*>EPA
February 2008
Evaluation of AOr
Toxics Mon toring
in EPA Region 9
Final Report
Promoting Environmental Results
< #»
Through Evaluation
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Acknowledgements
This evaluation was performed by Ross & Associates Environmental Consulting, Ltd.,
under contract to Industrial Economics, Inc. The evaluation was prepared for the U.S. EPA
Office of Policy Economics and Innovation (OPEI), Evaluation Support Division; the U.S.
EPA Office of Air Quality Planning and Standards (OAQPS), Air Quality Assessment
Division; and the EPA Region 9 Air Toxics Monitoring Program. The EPA team guiding
development of this evaluation was comprised of James Hemby, EPA OAQPS; Michael
Jones, EPA OAQPS; Meredith Kurpius, EPA Region 9; and Michelle Mandolia, EPA
OPEI. The Ross & Associates evaluation team was comprised of Timothy Larson, Jennifer
Major, and Nicole Wigder.
This report was developed under the Program Evaluation Competition, co-sponsored by
EPA's Office of Policy Economics and Innovation and the Office of the Chief Financial
Officer. To access copies of this or other EPA program evaluations, please go to the EPA
Evaluation Support Division website located at http:www.epa.gov/evaluate.
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Table of Contents
Introduction 1
Background 2
National Air Toxics Monitoring Program 2
Air Toxics Monitoring in EPA Region 9 6
Air Toxics Monitoring Methods and Quality Control 7
Storing, Sharing, and Using Air Toxics Data 8
Overview of Air Toxics Monitoring Activities in EPA Region 9 10
Arizona Department of Environmental Quality 10
Bay Area Air Quality Management District 10
California Air Resources Board 11
Hawaii Department of Health 12
Joint Air Toxics Assessment Project (Arizona) 12
Nevada Division of Environmental Protection 13
Placer County Air Pollution Control District 13
San Diego Air Pollution Control District 14
South Coast Air Quality Management District 15
Other Air Toxics Monitoring Efforts in EPA Region 9 16
Findings 17
Conclusions 47
Recommendations 49
Appendices
Appendix A: Quality Assurance Plan 56
Appendix B: National Air Toxics Program Logic Model 58
Appendix C: List of Evaluation Contributors 59
Appendix D: SLT Interview Questions 61
Appendix E: List of Documents and Websites Referenced During
Development of This Report 63
Appendix F: Federal Hazardous Air Pollutants 65
Appendix G: National Air Toxics Trends Stations Compounds 68
Appendix H: Photochemical Assessment Monitoring Stations Compounds 69
Appendix I: Air Toxics Performance Measures, Indicators, and Data 70
Appendix J: Air Toxics Monitored by State and Local Agencies in EPA Region 9 73
Appendix K: Arizona Hazardous Air Pollutants 77
Appendix L: California Toxic Air Contaminants 80
Appendix M: Analysis of AQS Data for the Six Core NATTS Pollutants 83
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Table of Exhibits
Box 1: Air Toxics Goals and Objectives from EPA's 2004 National
Monitoring Strategy 4
Table 1: NATTS Sites in EPA Region 9 5
Table 2: EPA Region 9 Community-Scale Air Toxics Monitoring Grants,
2004-2005 7
Table 3: Example Air Toxics Recently Piloted by One or More Agencies in
EPA Region 9 27
Figure 1: Factors Affecting Air Toxics Data Quality and Comparability 30
Table 4: EPA Region 9 Communication Forums 38
Table 5: Common Reported Issues with Using the AQS Database and User Interface 40
Table 6: EPA and SLT Websites 63
Table 7: Additional Documents and Websites Referenced in Development of
This Evaluation 64
Table 8: Hydrocarbons Monitored Through the PAMS Program 69
Table 9: Carbonyls Monitored Through the PAMS Program 69
Table 10: Air Toxics Monitored through the BAAQMD Trends Network 73
Table 11: Air Toxics Monitored through the CARB Trends Network 73
Table 12: Pesticides Monitored by CARB 74
Table 13: Air Toxics Monitored at the Pearl City Site 74
Table 14: Pollutants Monitored at Community-scale Monitoring Sites 75
Table 15: Additional Pollutants that will be Monitored at Community-scale
Monitoring Sites Starting in 2008 75
Table 16: Pollutants Monitored during MATES II 76
Table 17: Air Toxics Monitored during MATES III 76
Evaluation of Air Toxics Monitoring in EPA Region 9
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Abbreviations
ADAM
California Air Resources Board's air quality database
ADEQ
Arizona Department of Environmental Quality
AMTAC
Air Monitoring Technical Advisory Committee
AMTIC
Ambient Monitoring Technology Information Center
APCD
Air Pollution Control District
AQS
Air Quality System
ASPEN
Assessment System for Population Exposure Nationwide
ATRA
Air Toxics Risk Assessment
BAAQMD
Bay Area Air Quality Management District
CAA
Clean Air Act
CAPCOA
California Air Pollution Control Officers Association
CARB
California Air Resources Board
DAQEM
Department of Air Quality and Environmental Management
DEP
Division of Environmental Protection
DOH
Department of Health
DPR
Department of Pesticide Regulation
DVD
Digital Video Disk
EPA
Environmental Protection Agency
EPIC
Environmental Protection Indicators for California
ERG
Eastern Research Group
GIS
Geographic Information System
GPRA
Government Performance and Results Act
HAP
Hazardous Air Pollutant
10
Inorganic
JATAP
Joint Air Toxics Assessment Project
MACT
Maximum Achievable Control Technology
MATES
Multiple Air Toxics Exposure Study
MDL
Method Detection Limit
MDN
Mercury Deposition Network
MIP
Measure Implementation Plan
NACAA
National Association of Clean Air Agencies
NATA
National Air Toxics Assessment
NATTS
National Air Toxics Trends Stations
NEI
National Emissions Inventory
NELAC
National Environmental Laboratory Accreditation Council
NESCAUM
Northeast States for Coordinated Air Use Management
NIST
National Institute of Standards and Technology
NDOT
Nevada Department of Transportation
OAQPS
Office of Air Quality Planning and Standards
OAR
Office of Air and Radiation
OEHHA
Office of Health Hazard Assessment
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OMB U.S. Office of Management and Budget
OPEI Office of Policy Economics and Innovation
OPMO Office of Program Management Operations
PAH Polycyclic aromatic hydrocarbon
PAMS Photochemical Assessment Monitoring Stations
PART Program Assessment Rating Tool
POM Polycyclic organic matter
PM10 Particulate matter with a diameter less than or equal to 10 microns
PM2.5 Particulate matter with a diameter less than or equal to 2.5 microns
PT Proficiency Test
QA/QC Quality assurance/ quality control
RATC Regional Air Toxics Coordinators
SCAQMD South Coast Air Quality Management District
SLT State and Local Agencies and Tribes
STI Sonoma Technology, Inc.
