitoring locations are symmetrically arranged around
the predominant wind direction axis, and are horizontally distributed (over an
angle of approximate WIND ARC + 50%) to sample both the center and the edges
of the emission plume from the site, i.e., to help define the horizontal
extent of the plume.
Seven downwind monitoring locations were selected for this scenario
to achieve the following objectives:
• Provide measurements of air concentration of target compounds
as a function of distance from the remediation area, i.e., at
three distances: approximately 1000, 2000, and 3000 feet;
4-16
-------
TABLE 39. KEY PARAMETERS FOR EXAMPLE 2 - AIR MONITORING
1. Project Objective:
• Measure Impact on ambient air of emissions due to remediation
2. Meteorological Conditions:
Strong seasonal winds from the west, 5-15 mph
Small wind arc, 40-50*
Moderate temperatures, 60-80°F
Moderate relative humidity, 40-80% RH
Good historical meteorological records
3. Topography:
• Site located in low, sandy rolling hills
• Excavated flat terraces for emission sources
t Approximately 100 feet elevation difference between waste
processing area and lowest downhill monitoring location
4. Emission Sources Within Site:
t Major emissions from the site are fugitive sources localized in
the processing area
t Elevated point sources exist in the processing area but are not
major sources of target compounds
5. Regional Ambient Air Quality:
• Regional ambient air quality is good
6. Other Emission Sources:
• No industrial development or heavy vehicular traffic in the
area immediately upwind of site
• Other nearby emission sources are all downwind of the site: a
petroleum refinery, a wastewater treatment facility, an
interstate freeway
(Continued)
4-17
-------
TABLE 39. (Continued)
7. Power, Access, and Security at Monitor Sites:
a 115 VAC power available for meteorological station site only
• Site fenceline in the downwind direction is only 1200-1300 feet
from center of the processing area
0 Some monitoring sites will be located outside site property,
but no problems with access or security are expected
8. Receptor Locations:
0 Downwind fenceline is close enough to processing area that some
downwind monitoring sites must be located off the property
0 No problems with access to potential sampling sites for almost
360° around site
4-18
-------
Predominate
Wind Direction
Emission
Plume
Cross Section View
North I
Cross section
viewed above
Road
Figure 26. Two Views of Example 2 Site
4-19
-------
t Provide measurement of air concentrations as a function of %
Time Downwind, i.e., with normal variation in the wind
direction, sites 2, 4, 5, 7 might not be downwind of the site
for 100% of the sampling time, although sites 3, 6, and 8
should be;
• Address measurement of site emissions from points outside the
remediation; and
t Measure the air concentrations in the upwind air passing over
the site and in the downwind air before it is impacted by the
other emission sources farther downwind.
4.4 EXAMPLE 3 - AIR MONITORING APPLICATION
This example presents a monitoring situation complicated by another
emission source (a chemical plant) near to but upwind of the Superfund site,
nearby receptors (office complex and a road) and a wide expected wind arc
(approximately 180°). As in example 2, the presentation of example 3 centers
on the design of an air monitoring network employing refined monitoring
techniques for a planned remedial design employing on-site processing
(stabilization) of excavated soils. The key parameters for this site are
given in Table 40. The site is shown in a plot plan in l-'igure 27. This
monitoring scenario reflects the complexity that is encountered when Superfund
sites are located in developed industrial areas.
A total of ten monitoring locations are a minimum to achieve the
specific monitoring objectives for this scenario: two upwind and eight
downwind (plus an optional eleventh location). The rationale for the number
and location is given below.
4-20
-------
TABLE 40. KEY PARAMETERS FOR EXAMPLE 3 - AIR MONITORING
1. Project Objective:
t Measure impact on ambient air of emissions from remediation
2. Meteorological Conditions:
• Wind speeds are moderate, generally from the south, and
5-10 mph
• Wind direction variability over a 24-hour period is high during
this season; wind arc of approximately 180°
• Moderate temperatures, 60-80'F
• Moderate relative humidity, 40-80% RH
• Good historical meteorological records
3. Topography:
t Flat, no surface features
4. Emission Sources Within Site:
t Major emissions are fugitive emissions localized in the
processing area
• Elevated point sources exist in processing area but are not
major sources of target compounds
5. Regional Ambient Air Quality:
• Regional ambient air is impacted by refineries and chemical
plants in the region
6. Other Emission Sources:
• A chemical plant is nearby and upwind of the site part of the
time (when winds are from southwest)
t Vehicular traffic on a road on the western perimeter of the
site could be source of target compound emissions
(Continued)
4-21
-------
TABLE 40. (Continued)
7. Power, Access, and Security
t 115 VAC power is available for meteorological station site only
• Good access for 360* around the processing area, but another
source and receptors are within 1000-2000 feet of the
remediation area
• Access to the adjacent farm land was denied
8. Receptor Locations:
• Office complex northwest of remediation area and about 2000
feet away
• Vehicular traffic on road west of remediation area and about
2000 feet away
4-22
-------
ro
CO
tt>
ro
-o
n>
CO
CO
_j-
«-»•
o>
TJ
ft)
ftftf/fftttfttffff
tfttftttfftttttttt
tttttttftttttftttt
ttttftffttftittttf
-------
Monitoring locations 1 and 2 are upwind of the site and location 2
is between the Superfund site and the chemical plant. Two upwind locations
are needed to help separate the impact of the other emission source. Location
1 is on the line of the mean wind direction (as are locations 3, 5, and 8).
For winds from the southwest, samplers 2, 6, 9, and 10 would monitor for
emissions from the chemical plant flowing across the road and reaching the
office complex. Therefore, these samplers serve to isolate the impact of the
chemical plant.
Three downwind monitoring locations (3, 5, and 8) are on the mean
wind direction vector at distances of 500, 1000, and 2000 feet, respectively,
from the remediation area. These three sites sample the dispersion along the
axis of the emission plume.
Three sampling loations (6, 9, and 10) are situated on one side of
the plume axis, but on wind direction vectors between the center of the
processing area and the nearby receptors (the office complex and the road).
Locations 6 and 10 are at distances of 1000 and 2000 feet, respectively.
Location 9 is at the fence!ine adjacent to the office complex. Two sampling
locations (4 and 7) are on the other side of the plume axis. Two are adequate
since there are no receptors on that side.
An eleventh optional sampling location might be placed just downwind
of the center of the remediation area. This sampler would measure the maximum
impact of emissions from the site. This additional data point might be very
useful in separating the impact of the site cleanup from all the other nearby
sources.
4.5 EXAMPLE 4 - AIR MONITORING APPLICATION
This monitoring scenario presents a situation of complex meteorology
and topography, with the Superfund site located in a river valley in a heavily
industrialized region. The key parameters of the monitoring scenario are
given in Table 41 and the plan of the refinery area is shown in Figure 28.
4-24
-------
TABLE 41. KEY PARAMETERS FOR EXAMPLE 4 - AIR MONITORING
1. Project Objectives:
• Measure impact on ambient air of emissions from remediation
2. Meteorological Conditions:
• Seasonal air movement is weak (0-2 mph) and highly variable in
direction leading to extended periods of stagnant air
• Only short-term (1-2 days) weather forecasts are available and
relevant
• Rain, cloudiness, high humidity are also seasonal; moderate
temperatures 40-60*F
• Good historical records
3. Topography:
t Site is located in a narrow river valley in an area dominated
by steep-sided hills and valleys
• Emissions from the site are restricted by the walls of the
valley up to an elevation of 1000-2000 feet above the valley
floor
4. Emission Sources Within Site:
• Major emissions within the site are fugitive sources localized
in the process area
t The processing area is long and narrow and parallel to the
river
• The site contamination includes cyclopentane. There are no
other cyclopentane emission sources in the valley so that it
might be useful as a tracer compound unique to the site
5. Regional Ambient Air Quality:
• The region is characterized by heavy and diverse industrial
development
• Regional ambient air quality is poor especially under stagnant
air conditions
(Continued)
4-25
-------
TABLE 41. (Continued)
6. Other Emission Sources:
• There are major emission sources in the region as well as in
the river valley location of the site, e.g., a chemical plant
is located directly across the river and a road to the east
7. Power, Access, and Security at Monitor Sites:
• 115 VAC power is available at meteorological station site
t Access to potential sampling sites is very restricted by the
hilly topography and the river
8. Receptor Locations:
t A residential area is located near the site
• For chemical emissions that could become trapped in the river
valley under stagnant meteorological conditions, workers of the
Superfund site and chemical plant are potential receptors.
4-26
-------
ex.
O)
o>
"o.
00
CM
OJ
3
a»
-------
As in the two previous examples, the object is to assess off-site impacts from
remediation of the site. Remediation is again assumed to involve on-site
processing of the contaminated soils/waste with no thermally buoyant
emissions.
The sources in the processing area are at ground level but spread
out along the river. There are no structural obstructions within the area.
