OSWER Directive 9360.4-09
EPA 540/R-95/140
PB96-963206
December 1995
SUPERFUND PROGRAM
REPRESENTATIVE SAMPLING GUIDANCE
VOLUME 2: AIR (SHORT-TERM MONITORING)
Interim Final
Environmental Response Team
Office of Emergency and Remedial Response
Office of Solid Waste and Emergency Response
U.S. Environmental Protection Agency
Washington, D.C. 20460
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Notice
The policies and procedures established in this document are intended solely for the guidance of government
personnel, for use in the Superfund Program. They are not intended, and cannot be relied upon, to create any rights,
substantive or procedural, enforceable by any party in litigation with the United States. The Agency reserves the right
to act at variance with these policies and procedures and to change them at any time without public notice.
This guidance is applicable throughout the Superfund Program for short-term air sampling and monitoring. It is a
necessary component of Superfund guidance because of its focus on short-term air monitoring.
Though this document contains valid information for performing air impact assessments for long-term actions, it may
be useful to consult air sampling guidance which focuses on long-term monitoring, if applicable to the given situation.
The References section of this document contains a number of sources that focus on air sampling for long-term
monitoring.
Questions, comments, and recommendations are welcomed regarding the Superfund Program Representative
Sampling Guidance, Volume 2: Air (Short-Term Monitoring). Send remarks to:
Mr. William A. Coakley
Chairman, U.S. EPA Representative Sampling Committee
U.S. EPA-ERT
Rantan Depot - Building 18, MS-101
2890 Woodbridge Avenue
Edison, NJ 08837-3679
For additional copies of the Superfund Program Representative Sampling Guidance, Volume 2: Air (Short-Term
Monitoring), please contact:
Superfund Document Center
U.S. EPA-Headquarters
401 M Street, SW
Washington, DC 20460
(703)603-8719
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Disclaimer
This document has been reviewed under U.S. Environmental Protection Agency policy and approved for publication.
Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
The following trade names are mentioned in this document:
IBM® is a registered trademark of International Business Machines Corporation of Armonk, New York
XAD® is a registered trademark of Rohm and Haas Company of Philadelphia, Pennsylvania
MIRAN® is a registered trademark of Wilks Scientific Corporation of Norwalk, Connecticut
TEFLON® is a registered trademark of E.I. duPont de Nemours and Company of Wilmington, Delaware
TEDLAR® is a registered trademark of E.I. duPont de Nemours and Company of Wilmington, Delaware
HNu® is a registered trademark of HNu Systems, Inc. of Newton, Massachusetts
in
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Acknowledgments
This document was prepared by the U.S. EPA Committee on Representative Sampling for the Removal Program,
under the direction of Mr. William A. Coakley, Chairman, Representative Sampling Committee, Environmental
Response Team, Emergency Response Division, and Mr. Tom Pritchett, Environmental Response Team, Emergency
Response Division. The support provided by members of the Representative Air Sampling Workgroup in developing
and reviewing the document is greatly appreciated. Additional support was provided under U.S. EPA contract #68-
WO-0036.
EPA Headquarters
Office of Emergency and Remedial Response
Office of Research and Development
Sella Burchette
Philip Campagna
William Coakley
Joe LaFornara
Tom Pritchett
Rod Turpin
Joe Baumgarner
Bob Lewis
Bill McClenny
Bill Mitchell
Joe Touma
EPA Regions
Region 1
Region 2
Region 4
Region 6
Region 7
Region 8
Peter Kahn
Rick Spear
Larry Brannen
Danny France
Mark Hansen
John Rauscher
Jody Hudson
Norm Huey
Peter Stevenson
IV
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Table of Contents
1.0 INTRODUCTION 1
1.1 OBJECTIVE AND SCOPE 1
1.2 TERMINOLOGY 1
1.3 AIR IMPACT ASSESSMENT STRATEGIES 2
1.4 REPRESENTATIVE SAMPLING 2
1.5 CONCEPTUAL SITE MODEL 3
1.6 UNIQUENESS OF AIR AS A SAMPLING MEDIUM 5
1.7 EXAMPLE SITES 5
2.0 SAMPLING DESIGN 6
2.1 INTRODUCTION 6
2.2 OBJECTIVES 6
2.2.1 Data Quality Objectives 6
2.2.2 On-Site Health and Safety Assessment 7
2.2.3 Off-Site Acute Exposure Assessment 7
2.2.4 Off-Site Chronic Exposure Assessment 10
2.2.5 Environmental Impacts 10
2.2.6 Confirmatory Sampling 10
2.2.7 Odor Complaint Assessment 10
2.2.8 Source Evaluation 11
2.3 AIR SAMPLING PLAN CHECKLIST 11
2.3.1 Objectives of the Sampling Program and Implied Assumptions 13
2.3.2 Selection of Sampling and Analytical Methods 14
2.3.3 Location and Number of Individual Sampling Points 14
2.3.4 Time, Duration, and Frequency of Sampling Events 15
2.3.5 Meteorological Data Requirements 17
2.4 METEOROLOGICAL AND PHYSICAL/CHEMICAL CONSIDERATIONS 17
2.4.1 Meteorological Parameters 17
2.4.2 Meteorological Effects 17
2.4.3 Physical/Chemical Factors 18
2.4.4 Environmental Interferences 19
2.5 SAMPLING QA/QC 19
3.0 SAMPLING AND ANALYTICAL TECHNIQUES 20
3.1 INTRODUCTION 20
3.1.1 Air Sampling Methods Database 20
3.1.2 Overview of the Methods and Techniques for Air Sampling 20
3.2 DIRECT READING INSTRUMENTS AND TECHNIQUES 29
3.2.1 Portable Screening Devices 29
3.2.2 Specialized Analytical Instruments 30
3.3 SAMPLING EQUIPMENT 30
3.3.1 High Volume, Total Suspended Particulate (TSP) Samplers 30
3.3.2 PM-10 Samplers 30
3.3.3 High Volume PS-1 Samplers 30
3.3.4 Personal Sampling Pumps 30
3.3.5 Canister Samplers 31
3.4 SAMPLING COLLECTION MEDIA/DEVICES 31
3.4.1 Canisters 31
3.4.2 Passive Dosimeters 31
3.4.3 Polyurethane Foam (PUF) 31
3.4.4 Sampling Bags 31
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3.4.5 Impingers 31
3.4.6 Sorbent Tubes/Cartridges 32
3.4.7 Particulate Filters 33
3.5 ANALYTICAL TECHNIQUES 33
3.5.1 High Performance Liquid Chromatography (HPLC) 33
3.5.2 Gas Chromatography (GC) 33
3.5.3 Wet Chemical/Photometric Analyses 34
3.5.4 Ion Chromatography (1C) 34
3.5.5 Atomic Absorption (AA) 34
3.5.6 Inductively Coupled Plasma (ICP) Emission Spectrometry 34
3.5.7 X-Ray Fluorescence (XRF) 34
3.6 OVERVIEW OF AIR ASSESSMENT MODELS 34
3.6.1 Emissions Models 34
3.6.2 Atmospheric Dispersion Models 35
4.0 QUALITY ASSURANCE/QUALITY CONTROL EVALUATION 36
4.1 INTRODUCTION 36
4.2 DATA CATEGORIES 36
4.3 SOURCES OF ERROR 36
4.3.1 Sampling Design 36
4.3.2 Sampling Methodology 37
4.3.3 Analytical Procedures 37
4.4 REPRESENTATIVENESS OF THE SAMPLES (QA/QC OF THE METHOD) 37
4.5 QA/QC SAMPLES 37
Appendix A — Other Factors Affecting Sampling Design Parameters 42
Appendix B — Representative Air Sampling Plan: Example Sites 49
Appendix C — Example of Flow Diagram for Conceptual Site Model 64
References 67
VI
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Tables
Table
1
2
3
4
5
6
A-l
Air Sampling Objectives/Situations
Summary of Direct Reading Instruments and Techniques
Summary of Sampling Equipment
Summary of Sampling Collection Media/Devices
Summary of Analytical Techniques
Types of QA/QC Samples
Kev to Stability Classes
Page
9
22
24
25
28
40
43
Vll
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Figures
Figure Page
1 Conceptual Site Model 4
2 The Data Quality Objectives Process 8
3 Effects of Off-Site Contamination Sources on On-Site Monitoring and Sampling 16
A-l Effect of Typical Stability Data on Downwind Concentrations
From the Same Source 43
B-l Wood Preserving Company Site Map 52
B-2 Train Derailment Emergency Response Site Map 60
C-l Migration Routes of a Gas Contaminant 64
C-2 Migration Routes of a Liquid Contaminant 65
C-3 Migration Routes of a Solid Contaminant 66
Vlll
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1.0 INTRODUCTION
1.1 OBJECTIVE AND SCOPE
This document is the second volume of a series of
guidance documents designed to assist site managers
in obtaining representative samples at Superfund sites.
While most of the information contained within this
document is valid for any Superfund activity where air
sampling is necessary, the specific focus is on short-
term air monitoring (i.e., measuring for immediate
effects or worst-case scenarios rather than trends).
Unlike soil and water, air is an extremely variable
matrix. Contaminant concentrations in air can vary
naturally by orders of magnitude because of changes
in weather conditions on site. Thus, for air,
representative sampling strives to reflect accurately
the concentration of the contaminant(s) of concern at
a given time, and to determine whether that period of
time represents "typical" or "worst case" site
conditions, both spatially and temporally. This
guidance document aids in developing and
implementing a sampling design which assesses the
site's impact on ambient air while maintaining the
objectives and scope of the Superfund Program.
Impact assessments, when done properly, yield a
comprehensive set of data that is very useful for site
and risk characterization.
An air impact assessment (also referred to as air
pathway assessment or analysis) is a systematic
evaluation of the potential or actual effects of an
emission source on air quality. The primary goals of
an air impact or pathway assessment are:
• Characterization of air emission sources
• Determination of the effects of atmospheric
processes such as transport and dilution
• Evaluation of the exposure potential at receptors
of interest
1.2 TERMINOLOGY
In this document, the term air monitoring refers to
the use of direct-reading instruments and other
screening or monitoring equipment and techniques
which provide real-time data on the levels of airborne
contaminants. Examples of air monitoring equipment
are hand-held photoionization detectors (PIDs), flame
ionization detectors (FIDs), and oxygen/combustible
gas detectors.
Air sampling is defined as those sampling and
analytical techniques which require either off-site or
on-site laboratory analysis, and therefore do not
provide immediate results. Air sampling techniques
are used to gain more accurate information than most
air monitoring technologies in detecting, identifying,
and quantifying specific chemical compounds.
Examples of air sampling equipment include sampling
bags, sorbent tubes/cartridges, and impingers.
Both air monitoring and sampling under the Superfund
program are conducted in the following four
situations:
Site Assessments:
Site assessments are undertaken to determine if
hazardous substances are being released and the
extent of contamination at a site. This
information is useful for determining the
appropriate response to a release or threatened
release. Site assessments may include a site
inspection, multi-media sampling, and other data
collection.
Emergency Responses:
Emergency responses are immediate responses to
a release or threatened release of hazardous
substances presenting an imminent danger to
public health or welfare or the environment (e.g.
chemical spills, fires, or chemical process failures
resulting in an uncontrolled release of hazardous
substances).
Early Actions:
Early actions are initiated to eliminate non-
ubiquitous hazardous substances from locations
where problems have developed or are likely to
develop as a result of the presence of these
contaminants. Early actions are generally limited
to mitigating surface and shallow subsurface
contamination, access control, and addressing
other threats that can be dealt with relatively
quickly. The responses may include any activity
conducted to abate, prevent, minimize, stabilize,
or eliminate a threat to public health or welfare
and the environment.
Long-Term Actions:
Long-term actions are undertaken to address
situations that are (or have the potential to be)
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chronic in nature (e.g., ground water remediation,
wetland restoration). These actions often include
the use of treatment technologies to reduce
threats. In long-term actions, trends in
contaminant concentrations and mobility often are
studied to develop a cleanup strategy.
1.3 AIR IMPACT ASSESSMENT
STRATEGIES
Two basic approaches can be used to conduct air
impact assessments: either 1) modeling or 2)
monitoring (measurement). The modeling approach
forecasts the overall site emission rate(s) and
pattem(s). Data from preliminary air monitoring (e.g.,
wind direction, wind speed) are entered into an
appropriate air dispersion model which predicts either
the maximum or the average air concentrations at
selected locations or distances during the time period
of concern. This overall modeling strategy is
presented in Volume 4 of the Air/Superfund National
Technical Guidance Series on Air Pathway
Assessments. Specific applications of this strategy
are presented in various Air/Superfund technical
guidance documents (see References Section).
Note: Issues covered in this guidance document
apply only to monitoring (data gathering).
The second basic assessment strategy involves
monitoring actual air impacts during specific time
intervals (e.g., during clean-up operations). This
documented impact can be used to confirm or refute
modeling results, or to extrapolate the probable "worst
case" concentrations (i.e., when a combination of
meteorological and site conditions is expected to
cause the highest concentration of contaminants).
This extrapolation is important because worst-case
conditions may exist at a site over a longer time
period than the duration of sampling.
A strong technical background in air emissions
modeling, monitoring, and risk assessment is required
in order to make appropriate assumptions and
judgments when performing an air impact assessment.
The Air/Superfund National Technical Guidance
Series on Air Pathway Assessments should serve as a
guide to On-Scene Coordinators, Remedial Project
Managers, Site Assessment Managers, and Regional
air program staff when establishing data quality
objectives and appropriate approaches for an air
impact assessment. This series allows flexibility in
tailoring the air assessment to the specific conditions
at a site, the relative risk posed by air and other
pathways of exposure, and the resource constraints of
the program. The Air Methods Database, which
contains information on chemical analysis methods
can be a useful resource. Air impact assessments are
not simple, concrete procedures; the Air/Superfund
National Technical Guidance Series is designed for
flexibility and the use of professional judgment.
Because of the uniqueness of the air medium, this
representative sampling guidance document is not a
"how-to" manual for developing an air sampling plan;
rather, it presents factors that should be considered in
conjunction with other EPA guidance when
developing a site-specific sampling plan. These
considerations include:
• The selection of sampling and analytical methods
• The location and number of sampling points
• The time, duration, and frequency of sampling
events
• Meteorological data
• The impact of topographic, meteorologic, and
physical/chemical parameters on the sampling
plan design
This guidance document also presents an overview of
the sampling and analytical techniques used when
implementing the sampling plan, and the quality
assurance/quality control (QA/QC) requirements
which must be incorporated into sampling activities.
The Air/Superfund National Technical Guidance
Series on Air Pathway Assessments should be referred
to for more specific applications and guidance on air
monitoring and modeling.
1.4 REPRESENTATIVE SAMPLING
Representative air sampling ensures that a sample or
group of samples accurately reflects the concentration
of the contaminant(s) of concern at a given time and
that the selected time period is truly representative of
either "typical" or "worst case" conditions. The site-
specific sampling plan should be designed to identify
sources of contaminant emissions, to establish either
natural background or upwind conditions, to establish
baseline concentrations of contaminants (i.e., prior to
intrusive activities), and to identify contaminants of
concern and the ranges of their concentration on site
and downwind of the site. Each site's sampling plan
should be designed to answer the following questions:
• What objective will the sampling achieve?
• What sampling design approach is appropriate to
accurately characterize the on-site and upwind
emissions of contaminants and their downwind
transport?
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• How many samples need to be collected to
adequately depict site conditions, the impact of
upwind sources, and/or the variability of the
downwind transport of contaminants?
• During what time period should samples be
collected?
• What equipment should be used to collect and
analyze samples?
• What precautions should be taken when shipping
samples from the field to the laboratory?
• Which QA/QC samples are applicable?
The following factors affect the representativeness of
samples and measurements collected at a site:
• Meteorology, suspected upwind sources, and
topography of sampling locations
• Number of distinct sampling events
• Duration of sampling activities sufficient for the
period of exposure
• Timing of sampling activities with respect to
expected "ambient" or "worst case" emissions
(time of sampling also depends on downwind
transport of contaminants)
• Distinction between meteorology during the
sampling period(s) and the typical meteorology
during the entire period of concern
• Analytes of concern
• Type of release (e.g., sampling during a drum
rupture or instantaneous release, versus a
continuous release from contaminated soil)
1.5 CONCEPTUAL SITE MODEL
A conceptual site model is a useful tool for selecting
sampling locations. It helps ensure that sources,
pathways, and receptors throughout the site have been
considered before sampling locations are chosen. The
conceptual model assists the Site Manager in
evaluating the interaction of different site features.
Risk assessors use conceptual models to help plan for
risk assessment activities. Frequently, a conceptual
model is created as a site map (see Figure 1) or it may
be developed as a flow diagram which describes
potential migration of contaminants to site receptors
(see Appendix C).
A conceptual model follows contaminants from their
sources, to pathways (e.g., air, surface water), and
eventually to the assessment endpoints. Consider the
following when creating a conceptual model:
• The state(s) of each contaminant and its potential
mobility
• Site topographical features
• Meteorological conditions (e.g., wind
direction/speed, average precipitation,
temperature, humidity)
• Human/wildlife activities on or near the site
The conceptual site model on the next page is an
example created for this document. The model assists
in identifying the following site characteristics:
Potential Sources'.
Site (waste pile, lagoon, factory emissions); drum
dump (or associated soil gas); cropland (e.g., pesticide
application)
Potential Migration Pathway (Air):
Gases/vapors released from the waste pile, lagoon,
factory (emissions), drum dump (or associated soil
gas), or cropland
Potential Migration Routes'.
Inhalation, Absorption/Direct Contact — Gases/vapors
released from the waste pile, lagoon, factory
(emissions), drum dump (or associated soil gas), or
cropland
Potential Receptors of Concern'.
Human Population
Residents/Workers/Trespassers:
Inhalation or absorption/direct contact with
gases/vapors released from the waste pile, lagoon,
factory (emissions), drum dump (or associated
soil gas)
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\~^^PRECIPITATION
^\
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Biota
Endangered/threatened species or human food
chain organisms which are suspected to be
inhaling or in direct contact with contaminated air
Preliminary site information may provide the
identification of the contaminant(s) of concern and the
level(s) of the contamination. A sampling plan should
be developed based upon the selected receptors of
concern and the suspected sources and pathways. The
model may assist in the selection of on-site and off-
site sampling locations.
1.6 UNIQUENESS OF AIR AS A
SAMPLING MEDIUM
on-site conditions. When air measurements are used
to represent the average air impact due specifically to
a hazardous waste site (versus the overall ambient air
quality), error most often arises in extrapolating the
data from a limited time period to a much longer time
period. Because of the variability of contaminants
existing and dispersing in air, interval calculations,
such as those used with soil and water, do not apply.
1.7 EXAMPLE SITES
Two example sites are presented in Appendix B. The
examples, a wood preserving facility and a train
derailment site, have been included to illustrate the
development of a site-specific representative air
sampling plan for two different situations.
Because of its variability, air is a unique medium
when compared to soil and water. When proper
representative sampling procedures are used, soil and
water samples collected at the same location but at
different times should produce similar results. Results
from air samplescollected at the same location but at
different times can differ by orders of magnitude
because of changes in predominant wind direction and
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2.0 SAMPLING DESIGN
2.1 INTRODUCTION
In the Superfund Program, site managers conduct air
monitoring and sampling during site assessments,
emergency responses, early actions, and remedial
actions. Each of the activities has a related air
monitoring/sampling objective which is used to
determine the potential hazards to workers and/or the
community. This chapter discusses air
monitoring/sampling situations. It is important to
remember that the general sampling decisions
presented here should also be considered during a
more extensive air impact assessment, which might be
performed for remedial investigations.