TAC Toxic Air Contaminant
TAD Technical Assistance Document
TSA Technical System Audit
TO Toxic organic
TSP Total Suspended Particle
TTN Technology Transfer Network
UATMP Urban Air Toxics Monitoring Program
UP Union Pacific
US United States
VOC Volatile organic compound
WASBAQS Western Arizona/ Sonoma Border Air Quality Studies
WESTAR Western States Air Resources Council
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Evaluation of Air Toxics Monitoring
in EPA Region 9
Introduction
Hazardous Air Pollutants (HAP), also known as air toxics, are pollutants that are known or
suspected to cause cancer and other serious conditions including damage to respiratory,
immune, and neurological systems, as well as having negative reproductive and
developmental effects on those who are exposed at sufficient concentrations and durations.
The Environmental Protection Agency (EPA) and a number of state and local agencies and
tribes (SLT) across the United States (US) have air toxics monitoring experience extending
back more than two decades. Building on this breadth of experience, EPA initiated the
national air toxics monitoring program in 1998, which provided a consistent platform for
continued air toxics monitoring activities across the nation.
EPA Region 9—comprised of SLTs in Arizona, California, Hawaii, and Nevada—has one
of the largest and most well-developed sets of air toxics monitoring programs in the
country. EPA Region 9 has also been cited as having areas with the highest level of risk
from air toxics. This evaluation was launched to assess the design and implementation of
locally- and nationally- funded air toxics monitoring activities across the region and
identify ways in which program effectiveness can be improved based on the experiences of
SLTs throughout EPA Region 9 and EPA Program Managers and staff. We conducted this
review to pursue four key objectives:
1. Characterize air toxics monitoring programs across EPA Region 9, including
identification of SLT objectives as well as those of EPA Region 9.
2. Assess the design of EPA Region 9's air toxics monitoring programs and the extent
to which they meet stated objectives.
3. Distinguish ways in which EPA Region 9's monitoring programs contribute to the
objectives of the national air toxics monitoring program and areas for improvement.
4. Identify potential performance metrics for evaluating air toxics monitoring
programs at national and regional levels.
To conduct our work, we reviewed and analyzed key documents including various studies,
reports, and strategic planning documents; interviewed officials from EPA headquarters
and EPA Region 9; interviewed officials from nine Region 9 SLTs; and analyzed data from
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EPA's Air Quality System (AQS) database. Appendix A provides the Quality Assurance
Plan prepared for this evaluation and Appendix B contains the National Air Toxics
Program Logic Model, which describes the relationships between air toxics resources,
activities, outputs, customers, and outcomes, and is used by EPA to guide its management
of the national air toxics program. Appendix C lists the EPA and SLT officials who
contributed information for this evaluation; Appendix D lists the questions referenced
during these interviews; and Appendix E lists the websites and documents analyzed for this
evaluation.
The findings and recommendations presented in this report reflect the ideas and opinions of
the EPA and SLT officials that contributed to the evaluation. In general, this report
includes those ideas and opinions that were expressed by more than one party, rather than
presenting a comprehensive description of all ideas provided by the contributing officials.
This report is not intended to provide a full evaluation or audit of any SLT's air toxics
monitoring program or of the national air toxics monitoring program. Rather, the report
looks across the Region 9 agencies to identify and assess current air toxics monitoring
activities and to identify potential areas for improvement.
Background
National Air Toxics Monitoring Program
EPA is charged with controlling federally listed HAPs. The current federal list is based on
the HAPs defined in the 1990 amendments to the Clean Air Act (CAA), with several
modifications (see Appendix F). The federal HAPs list is comprised of a variety of air
toxics that fall into several categories: metals and inorganic compounds; volatile organic
compounds (VOC); semi-volatile organic compounds (semi-VOC); aldehydes and
carbonyls; and polycyclic organic matter (POM) and polycyclic aromatic hydrocarbons
(PAH). The EPA Office of Air and Radiation (OAR) and the Office of Air Quality
Planning and Standards (OAQPS) within OAR develop and manage the national air toxics
program to control emissions of the federally listed HAPs. EPA regional offices, including
EPA Region 9, support the execution of activities within their regions to meet the national
air toxics program goals and objectives.
One component of the national air toxics program is the monitoring of ambient
concentrations of air toxics. EPA outlined its goals and objectives for national air toxics
monitoring in the Air Toxics Component of the 2004 National Monitoring Strategy and the
2005 National Ambient Air Monitoring Strategy.1 The goal of national air toxics
1 The 2005 National Ambient Air Monitoring Strategy largely summarizes the air toxics monitoring goals and objectives
outlined in the Air Toxics Component of the 2004 National Monitoring Strategy. We reference the 2004 National
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monitoring, as articulated in the 2004 National Monitoring Strategy, is "to support
reduction of public exposure to HAPs." This goal is supported by three primary objectives
and three sub-objectives (see Box 1).
Monitoring Strategy throughout this report because it provides more detailed descriptions of the objectives and sub-
objectives for air toxics.
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Box 1: Air Toxics Goals and Objectives from EPA's 2004 National Monitoring Strategy
Goal
To support reduction of public exposure to Hazardous Air Pollutants.
Objectives
Trends: Measurements of key HAPs in representative areas of the nation to provide a
basic measure of air quality differences across cities and regions, and over time in
specific areas. Trends measurements provide one basis for accounting program
progress.
Exposure Assessments: Ambient measurements may serve as a surrogate for actual
human exposure. However, understanding relationships between ambient
concentrations and personal exposure and how human activities impact these
relationships is critical for true exposure assessments. Therefore, ambient
measurements support exposure assessments by providing ambient concentration
levels for comparison with personal measurements. In addition, ambient
measurements may also provide direct input into more detailed human exposure
models that can be used to estimate actual human exposures.
Air Quality Model Evaluation: Measurements provide basic ground truthing of models
which in turn are used for exposure assessment, development of emission control
strategies, and related assessments of program effectiveness. In addition,
measurements provide direct input into source-receptor models which provide relatively
direct linkage between emission sources and receptor locations.
Sub-objectives
Program Accountability: Monitoring data provide perhaps the most acceptable
measure of air program progress, i.e., observed changes in the atmosphere consistent
with expectations of emissions strategies. Accountability is the closest direct match to
measurement in addressing agency goals as outlined in the Government Performance
and Results Act of 1993 (GPRA), and applies for all program (MACT, residual risk, area
source, mobile source rules, local-scale projects).