The topography is complex with a range of hills east and south of the site, a
river along the south edge of the site's boundary and rolling hills west and
north of the site. Historical wind direction data and forecasted data
indicate a wind direction arc of approximately 270* from the southeast and
wind speeds from less than two mph to seven mph over a 24-hour period. Nearby
sources exist to the south (a chemical plant) and to the east (roadway).
Three receptor locations are identified; the residential area to the north of
the remediation area, the chemical plant to the south, and the roadway to the
east.
In this scenario it is obvious that the complex topography will
interact significantly with the complex meteorology. The movement of air in
the valley and the pattern of dispersion of the chemical emissions from the
Superfund site would be hard to predict. Under this condition, it will be
difficult to estimate the impact of the remediation emissions on the ambient
air in the valley. Several alternative courses of action for this scenario
are discussed below.
One option would be to modify the project goal to only measure
ambient air concentrations in the valley and not attempt to estimate the
site's contribution to these concentrations. For example, monitoring sites
could be located around all of the potential receptors: in the residential
area, on the road, on the Superfund site and around the chemical plant. Such
a strategy would serve to estimate the ambient air concentrations (and
inhalation exposure potential) at receptor locations without attempting to
evaluate the site's contribution.
4-28
-------
Another option would involve the use -of cyclopentane as a tracer
airborne chemical unique to the cleanup. In this option, ambient air
concentrations of cyclopentane would be measured along with several other
target compounds characteristic of the Superfund site. It would have to be
established that the tracer cyclopentane could act as a surrogate for the
other chemical emissions from the site. If the correlation could be
established, then measurement of ambient air concentrations of cyclopentane
and other target compounds at the receptor sites could be used to deduce the
impact of the remediation.
Another option involves collecting or developing three-dimensional
air patterns for the river valley as a function of different meteorological
conditions. With this site-specific meteorological and topographical input,
an air dispersion model could be calculated for the emissions from this site.
The modeling results could predict the areas of maximum air concentrations in
the valley to serve as guidance for the placement of sampling sites. All this
should be done as input to the study design.
Choices among the options outlined above will involve review of
project objectives and the resources available, e.g., budget and schedule.
These choices can only be made on a case-by-case basis. Thus, the complexity
of example 4 prevents a specific determination of a number and location of
sampler sites.
4-29
-------
SECTION 5
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 in Ambient Air. 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 in Ambient Air. 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-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. November, 1980. Ambient Monitoring Guidelines for Prevention of
Significant Deterioration (PSDK EPA-450/4-80/012. NTIS PB 81-153231.
Office of Air Quality Planning and Standards. Research Triangle Park, NC
27711.
5-1
-------
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
WS-846. GPO No. 955-001-00000-1. Office of Solid Waste. Washington, DC
20460.
ASTM. 1982. Toxic Materials in the Atmosphere. STP 786. American Society
for Testing and Materials. Philadelphia, PA.
ASTM. 1980. Sampling and Analysis of Toxic Organics 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.
APHA. 1977. Methods of Air Sampling and Analysis. American Public Health
Association. Cincinnati, OH.
ACGIH. 1983. Air Sampling Instruments for Evaluation of Atmospheric
Contaminants. American Conference of Governmental Industrial Hygienists.
Washington, DC.
U.S. EPA. 1984. Guide to the Preparation of Quality Assurance Pro.iect Plans.
Office of Toxic Substances. Office of Pesticides and Toxic Substances.
Washington, DC.
5-2
-------
U.S. EPA. 1988. Screening Procedures for Estimating the Air Quality Impact
of Stationary Sources. EPA-450/4-88-010. Office of Air Quality Planning and
Standards. Research Triangle Park, NC, 27711.
U.S. EPA. 1988. A Workbook of Screening Techniques for Assessing Impacts of
Toxic Air Pollutants. EPA-450/4-88-009. Office of Air Quality Planning and
Standards. Research Triangle Park, NC, 27711.
5-3
-------
APPENDIX A
BIBLIOGRAPHY OF AIR MONITORING METHODS
-------
APPENDIX A
BIBLIOGRAPHY
APCA. May 1987. Proceedings of the 1987 EPA/APCA Symposium on
Measurement of Toxic and Related Air Pollutants. VIP-8. Air 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 is 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 Organics 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
-------
organics 1n ambient, workplace, and source-related atmospheres;
analyzing for Important classes of pollutants such as polychlorinated
biphenyls (PCBs), polynuclear aromatic hydrocarbons (PAHs), and
polycyclic organic matter (POM); and measuring exposure to toxic
organics in the workplace.
CARB. February 1985. Toxic Ambient Air Monitoring Operation
Procedure. California Network. Aerometric 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 Air Resources Board. Sacramento, CA 95814.
These guidelines present standard operating procedures for the
sampling and analysis of ambient air collected in Tedlar bags.
Analytical procedures are primarily for halogenated volatile organics
and benzene.
Drager. May 1985. Detector Tube Handbook. Dragerwerk AG Lubeck.
Federal Republic of Germany.
This handbook presents procedures for the use of colorimetric
detector tubes for a wide range of organic and inorganic compounds.
Data is provided on standard ranges of measurement, precision and
accuracy, measurement principles, and cross-sensitivity.
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
-------
minimal modifications) to the measurement of ambient concentration
levels of concern 1n perimeter and offslte monitoring.
N.J. DEP. October 1987. Ambient A1r Monitoring at Hazardous Waste
and Suoerfund Sites. Division of Environmental Quality. Air 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 Air 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 in Ambient Air. EPA-600/4-84-041. Office of
Research and Development. Research Triangle Park, NC 27711.
Specific Standard Operating Procedures (SOPs) contained in this
compendium are as follows:
Method TO-1 Method for the Determination of Volatile Organic
Compounds in Ambient Air Using Tenax Adsorption and
Gas Chromatography/Mass Spectrometry (GC/MS).
(Applicable to volatile, non-polar organic compounds.)
A-4
-------
Method TO-2
Method TO-3
Method TO-4
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 Air Using Cryogenic
Preconcentration 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 Polychlorinated Biphenyls in Ambient
Air.
Method TO-5
Method for the Determination of Aldehydes and Ketones
in Ambient Air Using High Performance Liquid
Chromatography.
Method TO-6
Method TO-7
Method TO-8
Method for the Determination of Phosgene in Ambient
Air Using High Performance Liquid Chromatography.
Method for the Determination of N-Nitrosodimethylamine
in Ambient Air Using Gas Chromatography.
Method for the Determination of Phenol and
Methylphenols (Cresols) in Ambient Air Using High
Performance Liquid Chromatography.
Method TO-9
Method for the Determination of Polychlorinated
Dibenzo-p-dioxins (PCDDs) in Ambient Air Using High-
Resolution Gas Chromatography/High-Resolution Mass
Spectrometry (HRGC/HRMS).
A-5
-------
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 Passivated Canister Sampling
and Gas Chromatographic 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 is 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 in 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.
A-6
-------
U.S. EPA. December 1987. Development of Collection Methods for
SemivolatHe 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 in 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 Orqam'cs
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 Gillian 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.
A-7
-------
U.S. EPA. August 1983. Development of Protocols for Ambient Air
>1inQ 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 18. Office of Emergency and Remedial Response.
Washington, DC 20460.
U.S. EPA. 1983. Air 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 (PSD). EPA-450/4-80/012. NTIS PB
81-153231. Office of Air 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 in Ambient Air. 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 Air 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, N03, Pb, and PM-10 in
ambient air.
A-8
-------
-------
APPENDIX B
EXCERPT
FROM
TECHNICAL ASSISTANCE DOCUMENT
FOR
SAMPLING AND ANALYSIS
QF
TOXIC ORGANIC COMPOUNDS
IN AMBIENT AIR
(U.S. EPA, JUNE 1983)
B-l
-------
-------
United State* Environmental Monitoring EPA-600/4-83-027
Environmental Protection Syttema Laboratory June 1983
Agency Research Triangle Park NC 27711
Research and Development
Technical Assistance
Document for
Sampling and
Analysis of Toxic
Organic Compounds in
Ambient Air
-------
CONTENTS
Page
Foreward
Preface
v
Abstract .............................................. ....................
Figures 1X
Tables • • j
Abbreviations
1. Introduction *
2. Regulatory and Related Issues Concerning Toxic
Organic Monitoring • • *
3. Guidelines for Development of a Monitoring Plan 8
Definition of Objectives • *
Compilation and Evaluation of Available Information 1*
Selection of Sampling and Analysis Methods 18
Selection of Sampling Strategy ^J
Specification of Quality Assurance Protocols 27
Definition of Data Reporting Format 35
Safety Considerations 35
4. Sampling and Analysis State of the Art 37
Overview of Sampling Methods 37
Overview of Analytical Methods *'
Methods for Specific Compounds and Compound Classes 74
Quality Assurance Procedures 94
References •
Appendix *'' ! 19
Topic Index •
-------
SPECIFICATION OF QUALITY ASSURANCE PROTOCOLS
Overview
Th* term quality assurance (QA) refers to an overall system designed to monitor,
documwt and control ^Technical performance of a program. While the need for good
QA «o?oco^ L Sdrfy recognized, the design and implementation of thw. protocol is
f^auLntlv Seated as a secondary part of the overall monitoring program. If the QA
monlJor^ P^m«e to s«v. a useful purpose, they must (a) be readily
tthto the cost aSd time constraints of the program, (b) be •VS^f^^f.