The goal of an air sampling plan is to accurately
assess a site's effect on air quality. This effect is
expressed in terms of overall average and/or
maximum air concentrations. Unlike soil
concentrations, air concentrations at points of interest
can vary by orders of magnitude throughout the period
of concern. This variability is a major consideration
in designing an air sampling plan. Determining the
location of potential sources is essential to the
selection of sampling locations.
Downwind air concentration is determined by the
amount of material being released from the site into
the air (the emission rate) and by the degree that the
contamination dilutes as it is transported. On-site
activities and site meteorology greatly influence
contaminant emission rates, while local meteorology
and topography govern downwind dilution. Besides
the wind direction, the other meteorological condition
of major concern is the atmospheric stability class.
(See Section 1.3 of Appendix A for a discussion of
stability classes.) Incorporate all of these
considerations into an air sampling plan.
The complexity of a sampling strategy depends on its
objectives. Characterization studies of the pollutant
contribution from a single point source tend to be
simple. Characterization studies of the fate and
transport of components of multiple sources require a
more complex sampling strategy. Resource
constraints may also affect the complexity of the
sampling design.
An optimal sampling strategy accounts for the
following site parameters:
• Location of stationary as well as mobile sources
• Analytes of concern
• Analytical detection limit needed
• Rate of release and transport of pollutants from
sources
• Sufficient numbers of samples in terms of
location and time to meet sampling objectives
• Availability of space and utilities for operating
sampling equipment
• Meteorological monitoring data
• Meteorological conditions in which sampling is
to be conducted
The U.S. EPA's Quality Assurance Sampling Plan for
Environmental Response (QASPER), OSWER
Directive 9360.4-01, was designed to develop
sampling plans for response actions. QASPER is
menu-driven software which prompts the user to input
background information and to select prescribed
parameters for development of a site-specific
sampling plan. It also gives the user access to any
previously developed site-specific sampling plans.
QASPER is a useful resource that should be consulted
when developing a sampling plan.
2.2 OBJECTIVES
Air sampling is conducted to demonstrate the presence
or absence of airborne contaminants. Sampling
objectives determine sample quantities, sampling
program length, sample locations, detection limits,
and analytical response time. Detection limits depend
on the contaminants being investigated and the
particular site situation. It is important to know why
air sampling data are needed and how the data will be
used. Ensure that the sampling detection limits are
adequate for the intended use of the results. Legal and
liability objectives also need to be fulfilled.
2.2.1 Data Quality Objectives
Data Quality Objectives (DQOs) must be considered
when designing an air sampling plan. DQOs are used
to develop a scientific and resource-effective sampling
plan. The DQO process is a seven part planning tool
based on the scientific method, to ensure that the type,
quantity, and quality of environmental data used in
decision making are appropriate for the intended
application. Figure 2 describes the steps in the DQO
process.
Air samples are collected to address the following
specific objectives in the Superfund Program:
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On-Site Health and Safety Assessment — to
determine proper levels of protection for on-site
personnel.
Off-Site Acute Exposure Assessment — to
evaluate the potential of airborne contaminants
from the site to cause acute exposure to nearby
populations.
Off-Site Chronic Exposure Assessment — to
evaluate the potential of airborne contaminants
from the site to cause chronic exposure to nearby
populations.
Environmental Impacts — to evaluate potential
acute or chronic effects on environmental
receptors (e.g., fisheries or wetlands) from
airborne contaminants.
Confirmatory Sampling
monitoring data.
to confirm air
• Odor Complaint Assessment -- to investigate
odor sources.
• Source Evaluation — to identify potential
sources of airborne contaminants on site and off
site as well as the specific contaminants
associated with those sources.
Table 1 illustrates which of the above objectives apply
to the four air sampling site situations listed in
Section 2.1. When developing the sampling plan,
consider the following site and meteorological
conditions:
• Worst case — sampling conducted under
meteorological and/or site conditions which result
in elevated or "worst" ambient concentrations.
2.2.2 On-Site Health and Safety
Assessment
Data collection is necessary for selecting the proper
levels of personal protection for site workers. After
the level of protective equipment is selected,
subsequent air monitoring ensures that new releases
do not warrant either elevating the level of protection
or moving the support zone. Appropriate real-time
monitoring equipment can determine:
• Oxygen content (percent oxygen)
• Percent lower explosive limit (LEL)
• Total suspended particulates and aerosols
• Organic compound concentrations
• Radiation levels
• Toxic gases (e.g., HCN, H2S)
2.2.3 Off-Site Acute Exposure
Assessment
The exposure of off-site receptors is typically
evaluated at several steps of the Superfund process.
Both modeling and monitoring approaches may be
employed as part of an overall air impact assessment.
The potential of airborne contaminants from the site to
cause acute exposure (by inhalation, absorption, or
irritation) in nearby populations must be considered.
Acute exposure is defined as one or more short-term
chemical exposures that cause adverse health effects
in an individual. Acute health effects are generally
observed immediately or within the first few days
following exposure; however, there may be a longer
period of latency before effects appear.
Typical — routine daily sampling or routine
scheduled sampling at pre-established locations.
One-Time — only one chance is available to
collect a sample without regard to time or
conditions (e.g., during a fire). (Qualitative data
acquired under these conditions usually are
applicable only to the time period during which
the data were collected. They may not be
accurate enough to be used in estimating the
magnitude of an air impact during other periods
or over a long time interval.)
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Figure 2
The Data Quality Objectives Process
1 . State the Problem
Summarize the contamination problem that will require new environmental
data, and Identify the resources available to resolve the problem.
A
2. Identify the Decision
Identify the decision that requires new environmental
data to address the contamination problem.
4.
3. Identify Inputs to the Decision
Identify the Information needed to support the decision, and
specify which Inputs require new environmental measurements.
i
4. Define the Study Boundaries
Specify the spatial and temporal aspects of the environmental
media that the data must represent to support the decision.
1
5. Develop a Decision Rule
Develop a logical 'If... then...* statement that defines the conditions that
would determine the choice between alternative actions.
4
6. Specify Limits on Decision Errors
Specify the acceptable limits on decision errors, which are used to
establish performance goals for limiting uncertainty In the data.
7. Optimize the Design for Obtaining Data
Identify the most resource-effective sampling and analysis design
for generating data that satisfy the DQOs.
Adapted from Data Quality Objectives for Superfund
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TABLE 1: Air Sampling Objectives/Situations
SITUATIONS
OBJECTIVES
On-Site Health
and Safety Assessment
Off-Site Acute Exposure
Assessment
Off-Site Chronic Exposure
Assessment
Environmental Impact
Confirmatory Sampling
Odor Complaint Assessment
Source Evaluation
Air Pathway Assessment
Modeling
Emergency
Response
X
X
X
X
X
X
X
Site
Assessment
X
X
X
X
X
X
X
Early
Action
X
X
X
X
X
X
X
X
Long-Term
Action
X
X
X
X
X
X
X
X
Note: Removal actions can occur during an Emergency Response, Early Action, or Long-Term Action.
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Monitoring for off-site acute exposure provides a
basis for decisions to shelter-in-place or to evacuate
the surrounding population. Evacuation and/or
sheltering decisions are made by comparing the results
of on-site and off-site monitoring with established
health-based action levels. Real-time data are
necessary since most action levels for acute exposure
assessments are based on short-term average
contaminant concentrations (e.g., 15-minute, 1-hour,
8-hour average concentrations), and the decision to
evacuate must be made quickly. Off-site, real-time air
monitoring for acute exposure assessment provides
values for:
• Total organic compound concentrations
• Percent LELs
• Radiation levels
• Specific compound levels (or classes of
compounds)
2.2.4 Off-Site Chronic Exposure
Assessment
Long-term, average airborne contaminant data define
the health risk to the surrounding population over
time. Chronic health effects may appear after a period
of continuous or repeated exposure to a contaminant,
even at a low dosage. Off-site, long-term air sampling
techniques detect specific compounds at lower
concentration levels over longer periods than those
detected by real-time air monitoring techniques.
Air sampling is performed at the site perimeter, at off-
site locations (e.g., at selected receptor locations in
the surrounding community, such as a nearby school),
or on site, to determine:
• The presence of specific volatile and semi-
volatile particulates, and inorganic compounds
• Concentrations of airborne contaminants for 24-
hour and annual averages
• The rate of emissions from the site for subsequent
air dispersion modeling
A modeling approach for the evaluation of off-site
exposure generally involves atmospheric dispersion
modeling using an EPA-approved model (e.g.,
Industrial Source Complex (ISC) model). Contact
your Regional Air Program Coordinator for more
information regarding specific models and their
applications.
2.2.5 Environmental Impacts
For most sites, the evaluation of environmental
impacts will be associated with the evaluation of off-
site human exposures. The design of any air
monitoring or sampling network for environmental
impacts will focus primarily on determining exposure
of human populations off site. In general, the same
data used to evaluate the exposure of off-site
populations also can be used to evaluate adverse
effects on the environment. To address potential
environmental impacts completely, it may be
necessary to increase sampling locations (e.g., near
surface waters) and to include in the target analyte list
compounds that typically have a greater effect on
nonhuman targets. Modeling and monitoring
approaches may both be employed as part of the
evaluation of environmental impacts.
2.2.6 Confirmatory Sampling
During clean-up activities, confirmatory sampling
determines the accuracy of monitoring data and
whether an immediate or long-term health threat still
exists. Without confirmatory sampling, air releases of
unknown origin and/or composition would not be
detected. Air sampling is performed after real-time
air monitoring equipment has narrowed the number of
possible contaminants and has provided some measure
of contaminant concentration.
During emergency responses, confirmatory air
sampling is most often used to determine if an
evacuation order can be lifted and/or to ensure that
non-evacuated populations are not at risk.
Confirmatory sampling is warranted when the site
manager wishes to confirm that no airborne
contaminants are present, that a site is not affecting air
quality to a significant extent, or to verify real-time
monitoring information.
2.2.7 Odor Complaint Assessment
A site manager will generally initiate an odor
complaint assessment after local residents complain of
unpleasant, irritating odors, or when irritating odors
arise during a response action. Response to odor
complaints requires both the identification of the
contaminant(s) and its source (see Section 2.2.8). If
the odor complaint is a repeated one, try to perform air
sampling under the same meteorological conditions
that existed when previous odors were reported.
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2.2.8 Source Evaluation
Identification of potential sources of airborne
contaminants and quantification of specific
compounds emitted by these sources first require real-
time air monitoring to locate the source, followed by
air sampling to identify the compounds emitted.
Sometimes, source evaluation is accomplished
without sampling; it is possible to determine
emissions of certain contaminants with mathematical
formulas. During site assessment, source evaluation
may be required to help differentiate site emissions
from background air quality and off-site emissions
from other nearby sources such as industries and
highways.
Source emissions can then be used in an air quality
dispersion modeling analysis to predict pollutant
concentrations. Modeling results may provide the
basis for locating off-site monitoring equipment
and/or identifying potential evacuation areas. Air
monitoring/sampling for source evaluation is
performed to:
• Identify potential sources of air contaminants
Identify specific compounds emitted by a source
• Quantify emissions for subsequent air dispersion
modeling
2.3 AIR SAMPLING PLAN CHECKLIST
The following checklist consists of a series of questions to consider when developing the sampling program.
Additional information regarding each category follows the checklist.
I. Objectives of the Sampling Program and Implied Assumptions
A. Have clear, concise objectives for the sampling program been defined (such as those defined in section 2.2
of Chapter 2)?
B. Have the assumptions of the sampling program been defined (e.g., sampling under "worst-case" conditions,
sampling under "typical" conditions, sampling under a routine, periodic schedule, etc.)?
C. Other:
II. Selection of Sampling and Analytical Methods
A. Selection of Target Compounds
1. Has background site information been consulted?
B. Selection of Method (sampling and/or analytical)
1. Can selected methods detect the probable target compounds?
2. Do the selected analytical methods have detection limits low enough to meet the overall objectives
of the sampling program?
3. Would the selected methods be hampered by any interfering compounds?
C. Will the selected methods, when applied to the projected sampling location(s), adequately isolate the relative
downwind impact of the site from that of other upwind sources?
D. Are the selected methods logistically feasible at this site?
E. Other:
III. Location(s) and Number of Sampling Points
A. Does the selection of locations consider all the potential on-site emission sources that have been identified
from the initial site background information and from walk-through inspections?
B. Will the sampling locations take into account all the potential emission sources upwind from the site?
C. For short-term monitoring programs, has a forecast of the local winds been obtained for the day(s) of the
program?
D. For a long-term monitoring program, have long-term air quality dispersion models and historical
11
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meteorological data been used to predict probable areas of maximum impact (when applicable)?
E. Does the sampling plan take into account the effects of local topography on overall wind directions and
potential shifts in direction during the day (e.g., valley effects, shoreline effects, hillside effects)?
F. Do the sampling location decisions take into account the effects of topography on surface winds, especially
under more stable wind directions (e.g., channelization of surface winds due to buildings, stands of trees,
adjacent hills, etc.)?
G. Can sampling equipment left at these locations be adequately secured?
H. Other:
IV. Time, Duration, and Frequency of Sampling Events
A. When the sampling time periods (the actual days, as well as the time span during specific days) were
selected, were the effects of the following conditions on downwind transport of contaminants considered:
• Expected wind directions?
• Expected atmospheric stability classes and wind speeds?
• Evening and early morning temperature inversions?
• Changes in atmospheric pressure and surface soil permeability on lateral, off-site migration of gases from
methane-producing sources such as landfills?
• (During indoor air investigations) gas infiltration rates into homes affected by changes in atmospheric
pressure and by the depressurization of homes caused by many home heating systems?
• Other:
B. When the sampling time periods (the actual days, as well as the time span during specific days) were
selected, were the following effects on potential site emissions considered:
• Effect of site activities?
• Effect of temperature and solar radiation on volatile compounds?
• Effect of wind speeds on particulate-bound contaminants and on volatiles from lagoons?
• Effect of changes in atmospheric pressure on landfills and other methane-producing emission sources?
• Effect of recent precipitation on emissions of both volatile and particulate-bound compounds?
• Other:
C. Do the time periods selected allow for contingencies such as difficulties in properly securing the equipment,
or public reaction to the noise of generators for high volume samplers running late at night?
D. When determining the length of time over which individual samples are to be taken, were the following
questions considered (when applicable):
• Will sufficient sample volumes be taken to meet the desired analytical method detection limits?
• Will the sampling durations be adequate either to cover the full range of diurnal variations in emissions and
downwind transport, or to isolate the effects of these variations?
• When applicable, do the selected time intervals take into account potential wind shifts that could occur due
to local topography such as shorelines and valleys?
• Other:
V. Meteorological Data Requirements
A. Has a source of meteorological data been identified to document actual conditions at the time the sampling
event takes place?
B. Has the placement of an on-site meteorological station been considered in the sampling plan if no off-site
station has been identified?
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VI. QA/QC Requirements (see Chapter 5 for additional information on QA/QC requirements)
_ A. What level of QA/QC will be required?
B. Have the necessary QA/QC samples been incorporated into the sampling design to allow for the detection
of potential sources of error?
C. Does the QA/QC plan account for verification of the sampling design and the sample collection?
2.3.1 Objectives of the Sampling
Program and Implied
Assumptions
The sampling objectives must be addressed prior to
developing the sampling plan. Does the sampling
verify adequate levels of protection for on-site
personnel, or address potential off-site impacts
associated with the site or site activities? In addition
to defining the sampling objectives, also define the
assumptions associated with the sampling program.
These assumptions include whether the sampling is to
take place under "typical" or "worst case" conditions.
If the conditions present at the time of sampling are
different than those assumed during the development
of the sampling plan, then the quality of the data
collected may be affected.
The sampling objectives also determine the detection
limits. A sampling program may require several
detection limits for the same compound using various
sampling methods. Sampling objectives and their
associated methods and detection limits may include:
• On-Site Health and Safety Assessment
The primary sampling methods used are those of
NIOSH and OSHA. These methods utilize low
sample volumes with resultant high detection
limits in the mg/m3 range.
• Off-Site Acute Exposure Assessment
The same methods used for on-site health and
safety assessments are generally employed here.
However, more sensitive methods are available
which can yield lower detection limits in the
range of mg/m3 to Fg/rh , depending on the
compound.
• Off-Site Chronic Exposure Assessment and
Confirmatory/Odor Complaint Assessment
Sampling methods used require detection limits
of Fg/m3 to mg/m3, depending on the compound.
These methods generally are the most
complicated, and require large sample volumes
and extended sampling periods.
• Environmental Impacts
For determination of environmental impacts, site-
specific action levels (and associated detection
limits) should be developed, though guidance
may be limited. Procedures for evaluating
environmental exposure may also apply to the
evaluation of contaminant deposition onto
cropland, which may present a potential human
exposure pathway.
• Source Evaluation
Sources being sampled generally have an elevated
pollutant concentration, so methods with mg/m3
ranges are adequate.
The following are some general assumptions
regarding detection limits:
• The larger the sample volume, the lower the
detection limit which can be achieved.
• The larger the sample volume, the larger and
more complex the sampling equipment needed (in
most cases).
• The lower the detection limit, the greater the risk
of sample contamination.
• The larger the sample volume, the greater the
chance of breakthrough problems with sample
media
Each method has logistical constraints that need to be
taken into account (see Chapter 4).
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2.3.2 Selection of Sampling and
Analytical Methods
Unless the site is considered to present an emergency
requiring an immediate removal action, conduct a
thorough review of relevant site information in
addition to visiting the site, when feasible. This
information will assist in identifying compounds
likely to be encountered on site and can help identify
potential interference problems with the selected
methods. Time constraints often hinder
comprehensive research; concentrate on the most
important information first. A priority ranking of
information follows:
• Possible target compounds on site
• Possible concentration ranges of target
compounds
• Site maps
• Facility blueprints
• Data files including past and present storage,
process, and waste disposal areas (i.e., potential
emission sources)
• Area topographic maps
• Aerial photographs
Not all of the above information will be readily
available. No site-specific meteorological data will be
available for a site unless an air sampling program
was previously conducted at that site or at a nearby
meteorological station or large airport.
2.3.3 Location and Number of
Individual Sampling Points
Choose the number and location of sampling points
according to the variability or sensitivity of the
sampling and analytical methods being utilized, the
variability of contaminant concentrations over time at
the site, the level of precision required, and cost
limitations. Determine the number, locations, and
placement of samplers by considering: the nature of
the response; local terrain; meteorological conditions;
location of the site in relation to other conflicting
background sources; size of the site; and the number,
size, and proximity of separate on-site emission
sources and upwind sources. Meteorological effects
and other factors are discussed in Section 2.4.
Consider the following when placing samples:
• Location of potential on-site emission sources, as
identified from the review of site background
information or from preliminary on-site
inspections.
• The impact of potential off-site emission sources
located upwind of the sampling location(s).
Study local wind patterns to determine the
location of off-site sources.
• Location of topographic features which affect the
dispersion and transport of airborne toxic
constituents. Avoid natural obstructions when
placing air monitoring stations, and account for
channelization around those obstructions. (As a
general rule, the distance away from the
obstruction should be 10 times the height of the
obstruction.)
• Proximity of large water bodies which affect
atmospheric stability and dispersion of air
contaminants.
• Roadways (dirt or paved) which may generate
dust that could mask site contaminants. Traffic
patterns may also affect results.
• Vegetation such as trees and shrubs which
stabilize soil and slow the process of subsurface
contaminants becoming airborne. Vegetation also
affects air flow and scrubs some contaminants
from the air. Thick vegetation can make an
otherwise ideal air monitoring station location
inaccessible.