Problem Identification: Measurements are used to uncover suspected air quality
issues associated with a specific source or source groups, or confirm that a problem
does not exist. Given the numerous HAPs and variation in issues across the nation,
this particular objective is probably attributed to much of the historical toxics monitoring
as well as the emerging local-scale projects studies.
Science Support: Routine network measurements often provide a backbone of basis
measurements from which more expensive research studies can utilize in the areas of
model process development, exposure studies, and health effects. By themselves, data
studies associate adverse health impacts with observations, particularly where toxics
measurements are grouped with multiple pollutants. In addition, given the current
limited research efforts on methods development, the national air toxics program can
also provide opportunities to test and advance measurement methodologies for air
toxics.
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EPA conducted National Air Toxics Assessments (NATA) in 1996 and 1999 to evaluate the
distribution of air toxics across the United States. The NATA data were used to compile
national emissions inventories on air toxics, estimate air toxics levels across the nation,
estimate population exposures, and characterize public health risks. The 1999 NATA
focused on 177 pollutants, which included 176 of the federally listed HAPs and diesel
particulate matter.
EPA also seeks to estimate the national levels of air toxics through its National Emissions
Inventory (NEI). NEI includes estimates of HAP emissions from major sources, area
sources, and non-point sources. EPA has developed compilations of NEI data for 1996,
1999, and 2002.
To supplement the information produced through the NATA and the NEI, EPA launched a
national air toxics data monitoring effort in 2004, which is referred to as the National Air
Toxics Trends Station (NATTS) program. The NATTS program is currently comprised of
25 monitoring sites across the country that monitor for 21 air toxics (see Appendix G), and
three SLTs in EPA Region 9 currently maintain NATTS sites (see Table 1). The Eastern
Research Group, Inc. (ERG) and Sonoma Technology, Inc. (STI), under contract to EPA,
are currently analyzing data collected through the NATTS program and the Urban Air
Toxics Monitoring Program (UATMP). The UATMP, currently comprised of 59 air toxics
sampling sites in US urban areas, is an EPA contract vehicle allowing SLTs to access EPA
contractors to conduct some of their air toxics monitoring efforts. Some of the monitoring
sites for the UATMP and the NATTS program overlap, although the UATMP includes only
one site in EPA Region 9 (in Phoenix, Arizona) while the NATTS program has four sites in
the region. The preliminary results of recent NATTS and UATMP data analyses were
presented at the 2007 Air Toxics Data Analysis Work Shop and are available through
EPA's Technology Transfer Network (TTN) Ambient Monitoring Technology Information
Center (AMTIC).2
Table 1: NATTS Sites in EPA Region 9
Location of NATTS Site Agency Maintaining NATTS Site
Los Angeles, California (downtown)
South Coast Air Quality Management District ^
Los Angeles Area, California (Rubidoux)
South Coast Air Quality Management District
Phoenix, Arizona
Arizona Department of Environmental Quality
San Jose, California
Bay Area Air Quality Management District
2 The presentations from the 2007 Air Toxics Data Analysis Work Shop are located at http://www.epa.gov/ttn/amtic/airtox-
daw-2007.html.
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Air Toxics Monitoring in EPA Region 9
In addition to the NATTS monitoring program, many SLTs in EPA Region 9 manage local
air toxics monitoring programs and participate in related national monitoring programs.
Some SLTs maintain long-term3 state- or local-scale air toxics trends networks which
collect data on air toxics prevalent in their area. In addition, many SLTs regularly conduct
short-term and community-scale studies which focus on specific air toxics or
neighborhoods. These short-term and community-scale studies are often collaborative
projects that involve many stakeholders, including representatives from EPA, state and
local government, tribes, industry, academia, and the public, working together to address
concerns around potential sources of air toxics and to develop mitigation strategies. Some
SLTs in the region also participate in EPA's Photochemical Assessment Monitoring
Stations (PAMS) program, which involves monitoring for ozone and its precursors. The
target list of PAMS program compounds includes 58 VOCs (55 hydrocarbons and 3
carbonyls), nine of which are federally listed HAPs (see Appendix H).
SLTs in EPA Region 9 fund their air toxics monitoring activities through a number of
mechanisms. EPA provides many SLTs with funding through CAA Section 103 and 105
grants. Under Section 105, EPA is authorized to provide grants to cover up to three-fifths
of the of planning, developing, establishing, carrying out, improving, or maintaining of
programs that address the prevention and control of air pollution, and the grant recipient is
required to match a portion of the funds. Section 103 grants are provided to fund specific
air pollution projects including research, investigations, experiments, demonstrations,
surveys, studies, and training efforts. These grants do not include requirements for the
SLTs to match the funds received. NATTS program monitoring sites are funded through
Section 103 grants and some SLTs also receive Section 105 grants for PAMS sites and
other air toxics monitoring projects. In addition, since 2004 EPA has invited eligible SLTs
to apply for Section 103 community-scale monitoring grants that address current priorities
of the national air toxics monitoring program. Table 2 lists community-scale monitoring
grants awarded to SLTs in EPA Region 9 during the 2004 and 2005 grant cycles. SLTs in
EPA Region 9 supplement the grant funds received from EPA through a variety of state and
local funding mechanisms including taxes, permit fees, penalty fees, settlement funds, and
vehicle fees. State and local trends networks are typically funded through these state and
local funding sources, and SLTs fund short-term and community-scale air toxics
monitoring projects through one of three funding models: state and local funding
mechanisms, EPA community-scale monitoring grants, or a combination of EPA
community-scale grant dollars and state and local funding mechanisms.
3 For the purpose of this evaluation, long-term studies are defined as lasting longer than one year and short-term studies are
defined as lasting approximately one year or less.
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Table 2: EPA Region 9 Community-Scale Air Toxics Monitoring Grants, 2004-2005
Applicant and Grant Title Year Funding Project Period
Placer County APCD: Roseville Rail Yard Air
Monitoring Project
2005
$: ¦ ¦ ¦
5/1/06 - 10/31
Nevada DEP: Development of Broadly Deployable
Methods for Quantifying Atmospheric Hg Speciation in
Urban and Rural Settings in NV
2005
$363,890
6/1/06 - 8/31/
San Diego APCD: Untitled
2005
$457,000
6/1/06 - 6/30/
City of Los Angeles, Harbor Dept, EMD: Port of Los
Angeles Community-Based Air Toxics Exposure Study
2005
$250,000
7/1/06 - 1/31/
South Coast AQMD
2004
$495,242
Through 10 31 07
Gila River Indian Community
2004
$122,914
Through 3/31,
Salt River Indian Community
2004
$141,540
Through 1/31,
Arizona DEQ
2004
$230,788
Through 9/30,
Air Toxics Monitoring Methods and Quality Control
Air toxics monitoring programs can be generalized as having four components: sampling,
laboratory analysis (processing of samples), data analysis, and data reporting and
communication. Typically, air toxics samples are either collected using particulate matter
filters, known as PM2.s or PMio filters, or using canisters or cartridges that collect samples
of gaseous toxics. The equipment and equipment settings used for sampling and laboratory
analysis varies between SLTs in EPA Region 9 and nationwide.