^l^M of t~hni~l performance. and (c) be well understood by
rso. Preparation of the QA plan for a monitoring program should be
aTSTe sampling strategy and sampling and analysis »«thods have een
oned. This section of the TAD describes ^^e l»portant J
A simplified view of an overall QA system is given in Figure 4. QA "tivitie. to be
f uSns of QA management as well as the specific QA requirements for «mpling,
analysiTand data redaction are discussed in the following sections of the TAD.
A series of volumes entitled Quality Assurance Handbook for Air Pollution Measure-
QA Management
The functions and responsibilities of QA management are a ^ticri part of the
overall monitoring program. These functions and responsibilities are listed in Table 5.
Jd) control of chain of custody forms documenting sample deposition.
QA management is responsible for the evaluation of QA data^ m a ti™lj£a«
Failure to review the data immediately prevents implementation of timely corrective
action procedures and may result in poor data quality.
27
-------
QA
Management
QA
System
Design
Sampling
QA
Analytic*!
QA
Data
Reduction
QA
Figure 4. Quality assurance organization
26
-------
Table 5. Quality Assurance (QA) Activities to be
Specified in Program Plan
QA Management
QA System Design
Document Control
Data Evaluation and Storage
Audit Procedures
Corrective Action
QA Reports to Program Management
Training
Sampling QA
Site Selection
Instrument Calibration and Maintenance
Collection of Routine Quality Control Samples
Data Recording
Sample Labeling, Preservation, Storage and Transport
Chain 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
29
-------
Audit procedures include both performance and mtem audits. A performance audit
involves introduction of a reference sample (blank, spike, standard reference material,
etc ) into the analysis system in a blind fashion with subsequent assessment of the data.
System audits involve a review of program documentation such as record notebooks, data
files, and instrument logbooks to assess whether or not the QA system is operating
properly.
In many cases data review or audit procedures will result in the need for corrective
action. Corrective action may involve repeating certain aspects of the work or simply
providing more detailed documentation for work already performed;. In either case QA
management will be responsible for documenting the need for, type of, and imple-
mentation of corrective actions.
QA management is responsible for providing scheduled as we]l as nonscheduled
reports to program management. Scheduled reports include descriptions of the QA system
prior to program implementation, QA data reports, and audit reports. Unscheduled
reports generally describe corrective actions required and the impact of these actions on
the program.
A final responsibility of QA management is to provide training to technical
personnel. In particular, personnel need to be given a detailed view of the QA system and
their responsibilities for its implementation.
Sampling Quality Assurance
Aspects of sampling to be addressed in the QA plan are shown in Table 5. Site
•electionconsiderations have been discussed in the section on sampling strategy develop-
ment. However, the QA plan should specify factors which could result in a modification
of the siting plan during the course of the monitoring effort (e.g., changes in source
location or characteristics) and provisions for documenting any such modifications.
Instrument maintenance and calibration procedures should be specified to the extent
possible in the QA plan. Any maintenance or calibration activity, scheduled or non-
scheduled, should be recorded in an appropriate logbook in order to determine any effects
on the data obtained. Typical calibration data obtained should include:
• Flow measurements
• Volume measurements
• Temperature measurements
• Pressure measurements
e Determination of response factors, precision, and accuracy for
continuous monitors using span gases and zero gases.
In general the QA plan should specify routine calibration checks at several time points
during the program.
Quality control samples to check overall system performance may include «
or split samples, spiked samples, standard reference materials, blanks, and backup
".£ series impinlers or resin cartridges). Split or replicate samples are useful checks on
sampling and analysis precision and should be included with each group of samples. Field
bUaksjB which the sampling activity is duplicated exactly except that no air is sampled,
should also be routinely collected. Backup samples should be collected whenever the
30
-------
recovery performance of a particular sampling medium has not been documented or is
subject to wide variations depending on ambient conditions. Spiked samples should be
included wherever an accurate spiking procedure is available, provided that the spiked
material reasonably simulates the physical and chemical state of the native material.
Standard reference materials (SRMs) for organic analysis are rather sparse. The
National Bureau of Standards (NBS) has certified an urban dust (SRM 1649) for selected
polynuclear aromatic hydrocarbons and various gas suppliers will prepare certified
standards of many organic components as dilute gas mixtures. These gas mixtures should
be checked against NBS standard reference materials (e.g., propane in air) to ensure
accuracy of the gas mixture. Routine calibration of continuous monitors using these
certified gas mixtures is highly advisable. SRMs containing selected organic compounds
at trace levels in air or nitrogen are presently being developed and should be available in
the near future from NBS.
Data recording procedures to be specified in the sampling QA plan include (a)
periodic readings of the temperature, flow, volumes, and other parameters, (b) docu-
mentation of meteorological conditions at appropriate time points, (c) documentation of
instrument operating variables (e.g., resin cartridge number), (d) documentation of any
upset conditions such as sudden leakage or pressure surges, and (e) documentation of
calibration or maintenance activities. A logbook for the overall sampling program in
which sampling descriptions, meteorological data, and upset conditions arc documented
should be maintained. In addition a sampling data sheet, such as the example in Figure 5,
should be prepared for each sample or set of samples in which the periodic readings and
instrument parameters are recorded. Certain measurements such as filter numbers and
weights or impinger volumes which are required for analytical purposes can be recorded
on a separate sheet with provisions for recording subsequent analytical data on the same
sheet. Separate maintenance and calibration logbooks should be maintained for each
instrument. In most cases, sampling data forms specific for a given program must be
prepared because of differences in the sampling design between programs.
Sample labeling, preservation, storage, and transport procedures should be specified
in the QA plan and these procedures should be carefully explained to field personnel prior
to sampling to ensure proper implementation. Sample labels, prepared in advance, should
include sufficient information to associate the sample with a particular data sheet as well
as the overall program record notebook. In general each sample should be given a unique
identification number with a prefix describing the type of sample.
Sample preservation, storage, and transport procedures must be appropriate for the
type of analyses required. Participate samples generally should be placed in air tight
containers and stored in the dark to minimize analyte degradation. Resin cartridges and
impingers generally require more attention, because of analyte instability in the matrix,
and should be shipped to the laboratory for analysis within a relatively short time period
(e.g., a few days). These sample types should be placed in airtight, glass containers and
stored at subambient temperatures until analysis. Exposure to solvents must be avoided
for resin cartridges during all stages of handling in order to avoid sample contamination.
Chain of custody forms are required for certain programs having direct legal impli-
cations. The objective of the chain of custody procedures is to document the movement
of a sample from collection until analysis to ensure its integrity. A typical chain of
custody form is shown in Figure 6. Formal chain of custody requirements place a sub-
stantial burden on the field as well as laboratory personnel and should be employed only
31
-------
S«*pte Sample SUrt
I.D. Description Date TUw
Stop
Tt*e Location
Flow Rate.
liter/Bin.
Inlt. Final
Ataospheric Calibration
Pressure leap. • Data
•rift} *C Operator Reference Convents
Figure 5. Typical samplinq data sheet
-------
CHAIN OF CUSTODY RECORD
Sample Number:
Shipper Name: „
Address:
number street city state zip
Collector's Name__ Telephone: ( )
signature
Date Sampled Time Sampled hours
Type of Process Producing Waste —,
Field Information
Sample Receiver:
1.
name and address of organization receiving sample
2. —
3 _ —
Chain of Possession:
1.
signature title . inclusive dates
2.
signature title inclusive dates
3.
signature title inclusive dates
Figure 6. Typical Chain of Custody Form
33
-------
when the program objective specifically require such measures. However, if the data
obtained are to be used in litigation, the use of chain of custody procedures is mandatory.
Analytical Quality Assurance
Aspects of the analytical work to be addressed in the QA plan include:
e Method validation requirements
e Instrument maintenance and calibration
e Quality control sample analysis
e Data recording.
Most monitoring programs will use new methods or modifications of existing
methods to some extent. The QA plan must address the validation requirements for each
of these methods. Typical requirements will include determination of precision, accuracy,
detection limit, and specificity through the analysis of laboratory standards, and whenever
possible, representative samples. The validation requirements should be appropriate for
the program objectives and should simulate the actual sampling and Analytical situation as
nearly as possible. Validation data should be included as part of the monitoring report and
method writeups and any limitations of the data in terms of defining the performance
characteristics under the actual use conditions should be documented.
Instrument maintenance and calibration requirements for laboratory instruments
will be similar to those for field instruments, including the need to document any
activities of this type. To the extent possible calibration and preventive maintenance
schedules should be included in the QA plan. The format for recording calibration data
(e.g., injection of standards of known concentration) should be specified prior to initiation
of the monitoring effort.