Consider the duration of sampling activities when
determining the location and number of samples
collected. For example, if the sampling period is
limited to a few hours, one or two upwind and several
downwind samples may be adequate, especially
around major emission sources. However, the shorter
the sampling period the less likely it is that the plume
will be detected and defined.
A short-term monitoring program can range from
several days to a few weeks and generally includes
gathering data for site assessments, removal or early
actions, and source determination data (for further
modeling). Activities involved in a short-term
sampling strategy must maximize the limited
possibilities for data collection. Consider moving
upwind/downwind locations daily based on National
Oceanic and Atmospheric Administration (NOAA)
weather forecasts. Weather monitoring becomes
critical where complex terrain and local
meteorological effects frequently change wind
direction. Often, alternative sampler placements can
reduce weather-related sampling error.
Complex terrain situations commonly require an
increased number of sampling locations. For
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example, a complex valley requires more sampler
locations to account for wind variation than does a
valley where prevailing winds run its length. Site-
specific situations may require innovative planning to
collect representative samples. For example, to
sample in an area affected by an ocean or lake, placing
two sets of samplers next to each other (so that one set
is activated during sea-breeze conditions and the other
during no sea-breeze conditions) ensures sampling
during all wind conditions. After the sampling event,
the respective upwind and downwind samples are
combined. Alternatively, sampling near a large body
of water may be performed with automatic, wind-
vector-operated samplers which turn on only when the
wind comes from a specific direction. In another
situation where sites are located on hillsides, wind
will move down a valley and produce an upward fetch
at the same time. Sampling locations may have to
ring the site to measure the impact of the wind.
Figure 3 depicts sites where off-site sources could
affect on-site monitoring. In these cases, on-site
meteorological data, concurrent with sampling data,
are essential for interpretation of the acquired data.
Additional upwind sampler sites may be needed to
fully characterize ambient background contaminant
levels. Multiple off-site sources may require several
monitoring locations, but in cases where the sources
are at a sufficient distance from the site, only one
monitoring location may be necessary.
Topography and weather are not the only
considerations in the placement of samplers; the
sampling sites must be secure from vandals and
mishap. Secure all sampling locations to maintain
chain of custody and to prevent sample tampering and
loss of sampling units. High-volume sampling
methods often require the use of 110 volt AC electric
power. When portable generators are used, the power
quality may affect sampler operation. Be aware that
the generators themselves could be a potential
pollution source if their placement is not carefully
considered.
Air quality dispersion models can be used to
determine the placement of samplers. The models
incorporate source information, surrounding
topography, and meteorological data to predict the
general distance and directions of maximum ambient
concentrations. Use modeling results to select
sampling locations in areas of expected maximum
pollutant concentrations.
2.3.4 Time, Duration, and
Frequency of Sampling
Events
After choosing appropriate sampling or monitoring
locations, determine the sampling frequency and the
number of samples to be collected. The time of day
and duration and frequency of sampling events are
governed by:
• Effects of site activities and meteorology on
emission rates
• Diurnal effect of the meteorology on downwind
dispersion
• Time period(s) of concern as defined by the
objective
• Variability in the impact from other non-site-
related sources
• Degree of confidence needed for the mean or
maximum downwind concentrations observed
• Precision requirements for single measurements
• Cost and other logistical considerations
The duration of the response action and the number of
hours per day that site work is conducted determine
sampling time, duration, and frequency. Short-term
sampling programs may require daily sampling, while
long-term programs may require 24-hour sampling
every sixth or twelfth day. If the site will be
undergoing response activities 24 hours a day,
continuous air sampling may be warranted. If the site
activities will go on for only 8 hours per day and there
are no emissions likely during the remaining 16 hours,
then appropriate sampling would begin prior to the
start of daily activities, continue during operations,
and end at the conclusion of the day's activities. An
off-peak sample collection ensures that emissions do
not persist after the conclusion of daily clean-up
activities. For some sites, emissions are still a factor
several hours after daily site activities have been
completed. Because of the typically decreased
downwind dispersion in the evening, higher
downwind concentrations may be detected. For sites
where this is a possibility, lengthen the sampling
duration accordingly.
Air quality dispersion models can predict the
maximum air contaminant concentration expected
from a source. The meteorological and site conditions
expected to cause the highest concentration are known
as "worst-case" conditions and can be identified by
analyzing the modeling results. Depending on the
objective, sample at times when the model predicts
worst-case conditions to exist.
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Figure 3
Effects of Off-Site Contamination Sources on
On-Site Monitoring and Sampling
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16
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2.3.5 Meteorological Data
Requirements
A meteorological monitoring program is an integral
part of site monitoring activities. Meteorological data
which define local terrain impacts on air flow paths
should be examined in advance so they can be
appropriately used to interpret air concentration data.
Meteorological data may be available from an existing
station located near the site (e.g., at a local airport).
Otherwise, a station will need to be set up at the site.
The meteorological data will document the degree to
which samples collected were downwind, and verify
whether other worst-case assumptions were met. This
information then can be used to refine air quality
dispersion models. Meteorological parameters to be
monitored are, at minimum, wind speed and wind
direction. Wind direction is used to calculate "sigma
theta," which is the horizontal wind direction standard
deviation (an indicator of atmospheric stability).
2.4 METEOROLOGICAL AND
PHYSICAL/CHEMICAL
CONSIDERATIONS
2.4.1 Meteorological Parameters
Meteorological parameters are major considerations
when designing air sampling plans. Meteorological
stability classes, wind speed, and wind direction are
the most important parameters in the transport and
dispersion of contaminants and the placement of
monitoring sites. The remaining parameters primarily
affect the amount of a contaminant available in the air.
Appendix A contains a detailed overview of
meteorological and physical effects on pollutants.
Data collection for use with models is more
comprehensive and costly than data collected to
document basic meteorology (i.e., wind speed and
direction).
• Wind Speed
When the contaminant of concern is a particulate,
wind speed is critical in determining whether the
particulate will become airborne, and how much
and how far the contamination will travel from
the source. Wind speed contributes to the
volatilization of contaminants from liquid
sources.
• Wind Direction
Wind direction highly influences the path of
airborne contaminants. Variations in wind
direction increase the dispersion of pollutants
from a given source.
• Atmospheric Stability
Atmospheric stability refers to the degree to
which a parcel of air tends to dampen vertical and
horizontal motion. Stable atmospheric conditions
(e.g., in the evenings) dampen motion resulting in
low dispersion, while unstable atmospheric
conditions (e.g., on hot, sunny days) are less
dampening and result in higher dispersion.
• Temperature
Increased temperature increases the rate of
volatilization of organic and some inorganic
compounds, and affects the initial rise of gaseous
or vapor contaminants. Worst-case emission of
volatiles and semi-volatiles occurs at the hottest
time of day, or on the hottest day.
• Precipitation
Precipitation will scrub or remove airborne
contaminants from the atmosphere. The
effectiveness of this scrubbing depends on the
length and intensity of the precipitation and the
chemical and physical properties of the
contaminant. Precipitation generally suppresses
any generated particulate matter from becoming
airborne.
• Humidity
High humidity affects water-soluble chemicals
and particulates. Humid conditions may
determine the sampling media for collecting the
air sample, or may limit the volume of air
sampled and thereby increase the detection limit.
• Atmospheric Pressure
Migration of landfill gases through the landfill
surface and through surrounding soils is governed
by changes in atmospheric pressure.
Atmospheric pressure influences upward
migration of gaseous contaminants from shallow
aquifers into the basements of overlying
structures. Otherwise, the effect of atmospheric
pressure is generally minor.
2.4.2 Meteorological Effects
Normal diurnal variations, such as temperature
inversions, affect the dispersion of airborne
contaminants. Terrain features can enhance or create
air inversions and influence the path and speed of air
flow, complicating both transport and dispersion
patterns.
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Temperature Inversions
In an inversion, when radiant heat leaves the
lower (near ground) atmosphere, the temperature
increases with altitude to a certain height. Above
that height, the temperature begins to decrease
with altitude. The top of the inversion becomes
an effective cap where wind speeds above the
inversion could flow in a different direction and
at a much higher speed than those at the surface.
In this very stable atmospheric condition, the cap
effectively barricades pollutants, holding them
either close to the surface or above the warm
layer.
Valley Effects
As the slopes of a valley cool at night by
radiation, the air immediately adjacent to the
slopes cools also and becomes more dense than
the air over the center of the valley at the same
elevation. This density imbalance induces
convection, with winds flowing downslope to the
valley floor. This is commonly referred to as
drainage wind or drainage flow. The combination
of stable atmospheric conditions, light drainage
wind, and inversion can be a potentially
dangerous scenario, where pollutants may not
only be concentrated from a large area source, but
also may be transported over considerable
distance with little dispersion.
On clear days with light winds, an up-valley,
up slope flow can develop due to the heating of
the air adjacent to the sun-warmed slopes and
valley floor. Channeling occurs most often when
wind speeds are light to moderate and their
direction is not perpendicular to the valley.
During channeling, winds at the top of the valley
may be different from winds at the valley floor.
Shorelines
On summer days with clear skies and light winds,
the land surface adjacent to a large lake or ocean
is heated much more rapidly than the body of
water. This results in a temperature difference,
and consequently a density difference, between
the air just above the land surface and the air
above the water. Because of the density gradient,
a local circulation is established with wind
moving from the water toward the land. At night,
the rapid cooling of the land causes a reverse
wind flow toward the water.
Hills
During stable atmospheric conditions, the air will
tend to flow slowly around hills. Under unstable
conditions, air tends to move faster over
obstructions, with less impact to hillsides.
2.4.3 Physical/Chemical Factors
The chemical characteristics of a contaminant affect
its behavior in the atmosphere and can influence the
method used to sample and analyze it.
• Molecular Weight
When the release involves a pure gas, its
molecular weight may influence downwind
transport.
• Physical State
Pressure and temperature are the predominant
controllers of physical state. For sampling
purposes, airborne contaminants may be grouped
into three broad categories: gases, vapors, and
particulates. Semi-volatile compounds can be
distributed partially into each phase, as dictated
by atmospheric conditions and the compounds'
vapor pressures (compounds ranging from
naphthalene to PCB could be found in each phase,
depending upon conditions).
Particulates may exist as solids or liquids (such as
aerosols). Particulates are frequently subdivided
into dusts, mists, fumes, and smokes. The
distinction between subgroups is based upon
particle size, state, and means of generation.
The nature and state (solid, liquid, or gas) of the
contaminant determines the sampling method.
Gases and vapors are collected in an aqueous
medium, on adsorbates, in molecular sieves, or in
a suitable container. Particles are collected by
filters, impingers, impactors, centrifugal devices
(e.g., cyclones), settling chambers, electrostatic
precipitators, thermal precipitators, and diffusion
batteries.
• Vapor Pressure
Vapor pressures of target contaminants
determines sampling media selection. As
temperature increases, so does the vapor pressure,
resulting in more liquid evaporating or
vaporizing. Contaminants with high vapor
pressures (> 1 mm Hg) volatilize much more
readily than those with low vapor pressures. The
vapor pressure determines whether the substance
is found primarily in the vapor state, on the
surface of particles, or in both states.
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• Temperature
The temperature of contaminants at the time of
their release affects the state, transport, and
dispersion of the contaminant.
• Reactive Compounds
A reactive compound refers to a substance that
undergoes a reaction in the presence of water or
under normal ambient atmospheric conditions.
Among these types of hazard are the pyrophoric
liquids which can spontaneously ignite in ambient
air without added heat, shock, or friction, and the
water-reactive gases such as phosgene that will
be decomposed by ambient humidity as they are
transported downwind.
• Photodegradation
Some compounds undergo photolysis, where
ultraviolet (UV) radiation provides enough energy
to break bonds (e.g., PNAs).
2.4.4 Environmental Interferences
When designing an air sampling/monitoring program,
consider many environmental interferences. Note the
following sources of potential environmental
interference:
• Natural sources of pollution (e.g., pollen, spores,
terpenes, biologically produced waste compounds
such as hydrogen sulfide, methane, ore and
mineral deposits)
Extraneous anthropogenic contaminants (e.g.,
burning of fossil fuels; emissions from vehicular
traffic, especially diesels; volatiles from
petrochemical facilities; effluvium from smoke
stacks)
Photo-reactivity or reaction of the parameters of
concern with non-related compounds (e.g.,
nitrogen compounds, sulfur compounds,
poly aromatic hydrocarbons)
2.5 SAMPLING QA/QC
Sampling QA/QC involves the collection of
supplementary samples that will be analyzed in
addition to the normal sampling program. Extra
equipment and sample media are required to take the
QA/QC samples. Chapter 4, Quality
Assurance/Quality Control (QA/QC), provides a
detailed overview of the types of QA/QC samples and
their purpose.
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3.0 SAMPLING AND ANALYTICAL TECHNIQUES
3.1 INTRODUCTION
Air sampling and monitoring equipment and
techniques support Superfund Program objectives.
This chapter provides information on advantages and
disadvantages associated with their use. Given the
wide range of chemicals with properties that can vary
over time, the choice of available technologies is
understandably complex. If the wrong technique is
selected, the resulting data may be inappropriate or
incorrect. This chapter provides a basic understanding
of each air monitoring and sampling technique. The
summaries focus on the applicability of a wide range
of techniques for monitoring, sampling, and analysis
of organic and inorganic chemicals in the air. This
document does not address sampling and analytical
techniques for radiation, radon, or asbestos, but direct
reading instruments (radiation meters) are included in
the discussion.
3.1.1 Air
Database
Sampling Methods
In conjunction with this document, an air sampling
methods database has been developed to provide
additional assistance in preparing air sampling plans.
The Air Methods Database is a PC-based, self-
contained software package which allows the user to
access summarized standard methods for chemical
analysis. The software allows the user to make quick
determinations on which air sampling approach is
appropriate and what equipment should be used to
collect and analyze the sample. The database runs on
an IBM-compatible personal computer with a hard
drive and 640K RAM.
The database has the following features:
• It requires no other software for support (self-
contained)
• It provides smooth user interface
• It can search by chemical name, CAS number, or
by method
• It makes periodic updates available
• It generates hardcopy
• The user can add, delete, and edit methods
A copy of the database can be obtained by sending a
request to:
U.S. EPA - Environmental Response Team
Environmental Resource Center
2890 Woodbridge Avenue
Edison, NJ 08837-3679
Questions regarding the database should be directed to
the Environmental Protection Agency's Environmental
Response Team in Edison, New Jersey.
3.1.2 Overview of the Methods and
Techniques for Air Sampling
A wide range of sampling methods and techniques is
available to support air monitoring and sampling
activities. Selecting the most appropriate techniques
for a given situation depends on the following factors:
• Type of sampling applications
• Chemicals to be sampled (volatile organic, semi-
volatile organic, inorganic, corrosive, toxic,
particulate, etc.)
• Duration of response action
• Acquisition time for daily data gathering
• Mobilization and set-up time needed to collect
samples
• Weather conditions
• Specificity required in identifying chemicals
• Relative precision and accuracy attainable
• QA/QC objective required
• Detection levels attainable
Cost
Tables 2 to 5 summarize the capabilities, advantages,
and disadvantages of direct reading instruments and
techniques, sampling equipment, sampling collection
media/devices, and analytical techniques. These
tables are not inclusive, since methods and techniques
may be modified to fit a specific sampling scenario.
20
-------
Key to Tables 2, 3, 4, and 5
Applications (see Chapter 2 for additional information on sampling applications)
A - On-site health and safety E - Off-site chronic unknown exposure
B - Off-site acute known exposure F - Confirmatory sampling
C - Off-site acute unknown exposure G - Odor complaints
D - Off-site chronic known exposure H - Source identification
Mobilization Time
Short - Less than 2 hours to set up equipment
Long - More than 2 hours to set up equipment
Data Acquisition Time
Hours - Data from samples are available within hours
Days - Data from samples usually take days to process
Weeks - Data from samples usually take weeks to process
Specificity
Non-specific - No information about compound type or identity
Class - Type or class of compound provided, but not identity
Compound - Identity of compound is provided
Cmpd. Qualified - Identity of compound is provided only if a reference standard for comparison is available
Relative Precision and Accuracy
Poor - Technique produces highly variable data
Fair - Technique produces acceptable data using the recommended QA/QC level
Good - Technique produces data with good precision and little bias using the recommended QA/QC level
Excellent - Technique produces data with high precision and little bias using the recommended QA/QC level.
Detection Levels (units within parentheses apply to Table 3.1)
Very low - Detection limits routinely less than 1 pg (fractional ppb(v) and lower)
Low - Detection limits routinely less than 1 Fg (ppb(v))
Medium - Detection limits routinely greater than 1 mg (fractional ppm(v) to low ppb(v))
High - Detection limits routinely greater than 10 mg (ppm(v))
Relative Cost
$ - Instrumentation cost < $1,000; Sample cost < $50 per sample
$$ - Instrumentation cost $1,000 - $10,000; Sample cost $50 - $150 per sample
Instrumentation cost $10,000 - $50,000; Sample cost $150 - $500 per sample
- Instrumentation cost > $50,000; Sample cost > $500 per sample
21
-------
TABLE 2: Summary of Direct Reading Instruments and Techniques* (Part 1 of 2)
Instrument and
Technique
Flame lonization
Detector (FID)
Photoionization
Detector (PID)
Electro-Chemical
Monitors
Oxygen Meter
Lower Explosive
Limit Meter
Particulate
Monitor
Radiation Meter
(field)
Gold Film
Analyte
Category
VOCs,
Semi-
Volatiles
Applications
A,B,H
Data
Turnaround
Time
Minutes
Relative
Cost
$$<3)
Specificity
Non-specific
Advantages: Easy to use; Inexpensive
VOCs
A,B,H
Minutes
$$P)
Non-specific
Advantages: Easier to use than FIDs.
VOCs
A,B,H
Minutes
Compound
Advantages: Easy to use; Inexpensive; Compound-specific.
Oxygen
A
Minutes
$$(3)
Compound
Advantages: Easy to use; Compound-specific.
VOCs
A
Minutes
j>j>
Non-specific
Advantages: Easy to use.
Particulate
Monitor
A,B
Minutes
$
Non-specific
Advantages: Easy to use.
Radio-
nuclides
A,B,H
Minutes
Non-specific
Advantages: Easy to use.
Hydrogen
Sulfide,
Mercury
A,B,G,H
Minutes
$$(3)
Compound
Advantages: Easy to use; Good detection limits; Compound-specific.
False
Pos.
No
False
Neg.
No(1)
Precision
and
Accuracy
Fair
Detection
Level
Medium'2'
Disadvantages: Generally not compound specific; Response varies among
compounds.
No
Yes
Fair
High(2)
Disadvantages: Unable to differentiate between chemicals and chemical
classes; Cannot be used for aliphatic hydrocarbons; Response of instrument
dependent on proper bulb selection; Methane and moisture distort reading.
No
Yes
Fair
Medium
Disadvantages: Prone to interference from high ambient moisture; Affected
by freezing temperature.
Yes
Yes
Fair
High
Disadvantages: None significant.
No
Yes
Fair
High
Disadvantages: None significant.
No
No
Fair
Medium
Disadvantages: None significant.
No
Yes
Fair
N/A
Disadvantages: None significant.
No
Yes
Fair
Low
Disadvantages: None significant.
* Exceptions to some of these classifications can be found. This table is designed to provide a quick reference showing relative advantages and disadvantages among analytical
methods. (1) Only for selected halogenated compounds. (2) Affected by the variability of the background. (3) Cost of the instrument.
22
-------
TABLE 2: Summary of Direct Reading Instruments and Techniques* (Part 2 of 2)
Instrument and
Technique
Infrared Detectors
Colorimetric
Tubes
Remote Optical
Sensing
TAGA
Portable GCs
Analyte
Category
VOCs,
Semi-
Volatiles
Application
A,B,H
Data
Turnaround
Time
Minutes
Relative
Cost
$$(3)
Specificity
Class/
Compound
Advantages: Easy to use; Detects multiple compounds.