One key aspect of air toxics monitoring is the methods used. A methods document
typically provides a set of procedures and settings for using specified types of equipment to
collect and process samples for a category of air toxics compounds (e.g., VOCs), and
recommends quality assurance/ quality control (QA/QC) procedures. EPA promotes the
standardization of methods for air toxics through the guidance provided in the air toxics
technical assistance document4 (air toxics TAD). The air toxics TAD provides detailed
guidance on the use of EPA-recommended methods for NATTS program toxics, QA/QC
procedures, and reporting to the national Air Quality System (AQS) database. The sets of
methods recommended by EPA for use in the NATTS and other air toxics monitoring
programs are known as the toxic organic (TO) compendium methods and the inorganic (10)
compendium methods. In addition to the QA/QC procedures specified in the TO- and IO-
compendium methods, EPA manages a Proficiency Test (PT testing) program which allows
4 The air toxics TAD is located at http://www.epa.gov/ttiiamtil/files/ambieiit/airtox/toctad04.pdf.
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laboratories to analyze NATTS program audit samples and compare their results with the
actual quantities within the sample. SLTs conducting air toxics monitoring outside of the
NATTS program sometimes use these TO- and 10- compendium methods and participate in
the PT testing program, but alternatively may use other methods developed in-house or by
external agencies or organizations and may follow QA/QC procedures different from those
outlined in the air toxics TAD and the TO- and 10- compendium methods.
EPA also promotes standardization of air toxics monitoring through the identification of
limits at which SLTs should be able to detect specific air toxics compounds. In the
September 2007 version of the air toxics TAD, EPA defined the following related terms:
¦ Quantitation Limits: The lowest level at which the entire analytical system must
give a recognizable signal and acceptable calibration point for the analyte.
¦ Detection Limits: Minimum concentration of an analyte that can be measured above
instrument background.
¦ Sample Quantitation Limit (also known as a Practical Quantitation Limit): the
lowest concentration of an analyte that can be reliably measured within specified
limits of precision and accuracy during routine laboratory operating conditions.
¦ Method Detection Limits (MDL): the minimum concentration of a substance that
can be measured and reported with 99% confidence that the analyte concentration is
greater than zero and is determined from the analysis of a sample in a given matrix
containing the analyte.
EPA has set MDLs for many of the air toxics compounds monitored through the NATTS
program, which are based on the use of the recommended TO- and 10- compendium
methods.
Storing, Sharing, and Using Air Toxics Data
EPA maintains the AQS database as a repository for national air quality data, including air
toxics datasets, and specifies procedures in the air toxics TAD for flagging data points in
regards to how they compare with quantitation and detection limits. The AQS database has
a data entry and retrieval interface that can be accessed by anyone approved to hold an
AQS user account, typically EPA and SLT officials and their contractors. In addition to
submitting data to AQS, some SLTs in EPA Region 9 maintain other air toxics databases.
For example, the California Air Resources Board (CARB) maintains an air quality database
called ADAM that provides public access to California air quality data. The ADAM
database includes over twenty years of air toxics measurements.
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In addition to collecting and sharing air toxics data, EPA is continuously seeking
improvement on ways in which air toxics data is analyzed and used for evaluating program
performance. EPA's air toxics program was evaluated through the Office of Management
and Budget's (OMB) Program Assessment Rating Tool (PART) in 2004. In response to the
PART evaluation, EPA developed Measure Implementation Plans (MIP) for ambient air
toxics data and toxicity-weighted emissions. The ambient air toxics data MIP focused on
the role of NATTS data in evaluating the performance of the national air toxics program
and identified process steps for the annual development of public health risk metrics for air
toxics based on data from the NATTS program sites. The metrics detailed in the MIP rely
on two key computations: a weighting of the portion of the US population each NATTS site
represents and cancer and non-cancer risk factors determined using ambient monitoring
data and estimated unit risk factors. EPA also notes progress towards compiling NATTS
data for use in developing performance measures on the information webpage for the air
toxics PART evaluation.5
In addition, the 2006-2011 EPA Strategic Plan6 identified "healthier outdoor air" as an
objective, and for an air toxics sub-objective stated "by 2011, reduce the risk to public
health and the environment from toxic air pollutants by working with partners to reduce air
toxics emissions and implement area-specific approaches." The plan also identified two
strategic targets for the national air toxics program:
¦ By 2010, reduce toxicity-weighted (for cancer risk) emissions of air toxics to a
cumulative reduction of 19 percent from the 1993 non-weighted baseline of 7.24
million tons.
¦ By 2010, reduce toxicity-weighted (for non-cancer risk) emissions of air toxics to a
cumulative reduction of 55 percent from the 1993 non-weighted baseline of 7.24
million tons.
Following the development of the 2006-2011 EPA Strategic Plan, the EPA Office of
Program Management Operations (OPMO) developed a matrix which identifies national air
toxics performance measures, indicators, and data currently available to measure progress
towards the air toxics strategic targets (see Appendix I). Developed in January 2007, the
matrix will be used as a basis for further development of performance measures for the
national air toxics program.
3 The results of the 2004 air toxics program PART evaluation and subsequent improvement efforts are located at
http://www.whitehouse.gOv/omb/expectmore/detail/10000226.2004.html#improvementPlans.
6 The 2006-2011EPA Strategic Plan is located at http://www.epa.gov/cfo/plan/plan.htm.
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Overview of Air Toxics Monitoring Activities in EPA
Region 9
This section provides an overview of the air toxics monitoring activities of each of the nine
SLTs in EPA Region 9 that participated in this evaluation. Further details on the specific
air toxics monitored by these agencies are provided in Appendix J.