Quality control samples for evaluating analytical performance should include blanks,
spiked process blanks, spiked samples, standard reference materials, and replicate (or
split) samples. Standard reference materials and replicate or split samples should
generally be included as part of field QA and need not be additionally included at the
analysis stage. However additional blanks, spiked process blanks, and spiked samples
should be included at the analysis stage since problems with sample instability and con-
tamination during sampling storage or shipment can be determined separately from
laboratory related problems. Both spiked process blanks and spiked samples should be
included since this practice allows matrix effects to be distinguished! from analytical
losses.
Data recording requirements during analysis require a great deal of attention to
ensure that all necessary raw data are available for inspection should unexpected results
occur. The advent of computerized data handling tends to "hide" raw data from the
analyst. Hence the QA plan should specifically state which raw data are to be recorded,
the manner of presentation, and storage procedures. Laboratory data notebooks should
include all raw data or a clear reference as to where the data are recorded (e.g., 9-track
magnetic tape, etc.), equations used in performing intermediate calculations, and final
results. Equations used for calculations, including units for all parameters, should be
presented as part of the method writeups or program QA plan.
34
-------
Data Reduction Quality Assurance
Since sampling and analytical data processing occurs independently, in most cases,
the QA plan should address the manner in which data from the two activities are to be
treated and validated during the reduction process. The actual presentation of data is
described in the following portion of the TAD and will not be discussed here.
Aspects of data reduction to be treated in the QA plan are shown in Table 5. The
extent of documentation and verification required will be greatly dependent on the
program objectives, the nature of the raw data, and the complexity of the computational
process.
DEFINITION OF DATA REPORTING FORMAT
Many air monitoring programs are undertaken without prior definition of the data
reporting format. In some cases this appraoch is justified because of the unexpected
nature of the data obtained (e.g., unexpected compounds detected or previously unknown
sources identified). However, to the extent possible the format for data presentation
should be defined prior to initiation of the monitoring effort. This practice helps to
identify limitations on the available data and further clarifies the extent to which tech-
nical and management or policy personnel understand the program objectives. Stern's Air
Pollution series") contains an excellent discussion of procedures for analyzing and
presenting air quality data.
The optimal format for data presentation obviously is highly dependent on the
program objectives and the quantity of data obtained. In cases where only a few data
points are obtained around a point source (e.g., a hazardous waste landfill) tabular
presentation of data (compound concentrations at each site) may be appropriate.
However, in most monitoring situations the quantity and complexity of the data set will
require graphical presentation. This type of data format requires definition of the
important variables to be considered (e.g., source locations, sampling times, sampling
sites, meteorological effects, etc.). Statistical methods for evaluating correlation
between the important variables are usually required to obtain meaningful conclusions
from the data set. Typical methods for statistically evaluating and displaying air quality
data are given in Stern's book^) and therefore are not presented here.
SAFETY CONSIDERATIONS
Safety considerations in air monitoring are similar to those for other chemically
related occupations but should be considered for each air monitoring program since
unusual hazards may be present in these situations. A discussion of general safety con-
siderations is available^. Potential safety hazards can be subdivided into the following
broad categories:
• Chemical hazards
e Electrical equipment
e Mechanical equipment.
Chemical hazards include toxic chemicals such as carcinogenic compounds,
corrosive chemicals such as concentrated acids or bases, and explosive hazards such as
35
-------
compressed gases. Protective equipment should be employed to miinimixe direct exposure
to such haxards. Since most air monitoring programs require working with concentrated
standards of toxic organic compounds, special emphasis should be placed on minimizing
exposure to these materials. Programs involving investigation of concentrated or
potentially concentrated sources of hazardous organic compounds require additional
safety protocols to protect workers in the field as well as laboratory workers who could be
unexpectedly exposed to concentrated samples collected at such sites.
Haxards from corrosive chemical, compressed gases, glassware, mechanical
equipment, and electrical equipment are presented in the reference given above^' and do
not require special emphasis here. However, these haxards should be addressed in the
monitoring plan.
36
-------
QUALITY ASSURANCE PROCEDURES
The purpose of this part of the TAD is to address quality assurance and related
needs specific for the sampling and analysis approaches described above. The overall QA
requirements of ambient air monitoring programs have been described in Section 3 of the
TAD and references
Method Validation
Validation of method performance is important in all sampling and analysis programs
but is of special significance for trace organic monitoring because of the large number of
compounds of interest and variables affecting method performance. In many situations
time, cost, or technical limitations will preclude rigorous method validation and certain
assumptions will be required. Ideally any such assumptions will be based on sound tech-
nical judgement and/or prior experience.
Aspects of method performance requiring validation include the following:
Accuracy
Precision
Blank or background level
Detection limit
Interferences
Ruggedness (effect of important variables on method performance).
In the ideal situation each of these aspects of method performance will be evaluated using
the entire sampling and analysis scheme to monitor an atmosphere containing constant,
known amounts of the analytes under conditions identical to the field. Two technical
limitations prevent the accomplishment of this "ideal" method validation strategy in most
cases.
The most severe limitation is that duplication of field conditions is impossible
because of the wide variability in field conditions. The second limitation is that gener-
ating atmospheres of known constant composition is relatively difficult, especially for
unstable components which also pose the greatest problem for sampling and analysis.
A typical approach used to partially overcome these limitations is shown in Figure
12. In this scheme a laboratory validation effort is conducted wherein the emphasis is
94
-------
Generate atmosphere under laboratory conditions
containing known, constant amount of analyte.
For unstable compounds use dry inert gas and/or
reference analysis methods to ensure a known,
stable concentration.
Laboratory
Determine method detection limit, and accuracy
and check interference from known materials
using the laboratory generated atmosphere.
Determine method "ruggedness" by varying
temperature, humidity, sampling volumes, ei:c. in
cases where a stable concentration of analyte can be
maintained. Use series samples to check breakthrough
when appropriate.
Determine method precision by collecting
parallel samples.
Field
Estimate method accuracy by comparing data using
test and reference methods, running series
samples (check on breakthrough), and/oir
spiking field sample with known amounts
of analyte.
Figure 12. Method Validation Scheme
95
-------
on generating a known, stable concentration of analyte. Unstable compound! may
• U»J™of dry, inert gas (e.g., nitrogen) to make up the atmosphere. In some cases
-S^Wr.S3abli " • dick on compound stability such method, r*ed
not be highly specific since a relatively clean atmosphere is being employed).
Method detection limit, precision, accuracy, interferences, and background.can 1be»
determined using the laboratory generated atmosphere. Method ruggedness can be tested
provided the variables do not affect the analyte stability, unstable compounds often will
not meet this requirement.
The field method validation efforts include a check on precision using parallel
sampling. Accuracy can be estimated through the use of reference or alternate methods,
a^/o7sriking field samples with known quantities of analyte. The latter approach must
bVaccompSshed in such a manner that all of the spiked material enters the sampling
device. Alternatively, one can choose to spike the collected sample (e.g., impinger
liquid! resfacartridge etc.) a. a check only on the sample transport and ™*J^
p^ceduresV Series Samplers can be used as a check on capture efficiency (analyte
breakthrough) but will not determine accuracy, fa many cases, it.will be useful to
collect series samples using various sampling volumes to further document component
breakthrough characteristics.
Instrument Calibration
Instrument calibration requirements for sampling and analysis equipment are
outlined in Table 19. Specific calibration and maintenance procedures will vary somewhat
from^ne manufacturerTo another, hence the user should consult the instrument manual
for more specific information.
Sampling equipment calibration procedures for toxic organic monitoring are similar
to other type-To?monitoring and adequate information on this subject can be found in the
literature?!®. Continuous analyxers require that a suitable calibration standard be
available in the field. Ideally the calibration standard is a dilute mixture or series of
dilute mixtures of the analyte at stable concentrations. Methods for genera ting such
atmosphere, can be static (e.g., dilution flasks, compressed gas cylinders) or *V*™
?e.g., permeation tube,, diffusion tubes, syringe delivery systems . In all cases, a method
of generating clean air must be available in order to set the baseline level on the con-
UnSout monitor as well a. for the generation of calibration standards. Methods for gener-
ating clean air as well as static and dynamic calibration methods are discussed in the
literature^).
fa general, static systems are most convenient to use and are the preferred cali-
bration methodi provided the analyte, are stable in the dilution system. GenerallyAlight
hvdrocarbons and other stable, volatile compounds (e.g., halocarbons) are suitable for
static calibration. Dynamic calibration systems, while more complex for field use, are
often rAuLed for reactive materials (e.g. phosgene) which may be degraded in the static
systems.
Less volatile materials such as PCBs, organochlorine, pesticides, or PAHs are rarely
of interest for continuous monitors since the ambient concentrations of these materials
are usually not detectable using this approach. If atmospheres of such compounds are to
be generated probably the best approach is a heated dynamic dilution system wherein a
dilute solution of the material in a volatile solvent is delivered at a constant rate into the
gas stream using a syringe pump.