VOCs,
Inorganics
A,B
Minutes
$
($30-$60 box of
ten)
Class/
Compound
Advantages: Easy to use; Inexpensive; Compound-specific.
VOCs,
Inorganics
B,C,D,E,F,G,H
Minutes
$$$$">
Compound
Advantages: Provides new set of concentrations every 3-5 minutes; provides excellent
flexibility; Measures large number of compounds at low detection limits; good for
determination of the variation of emission rates overtime.
VOCs,
Semi-
Volatiles
B,D,G,H
Hours /Days
tttt*3)
lOiOiOiO
(Sample $$$)
Compound
Advantages: Mobile monitoring; Good detection limits for most solvents; Provides new
set of concentrations every 2-3 seconds; Real-time plume delineation; Detects and
identifies low levels of polar compounds.
VOCs,
Semi-
Volatiles
D,E,H
Hours
*c*c
J>J>
Compound
Advantages: Qualitative identification and quantitative determination of relative
concentrations in the field.
False
Pos.
Yes
False
Neg.
Yes
Precision
and
Accuracy
Fair
Detection
Level
High-
Medium
Disadvantages: Requires 115 VAC power; Target compounds should be
known; Prone to interference.
Yes
No
Poor
High-
Medium
Disadvantages: High detection limits; Prone to interference.
Yes
Yes
Good
Low
Disadvantages: Expensive; Requires trained operator; Prone to interference;
Used in conjunction with the collection of concurrent on-site meteorological
data or with releases of tracer gases.
Yes
No
Excellent
Low
Disadvantages: Target compounds should be known; Not capable of
resolving certain individual groups of compounds; Used for approximately
12-14 hours per day; Only one unit currently available for use; Requires at
least one day to switch from standard non-polar compound analysis to polar
compound analysis.
Yes
No
Good
Low
Disadvantages: Many require AC power; Shelter or trailer needed. Direct
air samples are not truly representative of either the average or maximum
plume concentrations; therefore, the results can only be considered semi-
quantitative.
* Exceptions to some of these classifications can be found. This tables designed to provide a quick reference showing relative advantages and disadvantages for the most common direct reading instruments
and techniques available for use. (3) Cost of the instrument.
23
-------
TABLE 3: Summary of Sampling Equipment*
Equipment
High Volume
TSP Samplers
PM-10
Samplers
High Volume
PS-1
Samplers
Personal
Sampling
Pumps
Canister
Samplers
Analyte
Category
Metals,
Particulates
Metals,
Particulates
Semi-Volatiles
Metals,
VOCs,
Semi-Volatiles,
Inorganics
VOCs
Applications
B,C,D,E,F,
Hd>
B,C,D,E,F,
H«
B,C,D,E,F,G
Hd)
A,B,C,D,E,F,G,H
B,C,D,E,F<2),
G«H<3)
Mobilization
Time
Short
Short
Short
Short
Short
Relative
Cost
$$<4)
*t*t<4)
j>j>
J>
(M4)
J>
Positive
Pressure
Samplers $$$4)
Sub- Ambient
Pressure
Samplers
$-$$$<4)
Advantages
Large air sample volume for low detection
limits;
Simple operation and rapid set-up;
Weather-proof, but weather influences
samples;
Easily automated.
High volume yields low detection limits;
Low volume X-Ray Fluorescence (XRF)
analysis;
Simple operation and easy set-up;
Not affected by weather;
Easily automated.
Provides detection at very low
concentrations;
Simple operation and rapid set-up;
Not affected by weather;
Easily automated.
Rapid set-up for time average sampling;
Small and compact;
Portable, reliable, and versatile;
Battery operated;
Intrinsically safe.
Reliable, flexible, and easy to operate;
Large air sample volume;
Weather-proof.
Disadvantages
Requires 110 VAC power;
Difficult to mobilize;
Bulky.
Requires 110 VAC power;
Difficult to mobilize;
Bulky (large unit size and weight).
No size selection inlet;
Requires 110 VAC power;
Difficult to mobilize;
Bulky.
Flow rates are too low to provide
detection of some compounds;
Pumps are not weather-proof;
Requires frequent monitoring to ensure
pumps are operating;
Sampling periods longer than 8 hours
usually require recharging the battery
(can be run on AC operation).
Pressurized units require 110 VAC or a
battery to operate pump;
Units without 110 VAC power may not
work properly in sub-freezing weather;
Units need to be checked for leaks
before each field assignment;
Rigorous QA/QC is required to ensure
cleanliness of samplers, especially
pressurized systems.
* Exceptions to some of these classifications can be found. This table is designed to provide a quick reference showing relative advantages and disadvantages for sampling equipment available for use.
(1) Requires the collection of multiple days of sampling with the concurrent collection of on-site meteorological data followed by a sophisticated statistical correlation analysis.
(2) Limited to only the non-polar and slightly polar compounds responsible for an odor complaint. (3) Sector sampler system. (4) Cost of the equipment only.
24
-------
TABLE 4: Summary of Sampling Collection Media/Devices* (Part 1 of 3)
Media/
Device
Canisters
Passive
Dosimeters
Polyurethane
Foam (PUF)
Sampling Bags
Analyte
Category
VOCs
VOCs,
Inorganics
Semi-Volatiles,
Non-Volatile
Organics
VOCs
Applications
C,D,E,F,G,H
A,C,E,F,G
A,B,C,D,E,F
A,G,H
Relative
Cost
$$(2)
$<2)
$<2)
$<2)
Advantages
Once samples are collected, there is little or no sample
degradation for most compounds for up to 30 days;
Sufficient sample volume for repeated analysis;
Straightforward cleaning procedure;
Excellent for non-polar VOCs;
Good for some polar VOCs;
Easily transported and operated;
Detection limits 0.05 - 1.0 ppb by volume achieved;
Obtain whole air sample with no possibility of
breakthrough problems;
Little sample degradation due to reactive component of
air (e.g., ozone);
No special extended holding times or shipment
requirements.
Easy to use;
Non-obtrusive to wearer;
Inexpensive.
Excellent for collection of heavier PCBs, most
pesticides, dioxins, furans, and long-chain PAHs;
With properly cleaned foam, excellent detection limits
with little or no background contamination;
Best when used with high volume sampling methods;
Multiple analysis of extracts is possible.
Large air sample volume;
Excellent for fixed gases and methane;
Inexpensive.
Disadvantages
Sample collection systems need to be rigorously cleaned to avoid
cross-contamination;
Not reliable for most polar (odorous) compounds;
Requires special procedures for cleaning canisters when they are
exposed to greater than ambient concentrations of a contaminant;
Leaks in valves may develop over time.
Difficult to recover some compounds from dosimeters;
Most relevant for industrial hygiene;
Results after the fact;
Relatively high detection limits.
Requires XAD backup when used for lighter PCBs and PAHs;
Samples need to be chilled when stored and shipped;
Care must be taken during setup, tear down, and cleanup to avoid
contamination;
Foam should be shipped ready for use in pre-cleaned glassware
from analytical laboratory;
Limited sample holding time.
Difficult to ship and bags may break;
Very limited holding time (maximum 1-2 days; less volatile
compounds, 1-2 hours);
Artifact formation;
Background contamination (especially below 1 ppm);
Sample loss from adsorption of some analytes to bag walls.
* Exceptions to some of these classifications can be found. This table is designed to provide a quick reference showing relative advantages and disadvantages for types of sampling collection media/devices available
for use. (2) Cost of the media only.
25
-------
TABLE 4: Summary of Sampling Collection Media/Devices* (Part 2 of 3)
Media/
Device
Impingers
Analyte
Category
Inorganics,
Gases
Applications
B,D,F,G
Relative
Cost
$
Advantages
Simple analysis;
Good collection efficiency;
Compound-specific.
Disadvantages
More difficult to set up than most samplers;
High detection limit ranges;
Care must be taken during sampling to avoid spilling of
impinger solution.
Thermally Desorbed Media
Tenax Tubes'1'
Carbonized
Polymers'1'
Mixed Sorbent
Tubes*1'
VOCs, Some
Semi-Volatiles,
Inorganics, Non-
Volatile
Organics
VOCs
VOCs, Semi-
Volatiles,
Inorganics, Non-
Volatile
Organics
A,B,C,D,E,F,
G,H
C,D,E,F,G,H
A,B,C,D,E,F,
G,H
(M2)
J>
Inexpensive, rugged, and reusable;
Large number of VOCs and semi-volatiles can be
sampled;
Easy to use and easily automated;
Low detection limits achievable.
Easy to use;
Good detection limits achievable.
Easy to use;
Quick set-up;
Good for polar compounds;
Sorbents can be silica gel and resins, and can be
pretreated with specific chemicals;
Optimized for specific classes of polar compounds.
Limited holding time for samples;
Samples need to be chilled when stored and shipped;
Breakthrough volumes vary by compound and temperature;
Analytes are not always quantitatively desorbed;
Background contamination, especially light aromatics due to
breakdown of polymer;
Artifact formation;
One analysis per sample tube;
Cleanup procedure time-consuming and easily contaminated.
Limited number of compounds that can be sampled;
Thermal desorption may not remove all compounds
quantitatively or reproducibly;
Easily contaminated;
Only one analysis available from each tube.
High humidity can affect flow rate;
Must know the compound to be monitored;
Not recommended for general ambient air levels when using
solvent extractions;
Tenax/charcoal tubes require samples be kept chilled when
stored and shipped.
* Exceptions to some of these classifications can be found. This table is designed to provide a quick reference showing relative advantages and disadvantages for types of sampling collection media/devices available
for use. (1) When solvent-extracted associated advantages and disadvantages will differ. (2) Cost of the media only.
26
-------
TABLE 4: Summary of Sampling Collection Media/Devices* (Part 3 of 3)
Media/
Device
Analyte
Category
Applications
Relative
Cost
Advantages
Disadvantages
Solvent-Extracted Media
Chemically
Treated Silica
Gel
XAD-2
Polymers
Carbon
Cartridges
Semi-Volatiles,
Non-Volatile
Organics
VOCs
A,B,C,D,E,F,H
A,B,C,D,E,F,G,H
*t<2)
j>
*t<2)
j>
t<2>
j>
Easy to use.
Excellent for the retention of short-chain semi-volatiles
(PAHs);
Soxhlet extraction, followed by concentration of the
artifacts, provides excellent detection limits.
Large number of VOCs can be sampled;
Quick set-up.
High humidity can affect results;
Must chemically treat for specific compounds.
Samples need to be chilled when stored and shipped;
Care must be taken during setup, tear down, and cleanup to
avoid contamination;
Only pre-cleaned resin furnished and certified by analytical
laboratory should be used;
Limited sample holding time after resin is cleaned or after a
sample is collected;
Artifacts from the polymer are usually present in measurable
amounts;
Resin may fracture after it has been cleaned.
Loss of target analytes by irreversible sorption on the carbon;
Loss of target analytes due to breakthrough of some VOCs;
Background contamination;
Requires two analyses (front and back section);
Possible artifact formation and selected compound
decomposition of lower concentrations.
Particulate Filters
Particulates,
Inorganics, Non-
Volatile
Organics
A,B,C,D,E,F,H
*t<2)
j>
Collects various airborne particulates;
Filters can be analyzed by various methods.
Some filters not applicable to specific analyses.
* Exceptions to some of these classifications can be found. This table is designed to provide a quick reference showing relative advantages and disadvantages for types of sampling collection media/devices available
for use. (2) Cost of the media only.
27
-------
TABLE 5: Summary of Analytical Techniques'
Analytical
Techniques
High
Performance
Liquid
Chromato graphy
(HPLC)
Gas
Chromato graphy
(GC)
Wet Chemical/
Photometric
Analyses
Ion
Chromato graphy
(1C)
Atomic
Absorption (AA)
Inductively
Coupled Plasma
(ICP) Emission
Spectrometer
X-Ray
Fluorescence
(XRF)
Analyte
Category
Semi-VOCs, Non-VOCs, Polars
Application
A,B,C,D,E,F,G
Data
Turnaroun
d
Time
Days/
Weeks
Relative
Cost
$$$(1)
Specificity
Compound
Advantages: Good for polar compounds, PAHs, high thermal energy compounds (explosives), and thermally unstable
compounds; Good separation between similar compounds; Low detection limits.
VOCs, Semi-Volatiles
A,B,C,D,E,F,
G,H
Hours/
Weeks
$$$to
$$$$(1)
Compound
Advantages: Easily automated; Best for non-polar compounds; Detects wide range of compounds with a single analysis; Good
detection limits; Good quantitative and qualitative results; GC/MS provides better confirmation of contaminants and detection
limits than less selective detectors; GC/MS in the SIM mode provides low detection limits and good selectivity.
Elements, Inorganics
A,D,E,F,H
Weeks
$ to $$$(1)
Class
Advantages: Easy to perform, even in the field; Reasonable quantitative results; Inexpensive.
Elements, Inorganics
A,B,C,D,E,F,H
Weeks
$ to $$$(1)
Class
Advantages: Detects inorganic anions; Low detection limits.
Metals
A,B,D,E,F,H
Days
$ to $$$(1)
Element
Advantages: Quantitative; Low detection limits.
Metals
A,B,C,D,E,F,H
Days
$ to $$$(1)
Element
Advantages: Automated analysis; Multiple elements detected in a single analysis; Detection limits comparable to Flame AA;
Inexpensive.
Metals
A,B,C,D,E,F,H
Days
$ to $$$(1)
Element
Advantages: No interferences; Low detection limits; Multiple metals analysis.
False
Pos.
Yes
False
Neg.
No
Precision
and
Accuracy
Good
Detection
Level
Low to
Very Low
Disadvantages: Interference problems; Less readily available
method than GC.
Yes
No
Good to
Excellent
Low to
Very Low
Disadvantages: GC/MS is relatively expensive; In SIM mode
the compound must be known and data on other compounds are
not collected; When analyzing for a wide range of compounds
resolution of similar compounds may be difficult.
Yes
No
Fair
Med. to
High
Disadvantages: Non-specific; Prone to interference; High
detection limits.
Yes
No
Good
Low to
Med.
Disadvantages: Prone to interference.
No
No
Excellent
Low
Disadvantages: Only one metal can be analyzed at a time;
Variability in analytical results for some metals.
No
No
Excellent
Low
Disadvantages: Detection limits are approximately an order of
magnitude less than Graphite Furnace AA; Detection limits for
some metals are poor (e.g., Cr).
No
No
Good
Low
Disadvantages: Costly if only a few elements desired; Semi-
qualitative; Only Teflon filters are recommended; Sensitive to
amount of particulate collected.
* Exceptions to some of these classifications can be found. This table is designed to provide a quick reference showing relative advantages and disadvantages among analytical methods.
(1) Cost of the sample.
28
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3.2 DIRECT READING
INSTRUMENTS
AND TECHNIQUES
There are two general types of direct reading
instruments: portable screening devices and
specialized analytical instruments. All these
techniques involve acquiring, for a specific location or
area, continuous or sequential direct air concentrations
in either a real-time or semi-real-time mode.
3.2.1 Portable Screening Devices
These portable instruments are useful for rapid
screening methods. They involve simple, relatively
inexpensive techniques. They are usually not very
selective and can produce false positive results. None
of these instruments can acquire true time-weighted
average concentrations. They are not capable of
acquiring simultaneous concentration readings at
multiple locations, although several can sequentially
analyze samples taken remotely from different
locations.
• Flame lonization Detectors (FIDs)
FIDs are sensitive to volatile organic vapor
compounds such as methane, propanol,
benzene, and toluene. They respond poorly to
organic compounds lacking hydrocarbon
characteristics. An example of an instrument
using an FID is the Organic Vapor Analyzer
(OVA).
• Photoionization Detectors (PIDs)
PIDs depend on the ionization potential of
compounds. PIDs are sensitive to aromatic
and olefinic (unsaturated) compounds such as
benzene, toluene, styrene, xylenes, and
acetylene. Greater selectivity is possible if
low-voltage lamps are used.
• Electrochemical Monitors
Electrochemical monitors use an
electrochemical sensor to determine the
concentration of a compound in air. These
monitors are compound-specific and operate
in a limited concentration range. High
humidity may produce low-bias results in
some models.
• Oxygen Meters
Oxygen meters use an electrochemical sensor
to determine the air's oxygen concentration.
The meters are calibrated for sea level and
may indicate a false negative (i.e., lower O2
content) at higher altitudes.
Lower Explosive Limit (LEL) Meters
LEL meters measure the concentration of a
flammable vapor or gas in air and present this
measurement as a percentage of the LEL. The
measurements are temperature dependent.
The calibration gas determines sensitivity.
Radiation Meters
Radiation meters determine the presence and
level of radiation. The meters use a gas or
solid ion detection medium which becomes
ionized when radiation is present. The meters
are normally calibrated to one probe.
Gold Film (H2S and Hg Monitors)
H2S and Hg monitors operate on the principle
that electric resistivity increases across a gold
film as a function of H2S and Hg
concentration. These monitors provide rapid
and relatively low detection limits for H2S and
Hg in air. After extensive sampling periods or
exposure to high concentrations of H2S and
Hg, the gold film must be heated to remove
contamination and to return the monitor to its
original sensitivity.
Infrared Detectors
Infrared detectors such as the Miniature
Infrared Analyzer (MIRAN) use infrared (IR)
absorption as a function of specific
compounds. MIRAN instruments are useful
when contaminants are identified but their
concentrations are unknown. The MIRAN-C,
however, is a screening model which can be
useful for identifying unknowns in simple
mixtures. MIRAN instruments generally
require AC power.
Colorimetric Tubes
Colorimetric tubes are small, calibrated glass
tubes filled with various reactive ingredients.
They can identify the presence of specific
vapors by a color change in the tube when
contaminated air is pumped or passively
diffused through the tube. Diffusion detector
tubes clipped to clothing can provide
contaminant measurements over time without
pumps. Colorimetric tubes are not continuous
monitors and can determine concentration
only in a grab sample.
29
-------
3.2.2 Specialized Analytical
Instruments
The continuous monitors already described provide
qualitative measurements of air contaminants. To
collect quantitative measurements in the field, more
sophisticated instruments, such as the portable Gas
Chromatograph, are used for analysis of grab samples.
Direct Air Sampling Portable Gas
Chromatographs (GCs)
Portable GCs use gas chromatography to
identify and quantify compounds. The time it
takes for a compound to move through a
chromatographic column is characteristic of
that specific compound or group of
compounds. A trained technician with
knowledge of the range of expected
concentrations of compounds can utilize a
portable GC in the field to analyze grab
samples. Operation of GCs generally requires
AC power and shelter. The accuracy of this
method is limited by the representativeness of
the short-term grab sample.
Remote Optical Sensing
This technique, also referred to as open-path
monitoring, involves using either an infrared
or an ultraviolet light beam across a long open
path and measuring the absorbance at specific
wavelengths. This technique is capable of
analyzing any pre-selected organic or
inorganic volatile compound which can be
resolved from compounds naturally occurring
in ambient air. Projected Superfund
applications include perimeter monitoring
during site cleanups and measurement of
emission source concentrations during site
assessments (Minnich, et al. 1990).
TAGA Direct Air Sampling Mass
Spectrometer
The Toxic Ambient Gas Analyzer (TAGA),
which is operated by the U.S. EPA
Environmental Response Team (ERT), is
capable of real-time detection of pre-selected
organic compounds at low parts per billion
concentrations. The instrument has been
successfully used by ERT for isolating
individual emission plumes and tracing those
plumes back to their sources.