Arizona Department of Environmental Quality
The Arizona Department of Environmental Quality (ADEQ) is currently involved in a
number of air toxics monitoring efforts. ADEQ maintains several toxics and PAMS
program sites, one of which—the Phoenix Supersite—has also been designated a
monitoring site for the NATTS program since 2004. At the Phoenix Supersite, ADEQ
currently monitors for VOCs, carbonyls, PAHs, hexavalent chromium, speciated PM2.5, and
PM10 metals. ADEQ has also led three short-term studies in the U.S.-Mexico border
region. The most recent study was the Western Arizona/Sonora Border Air Quality Study
(WASBAQS) in 2006-2007. WASBAQS included Supersites in Yuma, Arizona and
Mexico where the agency monitored for a variety of VOCs, semi-VOCs, carbonyls, metals,
and chlorinated pesticides.
ADEQ also participated in the monitoring studies conducted by the Joint Air Toxics
Assessment Project (JATAP) and has contributed data from several of their monitoring
sites, including the Phoenix Supersite, to the JATAP study. A description of current
JATAP activities is summarized below. ADEQ sends its air toxics samples to outside
laboratories for processing and analysis.
ADEQ also maintains a list of HAPs for the state (see appendix K).
Bay Area Air Quality Management District
The Bay Area Air Quality Management District (BAAQMD) maintains an ambient
monitoring network with twenty air toxics monitoring sites. BAAQMD primarily collects
VOC samples from these monitoring sites and processes the VOC canisters at an in-house
laboratory. BAAQMD also coordinates with CARB in its monitoring efforts: several of
BAAQMD's air toxics monitoring sites are used to collect samples that are processed in
CARB laboratories and included in CARB trends analyses.
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The BAAQMD trends network monitoring site located in San Jose is also part of the
NATTS network. Sampling at this site includes a broader range of compounds than what is
collected at the other BAAQMD air toxics monitoring sites, including several carbonyls.
BAAQMD also leads short-term monitoring studies which supplement the data from their
trends network. For example, BAAQMD has studied diesel particulate matter emissions
through analysis of elemental carbon data collected with PMio filters. In addition,
BAAQMD is planning to initiate a study of air toxics at the Port of Oakland in the next
year.
California Air Resources Board
CARB has engaged in long-term air toxics trends monitoring for over twenty years. CARB
established its air monitoring trends network—which currently includes monitoring for
over fifty air toxics including VOCs, metals, and carbonyls—in 1985 and currently samples
for air toxics at twenty sites in California and two sites in Mexico.
The California Office of Environmental Health Hazard Assessment (California OEHHA)
maintains a list of Toxic Air Contaminants (TAC) for the state (see Appendix L) that is
more extensive than EPA's HAPs list, and regularly performs risk assessments on potential
new TACs. The air toxics measured through CARB's monitoring network are drawn from
this TACs list, and CARB routinely evaluates and updates the list of air toxics monitored
through its trends network based on revisions to the TACs list. Several other California
agencies refer to CARB's TACs list when prioritizing compounds for air toxics monitoring
studies.
In addition to monitoring through its trends network, CARB has conducted numerous
special studies focused on a variety of air toxics thought to be prevalent in California.
CARB recently conducted special studies on acrolein, compounds found in wood smoke,
asbestos, diesel particulate matter, and hexavalent chromium and is currently leading a
special study on near-roadway effects to characterize concentrations of PAHs and black
carbon near Interstate-5. CARB also collaborates with California OEHHA, EPA, and local
air districts on an inter-agency working group focused on acrylonitrile monitoring. The
activities of this group have included significant monitoring for acrylonitrile and efforts to
use the monitoring data to validate models. CARB also conducts regular ambient
monitoring for dioxins and polybrominated diphenylethers (PBDE), and has performed
near-source PBDE monitoring in the past.
In 1999, the California legislature passed the Children's Environmental Health Protection
Act (Senate Bill 25), which required CARB and California OEHHA to review the
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effectiveness of California's ambient air quality standards and to assess the degree to which
the CARB air toxics monitoring network effectively represents the pollutants present
within the state. As part of its activities to address Senate Bill 25, California OEHHA
published a report in 2001 that provided an assessment of TACs in the state that
disproportionately affect infants and children.7 CARB is also leading a number of
children's health and exposure studies which respond to the bill.
CARB has conducted pesticide monitoring in rural areas in California since the mid-1980s
on behalf of California's Department of Pesticide Regulation (DPR). CARB conducts
ambient monitoring for pesticides and also performs short-term application site monitoring
during pesticide application periods. DPR uses data collected by CARB, in conjunction
with toxicity data, to determine whether pesticides should be listed as TACs. Since 1986,
CARB has conducted ambient and/or site application monitoring for 45 pesticides, some of
which have been listed as TACs in California.
CARB laboratories process all of the air toxics and pesticides samples collected through
these monitoring networks and through other special monitoring studies. CARB has also
been a leader in developing sampling and analysis methods for air toxics.
Hawaii Department of Health
The Hawaii Department of Health (Hawaii DOH) maintains a statewide air monitoring
network that is largely devoted to the monitoring of criteria air pollutants. On the island of
Hawaii, specialty monitoring is conducted to assess the impact that volcanic emissions are
having on the air quality through the signature pollutants of sulfur dioxide and particulate
matter. Hawaii DOH also monitors for seventeen carbonyls, VOCs, and metals at their
monitoring site in Pearl City, Oahu. Hawaii DOH laboratories process all of the air toxics
samples collected at the Pearl City site.
Joint Air Toxics Assessment Project (Arizona)
JATAP is a collaborative air toxics evaluation effort between state, county, and tribal
representatives in the Phoenix, Arizona area. JATAP is comprised of the following
entities: ADEQ, Maricopa County, Pinal County, the Gila River Indian Community, the Ft.
McDowell Yavapai-Apache Tribe, the Salt River Pima-Maricopa Indian Community, and
the Institute for Tribal Environmental Professionals. EPA also participates on the JATAP
Steering Committee.
7 The TACs assessment report is located at http://www.oehha.ca.gov/air/toxic_contamiiiaiits/SB25fiiialreport.htm.
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ADEQ and the Gila River Indian Community conducted pilot studies in 2003-2004 which
provided background information and preliminary data for a larger air toxics monitoring
study in 2005. The 2005 study was comprised of nine air toxics monitoring sites in
Phoenix and the surrounding tribal communities and collected data on a variety of VOCs
and compounds associated with PM2.5. JATAP used consultants to process the air toxics
samples from their 2003-2005 studies.
JATAP recently received an additional $200,000 to support analysis of the results of their
2005 monitoring study. The results of this analysis will be used to assess the health
impacts of air toxics in the Phoenix area.