96
-------
TABLE 19. CALIBRATION REQUIREMENTS FOR SAMPLING
AND ANALYSIS INSTRUMENTATION
Device
Parameter
Calibrated
Method of
Calibration
Appro*Imate
Frequency
Comments
Sampling Instrumentation
Sempllnq pump and
controller
Sortie volume measurement
device (usually a dry
test oxter)
MM rate
Total volume
Net or dry test Meekly
meter or calibrated
rotometer
Met test meter Meekly
Must be determined at
knoM atmospheric pressure
and temperature. Flew
rate should be startler to
that used for sampling.
Analytical Instruments
Continuous oanltors
(e.fl.. FIO. »ID. TfO.
etc.)
Chrometographlc
Instrunents
Chronotooraiihlc
iMtruncnts
CC/HS
GC/NS
•espouse
ColiMn perforaance
and retention
tine for each
analyte
Response for
each analyte
Response and
retention ttae
for each analyte
Mass spectral
resolution and
turning parameters
Ceneratlon of test
tUosphere of
known concentration
Dally or
Injection of
standard ustnf
the sane process
as for stople
Injection
Sane as above
frequently
If required
Dally or
frequently
If required
Test atnosphere should be
referenced to a prlnery
standard (e.e.. MS bentene
In air). Flow/pressure
conditions should duplicate
sanpllnf process.
Standard composition
should be checked analnst
prtnary standards If
available.
as
Sea* as for other chroMtooraphlc Instruments.
(a) Introduction
of perfluoro-
compound directly
Into MS
(b) Injection of
tuning standard
(e.e.. bromofluero-
bentene) Into tt
Dally
Selection of tunlnj
standards will be
dependent on type of
of analysis betne.
pcrfomed.
-------
Chromatographic instrumentation requires calibration of both the retention time
and response characteristics of the analytes under the conditions used for the analysis of
samples. Samples delivered to the instrument in liquid form (e.g., XAO or PUF extracts,
impingers, etc), represent no particular problems since liquid standards of the analytes
may be readily prepared. However, techniques such as whole air injection, cryogenic
trapping, and thermal desorption (e.g., Tenax) require the generation of a known, stable
gas phase calibration standard, using methods similar to those described for continuous
monitors. In the case of the Tenax thermal desorption method standards have been suc-
cessfully prepared using a heated static dilution flask wherein the sample is injected onto
a clean Tenax cartridge using a gas-tight syringe.
The performance of GC columns, especially capillary columns should be checked
periodically in terms of column efficiency (theoretical plates) and peak asymmetry
(especially for polar compounds). This performance check can be done using liquid cali-
bration standards and is a useful tool for determining when a column needs to be replaced.
Mass spectrometers require various calibration steps, in addition to the normal
Chromatographic calibration requirements. These include calibration of the mass spectral
relative intensities and mass resolution. Quadrupole MS systems are greatly effected by
such tuning parameters and hence data performance checks are required to ensure the
usefulness of the mass spectrum for peak identification.
In practice, two levels of MS tuning calibration are usually performed. First a
volatile perfluoro-compound (e.g., perfluorokerosine or perfluorotributylamine) is intro-
duced into the ion source and the MS tuning parameters are adjusted to yield certain
spectral characteristics. This tuning process is usually described in detail in the instru-
ment manual. A second level of tuning involves the injection of a particular compound
EPA methodology (70) prescribes bromofluorobenzene for volatile! and decafluorotri-
phenylphosphine (DFTPP) for s« mi volatile compounds onto the GC/MS system. If the
mass spectral characteristics for the reference compound are not correct, the parameters
are adjusted and the calibration process repeated.
Routine Quality Control
In addition to method validation and instrument calibration processes, the mon-
itoring program should include certain processes for periodically documenting per-
formance of the sampling and analysis procedures. Typical frequencies for sampling/
analysis QC samples are shown in Table 20. In the case of continuous monitors the cali-
bration process itself serves as a periodic indicator of method performance. Other
sampling and analysis systems require the collection or acquisition of QC samples to
check method performance. The types of QC samples of primary value include:
Blanks (both field and laboratory)
Spiked samples
Internal standards
Replicate parallel samples (or split samples)
Series samples
Reference samples.
Blanks should be processed exactly as the samples, except that no air is drawn
through the sampler. If samples are transported to the laboratory for analysis then labo-
ratory as well as field blanks should be included. In the case of resin samples (e.g., Tenax)
98
-------
Table 20. Typical Sampling/Analysil Frequencies
for QC Samples
Type of Sample
Field Blanks
Laboratory Blanks
Spiked Samples
Duplicate (parallel) Samples
Instrument Calibration Standards
Reference Samples
Series (Backup) Samples
Typical Frequency
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
of total number of samples; each
sample set.
Daily
Weekly
Each sample set.
99
-------
Ltory and field blanks should be routinely analyzed since contamination during
rfToM^febSm: Material blanks such as Tenax cartridges, impinger so-
• should be routinely analyzed prior to sampling to avoid wasting valuable field
•tton, ai»"to contamination. Blanks for whole air coUection or cryogenic trapping
Systems will simply be clean air as used for instrument calibration.
Sulked samples must be prepared in such a manner that (a) the sample form is not
S*£3& proce-SJto) aU of the spikematerial is availabletc> th.-mpUng
alter* by thsrfk proce»n a o e sp
!«£m fa manVcwSsVthe air stream itself cannot be spiked because of technical practi-
* thTmost common approach i, to spike the collection matrix (e.g.
nnger; etc.) either before or after sampling. Rerin cartridges can be
themtic dilution system described above, fa "menses (e.g., for volatile,
Sable compounds) a whole air sample can be collected in a cylinder or Teflon bag and
spiked with a known amount of analyte.
The use of internal standards (IS) is advisable for chromatographic methodi it or
which the IS can be placed into the sample without altering it. The use of an IS helps to
Irac" instrument sensitivity and to compensate for losses during sample processing.
fa"^S3Sd/lr. uncommonly employed for liquid injection or thermal *••**£*«
methods butsrenot advisable for whole air injection or cryogenic trapping m most cases.
faurnaf standards are especially useful for GC/MS techniques since the stable isotopicmUy
S r^eut^umTr 13C) Sbeled7analyte, can be placed into the sample "t"^""16
for any losses during processing or changes in instrument response. This approach has
been used extensively for Tenax thermal desorption procedures.
clnnot due to inhomojeneous distribution of the analytes in the
CoUection of replicate samples of varying sample volumes can be useful! for deter-
mining sampling volume effects on the method. Series samples are w"d
check on
solid adsorbent sampling procedures^00'.
Reference samples, especially standards available from NBS, are useful as a routine
on mr5^i"ccLracV although only a limited number of such samples are available.
rtududTfor organics (Zg., benzene) will become avaUable in the near future
w ^ o^r7at valJ! in the to'xic organic monitoring area. Secondary standard, ,»p-
Jlied by varioul manufacturers and caUbrated against an NBS reference (e.g., propane in
ak) are currently in widespread use both of instrument calibration and routine
-------
Most of the NIOSH and ASTM methods contain equations for converting raw ana-
lytical data to final concentrations, many of which are applicable to other sampling and
analysis methods. Raw data obtained during the sampling and analysis process should
include the following:
• Volume of sample collected (uncorrected for ambient pressure and
temperature)-VsA . A _
• Temperature of sample volume measuring system-TS
• Ambient atmospheric pressure at sampling site-Ps
e Quantity of analyte in total sample-Ox*
T« -imn.t all cases. the final data should be presented in terms of quantity of
analyt^"uSt^oSmt u^Jer standard condition, (25 C and 760 mm Hg press,*.).
A^Sal sTmplTvolume can be converted to standard sample volume V& using the
following equation:
, 298 PjjdnmHg)
m3) » VCA (™3) * - *
= 5A
The concentration of analyte (CA) in the sample under standard conditions can then be
readily calculated as follows:
T« m.,w r,«*. one mav wish to convert concentrations from pg/m3 to parts per
gw phase components at 25 C and 760 mm pressure:
CA (ppbv) = CA (Hi/™3)
where MWA • molecular weight of analyte.
ppbC:
NC
101
-------
•h«re Nr - the number of carbons in the analyte molecule. In a strict sense the term
Job?should be reserved for hydrocarbons since the presence of O, d, N, etc. greatly
affects the per carbon response of the FID.
102
-------
APPENDIX C
BACKGROUND INFORMATION
C-l
-------
APPENDIX C
BACKGROUND INFORMATION
Preparation and implementation of an Air Pathway Analysis (APA)
Emergency Field Guide is recommended to support site disturbance
activities. For example, excavation during remedial/removal actions can
result in an unplanned release of hazardous contaminants to the air
pathway. Implementation of a site/source-specific APA Field Guide can
provide a real-time capability to provide the following information
regarding an unplanned air release event during the remedial/removal
activities:
Identification of the impact area
• Estimation of arrival time of release at the impact area
• Air concentration predictions for the impact area that can be
compared to health and safety action levels, ARARs, and odor
thresholds
An APA Field Guide is based on a strategy that involves a systematic
combination of modeling and monitoring methods. Procedures for the
conduct of emission rate modeling/monitoring for disturbed-site conditions
have been provided in Volume III. Procedures for dispersion and air
monitoring have been presented in Volume IV, Sections 2 and 3,
respectively. The following is an example APA Field Guide.