3.3 SAMPLING EQUIPMENT
3.3.1 High Volume, Total Suspended
Particulate (TSP) Samplers
High volume, TSP samplers collect all suspended
particles by drawing air across an 8 by 10 inch glass-
quartz filter. The sample rate is adjusted to 40 cubic
feet per minute (cfm), or 18.9 liters per second, and
held constant by a flow controller over the sample
period. The mass of TSPs is determined by weighing
the filter before and after sampling. The composition
of the filter varies according to the analysis method
and the detection limit required.
3.3.2 PM-10 Samplers
PM-10 samplers collect particulates with a diameter
of 10 microns or less from ambient air. Particulates of
this size represent the respirable fraction, and thus are
of special significance. PM-10 samplers can be high
volume or low volume. The high volume sampler
operates in the same manner as the TSP sampler at a
constant flow rate of 40 cfm, drawing the sample
through a special impactor head which collects
particulates of 10 microns or less. The particulate is
collected on an 8 by 10 inch glass-fiber filter. The
low volume sampler or low volume PM-10 sampler
operates at a rate of approximately 17 liters per
minute. The flow must remain constant through the
impactor head to maintain the 10 micron cut-off point.
The low volume PM-10 collects its sample on 37-mm
Teflon filters.
3.3.3 High Volume PS-1 Samplers
High volume PS-1 samplers draw a sample through
polyurethane foam (PUF), or a combination foam and
XAD-2 resin plug, and a glass-quartz filter at a rate of
5 to 10 cfm, or 2.4 to 4.7 liters per second. This
system is excellent for measuring low concentrations
of semi-volatiles, PCBs, pesticides, or chlorinated
dioxins in ambient air.
3.3.4 Personal Sampling Pumps
Personal sampling pumps are reliable, portable
sampling devices that draw air samples through a
number of sampling media including resin tubes,
impingers, and filters. Flow rates are usually
adjustable from 0.1 to 4 liters per minute and can
remain constant for up to 8 hours on one battery
charge, or continuously with an AC charger/
converter.
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3.3.5 Canister Samplers
Generally, there are two types of canister samplers.
Evacuated systems simply use the pressure
differential between the evacuated canister and
ambient pressure to bleed air into the canister. The
sample is bled into the canister at a constant rate over
the sampling period until the canister is near
atmospheric pressure, using either a critical orifice,
mechanically compensated regulator, or a mass-flow
control device. Pressure systems use a pump to push
air into the canister. To maintain a higher, more
controlled flow, the pump typically controls the
pressure differential across a critical orifice at the inlet
of the canister, resulting in a pressurized canister at
the completion of sampling.
3.4 SAMPLING COLLECTION
MEDIA/DEVICES
Some of the more common sampling collection
media/devices used in air sampling are discussed
below. The advantages and disadvantages of each
medium/device, and its unique sample preservation
needs and holding times are identified in Table 2.
Before employing a specific sampling method, consult
the laboratory that will conduct the analyses, if
possible. Many of the methods can be modified to
provide better results, or a wider range of results.
3.4.1 Canisters
Canisters are highly polished, passivated stainless
steel containers. One method of canister preparation,
the SUMMA electro-polishing process, cleans and
reduces the inner surface area of the canister and
causes the formation of chromium and nickel oxides
on the surface so that the adsorption of VOCs is
reduced. The canister is cleaned and evacuated in the
laboratory prior to sampling. At the sampling site, the
canister is often placed in a sampler that is designed
for time-integrated collection at constant flow rates.
Samples can be collected by allowing air to bleed into
or be pumped into the canister. Canisters come in
various sizes, most commonly 6 and 15 liters.
Evacuated canisters can be opened in the field to
collect a grab sample.
3.4.2 Passive Dosimeters
Passive dosimeters are clip-on vapor monitors
(samplers) with specially prepared, active surfaces
which absorb the diffused contaminants. Industrial
hygienists commonly use dosimeters to obtain time-
weighted averages/concentrations of chemical vapors
because they can trap over 130 organic compounds.
Selective dosimeters have been developed for a
number of chemicals including formaldehyde,
ethylene oxide, hydrogen sulfide, mercury vapor,
nitrogen dioxide, sulfur dioxide, and ozone.
Dosimeters must be analyzed in a laboratory.
3.4.3 Polyurethane Foam (PDF)
PUF is a sorbent used with a glass or quartz filter for
the collection of semi-volatile and non-volatile
organic compounds such as pesticides, PCBs,
chlorinated dioxins and furans, and polynuclear
aromatic hydrocarbons (PAH). Fewer artifacts
(chemical changes that occur to collected compounds)
are produced than with some other solid sorbents.
PUF is used with the PS-1 sampler and EPA method
TO-13. Breakthrough of the more volatile PCBs and
PAHs may occur when using PUF.
3.4.4 Sampling Bags
Sampling bags, like canisters, transport an air sample
to the laboratory for analysis. Samples are generally
pumped into the bags, but sometimes a "lung" system
is used which uses a pump to create a vacuum around
the bag in a drum. This in turn draws air from the
source into the bag without the potential for cross-
contamination from the pump. This vacuum method
is used for volatile organic compounds (VOCs), fixed
gases (CO2, O2, and N2), and methane.
3.4.5 Impingers
Impingers allow an air sample to bubble through a
solution which collects a specific contaminant by
either chemical reaction or absorption. During long
sampling periods, the impinger may need to be kept in
an ice bath to prevent the solution from evaporating
during sampling. A sampling pump draws the sample
through the impinger or, in more elaborate sampling
trains, through multiple impingers. Take care to avoid
spilling impinger solution during sample collection,
storage, and shipping.
3.4.6 Sorbent Tubes/Cartridges
Various sampling media are available in sorbent
tubes, which are used primarily for industrial hygiene.
A few examples are carbon cartridges, carbon
molecular sieves, Tenax tubes, and the XAD-2
polymer. Depending upon the sorbent material, tubes
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can be analyzed using either solvent extraction or
thermal desorption. The former technique uses
standard laboratory equipment and allows for multiple
analyses of the same sample. The latter technique
requires special, but readily available, laboratory
equipment and allows only one analysis per sample.
Thermal desorption typically allows for lower
detection limits (by two or more orders of magnitude)
than solvent extraction. Whenever sorbent tubes are
used for thermal desorption, they should always be
certified as clean by the analytical laboratory.
Thermally Desorbed Media
Thermally desorbed media use high temperature gas
streams to remove the compounds collected on a
sorbent medium. The gas stream is injected and often
cryofocused into an analytical instrument, such as a
GC, for compound analysis. The following are
examples of thermally desorbed media:
• Tenax Tubes
Tenax tubes are made from a commercially
available polymer (p-phenylene oxide) packed
in glass or stainless steel tubes through which
air samples are drawn or sometimes pumped.
The tubes are used in EPA Method TO-1 and
VOST. These collection media are
appropriate for sampling volatile, nonpolar
organics; some polar organics; and some of
the more volatile of the semi-volatileanics.
Tenax tubes are not appropriate for many of
the highly volatile organics (i.e., with vapor
pressures greater than approximately
200 mm Hg).
• Carbonized Polymers
The carbonized molecular sieve, a carbonized
polymer, is a commercially available carbon
sorbent packed in glass or stainless steel
sampling tubes through which air samples are
drawn or pumped. These are used in EPA
Method TO-2 for highly volatile nonpolar
compounds which have low breakthrough
volumes on other sorbents. High thermal-
desorption temperatures may cause more
variability in analysis when used with
carbonized molecular sieves than with other
sorbents.
• Mixed Sorbent Tubes
Sorbent tubes can contain two types of
sorbents. Combining the advantages of each
sorbent into one tube increases the types of
compounds that can be sampled. The
combination of two sorbents can also reduce
the chance that highly volatile compounds will
break through the sorbent media. An example
of a mixed sorbent tube is the combination of
Tenax and charcoal with a carbonized
molecular sieve. A potential problem with
mixed sorbent tubes is the breakthrough of a
compound from an earlier sorbent (from
which it cannot be desorbed) to a later
sorbent.
Solvent-Extracted Media
Solvent-extracted media use the principle of chemical
desorption to remove compounds collected on a
sorbent medium. The chemical solvent is injected
into an instrument such as a GC for analysis of
compounds. Examples of solvent-extracted media
follow:
• Chemically Treated Silica Gel
Silica gel is a sorbent which can be treated
with various chemicals before being used to
sample for specific compounds in air.
Examples of chemically treated silica gel
include the DNPH-coated silica gel
cartridges used with EPA Method TO-11.
XAD-2 Polymers
XAD-2 polymers usually are placed in tubes,
custom packed sandwich-style with
polyurethane foam, and prepared for use with
EPA Method TO-13 or the semi-VOST
method. The polymers are used for the
collection of semi-volatile polar and nonpolar
organic compounds. The compounds
collected on the XAD-2 polymer are
chemically extracted for analysis.
• Carbon Cartridges
Carbon cartridges, consisting of primary and
backup sections, trap compounds by
adsorption. Ambient air is drawn through
them so that the backup section verifies that
breakthrough of the analytes on the first
section did not occur, and that therefore the
sample collection was quantitative.
Quantitative sample collection is evidenced
by the presence of target chemicals on the
first carbon section, and their absence on the
second section. The adsorbed compounds
must then be eluted, usually with a solvent
extraction, and analyzed by GC with a
detector such as a mass spectrometer (MS).
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• Tenax Tubes
Tenax tubes are used in OSHA and NIOSH
methods in a manner similar to carbon
cartridges; they are typically used for less
volatile compounds.
3.4.7 Particulate Filters
Particulate filters collect particulates present in the air
pumped through them. The filter is then analyzed for
particulate mass, or chemical or radiological
composition. Particulate filters are made from a
variety of materials which are described below. An
example of a common use for each filter is also given.
Mixed Cellulose Ester (MCE)
MCE is manufactured from mixed esters of
cellulose which are a blend of nitro-cellulose
and cellulose acetate. MCE filters are used
primarily for particulate sampling, with
subsequent analysis for metals or asbestos.
• Glass Fiber
Glass fiber is manufactured from glass fibers
without a binder. Particulate filters with
glass fiber provide high flow rates, wet
strength, and high, solid holding capacity.
Glass fiber filters are generally used for
gravimetric analysis of particulates.
• Polyvinyl Chloride
Particulate filters with polyvinyl chloride are
resistant to concentrated acids and alkalis.
Their low moisture pickup and light tare
weight make them ideal for gravimetric
analysis.
• Teflon
Teflon is manufactured from poly-
tetrafluorethylene. Particulate filters with
Teflon are easy to handle and exceptionally
durable. Teflon filters are used for metal
collection and analysis.
Silver
Particulate filters manufactured from pure
silver have high collection efficiency and
uniform pore size. These filters are used for
mercury, chlorine, chrysene, and coal tar
collection and analysis.
• Cellulose
Particulate filters with cellulose contain less
than 0.01 percent ash. These filters are used
to collect particulates.
3.5 ANALYTICAL TECHNIQUES
This section describes types of analyses that are used
for air samples.
3.5.1 High Performance Liquid
Chromatography (HPLC)
HPLC is a technique that separates organic
compounds by passing a solution containing organics
through a tube column packed with an adsorbing
material (packing). The solvent or mobile phase
(usually water or a water/solvent mixture) is pumped
through the tube under high pressure, forcing the
compounds through the column. By the time the
individual compounds reach the end of the column,
they have separated because of their relative
adsorption on the packing. The solvent then pushes
the compounds into the detector, which generates a
signal proportional to the quantity of each compound
present. The most commonly used detector is the
ultraviolet/visible (UV/Vis) absorbance detector
which responds to nanogram quantities of many
organics. The second most commonly used detectors
are fluorescence and electrochemical detectors, which
respond to more selective classes of organic
compounds in the sub-nanogram to sub-picogram
quantities. Other detectors used include conductivity
(inorganic compounds), infrared (IR), and mass
spectrometry (MS) (the last two for organic
compounds).
3.5.2 Gas Chromatography (GC)
GC separates mixtures of volatile and semi-volatile
chemicals by vaporizing them and passing them
through long tubes (contained in an oven) that are
either packed (packed columns), or coated (open tube
capillary columns) with various substances. A carrier
gas (nitrogen or helium) sweeps the vapor through the
column as the temperature in the oven is gradually
increased. The chemicals are separated by affinity for
the column coating and/or by their boiling points in
the column, and are then eluted to a detector.
There is a wide variety of detectors. FIDs are general
purpose, non-specific detectors which are not very
sensitive to halogen-containing compounds. PIDs
respond to compounds that contain one or more
double bonds which are ionized by the photons
emitted from the PID source. Electron capture
detectors (ECDs), which are not compound-specific,
are very sensitive to halogen-, oxygen-, and sulfur-
containing compounds but considerably less sensitive
to hydrocarbons. Nitrogen/phosphorus detectors
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(NPDs) are specific and sensitive to those elements.
Halogen-specific electroconductivity detectors
(HECDs) are selective and very sensitive to
halogenated compounds. Flame Photometric
Detectors (FPDs) are selective for sulfur and
phosphorous compounds. Mass spectrometry (MS),
the most selective and the most general-purpose
detector, is also the most expensive. When operated
in the full scan mode, MS will respond to nanogram
levels of all organic compounds while retaining the
ability to differentiate between co-eluting compounds
based upon different unique fragmented ions. Use of
an MS in the full scan mode allows for the tentative
identification of unknown non-target compounds. If
sub-nanogram detection limits are needed, the MS can
be operated in the selected ion monitoring (SIM)
mode, but then identification of non-target compounds
cannot be made.
3.5.3 Wet Chemical/Photometric
Analyses
Colorimetric analysis identifies and quantifies several
anions and cations. Various reagents are usually
automatically mixed with the samples interspersed
with standards. After undergoing color-producing
reactions, the mixture is passed though a colorimeter.
The absorption of light at specific wavelengths in the
visible range compared to established standards
measures the amount of chemical present.
3.5.4 Ion Chromatography (1C)
The only differences between 1C and HPLC are: (1)
1C is typically used to separate inorganic ions while
HPLC is used to separate organic compounds; and (2)
1C can be performed using either low or high pressure
systems. A column containing ion exchange resins
separates anions (e.g., nitrate, sulfate, chloride) from
one another and measures their concentration.
3.5.5 Atomic Absorption (AA)
Spectrometry
An AA instrument measures one element at a time,
most commonly metals. An acid-digested solution is
either aspirated into a flame by flame atomic
absorption spectrometry (FAAS), or placed in a
graphite vessel and heated in a furnace by graphite
furnace atomic absorption spectrometry (GFAAS).
GFAAS provides better detection limits than FAAS
by an order of magnitude, but at much higher cost.
Glass-fiber or glass-quartz air sampling filters are
usually used in conjunction with this method. Teflon
filters are not recommended for AA analysis since the
filter cannot be digested.
3.5.6 Inductively Coupled Plasma
(ICP) Emission Spectrometry
The ICP emission spectrometer analyzes about 40
elements simultaneously. An acid-digested solution
of the sample is aspirated into an argon plasma where
the heat is so intense that it produces an emission
(light) spectrum of the elements. The spectrum is
used to identify the individual elements and to
quantitate them based on their light intensity. ICP-
MS yields better accuracy and detection limits than
standard ICP, but at a greater cost.
3.5.7 X-Ray Fluorescence (XRF)
The XRF irradiates a sample with X-rays, inducing
the atoms present to give off light. To use XRF for
the air medium, a sample would be collected on a
filter and then analyzed. When used with a high-
resolution instrument, this method provides excellent
detection limits for a variety of metals. Cost is on a
filter by filter basis, not on a given element. As a
result, XRF can be a cost-effective method to define
specific contaminants of concern.
3.6 OVERVIEW OF AIR
ASSESSMENT MODELS
A number of references are available on the selection
and uses of various air assessment models. Two
general categories of air modeling are discussed here:
emission rates models and atmospheric dispersion
models.
3.6.1 Emissions Models
The Air/Superfund National Technical Guidance
Series on Air Pathway Assessments Volume I
(Revised) provides recommended models for
estimating emission rates for various sources. The
procedures and recommendations made in that volume
supersede guidance provided in the earlier Volume II
of the series. The models were compiled for
Superfund applications.
Emissions models cited in the series require site-
specific data such as soil or water contaminant
concentrations, and physical property data such as
vapor pressure and Henry's Law constant.
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3.6.2 Atmospheric
Models
Dispersion
General procedures for atmospheric dispersion
modeling are also well established; Volume V of the
Air/Superfund National Technical Guidance Series
provides information for performing a detailed
modeling study for a Superfund site. That volume
also provides lists of models suitable for various
applications and further references.
Screening modeling for volatiles emissions can be
performed using EPA's SCREEN or TSCREEN
computer models. Refined modeling for volatiles
emissions is typically performed using EPA
recommended models, such as the ISC model or the
Point, Area, Line (PAL) model.
One of the most difficult aspects of air dispersion
modeling is determining how to approximate the area
or volume of a source. Volume I (Revised) of the
series provides an overview on completing such
approximations.
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4.0 QUALITY ASSURANCE/QUALITY CONTROL EVALUATION
4.1 INTRODUCTION
The goal of representative sampling is to produce
analytical results which accurately depict site
conditions during a given time frame. The goal of
quality assurance/quality control (QA/QC) is to
implement appropriate methodologies in order to limit
the introduction of error into the sampling and
analytical procedures and, consequently, into the
analytical data and conclusions regarding the impact
on air quality. QA/QC procedures allow site
managers to evaluate the quality and adequacy of the
data in terms of how accurately they represent
ambient site conditions and how well they satisfy
sampling objectives.
QA/QC samples allow personnel to: (1) evaluate the
degree of site variation; (2) determine whether
samples were cross-contaminated during sampling or
sample handling; (3) assess if a discrepancy in sample
results is due to laboratory handling and analysis
procedures; and (4) evaluate the sampling procedure.
Refer to EPA's Quality Assurance/Quality Control
Guidance for Removal Activities for further
information.
4.2 DATA CATEGORIES
EPA has established data quality objectives (DQOs)
which ensure that the precision, accuracy,
representativeness, and quality of environmental data
are appropriate for their intended application.
Superfund DQO guidance defines two broad
categories of analytical data: screening and
definitive.
Screening data are generated by rapid, less precise
methods of analysis with less rigorous sample
preparation. Sample preparation steps may be
restricted to simple procedures such as dilution with
a solvent, rather than elaborate extraction/digestion
and cleanup. At least 10 percent of the screening data
are confirmed using the analytical methods and
QA/QC procedures and criteria associated with
definitive data. Screening data without associated
confirmation data are not considered to be data of
known quality. To be acceptable, screening data must
include the following: chain of custody, initial and
continuing calibration, analyte identification, and
analyte quantification. Streamlined QC requirements
are the defining characteristic of screening data.
Definitive data are generated using rigorous analytical
methods (e.g., approved EPA reference methods).
These data are analyte-specific, with confirmation of
analyte identity and concentration. Methods produce
tangible raw data (e.g., chromatograms, spectra,
digital values) in the form of paper printouts or
computer-generated electronic files. Data may be
generated at the site or at an off-site location, as long
as the QA/QC requirements are satisfied. For the data
to be definitive, either analytical or total measurement
error must be determined. QC measures for definitive
data contain all of the elements associated with
screening data, but also may include trip, method, and
rinsate blanks; matrix spikes; performance evaluation
samples; and replicate analyses for error
determination.
For further information on these QA/QC objectives,
please refer to EPA's Quality Assurance/Quality
Control Guidance for Removal Activities or EPA's
Data Quality Objectives Process for Superfund.
4.3 SOURCES OF ERROR
Sampling errors which affect the success of a
representative air sampling program can be introduced
in the planning or implementation of the program, or
during sample collection, handling, and analysis.