Nevada Division of Environmental Protection
The Nevada Division of Environmental Protection (Nevada DEP) conducts air toxics
monitoring activities focused on mercury emissions. Nevada DEP monitors for mercury at
three Mercury Deposition Network (MDN) sites across the state, two of which were
established by EPA. Comprised of over 85 monitoring sites nationwide, the MDN collects
weekly data on the mercury concentrations in precipitation and wet depositions. Nevada
DEP also received funding from EPA in 2006 to develop a sampling system that detects
mercury in the air.
Nevada DEP is currently teaming with researchers at the University of Nevada to study
mercury emissions from mining operations in the State of Nevada. This study is focusing
on monitoring for elemental mercury and reactive gaseous mercury at several monitoring
sites. One goal of this study is to develop a framework for comparing mercury emissions
from mining areas to non-disturbed, naturally-enriched areas.
Placer County Air Pollution Control District
The Placer County Air Pollution Control District (Placer County APCD) is currently
engaged in an effort to monitor and mitigate diesel particulate matter emissions from the
Union Pacific J.R. Davis Yard in Roseville, California (Roseville Rail Yard). In 2000-
2004, CARB conducted a risk assessment analysis of the Roseville Rail Yard that provided
a baseline for the emissions and associated cancer risks from the yard. After CARB's final
report was released in 2004, Placer County APCD concluded that further monitoring of the
rail yard was warranted to address public concerns.
In late 2004, Placer County APCD and the Union Pacific Rail Road (UP) signed an
agreement in which UP consented to voluntarily cut emissions from the Roseville Rail
Yard, fund an incentive program, and fund continued monitoring at the yard by Placer
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County APCD. Using the funds provided through the agreement, Placer County APCD
conducted monitoring at four sites during the summers of 2005-2007. The agency
monitored for a variety of compounds associated with the combustion of diesel including
nitrogen oxides, elemental and organic carbon (using PM2.5 and PM10 filters), continuous
PM2.5, and black carbon.
Several agencies helped support Placer County APCD in their monitoring effort. CARB
and the South Coast Air Quality Management District (SCAQMD) provided a variety of in-
kind services, including modeling, participation on the project advisory board, lab and
auditing services, in addition to loaning Placer County APCD much of the sampling
equipment for the project. EPA awarded Placer County APCD a community-scale
monitoring grant for the project and participated in the project advisory board. Sacramento
Metro Air Quality Management District also provided limited funding for the project
because the rail yard crosses into Sacramento County.
Placer County APCD is interested in continuing the Roseville Rail Yard monitoring study
to further assess the effects of UP's mitigation strategies. The agency is currently looking
into funding options for continued monitoring and data analysis.
San Diego Air Pollution Control District
The San Diego Air Pollution Control District (San Diego APCD) maintains nine monitoring
sites where air toxics VOC samples are collected. Four of these sites are part of the PAMS
network, two are part of CARB's trends network, and three are community-scale
monitoring sites that opened in January 2007. San Diego APCD currently samples for 44
toxic VOCs at the three community-scale monitoring sites and will report the data to the
AQS database. The agency plans to add acrolein and acrylonitrile to the target compound
list in 2008. San Diego APCD monitors for PAMS hydrocarbons at all four of their PAMS
network sites and, at two of these sites, also monitors for carbonyls. Four 3-hour samples
are collected at each site during the PAMS season, and one 24-hour sample is collected at
each site during the non-PAMS season. These samples are collected according to the
PAMS methodology and the data are submitted to the AQS database as part of the PAMS
dataset. The two CARB trends network sites opened in 1988-1989 and San Diego APCD
samples for carbonyls, toxic VOCs, and toxic metals at these sites. The data from the
CARB sites is available through the ADAM database.
San Diego APCD maintains six monitoring sites where air toxics metals samples are
collected. Two are part of the PM2.5 Speciation Trends Network, two are the CARB trends
network sites described above, and two are community-scale monitoring sites that opened
in 1994. An EPA community-scale monitoring grant allowed the purchase of an
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inductively coupled plasma mass spectrometer that will replace the previous analytical
methodology and allow for the speciation of hexavalent chromium and the addition of
several more toxic metals to the target compound list. San Diego APCD will begin the
hexavalent chromium speciation in 2008.
In addition to collecting the samples at all of the sites described above, San Diego APCD
performs the analyses for the VOC and metals samples collected at the agency's
community-scale and PAMS program monitoring sites at their in-house laboratory. San
Diego APCD ships the samples from the CARB trends network sites to a CARB laboratory
for processing. At the two PM2.5 Speciation Network sites, San Diego APCD personnel
maintain the instruments and collect samples. Samples from one site are shipped to a
CARB laboratory in Sacramento and samples from the other site are shipped to an EPA
contract laboratory in North Carolina.
Another result of the agency's community-scale monitoring grant was the purchase of a
Desert Research Institute Thermal/Optical Carbon Analyzer. San Diego APCD will use
this analyzer to collect organic and elemental carbon samples at three monitoring sites
starting in 2008, and will analyze the data at their in-house laboratory. Organic and
elemental carbon data for the agency's two PM2.5 Speciation Trends Network sites is also
available through the AQS database.
San Diego APCD also collaborates with CARB on some community-scale monitoring
efforts, including a recent environmental justice monitoring project in the Barrio Logan
neighborhood that measured hexavalent chromium emissions from a nearby decorative
chrome plater.
South Coast Air Quality Management District
SCAQMD is involved in numerous air toxics monitoring efforts. SCAQMD conducted the
first Multiple Air Toxics Exposure Study, MATES I, in 1986-1987, providing the agency
with a baseline of air toxics concentrations in the South Coast air basin. SCAQMD built on
the results of this study in 1998-1999 by completing a second, more comprehensive study
(MATES II), that monitored for over 30 VOCs, carbonyls, PAHs, and metals, and collected
elemental carbon data as a surrogate for diesel particulate matter. The agency monitored at
10 fixed sites and conducted micro-scale studies using three mobile platforms to sample at
14 communities. MATES II also included significant data analysis, modeling, and
development of an emissions inventory. Laboratory analysis for the data collected through
MATES II was jointly conducted by SCAQMD and CARB.
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With partial funding from EPA, SCAQMD recently completed monitoring for a MATES III
study and released a draft report. This study consisted of 10 fixed sites that monitored for
many of the compounds that were found to be prevalent in the air basin during MATES II,
and additional compounds of interest such as naphthalene. SCAQMD will use the data
from MATES III to perform a variety of trends analyses and modeling projects, which will
build on the analyses performed on the MATES II data. The agency also hopes to use the
data from the study to complete source apportionment analyses. SCAQMD's laboratory
will analyze all of the samples from the MATES III study with the exception of the semi-
volatile hydrocarbons.