C-2
-------
APPENDIX C - EXAMPLE APA FIELD GUIDE OUTLINE
C.I Overview
C.I.I Objectives
C.I.2 Site/Source Description
C.I.3 A1r Pathway Analysis Uncertainty
C.2 Air Pathway Analysis Strategy
C.2.1 Routine Meteorological Monitoring
C.2.2 Routine Air Monitoring
C.2.3 Release Assessment Methodology
C-3
-------
C.I OVERVIEW
C.I.I Objectives
This Field Guide has been prepared to provide a basis for onsite
decision-makers to obtain rapid assessments of potential downwind (onsite
and offsite) concentrations 1n the event of nonroutine air emissions
during remedial actions. Specific information obtainable by the
application of the Field Guide includes an estimate of the Impact area and
release arrival times at downwind locations of interest, as well as a
prediction of air concentration. The Field Guide has been developed for
use by onsite health and safety staff. Familiarity with the procedural
instructions of this Field Guide will allow an assessment in a matter of
minutes.
C.I.2 Site/Source Description
Site X 1s located on flat terrain in a community that has a mix of
small industrial plants and residential housing. The closest resident
lives approximately 1 kilometer from the uncontrolled landfill at the
site. The primary air emission source during site remediation will be
excavation operations; numerous volatile organic compounds (VOCs) will be
emitted.
Candidate air emission constituents of concern identified from air
pathway analyses (APAs) conducted during the Remedial
Investigation/Feasibility Study (RI/FS) include the following VOCs:
• Benzene
• Carbon tetrachloride
Chloroform
Ethyl benzene
• Tetrachloroethane
Tetrach1oroethy1ene
Moist soil conditions are expected to minimize the potential for
particulate emissions during excavation operations.
C-4
-------
C.I.3 A1r Pathway Analysis Uncertainty
Because of monitoring and modeling uncertainties, Field Guide air
concentration predictions should be used for decision-making. For this
application, the Industrial Source Complex Short-Term (ISCST) dispersion
model was used. Portable organic detectors and colorimetric tubes are the
primary monitoring methods for this application. Therefore, the combined
Uncertainty Factor (UF) of ±5 for Field Guide air concentration
predictions has been estimated for continuous releases. A UF of ±10 has
been assumed for instantaneous (puff) releases.
The UFs discussed above refer to maximum (i.e., plume center!ine)
concentrations at downwind locations of interest. However, for real-time
applications there is the potential for large wind direction
variabilities. Therefore, for this application it has been assumed that
the maximum concentrations, as a function of downwind distance, can occur
anywhere within the horizontal boundaries of the impact area. The impact
area has been conservatively defined as the plume center-line ±3 sigma y
(where sigma y is the horizontal dispersion parameter). Typically,
concentrations at ±3 sigma y are approximately a factor of 0.05 of plume
center!ine values.
The application of this Field Guide is intended for releases that can
be characterized as neutrally buoyant. Additionally, the modeling
approach selected is based on the assumption that chemical or physical
removal mechanisms in the atmosphere are negligible.
C-5
-------
C.2 AIR PATHWAY ANALYSIS STRATEGY
The APA strategy developed for this Field Guide 1s Illustrated 1n
Figure C-l. Routine onslte meteorological monitoring should be conducted
to ensure that Input data are available for characterizing dispersion
conditions. Routine air monitoring close to the source should be
conducted during excavation operations to detect nonroutine air release
conditions. If a nonroutine release 1s detected, then the multistep
release assessment methodology presented in this Field Guide should be
implemented. This methodology involves plume measurements (horizontal
traverse) 10 meters downwind from the source. The maximum concentration
detected 10 meters from the source is extrapolated using dilution factors
(based on dispersion modeling results) to obtain concentration estimates
at downwind locations of interest. Acetate overlays (stability class-
specific) are used in conjunction with a site base map to identify
potential impact areas.
C.2.1 Routine Meteorological Monitoring
A 10-meter meteorological station should be operated onslte during
the site remediation phase. At a minimum, wind speed, wind direction, and
sigma theta should be measured. Sigma theta 1s the standard deviation of
horizontal wind direction; 1t is used as an 'indicator of atmospheric
stability. The averaging time for the measurements should be 15 minutes.
An onsite data logger is planned to facilitate obtaining 15-minute
averaged meteorological data automatically.
C.2.2 Routine Air Monitoring
Routine air monitoring during the remedial action phase will be
limited to near-source measurements using portable organic detectors and
compound-specific colorimetric tubes. As warranted, additional downwind
sampling will also be implemented. An onsite gas chromatograph will also
be available to conduct confirmatory compound-specific analyses.
C-6
-------
Routine Air
(Near-Source)
Monitoring
Routine
Meteorological
Monitoring
Implement
Reieaae Aaaeaament
Methodology
o Stap 1 - Collect input
Data
o Stap 2 - Datarmlna
Impact Araa
o Stap 3 - Datarmlna
Dilution Faotora
o Stap 4 - Eatlmata
Downwind Coneantratlona
o Stap 5 - Compara
Coneantratlona to Action
Lavala. Haalth Crltarla,
and Odor Thraaholda
Repeat Procedure
Aa Necessary
Rgur* C-1. APA Em«rg«noy Fl»ld Quid* Strategy - Ov*rvl*w.
C-7
-------
C.2.3 Release Assessment Methodology
The release assessment methodology presented below should be
implemented 1f a nonroutine air release is detected (via monitoring or
visual observation).
Step 1 - Collect Input Data
• Measure maximum air concentrations based on a horizontal
traverse of the plume at 10 meters from the downwind edge of the
source.
Total organic concentrations based on portable detector
measurements.
Specific organic concentrations based on colorimetric tube
samples.
Whole air samples subject to onsite gas chromatographic
analyses as confirmatory information.
• If air concentration measurements are not available, consider
the use of default emission rate scenarios (Table C-l).
Collect onsite meteorological data using the most recently
available 15-minute averages.
Wind direction.
Wind speed.
Atmospheric stability (based on sigma theta classification
presented in Table C-2).
C-8
-------
TABLE C-l. DEFAULT EMISSION RATE SCENARIOS TOR SITE X
Continuous Point Source
Benzene
Carbon tetrachloride
Chloroform
Ethyl Benzene
Tetrachloroethane
Tetrachloroethylene
Continuous Area Source
Benzene
Carbon tetrachloride
Chloroform
Ethyl Benzene
Tetrachloroethane
Tetrachloroethylene
Instantaneous Source
Benzene
Carbon tetrachloride
Chloroform
Ethyl Benzene
Tetrachloroethane
Tetrachl oroethy 1 ene
Typical
Emission
Rates
(ug/sec)
Release
omposition
(percent)
10
20
30
5
15
_20
100
Worst Case
mission
Rates
ug/sec)
Release
omposition
(percent)
C-9
-------
TABLE C-2. SIGMA THETA STABILITY CLASSIFICATION
Sigma Theta Value
Classification
Sigma theta greater than or equal to 12.5°
Sigma theta greater than or equal to 7.5° but
less than 12.5°
Sigma theta less than 7.5°
Unstable
Neutral
Stable
C-10
-------
Step 2 - Determine Impact Area
• Select the appropriate Impact area overlay set as follows:
Continuous point source (Figures C-2 through C-4).
Continuous area source (Figures C-2 through C-4).
Instantaneous source (Figures C-5 through C-7).
• Select the stability-specific impact area overlay from the
appropriate set of figures:
Unstable.
Neutral.
Stable.
• Align the overlay over the base map (Figure C-8) along the
direction toward which the wind is flowing. (Wind direction
data obtained from the meteorological station will be in terms
of direction from which the wind is flowing.) The result should
be that the impact area is located downwind of the source, as
illustrated in Figure C-9.
C-ll
-------
UNSTABLE CONDITIONS'
Rtl«att Point
*Example overlay. Do not directly use this overlay for site applications. Site-
specific values should be developed for actual calculations.
Figure C-2 Example Impact Area Overlay-Continuous Sources (Unstable
Conditions)
C-12
-------
NEUTRAL CONDITIONS*
Point
*Example overlay. Do not directly use this overlay for site applications. Site-
specific values should be developed for actual applications.
Figure C-3 Example Impact Area Overlay-Continuous Sources (Neutral
Conditions)
C-13
-------
STABLE
CONDITIONS
R«l«as« Point
*Example overlay. Do not directly use this overlay for site applications. Site-
specific values should be developed for actual applications.
Figure C-4 Example Impact Area Overlay-Continuous Sources (Stable
Conditions)
C-14
-------
UNSTABLE CONDITIONS*
Point
*Example overlay. Do not directly use this overlay for site applications. Site-
specific values should be developed for actual applications.