Identifying the source of error in a sampling program
is difficult. Generally, three potential sources of error
exist:
• Sampling design — Sample
representativeness
• Sampling methodology — Sample
collection, handling, shipment
• Analytical procedures — Sample storage
preparation, analysis
4.3.1 Sampling Design
Site variation includes variation both in the types and
in the concentration levels of contaminants present.
Representative sampling should accurately identify
and reflect these variations. Error can be introduced
by the design of a sampling plan which does not take
this variation into account.
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4.3.2 Sampling Methodology
Error can be introduced by the sampling methodology
and sample handling procedures, such as cross-
contamination from inappropriate use of sample
collection equipment, unclean sample media,
improper sampling equipment decontamination and
shipment procedures, and other factors. Standardized
procedures for collecting, handling, and shipping
samples allow for easier identification of the source(s)
of error, and can limit error associated with sampling
methodology. The use of standard operating
procedures ensures that all sampling tasks for a given
matrix and analyte will be performed in the same
manner regardless of the individual sampling team,
date, or location of sampling activity. Trip blanks,
field blanks, replicate samples, and rinsate blanks are
used to identify errors due to sampling methodology
and sample handling procedures.
4.3.3 Analytical Procedures
Errors which may originate in analytical procedures
include cross-contamination, inefficient extraction,
and inappropriate methodology. Matrix spike
samples, replicate samples, performance evaluation
samples, and associated quality assurance evaluation
of recovery, precision, and bias can be used to
distinguish analytical error from error introduced
during sampling activities.
4.4 REPRESENTATIVENESS OF
THE SAMPLES (QA/QC OF
THE METHOD)
To determine the adequacy or representativeness of air
samples, compare the meteorological and emission
source conditions during sampling activities with
those required to satisfy the sampling objectives
defined in the sampling plan. During most Superfund
Program applications, representative sampling
demands collection of air samples during periods of
expected high contaminant concentration, such as
worst-case meteorological conditions and/or periods
of high pollutant emissions.
If a sample design is based on a prevailing wind
direction, wind speed, and/or atmospheric stability
class during sampling, the meteorological data
collected during the sampling program are reviewed to
determine if these meteorological conditions did in
fact occur, and the percentage of time they occurred
during the sampling. If these meteorological
conditions did not persist during most of the sampling
time, the data may not be representative of site
conditions.
If a sample design is based upon a specific rate or
duration of emission, then it is necessary to document
that the specific rate or duration of emission occurred
during sampling. The sample design and application
must correspond in order to evaluate the
representativeness of the samples.
4.5 QA/QC SAMPLES
QA/QC samples provide information on the variability
and reliability of environmental sample results.
Various QA/QC samples may be collected to detect
error. This section briefly describes the types and
uses of QA/QC samples collected in the field, and
those prepared for or by the laboratory. QA/QC
samples submitted for analysis with the field samples
help to identify the origin of analytical discrepancies.
The site manager can utilize these QA/QC samples to
determine how the analytical results should be
employed.
Replicate, collocated and background samples are the
most commonly collected QA/QC field samples.
Performance evaluation samples and matrix spikes
provide additional measures of QA/QC data control.
QA/QC results may suggest the need for modifying
sample collection, preparation, handling, or analytical
procedures if the resultant data do not meet site-
specific quality assurance objectives. Refer to data
validation procedures in EPA's Quality
Assurance/Quality Control Guidance for Removal
Activities for guidelines on utilizing QA/QC results.
Field blanks, trip blanks, lot blanks, reagent/method
blanks, replicate/collocated samples, breakthrough
samples, and distributed volume samples are the most
common field QA/QC samples. Blanks, surrogate
spikes, matrix spikes, blind spikes, and performance
evaluation samples are prepared either for or by the
laboratory to provide additional quality control
measures for the data generated. Table 6 summarizes
the application of the various QA/QC samples and the
frequency of their use.
Field Blank
A field blank sample undergoes the full handling
and shipping process of an actual sample. It is
designed to detect sample contamination that can
occur during field operations or during shipment.
The field blank must be associated with an actual
sampling period.
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When using adsorbent media that is sealed by the
manufacturer, the field blank is opened with the
other sample media, resealed, and carried through
the sample handling process. Tedlar bag field
blanks are filled with zero air and carried with
other samples during sampling activities. When
canister samples are collected using critical
orifices or as grab samples, evacuated canisters
are carried out to the field with the sampling
canisters and serve as field blanks. However, if
the canister samples are collected using more
complex systems, such as mass flow controllers
or stainless steel bellows pumps (e.g., Anderson
sampler), the field blanks should test the full
sampling system. Do this by purging humidified
zero air through the sampling system into the
field blank canister. Impinger field blanks consist
of an aliquot of reagent that is prepared prior to
going into the field and then carried into the field
with the actual impinger solutions and taken
through the sample handling process.
Trip Blank
A trip blank sample detects whether samples are
contaminated during shipping and storage. Trip
blanks are used only when sampling for volatile
organic compounds (VOCs). Trip blanks are
typically used in conjunction with field blanks to
isolate sources of sample contamination already
noted in previous field blanks. The trip blank is
prepared and added to the site samples after
sampling has been completed, just prior to
shipping the samples for analysis. If the
absorbent tubes are manufacturer-sealed, their
seals should be broken at this point. For sorbent
tubes that have been recycled and resealed by the
laboratory, there is no need to break these
temporary seals prior to shipping. Canister trip
blanks are evacuated containers that are shipped
to and from the site with the canisters used for air
sampling. A trip blank for an impinger-based
sampling method consists of an aliquot of
impinger reagent that is shipped back to the
laboratory with the samples.
Collocated Sample
Collocated sampling involves placing two
identical samplers next to each other. A
collocated sample can be collected in one of two
ways: (1) air is drawn from one source and split
with a manifold; or (2) two adjacent pumps are
set up so that each collects a sample at the same
flow rate. Depending upon the method used to
collect and analyze the samples, collocated
samples can determine the variation due to both
sampling error and imprecision in the analyses
(e.g., when using thermally desorbed adsorbent
tubes), or can be used to isolate the variation due
to sampling error only (e.g.,when using solvent-
extracted tubes and SUMMA canisters).
Breakthrough Sample
A breakthrough sample detects false negative
results and significant negative biases in the data.
These problems arise when compounds elute
from the sampling media before the sampling run
is completed. The two types of breakthrough
samples are serial media samples and spiked
media samples. To collect a serial media sample,
a sampling train is set up with a primary sampling
device and backed by a secondary sampling
device. A spiked media breakthrough sample is
obtained by pulling air through a sampling train
that was either spiked in the field with a standard
solution or spiked in the laboratory prior to being
shipped to the field. A breakthrough sample
typically is used to determine whether the first
sampling device has retained all of the
compounds of concern.
Distributed Volume Sample
A distributed volume sample detects problems
arising from the actual pulling of air through a
sorbent; these samples are particularly useful for
detecting sample breakthrough and sample
decomposition due to reactive species in the air.
A distributed volume sample involves setting up
collocated samplers that sample at flow rates
which differ by a factor of two or more. If there
are no problems associated with the actual
sampling, then the calculated concentrations for
all the distributed volumes should agree within
the experimental error range of the method.
Performance Evaluation (PE) Sample/Blind
Spike
A PE sample evaluates the overall accuracy of the
analytical laboratory and detects any bias in the
analytical method used. The PE sample contains
a quantity of analyte(s) which is known to the
sampling team but unknown to the laboratory.
The sample is usually prepared by a third party
and always undergoes some type of certification
analysis. The analyte(s) used to prepare the PE
sample is the same as the analyte(s) of concern.
The laboratory's accuracy is evaluated by
comparing the percentage of analyte identified in
the PE sample with the analytical results of the
site samples.
A blind spike is a rarely used proficiency sample
that is prepared and sent "blind" to a laboratory to
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undergo the same analyses as the other samples.
A blind spike is used when: (1) the desired
frequency of check samples for the laboratory
exceeds the number of available PE samples; (2)
the background matrix of the PE does not truly
reflect the background matrix of the samples
(e.g., high summer-time humidity or the exhaust
from soil vapor extraction or methane gas
collection systems); or (3) many or all of the
compounds of concern are not readily available in
a PE sample. In the last case, because of uncertainties
of the stability and half-lives of "new" compounds in
or on the sample media, the preparing laboratory must
both certify the blind spikes which will be shipped to
the field, and hold back a few spike samples for re-
certification analyses in the same time period as the
actual sample analyses. A blind spike should be
prepared by an individual who is proficient in its
preparation.
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TABLE 6: Types of QA/QC Samples
QA/QC
Sample Type
Field Blank
Trip Blank
Replicate/
Collocated Sample
Breakthrough Sample
Distributed Volume Sample
Performance
Evaluation Sample/
Blind Spike
Lot Blank
Reagent/Method Blank
Surrogate Spike
Matrix Spike
Suggested
Minimum
Frequency
Method dependent, typically
not less than 5%
5% or minimum of 1 per
shipment (0 if field blank used
in lieu of trip blank)
5% or minimum of 1 per
sampling event
Minimum of 1 per event
unless supplanted by
distributed volume sampling
When applicable,
minimum of 1 per day
1 per week when user requires
more stringent QC controls,
when available
Minimum of 1 per event per
lot,
3-6 whenever new lot of
absorbent acquired
1 per reagent blank per batch
Every sample when used
10% when user requires more
stringent QC controls
Responsible
Party
Field Crew
Field Crew
Field Crew
Field Crew
Field Crew
Field Crew
Laboratory
Laboratory
Laboratory
Laboratory
Application
Used to detect contamination during field
operations and shipping.
Used to detect contamination during shipping.
Used to determine variation due to sample
collection and/or ambient
conditions.
Indicates when the medium has become
saturated. Typically required when atmospheric
conditions may cause saturation of the
sampling tubes.
Used with adsorbent-based sampling methods -
- especially tube samples. Detects both
breakthrough, compound degradation, and
compound formation caused by the sampling
event itself.
Used to evaluate laboratory capability. In
addition, a blank spike evaluates air matrix and
sorbent, if used for sampling.
Used whenever manufacturers supply one lot
of samplers or when a fresh lot of sampling
media is cleaned.
Used for impinger samples and for solvent
desorbed sorbent media.
Used to verify that bias results are not being
reported high or low due to problems with a
specific analysis.
Not appropriate for total particulates. Very
appropriate for particulate bound pollutants.
Used to verify retention times, concentrations,
percent recovery, analytical error, and matrix
interference.
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Caution: Because of the great potential for errors
and the difficulty in calculating the amount of
spike needed and the distribution of spike
compound throughout the sample, it is not
recommended that field/blind spikes be used to
evaluate laboratories. If they are used, the
preparing lab must take all precautions to ensure
accuracy and to reanalyze samples if there are
any discrepancies.
Lot Blank
A lot blank detects contamination producing false
positive results due strictly to the sampling
medium itself. It consists of a sample device
from the same lot as the sample devices used
during a particular day or time period. The lot
blank comes from the manufacturer or laboratory
with the seal intact. It is included with the
samples when they are delivered to the
laboratory. Whenever a set of canisters is
cleaned by the laboratory for reuse, the previously
most-contaminated canister should be re-analyzed
as a lot blank at least 24 hours later in order to
check the cleanliness of that lot of "cleaned"
canisters. Whenever a new sampler system (e.g.,
Anderson stainless steel bellows pump) is
initially received from the manufacturer or from
a laboratory, a lot blank should be pulled off the
system using humidified zero air or humidified
nitrogen. In a similar manner, whenever a
sampler system is cleaned, the sampler(s) that
had generated the most contaminated canister
sample(s) should be checked with humidified
zero air.
Reagent/Method Blank
A reagent/method blank is a reagent sample used
in sample analyses. Unlike field and trip blanks,
a reagent/method blank is prepared in the
laboratory and is designed to detect
contamination that could arise from the reagents
and laboratory equipment used in the analysis.
This would include the reagents used in preparing
impinger solutions and the reagents used in the
extraction and cleanup of solvent extracted
adsorbent media.
Surrogate Spike
A surrogate spike, which is typically used only
with GC-, GC/MS-, and HPLC-based methods, is
designed to detect potential quantitative errors in
the actual analysis of each sample. The surrogate
compounds, which are usually non-target
compounds that elute throughout the analyses, are
typically spiked into each sample prior to its
analysis. The surrogate results are used to check
retention times, concentrations, percent recovery,
and matrix interferences.
Matrix Spike
A matrix spike is designed to test the ability of
the method to detect known concentrations of the
target compounds. As a laboratory-prepared
sample, a matrix spike contains known
concentrations of the target compounds which are
spiked into a sample prior to its analysis. The
matrix spike results are used to verify retention
times and percent recoveries in the extraction
procedure and to determine the degree to which
matrix interferences will affect the overall
identification and quantification of the target
compounds.
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Appendix A -- Other Factors Affecting Sampling Design Parameters
1.0 METEOROLOGICAL PARAMETERS
Understanding meteorological parameters is important to the development of an effective ambient air monitoring
scenario. Wind speed, wind direction, and atmospheric stability determine the transport and dispersion of
contaminants and thus dictate the placement of sampling and monitoring sites to measure those contaminants. Other
parameters (temperature, precipitation, humidity, etc.) primarily affect the amount of a contaminant emitted into the
air. Additional discussion on these parameters is contained in Chapter 3.
1.1 Wind Speed
When the contaminant of concern is a particulate, wind speed is critical to measuring if and how much of the
contaminant becomes airborne, and how far the contamination travels from the source. Wind speed may affect the
number of samples needed to ensure that at least one location is truly representative of the downwind plume. Wind
speed may be a factor in determining whether "worst-case" conditions existed at the site when samples were collected.
Wind speed plays a role in the volatilization of contaminants from liquid sources. Calm or low wind speeds may
reduce volatilization from a liquid surface by creating a saturated layer near the surface, while higher wind speeds
increase volatilization.
Wind speed affects the dispersion of downwind concentrations for a given source. Low wind speeds (less than 5 mph)
or calm conditions result in little dispersion of airborne contaminants and provide for worst-case conditions. The
concentration of air pollutants directly downwind of a source is inversely proportional to wind speed during most
meteorological conditions.
1.2 Wind Direction
Wind direction heavily influences the path in which airborne contaminants travel. Terrain features, large bodies of
water, and localized meteorological conditions cause changes in surface wind direction. Wind directions change
rapidly in the vicinity of weather fronts and the onset or end of localized meteorological events (e.g., inversions, sea
breezes). Variable winds increase the dispersion of pollutants from a given source. Worst-case conditions would
result from light winds and constant direction, such as channelized winds or valley effects. Under very light evening
winds, the plume can follow terrain features, resulting in higher concentrations in these areas.
1.3 Atmospheric Stability
Atmospheric stability refers to the degree to which the atmosphere tends to dampen vertical and horizontal motion.
It may affect the time of day samples should be taken, as well as the average "width" of the expected plume, a
determining factor in obtaining a worst-case condition sample. Stable atmospheric conditions result in little
dispersion; conversely, unstable atmospheric conditions result in greater dispersion. Dispersion depends on several
interrelated factors, including wind speed, variability of wind direction, vertical temperature profile, and incoming
solar radiation.
Figure A-l illustrates the effect of stability on downwind concentrations. The logarithm of concentration is plotted
for four different stability conditions versus downwind distance for a point source with constant emissions. A class
F stability (moderately stable) shows less dispersion of contaminants by two orders of magnitude, at a distance of one
kilometer, than does a class A stability.
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Figure A-1: Effect of Typical Stability Data on Downwind
Concentrations From the Same Source
O
O
0.05 0.2 0.4 0.6 0.8
Downwind Distance in Kilometers
STABILITY CLASSES
1.2
Class A + Class C * D Night -* Class F
Table A-1: Key to Stability Classes
A - Extremely unstable conditions
B - Moderately unstable conditions
C - Slightly unstable conditions
D - Neutral conditions*
E - Slightly stable conditions
F - Moderately stable conditions
Daytime Conditions
Surface wind speed, in ph
Thin Overcast or> 4/8
Cloudiness**
Nighttime Conditions
< 3/8 Cloudiness**
<4.5
4.5
9
13.4
>13.4
Strong
A
A-B
B
C
C
Moderate
A-B
B
B-C
C-D
D
Slight
B
C
C
D
D
E
D
D
D
F
E
D
D
Applicable to heavy overcast, day or night.
* The degree of cloudiness is defined as that fraction of the sky above the local apparent horizon which is covered by clouds.
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Table 7 illustrates the commonly used Pasquill stability classification. If the sampling plan design is based on worst-
case downwind dispersion from a constant emission source, some nighttime sampling under the most stable
conditions may be warranted.
1.4 Temperature
Increased temperature typically increases the rate of volatilization of organic and some inorganic compounds. It also
affects the initial rise of gaseous or vapor contaminants. Therefore, when determining the day or time of day to
collect worst-case air samples, ambient temperature is an important consideration.
1.5 Precipitation
Precipitation will scrub the atmosphere of airborne contaminants. It physically scrubs the air of particulate matter
and chemically reacts with airborne compounds such as SO2 to produce acid rain. The effectiveness of this scrubbing
is dependent on the length and intensity of the precipitation and the chemical and physical properties of the
contaminant.
Precipitation decreases the potential for contaminated particulate matter to become airborne. Because wet soils tend
to coalesce, thereby increasing the wind speed required to make their particles become airborne, transport of
contaminated particulate matter is generally not a concern when the surface soil is wet. Wet soil also reduces
volatilization of contaminants from the soil surface and sub-surfaces. However, during the onset of a rain storm,
emission of volatiles increases for a short period of time, followed by a decrease in emission. This flux is caused by
the rain displacing gases in the near-surface soil. Precipitation may be significant in determining whether worst-case
or representative plumes will be present during a planned air sampling program.
1.6 Humidity
Humidity generally does not affect generation and transport of air contaminant plumes, but water-soluble chemicals
and particulates may be affected by high humidity. Particulates act as condensation nuclei for water vapor which
causes the particles to settle. Water-soluble chemicals often behave in a similar manner. Humid conditions can
dictate the sampling media used for air sample collection, as well as limit the volume of air sampled, thereby
increasing the detection limit (e.g., 0.05 ppm to 10 ppm).
1.7 Atmospheric Pressure
The effect of atmospheric pressure on air contaminants is generally negligible with the exception of landfill emissions.
Migration of landfill gases through the landfill surface can be governed by changes in atmospheric pressure. The
landfill can off-gas at much higher rates following a drop in atmospheric pressure, and may cease off-gassing
altogether when the atmospheric pressure suddenly rises. Significant lag times are associated with this phenomenon,
and each landfill behaves differently. It may be necessary to measure methane fluxes versus time in order to
determine how long it will be before the landfill responds to atmospheric pressure changes.
Changes in atmospheric pressure can significantly affect the infiltration of subsurface vapors into homes. Since the
internal pressures of homes almost always relate to outdoor atmospheric pressures, drops in atmospheric pressure will
temporarily increase the tendency of subsurface vapors to infiltrate basements. Also, landfill gases tend to migrate
off site in response to atmospheric pressure increases. When estimating worst-case conditions at a site (especially
landfills), be sure to monitor changes in atmospheric pressure.
2.0 METEOROLOGICAL EFFECTS
In many cases, local meteorology complicates the transport and dispersion of air pollutants. Normal diurnal
variations, such as temperature inversions, affect dispersion of airborne contaminants. Terrain features potentially
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create or enhance air inversions, and also influence the movement and path of air flow, causing more intricate
transport and dispersion patterns.