Since 2007, SCAQMD has maintained two NATTS sites. At these sites, the agency
monitors for additional compounds not measured through MATES III, such as acrolein and
PAHs. SCAQMD's laboratory processes much of the NATTS data, although the agency
sends the PAH samples to outside laboratories for processing.
SCAQMD was also recently awarded a community-scale monitoring grant to conduct an air
toxics monitoring project at Los Angeles International Airport.
Other Air Toxics Monitoring Efforts in EPA Region 9
In addition to the nine SLTs listed above, there are several other entities in EPA Region 9
that manage air toxics monitoring programs. Several of the projects being conducted by
these entities were mentioned by participants in this evaluation, including:
¦ The Nevada Department of Transportation (NDOT), with oversight from the Clark
County Department of Air Quality and Environmental Management (DAQEM), is
monitoring near-roadway exposures of air toxics on a segment of US-95. This
study is part of a larger national mobile source air toxics study being conducted by
the Federal Highway Administration.
¦ NDOT and the Federal Highway Administration, with oversight from the Clark
County DAQEM, will soon begin monitoring for mobile source emissions,
potentially including emissions from the local McCarran International Airport, on a
segment of Interstate-15.
¦ In 2006, the City of Los Angeles was awarded a community-scale monitoring grant
to conduct an air toxics monitoring study at the Port of Los Angeles.
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Findings
The following six findings summarize the opinions and ideas expressed by EPA and SLT
officials during development of this report. These findings are not presented to indicate
critical issues with the national air toxics monitoring program or SLT air toxics monitoring
efforts. Rather, these findings are presented to indicate common air toxics monitoring
challenges experienced by EPA and SLT officials, and are intended to be used as a basis
for continued discussions on how to improve coordination and communication around air
toxics monitoring in EPA Region 9 and nationally.
Finding 1: There Is a Significant Amount of Consistency in Air Toxics Monitoring
Objectives across Agencies in EPA Region 9 with the National Objectives, although
Differences in Program Design and Implementation Reflect Variation in Priorities across
These Objectives.
Officials from EPA headquarters, EPA Region 9, and SLTs in EPA Region 9 agree that the
overarching goal of current national, state, tribal, and local air toxics monitoring programs
is to reduce human health risks caused by exposure to air toxics. The objectives in EPA's
2004 National Monitoring Strategy achieve this goal through a dual emphasis on NATTS
program sites and community-scale monitoring efforts. Objectives set by SLTs within EPA
Region 9 are highly consistent with EPA's air toxics monitoring objectives: three SLTs in
the region maintain NATTS program sites and all of the SLTs in EPA Region 9 that have
received community-scale monitoring grants manage these efforts consistent with the
objectives detailed in the 2004 National Monitoring Strategy. The data resulting from
these NATTS program sites and community-scale monitoring efforts provides a picture of
the distribution of air toxics concentrations at and between NATTS program sites in the
region. In addition, some SLTs in EPA Region 9 are working towards objectives which
complement and expand on the current scope of objectives listed in the EPA strategy.
However, SLTs in the region vary in the relative emphasis they place on the NATTS
program, their own trends networks, and various local-scale monitoring efforts, reflecting a
balance between nationally- and locally- funded air toxics monitoring efforts. The
patchwork of SLT air toxics monitoring activities across EPA Region 9 largely reflects the
varying emphasis on specific program objectives, as well as the relative priority of air
toxics compared with other air quality and environmental issues at each agency.
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There Is Relative Consistency in the Stated and Implied Air Toxics Monitoring
Program Objectives across Air Districts in EPA Region 9, and Potential Interest in
Expanding Current Program Objectives in the Future.
EPA headquarters, EPA Region 9, and SLTs in EPA Region 9 have highly consistent
objectives for achieving a reduction in human health risk due to air toxics exposure. EPA
Region 9 and SLT officials that participated in this evaluation verbally articulated air
toxics monitoring objectives consistent with those in EPA's 2004 National Monitoring
Strategy. These objectives include: trends measurements, exposure assessments, problem
identification, program accountability, air quality model evaluation, and science support.
Some SLTs in the region also maintain written sets of air toxics objectives. For example,
San Diego APCD includes air toxics monitoring program objectives in its County of San
Diego Adopted Operational Plan. The operational plan for fiscal years 2007-2008 and
2008-20098 lists specific objectives under two categories: the environment and safe and
livable communities. These objectives include community outreach, rulemaking, and
process development needs, and also describe plans for additional air toxics monitoring
studies and risk assessments.
Some SLTs within the region also expand upon the objectives set by EPA in the 2004
National Monitoring Strategy. First, some agencies indicated that they are focusing on
airborne substances beyond those listed by EPA as HAPs. For example, CARB has
adopted a broader list of air toxics, known as TACs, which currently includes 244
substances, including all HAPs currently listed by EPA.9 CARB, in consultation with
California OEHHA, regularly performs risk assessments on potential TACs and updates the
register of TACs accordingly. This continuous update process allows CARB to expand its
air toxics monitoring program to include new compounds on a regular basis and provides a
means for prioritizing continued monitoring of compounds that are prevalent in the region
but are not as prevalent on the national scale, and therefore are not monitored through the
NATTS program. Several of the local agencies in California also use the CARB TACs list
when prioritizing compounds for studies within their air districts.
Second, some agencies have found that ambient air toxics monitoring data is not only
useful for addressing problem identification objectives, but also for leveraging voluntary
air toxics emissions reductions from sources. For example, some community-scale
monitoring programs, such as Placer County APCD's Roseville Rail Yard project, have
used ambient monitoring data to leverage actual, voluntary emissions reductions from a
source and to measure the effectiveness of emissions reduction and mitigation efforts.
8 The County of San Diego Adopted Operation Plan Fiscal Years 2007-2008 & 2008-2009 is located at
http://www.sdcounty.ca.gov/auditor/pdf/adoptedplan_07-09.pdf.
9 Information collected on November 15, 2007 from the CARB air toxics website
(http://www.arb.ca.gov/toxics/toxics.htm).
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Third, several EPA and SLT officials noted that there may be pressure in the future from
federal agencies, SLTs, and non-profit groups to expand the scope of air toxics monitoring
activities and objectives to include attention to ecosystem health. Currently, EPA and
SLTs in EPA Region 9 define public exposure to air toxics, and the associated human
health risks, as the primary driver for investment in air toxics monitoring activities. A few
agency officials noted, however, that attention to the ecosystem health effects of air toxics
will likely increase in the coming years, and SLTs in EPA Region 9 may pioneer air toxics
monitoring objectives to assess these effects. For example, there is evidence of growing
attention to the effects of deposition of mercury and other air toxics in terrestrial and
aquatic ecosystems in National Parks and in other sensitive ecosystems, which may
catalyze SLT interest in ecosystem effects.