Figure C-5 Example Impact Area Overlay - Instantaneous Sources (Unstable
Conditions)
C-15
-------
NEUTRAL
CONDITIONS
R«l«at« Point
*Example overlay. Do not directly use this overlay for site applications. Site-
specific values should be developed for actual applications.
Figure C-6 Example Impact Area Overlays - Instantaneous Sources (Neutral
Conditions)
C-16
-------
STABLE
CONDITIONS
Point
'Example overlay. Do not directly use this overlay foir site applications. Site-
specific values should be developed for actual applications.
Figure C-7 Example Impact Area Overlays - Instantaneous Sources (Stable
Conditions)
C-17
-------
w
Actual Offsite
Receptor (with
expected maximum
release impact)
to ff
Figure C-8 Example Base Map-Site X
C-18
-------
Wind
OirwttoiT
Wind
Oirwtton
.1*
| 10m TrwcrM Lint
Figure C-9 Example Impact Area Overlay Alignment Relative to Wind
Direction and Source
C-19
-------
Step 3 - Determine Dilution Factors
• Select the appropriate dilution factor table as follows:
Continuous point source (Table C-3).
Continuous area source.
Unstable (Table C-4).
Neutral (Table C-5).
Stable (Table C-6).
Instantaneous source (Table C-7).
Select the stability-specific dilution factor for downwind
distance(s) of interest (use the appropriate column based on
source size for area/volume sources).
C-20
-------
TABLE C-3. EXAMPLE DILUTION FACTORS - POINT-SOURCE RELEASE
Downwi nd
Distance
(km)
0.1
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
10.5
11.0
11.5
Dilution Factor (dlmensionless)
Unstable*
1.3 x 10-2
6.1 x 10-4
1.7 x 10-4
8.5 x 10-5
5.2 x 10-5
3.5 x 10-5
2.6 x 10-5
2.0 x 10-5
1.6 x 10-5
1.3 x 10-5
1.1 x 10-5
9.4 x 10-6
8.1 x 10-6
7.1 x 10-6
6.3 x 10-6
5.6 x 10-6
5.1 x 10-6
4.6 x 10-6
4.2 x 10-6
3.9 x 10-6
3.6 x 10-6
3.3 x 10-6
3.0 x 10-6
2.8 x 10-6
Neutral*
1.1 x 10-2
6.3 x 10-4
2.0 x 10-4
1.0 x 10-4
6.5 x 10-5
4.6 x 10-5
3.5 x 10-5
2.8 x 10-5
2.3 x 10-5
1.9 x 10-5
1.6 x 10-5
1.4 x 10-5
1.2 x 10-5
1.1 x 10-5
9.9 x 10-6
8.9 x 10-6
8.1 x 10-6
7.4 x 10-6
6.9 x 10-6
6.4 x 10-6
5.9 x 10-6
5.4 x 10-6
5.2 x 10-6
4.8 x 10-6
Stable*
9.4 x 10-3
5.2 x 10-4
1.7 x 10-4
9.2 x 10-5
6.0 x 10-5
4.4 x 10-5
3.4 x 10-5
2.7 x 10-5
2.3 x 10-5
1.9 x 10-5
1.7 x 10-5
1.5 x 10-5
1.3 x 10-5
1.2 x 10-5
1.1 x 10-6
9.9 x 10-5
9.2 x 10-6
8.5 x 10-5
7.9 x 10-6
7.4 x 10-5
6.9 x 10-6
6.5 x 10-5
6.2 x 10-6
5.8 x 10-5
*Atmospheric stability condition as determined from sigma theta reading
Example values. Do
applications. Site
applications.
not directly use these values for site
•specific values should be developed for actual
C-21
-------
TABLE C-4. EXAMPLE DILUTION FACTORS (DIMENSIONLESS) - CONTINUOUS AREA
SOURCE (UNSTABLE CONDITIONS) *
Downwind Distance (km)
0.1
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0 - 11.5
Source Area (Acres)
0.5
4.0 x 10-1
6.7 x 10-2
2.0 x 10-2
1.0 x 10-2
6.7 x 10-3
4.0 x 10-3
4.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
1.0 x 10-3
1.0 x 10-3
6.7 x 10-4
6.7 x 10-4
6.7 x 10-4
6.7 x 10-4
4.0 x 10-4
4.0 x 10-4
4.0 x 10-4
4.0 x 10-4
1.0
6.7 x 10-1
1.0 x 10-1
4.0 x 10-2
2.0 x 10-2
1.0 x 10-2
6.7 x 10-3
6.7 x 10-3
4.0 x 10-3
4.0 x 10-3
4.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
1.0 x 10-3
1.0 x 10-3
1.0 x 10-3
1.0 x 10-3
6.7 x 10-4
6.7 x 10-4
2.0
6.7 x 10-1
2.0 x 10-1
6.7 x 10-2
4.0 x 10-2
2.0 x 10-2
2.0 x 10-2
1.0 x 10-2
6.7 x 10-3
6.7 x 10-3
4.0 x 10-3
4.0 x 10-3
4.0 x 10-3
4.0 x 10-3
4.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
1.0 x 10-3
5.0
6.7 x 10-1
4.0 x 10-1
2.0 x 10-1
6.7 x 10-2
4.0 x 10-2
4.0 x 10-2
2.0 x 10-2
2.0 x 10-2
2.0 x 10-2
1.0 x 10-2
1.0 x 10-2
6.7 x 10-3
6.7 x 10-3
6.7 x 10-3
6.7 x 10-3
4.0 x 10-3
4.0 x 10-3
2.0 x 10-3
4.0 x 10-3
4.0 x 10-3
4.0 x 10-3
* Example values. Do not directly use these values for site
applications. Site-specific values should be developed for actual
applications.
C-22
-------
TABLE C-5. EXAMPLE DILUTION FACTORS (DIMENSIONLESS) - CONTINUOUS AREA
SOURCE (NEUTRAL CONDITIONS) *
Downwind Distance (km)
0.1
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
10.5
11.0 - 11.5
Source Area (Acres)
0.5
4.0 x 10-1
6.7 x 10-2
4.0 x 10-2
2.0 x 10-2
1.0 x 10-2
6.7 x 10-3
6.7 x 10-3
4.0 x 10-3
4.0 x 10-3
4.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
1.0 x 10-2
1.0 x 10-2
1.0 x 10-2
1.0 x 10-2
1.0 x 10-2
6.7 x 10-3
6.7 x 10-3
1.0
6.7 x 10-1
1.0 x 10-1
4.0 x 10-2
2.0 x 10-2
2.0 x 10-2
1.0 x 10-2
1.0 x 10-2
6.7 x 10-3
6.7 x 10-3
4.0 x 10-3
4.0 x 10-3
4.0 x 10-3
4.0 x 10-3
4.0 x 10-3
4.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
1.0 x 10-2
2.0
6.7 x 10-1
2.0 x 10-1
6.7 x 10-2
4.0 x 10-2
4.0 x 10-2
2.0 x 10-2
2.0 x 10-2
2.0 x 10-2
1.0 x 10-2
1.0 x 10-2
6.7 x 10-3
6.7 x 10-3
6.7 x 10-3
6.7 x 10-3
4.0 x 10-3
4.0 x 10-3
4..C) x 10-3
4.0 x 10-3
4.0 x 10-3
4.0 x 10-3
4.0 x 10-3
4.0 x 10-3
2.0 x 10-3
5.0
6.7 x 10-1
4.0 x 10-1
2.0 x 10-1
1.0 x 10-1
6.7 x 10-2
4.0 x 10-2
4.0 x 10-2
4.0 x 10-2
2.0 x 10-2
2.0 x 10-2
2.0 x 10-2
2.0 x 10-2
2.0 x 10-2
1.0 x 10-2
1.0 x 10-2
1.0 x 10-2
6.7 x 10-3
6.7 x 10-3
6.7 x 10-3
6.7 x 10-3
6.7 x 10-3
6.7 x 10-3
6.7 x 10-3
* Example values. Do not directly use these values for site
applications. Site-specific values should be developed for actual
applications.