2.1 Temperature Inversions
Temperature inversions generally occur during fair weather. They start as early as late afternoon, endure through the
night and slowly dissipate, ending by mid-morning. In an inversion, radiant heat leaves the lower (or near ground)
atmosphere so that temperature increases with altitude to a certain height. Above that height, the temperature begins
to decrease with altitude. The top of the inversion becomes an effective cap where wind speeds above the inversion
could flow in a different direction and at a much higher speed than those at the surface. This cap is an effective
barrier to pollutants, which are held close to the surface under this very stable atmospheric condition. Inversions
generally result in a worst-case scenario for pollutants. However, if the pollutant source is able to penetrate the
inversion by means of stack height or effective stack height (the height the plume reaches by means of velocity and
thermal buoyancy), the inversion will effectively keep pollutants from affecting the surface "below" the inversion top.
The height of an inversion can range from several meters to several hundred meters. Once the inversion breaks, wind
speed and direction are more uniform.
2.2 Valley Effects
During clear nights when the prevailing wind is light, the slopes of a valley cool by radiation. Air immediately
adj acent to the slopes cools and becomes denser than air over the center of the valley at the same elevation. The
density imbalance induces convection, which causes winds to flow downslope to the valley floor. This situation is
commonly referred to as drainage wind or drainage flow. The combination of stable conditions, light drainage wind,
and inversion is a scenario where pollutants may not only be concentrated from a large source area, but also may be
transported over considerable distance with little dispersion.
On clear days with light winds, an opposite circulation pattern develops. An up-valley, upslope flow is due to the
heating of the air adjacent to the sun-warmed slopes and valley floor. Valleys are prone to temperature inversions
because of their natural protection from winds. Valleys can also channel the prevailing wind to coincide with
orientation of the valley. Channeling occurs most often when wind speeds are light to moderate and the direction is
not perpendicular to the valley. During this situation, winds at the top of the valley may be different than winds at
the valley floor.
2.3 Shorelines
During light winds, differences in heating and cooling of land and water surfaces and the air above them result in air
circulation. On summer days with clear skies and light winds, the land surface adjacent to a large lake or ocean is
heated much more rapidly than the body of water. A temperature difference and consequently a density difference
results between the air just above the land surface and the air over the water. Because of the density gradient, a local
circulation is established with wind moving from the water toward the land. There is usually some upwind motion
over the land and subsidence over the water accompanying the sea breeze or lake breeze. These breezes more likely
occur and tend to be stronger when land/water temperature differences are greatest (normally during the spring and
early summer). Strong breezes may extend inland 5 to 10 miles; however, they usually extend less than one mile.
Shoreline effects alter the sampling plan. At night, the rapid cooling of the land causes lower temperatures above
the land surface than above the water surface. Thus a land breeze may result in a reverse flow. A land breeze does
not usually achieve as high a velocity or inland extent as a lake breeze. Wind may shift 180 degrees with the onset
of the breezes. Sampling locations and periods may require adjustment to obtain upwind or downwind samples.
Since the breezes are circular, pollutants can build up over the time period of these breezes, but not to the levels
associated with many other meteorological conditions.
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2.4 Hills
The influence of hills on the transport of contaminants depends upon a number of factors, complicating the siting of
sample locations. During stable atmospheric conditions, air tends to flow around obstructions and affect the facing
slope. This situation provides worst-case conditions, especially if the hillside location lies in the path of an elevated
plume, or if an inversion top intersects the hillside where pollutant concentrations are higher. Under unstable
conditions, air tends to move over obstructions. Airborne contaminants can accumulate in eddies formed on the lee
side of a hill.
3.0 PHYSICAL/CHEMICAL FACTORS
The chemical characteristics of a contaminant affect its behavior in the atmosphere and influence the sampling and
analytical method. This section discusses some of the more important physical and chemical parameters which affect
the behavior of a contaminant, particularly those factors which should be considered before selecting sampling
methods and procedures.
3.1 Molecular Weight
Molecular weight is an important factor when the release involves a pure gas. Pure dense gases (having a molecular
weight greater than air) do not mix rapidly with the atmosphere and generally follow the terrain based on mean wind
direction and gravity until diluted to below percent level concentrations. If released indoors, the gases tend to
accumulate near the floor. Pure light gases, if released indoors, accumulate near the ceiling; outdoors, they rapidly
disperse.
3.2 Physical State
Materials in their pure state pose special but predictable problems. If a contaminant of interest is immersed or
dissolved in another matrix, then sampling varies from the approach used to sample a material in its pure state.
Pressure and temperature are the predominant controllers of physical state.
For sampling purposes, airborne contaminants may be grouped into three broad categories: gases, vapors, and
particulates. However, most compounds are distributed partially into each phase, as dictated by atmospheric
conditions.
Particulates may exist as solids or gas mixed with liquids, such as aerosols. Particulates are frequently subdivided
into dusts, mists, fumes, and smokes. The distinction between subgroups is based upon particle size, state, and means
of generation.
• Dusts are formed from solid materials which have been reduced in size by mechanical processes such as
grinding, crushing, blasting, drilling, and pulverizing; these particles range in size from the visible to the sub-
microscopic.
• Mists are formed from either the mechanical disturbance of liquid or the evaporation and condensation of
a liquid. These particles range in size from the visible to the microscopic.
• Fumes are formed from solid materials by evaporation and condensation and by gas phase molecular
reactions; particles generally range in size from 1.0 (im to 0.0001 (im.
• Smokes are products of incomplete combustion of organic materials and are characterized by optical density;
the size of smoke particles is usually less than 0.5 (im.
The nature and state (solid, gas, or gas mixed with liquid) of the contaminant determines the sampling method. Gases
and vapors are collected in an aqueous medium, on adsorbates, in molecular sieves, or in a suitable container.
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Particles are collected by filters, impingers, impactors, centrifugal devices (e.g., cyclones), settling chambers,
electrostatic precipitators, thermal precipitators, and diffusion batteries.
3.3 Vapor Pressure
Vapor pressure is a measure of the pressure exerted by a vapor against the sides of a closed container. Vapor pressure
is temperature dependent: as temperature increases, so does the vapor pressure, resulting in more liquid evaporating
or vaporizing. The lower the boiling point of the liquid, the greater the vapor pressure it will exert at a given
temperature. Values for vapor pressure are most often given as millimeters of mercury (mm Hg) at a specific
temperature.
In general, contaminant volatilization is a function of vapor pressure. Contaminants with high vapor pressures
(> 1 mm Hg) volatilize much more readily than those with low vapor pressures. The vapor pressure determines
whether the substance is found primarily in the vapor state (volatile), on the surface of particles (non-volatile), or in
both states (semi-volatile). The vapor pressure also determines whether a particulate-bound compound is capable of
volatilizing off the particulates during sampling with filters.
3.4 Aerodynamic Size
The ability of a particle to become and remain airborne is a function of its size and aerodynamic diameter. In general,
larger particles require greater force (typically wind) to become entrained in the air. Larger particles also tend to
settle more rapidly.
3.5 Temperature
The temperature of contaminants at the time of their release affects the state of the contaminant as well as its transport
and dispersion. Gaseous or vapor phase contaminants with a temperature greater than ambient air temperature will
have thermal buoyancy that will cause the contaminant to exhibit an initial vertical rise above its point of release.
As the contaminant cools, it will sink to, or even below, its original release point. If the temperature of a contaminant
is significantly below ambient air temperature, the contaminant may sink and act in a manner similar to a dense gas,
remaining close to the ground and settling in low-lying pockets.
3.6 Reactive Compounds
A reactive material can undergo a chemical reaction under certain specified conditions. Generally, the term reactive
hazard refers to a substance that undergoes a violent or abnormal reaction in the presence of water or under normal
ambient atmospheric conditions. Among these types of hazard are the pyrophoric liquids which can spontaneously
ignite in ambient air without added heat, shock, or friction, and the water-reactive flammable solids which undergo
a spontaneous and possibly violent reaction upon contact with water (e.g., sulfur trioxide and sodium metal).
3.7 Photodegradation
Some compounds undergo photolysis where UV radiation provides enough energy to break bonds. It may be
necessary to sample with opaque cassettes or to cover tubes with aluminum foil to prevent the photolysis of certain
compounds. This is a problem with polynuclear hydrocarbons and many pesticides and herbicides.
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4.0 ENVIRONMENTAL INTERFERENCES
When designing an air sampling/monitoring program, consider the potential effects of environmental interferences
on sampling. Sources of potential environmental interferences include:
• Natural sources of pollution (e.g., pollen, spores, terpenes, biologically produced waste compounds such
as hydrogen sulfide, methane, ore and mineral deposits, etc)
• Extraneous anthropogenic contaminants (e.g., emissions from burning of fossil fuels, emissions from
vehicular traffic, especially diesels, volatiles from petrochemical facilities, effluvium from smoke stacks)
• Photo-reactivity or reaction of the parameters of concern with non-related compounds (e.g., nitrogen
compounds, sulfur compounds, and poly aromatic hydrocarbons)
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Appendix B -- Representative Air Sampling Plan: Example Sites
Example Site 1 -- Wood Preserving Facility
1.0 SITE BACKGROUND INFORMATION
The Wood Preserving Company, Inc., began operation in 1950 when a swamp area was graded and converted to land
suitable for wood storage. In the early 1970s, pentachlorophenol (PCP) began to be used in the wood preserving
process. The facility also used creosote in its process through the 1980s.
Land use and zoning in the area surrounding the facility is mixed. An industrial area is located south of the site and
residential areas are located to the north and west.
Several surface impoundments were used for disposal operations at the facility. Contact cooling waters were placed
in two ponds, and process wastewaters were discharged into another large impoundment. A creosote recovery unit
received some wastewater until its use was discontinued in the late 1980s. The discharge of wastewater containing
hazardous constituents into these impoundments over the years created hazardous sludge.
The wood preserving process generates drippage at two points: immediately after the treated wood is removed from
the treatment cylinders while it is held in the drip track area, and when the wood is retained in on-site storage after
treatment has been completed. Because the facility utilized both creosote and PCP over its operational life, these
drippage areas are cross-contaminated.
In 1986, EPA conducted Phase I of an emergency removal action to stabilize the three unlined surface impoundments.
The sludges and contaminated soils were stabilized with cement kiln dust and stockpiled on site for future treatment
or disposal during Phase II of the removal action.
Phase II involves bioremediation of the stockpiled contaminated soil. This treatment process includes screening of
waste media, mixing with water, slurrying in bioreactors, and final treatment in a land treatment unit. During Phase
II, air sampling will be conducted to address health and safety concerns for on-site personnel and to monitor off-site
acute exposure.
The selection of air sampling locations will be based in part on an updated conceptual site model. Historical
information (e.g., activities during the Phase I emergency removal action) and knowledge of planned activities for
Phase II will be incorporated into the original model for the site (which described sources, pathways, and potential
receptors). This process will allow the conceptual site model to continue as a useful tool in selecting sample
locations.
2.0 SAMPLING OBJECTIVES
The air sampling objectives for Phase II varied with changing activity at the site. During the initial three months
when soil screening, slurrying, and sludge application were taking place, the contaminant released to the air was
unknown. The sampling objectives then were to determine the types of pollutants encountered and their
concentrations. During land treatment activity at the site when soil was tilled, the sampling objectives were to
document how well control measures were working and how releases to the air from the tilling were minimized.
The following have been identified as air monitoring and sampling objectives for Phase II activities:
1. Assess the health and safely of response personnel. Because of the planned nature of the response, sufficient
sampling and monitoring equipment will be available at the site. Health and safety guidelines will be
determined for the three months of land application and six months of tilling.
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2. Assess the off-site, acute exposure of the public, particularly those residences across the street from the site.
Off-site, acute exposure will be assessed for worst-case meteorological conditions during land applications,
and for normal or expected meteorological conditions during soil tilling operations.
3.0 SAMPLING PLAN DESIGN
3.1 Selection of Sampling and Analytical Methods
During Phase I, soil/water samples were collected to identify the contaminants present at the site. The response team
used this contaminant information to develop the sampling plan for Phase II activities. The contaminants of concern
were PCP and creosote (aromatic hydrocarbons, PAHs/PNAs). Preliminary research into the chemical and physical
properties of the compounds present included the following information:
Pentachlorophenol (PCP) C6C15OH
OSHA PEL - 0.5 mg/m3
IDLH - 150 mg/m3
Sample Collection — Filter with impinger, methanol solvent
Instrument - HPLC/UVD
Method -NIOSH 5512
Creosote ~ (aromatic hydrocarbons, PAHs/PNAs):
Aromatic Hydrocarbons
Sample Collection — Carbon tubes/personal sampling pumps
Instrument — HPLC
Method - NIOSH 1501
PAHs/PNAs
Sample Collection — Carbon tubes/personal sampling pumps
Instrument - HPLC
Method - NIOSH 5506, 5515
The above information was used to select the sampling and analytical methods for assessing on-site health and safety
and off-site acute exposure. The equipment and methods selected for sampling activities are listed in section 5.0.
To ensure the safety of the response personnel, monitoring was performed using HNu and OVA portable gas
analyzers prior to initiating any site activities. No readings above background values were encountered anywhere
on site, even when the probes were placed near areas of disturbed soil. A Real-time Aerosol Monitoring (RAM)
instrument was used for particulate monitoring. Above-background readings were obtained only when soils were
disturbed near the instrument.
The RAM instrument reads total particulate matter concentrations. These readings can be ratioed by the known
concentration of a specific compound in soil which yields an estimate of the concentration for that compound in the
air as a fraction of the total particulate matter. The estimated compound-specific concentration can then be compared
to an action limit such as a TL V or PEL to assess air quality levels.
To assess off-site acute exposure, portable personal sampling pumps that were capable of collecting 8-hour, time-
integrated air samples were used.
3.2 Meteorological and Topographic Considerations
The site was located in a generally open area, with the only rise in elevation occurring towards the western border
of the site. A monitoring station was established to collect meteorological data (wind speed, wind direction,
temperature, sigma theta) during sampling. The wind data helped to determine if the off-site sampling locations were
50
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exposed to air that passed over the site, to document any shifts in winds during sampling due to topographic features,
and to calculate changes in atmospheric stability. Figure B-l is a map of the site.
3.3 Time, Duration, and Frequency of Sampling
Sampling for on-site health and safety was performed during all on-site activities. Sampling for off-site acute
exposure was performed during the Phase II soil screening, slurrying, and land application (three months), and tilling
operations (six months). During screening activities, increased volatilization and dust generation was anticipated.
Eight-hour, time-integrated samples were collected during days when site operations were in progress. Sampling was
conducted at four locations around the site border, with one close to the private residence nearest the site.
During land application, the sludge applied to the land treatment area became drier late in the day and released more
volatile compounds. During the late afternoon when the atmosphere became more stable and less mixing occurred,
higher ambient concentrations of contaminants existed. To address this potential elevation of pollutant
concentrations, an additional daily sampling period running from late afternoon (4 to 5 p.m.) to early evening (6 to
7 p.m.) was established at a location downwind of the land treatment area during land application activities (initial
three months).
3.4 Location of Sampling Points
Four locations on the perimeter of the site (sampling locations 1 to 4) were selected for sampling with the personal
sampling pumps and charcoal tubes. The sampling equipment was placed at each of the four compass points (north,
south, east, and west) from the site and along the site boundary. This configuration enabled the collection of upwind
and downwind air samples during Phase II activities. A fifth sampling location (sampling location 5) northwest of
the site was situated near the residence closest to the site. Sampling at this location documented the exposure of the
nearest residence to any emissions during Phase II site activities.
3.5 QA/QC Requirements
The QA/QC requirements covered field equipment calibrations, field sampling activities, laboratory analytical
activities, and evaluations of meteorological conditions during sampling. All monitoring equipment was calibrated
prior to its use in the initial assessment of health and safety conditions.
During sampling activities, trip blanks, field blanks, collocated samples, distributed volume samples, and
breakthrough samples were utilized. Field samples were confirmed by definite analyses, including a performance
sample, lot blank, method blank, surrogate spike, and matrix spike.
The meteorological data collected with the on-site monitoring station were utilized for QA/QC and data validation.
The collected data helped to determine which of the sampling locations surrounding the site were upwind and which
were downwind during each 8-hour sampling period, as well as to determine if samples were collected during worst-
case meteorological conditions. A comparison of the sampling results between upwind and downwind locations was
used to determine if the site emissions were significantly affecting air quality levels.
An air quality modeling analysis performed by the EPA Regional meteorologist was used to evaluate the
representativeness of the sampling locations for identifying the maximum air concentrations due to emissions from
the land treatment unit. The result of this analysis determined if air sampling locations corresponded to areas of
maximum concentration predicted by the model. If sampling locations did not include these areas, the information
provided by the model would be utilized for siting additional sampling locations.
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Figure B-l
Wood Preserving Company Site Map
Prevailing Wind
Key:
1 • Contaminated Soil Pile
2 - Soil Suspension System (Tanks)
3 - Bioreactors
4 - Water Management Tank
5 • Land Treatment Unit
6 - Decontamination Trailer
X - Sampling Location
tin - Residences
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4.0 SAMPLING PLAN DEVELOPMENT CHECKLIST
I. Objectives of the Sampling Program and Implied Assumptions
Yes A. Have clear, concise objectives for the sampling program been defined?
Yes B. Have the assumptions of the sampling program been clearly defined (e.g., sampling under
"worst-case" conditions, sampling under "typical" conditions, sampling under a routine, periodic
schedule, etc.)?
NA C. Other:
II. Selection of Sampling and Analytical Methods
A. Selection of Target Compounds
Yes 1. Has background site information been consulted?
B. Selection of Method
Yes 1. Can selected methods detect the probable target compounds?
Yes 2. Do the selected analytical methods have detection limits low enough to meet the overall
objectives of the sampling program?
Yes 3. Would the selected methods be hampered by any interfering compounds?
Yes C. Will the selected methods, when applied to the projected sampling location(s), adequately isolate
the relative downwind impact of the site from that of other upwind sources?
Yes D. Are the selected methods logistically feasible at this site?
NA E. Other:
III. Location(s) and Number of Sampling Points
NA A. Do the locations account for all the potential on-site emission sources that have been identified from
the initial site background information and from walk-through inspections?
NA B. Will the sampling locations account for all the potential emission sources upwind from the site?
NA C. For short-term monitoring programs, has a forecast of the local winds been obtained for the day (s)
of the program?
Yes D. For a long-term monitoring program, have long-term air quality dispersion models and historical
meteorological data been used to predict probable area of maximum impact (when applicable)?
Yes E. Does the sampling plan account for the effects of local topography on overall wind directions and
for potential shifts in direction during the day (e.g., valley effects, shoreline effects, hillside
effects)?
Yes F. Do the sampling location decisions account for the effects of topography on surface winds,
especially under more stable wind directions (e.g., channelization of surface winds due to buildings,
stands of trees, adjacent hills, etc.)?
Yes G. Can any sampling equipment left at these locations be adequately secured?
NA H. Other:
IV. Time, Duration, and Frequency of Sampling Events
A. When the sampling time periods (the actual days, as well as the time span during specific days)
were selected, were the effects of the following conditions on downwind transport of contaminants
considered:
C Yes Expected wind directions?
Yes C Expected atmospheric stability classes and wind speeds?
C Yes Evening and early morning temperature inversions?
C NA Changes in atmospheric pressure and surface soil permeability on lateral, off-site migration of gases
from methane-producing sources such as landfills?
C NA During indoor air investigations, gas infiltration rates into homes due to changes in atmospheric
pressure and to the depressurization of homes caused by many home heating systems?
C NA Other:
53
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B. When selecting the sampling time periods (the actual days, as well as the time span during specific
days), were the effects on potential site emissions listed below considered:
Yes C Effect of site activities?
C Yes Effect of temperature and solar radiation on volatile compounds?
C Yes Effect of wind speeds on particulate-bound contaminants and on volatiles from lagoons?
C NA Effect of changes in atmospheric pressure on landfills and other methane-producing emission
sources?
NA C Effect of recent precipitation on emissions of both volatile and particulate-bound compounds?
C NA Other:
Yes C. Do the time periods selected allow for contingencies such as difficulties in properly securing the
equipment, or public reaction to the noise of generators for high volume samplers running late at
night?
D. When determining the length of time over which individual samples are to be taken, were the
following questions considered (when applicable)?
Yes C Will sufficient sample volumes be taken to meet the desired analytical method detection limits?
C Yes Will the sampling durations be adequate either to cover the full range of diurnal variations in
emissions and downwind transport, or to isolate the effects of these variations?
YesC When applicable, do the selected time intervals account for potential wind shifts that could occur
due to local topography such as shorelines and valleys?
C NA Other:
V. Meteorological Data Requirements
NA A. Has a source of meteorological data been identified to document actual conditions at the time the
sampling event takes place?
Yes B. Has the placement of an on-site meteorological station been considered in the sampling plan if no
off-site station has been identified?
VI. QA/QC Requirements
Yes A. Are screening data confirmed by definitive data at a minimum of a 10% rate?
Yes B. Have the necessary QA/QC samples been incorporated into the sample design to allow for the
detection of potential sources of error?
Yes C. Does the QA/QC plan account for verification of the sampling design and of sample collection?
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5.0 SAMPLING PLAN DEVELOPMENT SUMMARY
Selected Direct Reading Instruments and Techniques:
C Flame ionization detector
C Photoionization detector
C Particulate monitor
Selected Sampling Equipment:
C Personal sampling pump
Selected Sampling Collection Media/Devices:
C Mixed sorbent tubes
C Impingers
Selected Analytical Techniques:
C High performance liquid chromatography
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Example Site 2 -- Emergency Response at a Train Derailment
1.0 SITE BACKGROUND INFORMATION
At 1900 hours on a Sunday evening in early May 1991, a Western Consolidated Freight train derailed outside of
Jonesburg, Oregon. Three of the rail cars were leaking and impinged by the resultant fire. These three rail cars were
tentatively identified to be carrying toluene, chloroform, and carbaryl (solid), respectively. The fire department
initially responding was Jonesburg Engine Company 51. Upon arrival at the scene, the assistant chief of Engine
Company 51 called for a half-mile evacuation zone and isolated the site awaiting mutual aid assistance.
Jonesburg is an old timber and pulp industry town of about 25,000 residents. The town is situated along a large lake
which was once used to float logs to the mills. The city is served by a paid fire department. The regional Haz-Mat
team and The County Health Department are located in the county seat, approximately 19 miles to the west. The
State Department of the Environment is 40 miles to the north, and the nearest EPA regional office is approximately
200 miles away.
The potentially affected residential area to the immediate west consists of small scattered developments of new homes
and condominiums. An elementary school is located one mile west of the incident. Interstate Highway 6 runs east-
west approximately one mile north of the derailment.
2.0 SAMPLING OBJECTIVES
The emergency response personnel identified three initial air monitoring/sampling objectives:
1. Assess the health and safety of the response personnel. Because of the emergency nature of the response,
this objective must initially be accomplished by the local fire department and county Haz-Mat team, often
using a limited collection of air monitoring equipment. Generally, air sampling equipment is not available
within the first six hours of an emergency response.
2. Assess off-site, acute exposure of the public and the staged response personnel (e.g., police). Decisions on
the size of evacuation zone and method of notification depend on the location and movement of chemical
vapors and particulates.
3. Use confirmatory sampling to confirm the identity of compounds suspected of being released. The air
sampling methods used are compound-specific and provide lower detection limits.
A map detailing the sources (railcars), pathways (e.g., prevailing wind direction/speed), and potential receptors
(location of nearby houses, schools, offices) will help in the selection of off-site sampling locations. In an emergency,
even a simple conceptual site model can be quite useful. Figure B-2 is an example of a simplified conceptual site
model.
56
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3.0 SAMPLING PLAN DESIGN
3.1 Selection of Sampling and Analytical Methods
The chemicals were identified from the railroad shipping manifests. The impinged rail cars contained toluene,
chloroform-n, and carbaryl pesticide. Preliminary research into the chemical and physical properties of each
compound, using the air methods database and other references, included the following information:
Toluene C6H5CH3 (1 tank car)
OSHA PEL - 200 ppm
IDLH - 2,000 ppm
Sample Collection — Charcoal tube
Instrument -- GC/FID
Method - NIOSH 1500
Chloroform CHC13 (1 tank car)
OSHA PEL - 2 ppm
IDLH - 1,000 ppm
Sample Collection — Charcoal tube
Instrument -- GC/FID
Method - NIOSH 1003
Note: Decomposition by fire may generate phosgene gas, which reacts with strong oxidizers to form
phosgene and chlorine gas.
Chlorine C12
OSHA PEL-0.5 ppm
IDLH - 30 ppm
Sample Collection — Midget impinger
Instrument — Ion-specific electrode
Method-OSHA ID-101
Phosgene COC12
OSHA PEL-0.1 ppm
IDLH - 2 ppm
Sample Collection — Midget impinger
Instrument — Colorimetric
Method - NIOSH P+CAM 219
Carbaryl — (1 box car)
OSHA PEL - 5 mg/m3
IDLH - 600 mg/m3
Sample Collection — Particulate filter
Instrument — Visible spectrometry
Method - NIOSH 5006
The above information was used to select the sampling and analytical methods for assessing on-site health and safety
and off-site acute exposure. The equipment and methods selected for sampling activities are listed in Section 5.0.
Note: The time required for mobilization affects the level of expertise and equipment available at the initial site
response.
Health and Safety assessment was conducted by the local fire department and county Haz-Mat team using available
equipment consisting of a flame ionization detector (FID), explosimeter, calorimetric tubes, and chemical-specific
57
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monitors. These instruments monitored continuously during site activities. Worst-case exposure scenarios were
assumed pending the results of confirmatory sampling. Data from the monitoring were used to establish site response
work zones, levels of personal protection equipment, and placement of the command post. Potential interference
problems associated with these detection methods were taken into account when making decisions affecting impacting
response personnel.
Off-site acute exposure was assessed by collecting 8-hour samples at locations established around the perimeter of
the evacuation zone (see Section 3.4). The assumption of a worst-case situation and establishment of a one-half-mile
evacuation zone reduced the potential for acute human exposure during the response.
Sampling was conducted to confirm the identity of suspected contaminants and to backup the results of screening
methods. These methods involve the use of personal sampling pumps and various sorbent filter media. As a general
rule, these samples are collected for an 8 to 12 hour period; however, because of the extremely time-critical nature
of this information, sampling times were modified. Sampling was designed to be compound-specific and to provide
lower detection limits than would Direct-Reading Instruments (DRIs). The sampling required analysis, thus
laboratory availability and turnaround time information was gathered in the initial phases of the response and was
factored into the sampling strategy.
3.2 Meteorological and Topographical Considerations
The site was on the west coast in a generally flat, open area one-half mile from a lake. Local weather history was
obtained from the National Weather Service once EPA received notification of the incident. The predominant local
meteorology displayed stable atmospheric conditions during the evening, with inversions setting up approximately
one hour before nightfall. A westerly wind occurred during the day (not a sea breeze). A meteorological monitoring
station was established near the incident to collect real-time meteorologic data which were integrated into a modeling
program. The data helped to determine if the sampling locations were exposed to air that passed over the site and
to document any shifts in winds during sampling due to local topographic features. Because of the potential for
complex meteorological conditions at this site, a meteorologist was involved in the decision process. Figure B-2 is
a map of the site.
3.3 Time, Duration, and Frequency of Sampling
On-site health and safety monitoring with real-time instruments was performed whenever response personnel were
within the hot zone. Continuous sampling for off-site acute exposure assessment and confirmatory sampling were
conducted during the fire, tank venting, and cleanup activities. Sampling was also conducted continuously with DRIs
at the on-site command post and support areas. Based on measured meteorological conditions and the spilled
quantities, the CAMEO model was used to predict the location and concentration of the chemical plume during the
various atmospheric stability conditions over the two-day fire and ensuing cleanup. To account for potential
inversions during the response, monitoring was conducted with DRIs to ensure the adequacy of the evacuation
corridors As weather conditions or forecast conditions changed, new plume predictions were made and sampling
locations moved accordingly.
3.4 Location of Sampling Points
Five sampling locations were established: three points along the evacuation border of the site, one point at the
command post, and one point inside the evacuation zone. The command post sample established a background level
and determined the appropriate level of protective equipment for response personnel.
58
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3.5 QA/QC Requirements
The QA/QC requirements covered field equipment calibrations, field sampling activities, laboratory analytical
activities, and evaluations of meteorological conditions during sampling. All monitoring equipment was calibrated
prior to its use in the initial assessment of health and safety conditions.
It is important to note that meeting specific QA objectives is not of paramount concern during an emergency response,
primarily because of the presence of the contaminant in elevated concentrations (ppm).
59
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Figure B-2
Train Derailment Emergency Response Site Map
KEY:
Interstate Highway
Local Roadway
Evacuation Zone
Command Post
Tank Car
Carbaryl Box Car
Residence
Sampling Location
60
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4.0 SAMPLING PLAN DEVELOPMENT CHECKLIST
I. Objectives of the Sampling Program and Implied Assumptions
Yes A. Have clear, concise objectives for the sampling program been defined?
NA B. Have the assumptions of the sampling program been clearly defined (e.g., sampling under
"worst-case" conditions, sampling under "typical" conditions, sampling under a routine, periodic
schedule, etc.)?
Yes C. Other: Emergency Response
II. Selection of Sampling and Analytical Methods
A. Selection of Target Compounds
Yes Has background site information been consulted?
B. Selection of Method
Yes 1. Can selected methods detect the probable target compounds?
Yes 2. Do the selected analytical methods have detection limits low enough to meet the overall
objectives of the sampling program?
Yes 3. Would the selected methods be hampered by any interfering compounds?
NA C. Will the selected methods, when applied to the projected sampling location(s), adequately isolate
the relative downwind impact of the site from that of other upwind sources?
Yes D. Are the selected methods logistically feasible at this site?
NA E. Other:
III. Location(s) and Number of Sampling Points
NA A. Do the locations account for all the potential on-site emission sources that have been identified from
the initial site background information and from walk-through inspections?
NA B. Will the sampling locations account for all the potential emission sources upwind from the site?
Yes C. For short-term monitoring programs, has a forecast of the local winds been obtained for the day (s)
of the program?
NA D. For a long-term monitoring program, have long-term air quality dispersion models and historical
meteorological data been used to predict probable area of maximum impact (when applicable)?
Yes E. Does the sampling plan account for the effects of local topography on overall wind directions and
for potential shifts in direction during the day (e.g., valley effects, shoreline effects, hillside
effects)?
Yes F. Do the sampling location decisions account for the effects of topography on surface winds,
especially under more stable wind directions (e.g., channelization of surface winds due to buildings,
stands of trees, adjacent hills, etc.)?
Yes G. Can any sampling equipment left at these locations be adequately secured?
NA H. Other:
IV. Time, Duration, and Frequency of Sampling Events
A. When the sampling time periods (the actual days, as well as the time span during specific days)
were selected, were the effects of the following conditions on downwind transport of contaminants
considered:
Yes C Expected wind directions?
YesC Expected atmospheric stability classes and wind speeds?
C Yes Evening and early morning temperature inversions?
NAG Changes in atmospheric pressure and surface soil permeability on lateral, off-site migration of gases
from methane-producing sources such as landfills?
NA C During indoor air investigations, gas infiltration rates into homes due to changes in atmospheric
pressure and to the depressurization of homes caused by many home heating systems?
NA C Other:
61
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B. When selecting the sampling time periods (the actual days, as well as the time span during specific
days), were the effects on potential site emissions listed below considered:
Yes C Effect of site activities?
NA C Effect of temperature and solar radiation on volatile compounds?
Yes C Effect of wind speeds on particulate-bound contaminants and on volatiles from lagoons?
NA C Effect of changes in atmospheric pressure on landfills and other methane-producing emission
sources?
NA C Effect of recent precipitation on emissions of both volatile and particulate-bound compounds?
NA C Other:
Yes C. Do the time periods selected allow for contingencies such as difficulties in properly securing the
equipment, or public reaction to the noise of generators for high volume samplers running late at
night?
D. When determining the length of time over which individual samples are to be taken, were the
following questions considered (when applicable)?
Yes C Will sufficient sample volumes be taken to meet the desired analytical method detection limits?
NA C Will the sampling durations be adequate either to cover the full range of diurnal variations in
emissions and downwind transport, or to isolate the effects of these variations?
Yes C When applicable, do the selected time intervals account for potential wind shifts that could occur
due to local topography such as shorelines and valleys?
NA C Other:
V. Meteorological Data Requirements
NA A. Has a source of meteorological data been identified to document actual conditions at the time the
sampling event takes place?
Yes B. Has the placement of an on-site meteorological station been considered in the sampling plan if no
off-site station has been identified?
VI. QA/QC Requirements
Yes A. Are screening data confirmed by definitive data at a minimum of a 10% rate?
NA B. Have the necessary QA/QC samples been incorporated into the sample design to allow for the
detection of potential sources of error?
Yes C. Does the QA/QC plan account for verification of the sample design and of the sample collection?
62
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5.0 SAMPLING PLAN DEVELOPMENT SUMMARY
Selected Direct Reading Instruments and Techniques:
C Flame ionization detector
C Explosimeter
C Colorimetric Tubes
C Chemical-specific monitors
Selected Sampling Equipment:
C Personal sampling pump
Selected Sampling Collection Media/Devices:
C Charcoal tubes
C Impinger
Selected Analytical Techniques:
C Gas Chromatography/Flame Ionization Detector (GC/FID)
63
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APPENDIX C -- Example of Flow Diagram For Conceptual Site Model
Figure C-l
Migration Routes of a Gas Contaminant
from Origin to Receptor
Change of
Original state Pathway contaminant
of contaminant from state In
of concern" origin pathway
conch
RpQ > A:r
V-^CIO r Mil
solldl
insatlon
> Liquid
_ **
— > Solid
Mcatlon
Final
pathway
to receptor
> SO
^ sw
> so
> AT
>• ^V J.
> sw
^ so
^ sw
Receptor
Human
G,D
G,D
I,D
I,D
G,D
G,D
G,D
Ecological Threat
Terrestrial
G,D
G,D
I,D
I,D
I,D
G,D
G,D
Aquatic
N/A
G,D
N/A
N/A
G,D
N/A
G,D
* May be a transformation product
** Includes vapors
Receptor Key
D - Dermal Contact
] - Inhalation
G — Ingestlon
N/A - Not Applicable
Pathway Key
Al -Air
SO - Soil
SW = Surface Water
(Including sediments)
GW - Ground Water
64
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Figure C-2
Migration Routes of a Liquid Contaminant
from Origin to Receptor
Original state
of contaminant
of concern*
Liquid
sw
crystallization
so
leachate,
Infiltration
AI
* May be a transformation product
** Includes vapors
Liquid
**
Gas
Solid
Liquid
Gas
**
sw
AI
SW
sw
so
sw
GW
SO
AI
SW
Pathway Key
AI -Air
SO - Soil
SW - Surface Water
(Including sediments)
GW = Ground Water
Receptor
Human
G,D
I,D
G,D
G,D
Ecological Threat
Terrestrial
G,D
I,D
G,D
G,D
Aquatic
G,D
N/A
G,A
G,D
G,D
G,D
G,D
G,D
G,D
N/A
N/A
G,D
N/A
G,D
I,D
G,D
G,D
I,D
G,D
N/A
N/A
G,D
Receptor Key
D = Dermal Contact
I = Inhalation
G - Ingestlon
N/A - Not Applicable
65
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Figure C-3
Migration Routes of a Solid Contaminant
from Origin to Receptor
Original state
of contaminant
of concern*
Pathway
from
origin
A T
Change of
contaminant
state In
pathway
k. O <% 1 •! ri
Final
pathway
to receptor
> A]
> Ml r OU-L-LU r o'V\|
partlculates/
dust t sc
Solid
k- CIA/
r owv
^ VJW -L -L \J •• OVV
r- I_-H_|U-LU •• OVV
+ SC
vjiao
k Cr\ 1 -I r
^ Liqui
r /"vj
>> sv
* sc
dk ftW
^ lav
t. on
* May be a transformation product
** Includes vapors
D - Dermal Contact
I - Inhalation
,,^ hl
N/A = Not Applicable
Pathway Key
AI .Air
SO - Soil
SW - Surface Water
(Including sediments)
GW - Ground Water
Receptor
Human
I,D
G,D
G,D
Ecological Threat
Terrestrial
I,D
G,D
G,D
Aquatic
N/A
G,D
N/A
G,D
G,D
G,D
G,D
G,D
G,D
G,D
I,D
G,D
G,D
G,D
G,D
G,D
G,D
I,D
G,D
G,D
G,D
N/A
G,D
N/A
N/A
G,D
N/A
N/A
N/A
G,D
66
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References*
American Society of Testing Materials (ASTM). 1990. Annual Book of Standards, Volume 11.03.
Minnich, T.R., R.L. Scotts, and T.H. Pritchett. Remote Optical Sensing of VOCS: Application to Superfund
Activities. Presented at 1990 EPA/AWWA International Symposium on Measurement of Toxic and Related
Air Pollutants, Raleigh, NC. May, 1990.
National Institute for Occupational Safety and Health. Manual of Analytical Methods, Third Edition. 1984. U.S.
Department of Health and Human Services Publication No. 84-100.
Plog, B.H., Fundamentals of Industrial Hygiene, Third Edition, National Safety Council.
Riggin, R.M. Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air. U.S.
EPA. EPA/600/4-84/041.
Stem, A.C., H.C. Wohlers, R.W. Boubel, and W.P. Lowry. Fundamentals of Air Pollution Academic Press. 1973.
U.S. EPA. Air Superfund National Technical Guidance Series. Volume 1. Application of Air Pathway Analyses for
Superfund Activities. EPA/450/1-89/001.
U.S. EPA. Air Superfund National Technical Guidance Series. Volume I (Revised). Overview of Air Pathway
Assessments for Superfund Sites. EPA/450/1-89/00la.
U.S. EPA. Air Superfund National Technical Guidance Series. Volume II. Estimation of Baseline Air Emissions
at Superfund Sites. EPA/450/1-89/002.
U.S. EPA. Air Superfund National Technical Guidance Series. Volume III. Estimations of Air Emissions from
Cleanup Activities at Superfund Sites. EPA/450/1-89/003.
U.S. EPA. Air Superfund National Technical Guidance Series. Volume IV. Procedures for Dispersion Air Modeling
and Air Monitoring for Superfund Air Pathway Analysis. EPA/450/1-89/004.
U.S. EPA. Ambient Monitoring Guidelines for Prevention of Significant Deterioration (PSD). EPA/450/4-87/007.
U.S. EPA. Data Quality Objectives Process for Superfund. EPA/540/R-93/071.
U.S. EPA. On-Site Meteorological Program Guidance for Regulatory Modeling Applications. EPA/450/4-87/013.
U.S. EPA. Quality Assurance/Quality Control (QA/QC) Guidance for Removal Activities, Sampling QA/QC Plan
and Data Validation Procedures. EPA/540/G-90/004.
Winberry, W.T. Supplement to EPA/600/4-84/041: Compendium of Methods for the Determination of Toxic Organic
Compounds in Ambient Air. EPA/600/4-87/006.
* For additional information or assistance, contact the Superfund Air Coordinator in your EPA Regional office.
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