C-23
-------
TABLE C-6. EXAMPLE AREA SOURCE DILUTION FACTORS (DIMENSIONLESS) -
CONTINUOUS (STABLE CONDITIONS) *
Downwind Distance (km)
0.1
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6,0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0 - 11.5
Source Area (Acres)
0.5
4.0 x 10-1
6.7 x 10-2
4.0 x 10-2
2.0 x 10-2
1.0 x 10-2
6.7 x 10-3
6.7 x 10-3
4.0 x 10-3
4.0 x 10-3
4.0 x 10-3
4.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
1.0 x 10-3
1.0 x 10-3
1.0
6.7 x 10-1
2.0 x 10-1
6.7 x 10-2
4.0 x 10-2
2.0 x 10-2
2.0 x 10-2
1.0 x 10-2
1.0 x 10-3
6.7 x 10-3
6.7 x 10-3
6.7 x 10-3
4.0 x 10-3
4.0 x 10-3
4.0 x 10-3
4.0 x 10-3
4.0 x 10-3
4.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0 x 10-3
2.0
6.7 x 10-1
2.0 x 10-1
6.7 x 10-2
4.0 x 10-2
4.0 x 10-2
2.0 x 10-2
2.0 x 10-2
2.0 x 10-2
1.0 x 10-2
1.0 x 10-2
1.0 x 10-3
6.7 x 10-3
6.7 x 10-3
6.7 x 10-3
6.7 x 10-3
6.7 x 10-3
4.0 x 10-3
4.0 x 10-3
4.0 x 10-3
4.0 x 10-3
4.0 x 10-3
5.0
6.7 x 10-1
4.0 x 10-1
2.0 x 10-1
1.0 x 10-1
6.7 x 10-2
4.0 x 10-2
4.0 x 10-2
4.0 x 10-2
4.0 x 10-2
2.0 x 10-2
2.0 x 10-2
2.0 x 10-2
2.0 x 10-2
2.0 x 10-2
1.0 x 10-2
1.0 x 10-2
1.0 x 10-3
1.0 x 10-3
1.0 x 10-3
1.0 x 10-3
6.7 x 10-3
* Example values. Do not directly use these values for site
applications. Site-specific values should be developed for actual
applications.
C-24
-------
TABLE C-7. EXAMPLE DILUTION FACTORS - INSTANTANEOUS RELEASE
Downwind
Distance
(km)
0.1
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
10.5
11.0
11.5
Dilution Factor (dlmenslonless)
Unstable*
Neutral*
Stable*
* Site-specific values should be developed.
C-25
-------
Step 4 - Estimate Downwind Concentrations
• Use Equation C-l if the 10-meter downwind concentration has been
measured.
(Dilution
(Concentration (Concentration w Factor ir -\\
at Distance X) s at 10 m) x aj (C"1}
Distance X)
Example:
A release occurs at an excavation pit. The measured peak
concentration is 500 parts per million (ppm) at a nominal
distance of 10 meters from the source.
According to data from the meteorological tower, the sigma theta
value indicates neutral stability.
Using the dilution factor table, neutral stability at
1 kilometer yields a dilution factor of 2.0xlO-4.
The calculation using the above formula for determining the
concentration at 1 kilometer is as follows:
500 ppm x 2.0x10-4 = 1.0x10-1 ppm
= 0.01 ppm
= 100 parts per billion (ppb)
Use Equation C-2 to estimate 10-meter concentrations if the
default emission rates (Table C-l) or measured emission rates
are used to characterize the release (obtain the 10-meter
dilution factor values from Table C-8).
C-26
-------
TABLE C-8. EXAMPLE DILUTION FACTORS
(sec/m3) AT 10 METERS IF EMISSION RATE DATA ARE
AVAILABLE*
Point Source
Area Source
0.5 acre
1.0 acre
2.0 acres
5.0 acres
Instantaneous
Unstable
Neutral
Stable
Site-specific values should be developed.
C-27
-------
(Dilution
(Concentration (Emission Rate, Factor at
at 10 m. vg/m3) = ug/sec) * Distance X,
sec/m3)
• Use Equations C-3 and C-4 to convert concentration units, as
necessary.
Concentration, ppb * (Concentration, yg/m3) x 24.04 (C-3)
M
where
M is the molecular weight of the constituent of interest
ppb is parts per billion by volume at 20°C
M
Concentration, yg/m3 = (Concentration, ppb) x _ (C-4)
C-28
-------
Step 5 - Compare Concentrations to Action Levels, Health Criteria, and
Odor Thresholds
• Compare concentration predictions at downwind distances of
Interest to the criteria presented in Table C-9.
• If only total organic concentration data are available, these
concentrations can be conservatively scaled using the
constituent-specific composition values presented in Table C-l.
C-29
-------
TABLE C 9. EXAMPLE AIR CRITERIA FOR SITE X *
Total Organics
Benzene
Carbon Tetrachloride
Chloroform
Ethyl Benzene
1 , 1 ,2,2-Tetrachloroethane
Tetrachloroethylene
Site Health and
Safety Plan
Action Levels
STELa
(15 min)
25 ppm
20 ppm
50 ppm
125 ppm
5 ppm
IDLHb
(30 min)
10 ppm
300 ppm
1,000 ppm
2,000 ppm
150 ppm
500 ppm
State ARAR
(1 hr)
0.1 ppm
0.05 ppm
0.1 ppm
1.0 ppm
0.01 ppm
5.0 ppm
PELC
(8 hr)
0.1 ppm
10 ppm
50 ppm
100 ppm
5 ppm
100 ppm
Odor
Threshold
31 ppm
725 ppm
733 ppm
4.7 ppm
o
I
Cv*
o
a STEL - Short Term Exposure Limit (ACGIH)
b IDLH - Immediately Dangerous to Life or Health (NIOSH/OSHA)
c PEL - Permissible Exposure Limit (NIOSH/OSHA)
* Example values. Do not directly use these values for site applications.
Site-specific values should be developed for actual applications.
-------
Step 6 - Estimate Plume Travel Times
• Determine the downwind distance from the source to potential
receptors of interest.
• Select unit travel time (i.e., for 1 km or 1 mile) from Table
C-10.
• Estimate plume travel time based on Equation C-5
(Travel
Time to
Receptor)
(Receptor
Downwi nd
Distance)
(Unit
Travel
Time)
(Eq. C-5)
C-31
-------
TABLE C-10
EXAMPLE PLUME TRAVEL TIME
VALUES FOR UNIT (1 KM AND 1 MILE) DISTANCES *
Wind Speed
(M/S)
0.447
0.894
1.341
1.788
2.235
2.682
3.129
3.576
4.023
4.470
4.917
5.364
5.811
6.258
6.705
7.152
7.599
8.046
8.493
8.940
Wind Speed
(MPH)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Time to Travel 1 km
Minutes
37.0
18.6
12.4
9.3
7.5
6.2
5.3
4.7
4.1
3.7
3.4
3.1
2.9
2.7
2.5
2.4
2.2
2.1
2.0
1.9
Seconds
2,240
1,120
745
560
450
370
320
280
250
225
205
190
170
160
150
140
130
125
120
1110
Time to Travel 1 Mile
Minutes
60.0
30.0
20.0
15.0
12.0
10.0
8.6
7.5
6.7
6.0
5,5
5.0
4.6
4.3
4.0
3.7
3.5
3.3
3.2
3.0
Seconds
3,600
1,800
1,200
900
720
600
514
450
400
360
327
300
277
257
240
225
212
200
189
180
* Example values. Do not directly use these values for site
applications. Site-specific values should be developed for actual
applications.
C-32
-------
Step 7 - Document Assessment/Results
• Document the results using a standard form (Table C-ll)
• Repeat the steps 1f the release continues.
C-33
-------
TABLE C-ll. EXAMPLE OF APA FIELD GUIDE
INFORMATION FORM (page 1 of 4)
A. Date: Person providing Information:
B. Point Source - use Appendix A
(Circle one)
Area source - use Appendix B
Area source size: acre(s)
C. OBSERVED DATA Time:
Maximum concentration at 10 meters from the source
ug/m3 or ppm
Wind direction* degrees from true N
Wind speed* m/sec
Sigma theta* degrees
*15-minute averages unless otherwise noted
D. IMPACTED AREA
Plume direction from the source: degrees
Overlay used: Unstable Neutral Stable (Circle one)
Impacted receptors of concern (list):
E. DILUTION FACTOR
Unstable Neutral Stable (Circle one)
C-34
-------
TABLE C-ll (page 2 of 4)
F. CALCULATE DOWNWIND CONCENTRATION
Distance
(km)
0.1
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
10.5
11.0
Dilution
Factor
Maximum Concentration
Measured at 10 m (Ch1)
(ug/m3 or ppm)
Computed
Downwind
Concentration
(wg/m3 or
ppm)
Air
Criteria
(ug/m3)
C-35
-------
TABLE C-ll (page 3 of 4)
G. PLUME TRAVEL TIME
To potentially Impacted receptors of concern:
Receptor Distance (Km or Mi) Travel Time (minutes or seconds)
H. COMMENTS
I. ADDITIONAL INFORMATION
Spill chemical compound(s)1
Spill amount: gal. or L
Spill area: m2
*If unknown, indicate the compound used for the Health Criteria Assessment
C-36
-------
TABLE C-ll (page 4 of 4)
Concentrations measured at locations other than 10 meters downwind:
Location Concentration (wg/n»3 or ppm)
C-37
-------
NOTICE TO THE READER - IF YOU WOULD LIKE TO RECEIVE
UPDATED AND/OR REVISED COPIES OF THIS VOLUME IN THE
NATIONAL TECHNICAL GUIDANCE STUDIES SERIES, PLEASE
COMPLETE THE FOLLOWING AND MAIL TO:
Mr. Joseph Padgett
U.S. Environmental Protection Agency
MD-10
Research Triangle Park, North Carolina 27711
Volume No.
Title
Name
Address
Telephone No.
------- |