Agencies' Prioritization of Objectives Illustrates a Balance Between Nationally- and
Locally-Funded Monitoring Efforts.
Since the early stages of developing national air toxics monitoring program capacity, EPA
has recognized the need to balance national-scale, standardized approaches to air toxics
measurements with community-scale, custom approaches. EPA has integrated these two
guiding approaches under the framework of the 2004 National Monitoring Strategy. The
balance between the NATTS program, regional trends monitoring, and community-scale
monitoring projects in EPA Region 9 reflects adherence to this principle.
All the air toxics monitoring efforts managed by SLTs in EPA Region 9 address the
objectives framed in the 2004 National Monitoring Strategy; however we found that each
SLT uses a different set of activities to fulfill the objectives, resulting in a patchwork of air
toxics monitoring activities across the region. The set of air toxics monitoring activities
managed by each SLT in the region depends on a variety of factors including the relative
priority of air toxics issues compared with other air quality and environmental issues (e.g.,
criteria pollutant issues), the local funding mechanisms available, the national monitoring
programs (e.g., NATTS or PAMS) in which the agency participates, and other available
federal funding mechanisms (e.g., community-scale monitoring grants and Section 105
grants). For those agencies with relatively smaller local funding mechanisms, the primary
focus of air toxics monitoring efforts is on projects that can be federally funded. For
example, ADEQ focuses its air toxics monitoring efforts around a NATTS site and several
PAMS sites and has received community-scale monitoring grants to support some of the
agency's additional air toxics monitoring activities, such as the JATAP monitoring efforts.
SLTs with more consistent local funding mechanisms tend to focus more extensively on
local-scale projects, and participation in the NATTS program is an added element in the
agency's suite of air toxics monitoring activities. For example, SCAQMD focuses much of
its air toxics monitoring efforts on the local-scale MATES studies, which are funded
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through a combination of local and federal mechanisms, and also maintains two NATTS
sites.
Officials in EPA headquarters, EPA Region 9, and SLTs within the region all cited
challenges associated with air toxics monitoring as a restriction to expanding air toxics
monitoring capacity in the region. Compared with criteria pollutants, the methods for
collecting and analyzing air toxics samples are relatively new. Agency officials noted that
even if time-tested air toxics methods were available for all HAPs, laboratory analyses of
these compounds would still take considerably more effort than analyses of criteria
pollutants, as air toxics are by nature more difficult to isolate and measure. Therefore, each
new air toxics activity represents a significant investment of resources and staff time for
EPA and SLTs.
Due to the complexity of air toxics monitoring, EPA and SLTs tend to prioritize monitoring
efforts which provide the most benefit. However, perspectives on the relative benefits of
air toxics activities can differ between EPA headquarters and SLTs. While SLTs
understand the importance of the NATTS program and always seek to fulfill the
requirements of their NATTS grants, many SLTs in EPA Region 9 prefer to focus on trends
monitoring for compounds thought to be prevalent in their region in order to address local
community concerns, rather than prioritizing further national trends monitoring efforts. In
addition, other EPA objectives such as program accountability and science support tend to
be less salient to SLTs except in cases where there are direct implications for the
understanding or control of local risks from public exposure to air toxics. This preference
to address local needs has created a patchwork of air toxics monitoring activity across EPA
Region 9, where each air district is attempting to focus on compounds most important to its
area while at the same time balancing the objectives of the NATTS program. SLT officials
noted that explicitly understanding NATTS and community-scale monitoring program
objectives would help them meet the objectives for these programs in addition to the
objectives of other local-scale monitoring efforts.
In addition, both EPA and SLT officials noted that the best tactic for addressing the 2004
National Monitoring Strategy air toxics objectives is not always clearly defined. For
example, the objective for air quality model evaluation envisions the use of air toxics
monitoring data to ground-truth national models and to develop a variety of air toxics
assessments and control strategies, as was done through the 1996 and 1999 NATA
assessments.10 Both EPA and SLT officials recognized that data beyond that available
through the 25 current NATTS sites will be needed to effectively ground-truth national
10 EPA compared the Assessment System Population Exposure Nationwide (ASPEN) modeling system results from the
1996 and 1999 NATA Assessments with monitored concentration data to evaluate the accuracy of NATA results
(http://www.epa.gov/ttn/atw/nata/mtom_pre.html and http://www.epa.gov/ttn/atw/natal999/nsata99.html).
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models, although these officials noted that further research is needed to understand the
extent of data needed to evaluate the models. These agency officials cited the effectiveness
of past SLT efforts using local monitoring data for local trends assessments, control
strategies, and modeling efforts and previous UATMP and NATA analyses as examples of
how monitoring data can be used for significant data analyses.
Some SLTs in EPA Region 9 are also beginning to use monitoring data for model
verification efforts at a regional scale. For example, as part of SCAQMD's MATES III
study, regional modeling results will be compared to air toxics monitoring data. However,
EPA officials noted that verification of community-scale models has been an allowable
activity under recent community-scale grant competitions, but that they have received few
applications for this type of activity in the past.
Finding 2: National and SLT Trends Monitoring Networks Are Complementary Efforts,
although SLTs Have Experienced Challenges with Participation in the NATTS Program that
Differ from Challenges They Face in Their Own Air Toxics Monitoring Efforts.
National ambient monitoring networks and SLT trends monitoring networks are
complementary efforts that jointly provide data on the prevalence of air toxics in EPA
Region 9 and across the nation. Most of the air toxics monitoring in Region 9 is not part of
the national monitoring network, rather, these monitoring activities are independent efforts
managed by SLTs. The SLTs in EPA Region 9 participating in the NATTS program have
received substantial benefits from the program, but have also encountered unanticipated
set-up and analytical challenges that in some cases exceeded the resource needs covered by
EPA funding. Most of the NATTS sites in EPA Region 9 were established at sites where
air toxics monitoring was already being conducted by experienced districts with well-
developed methods. These methods differed from EPA's methods, setting up a challenge
for the SLTs in conforming to the national methods. Joining the NATTS program
necessitated redesign of the SLTs' methods and retraining of agency personnel. In
addition, these SLTs were faced with the decision of whether to switch all their air toxics
sites or just the NATTS program sites to the EPA methods. In addition, both EPA and SLT
officials noted that many of the challenges associated with past participation in the NATTS
program are direct results of the program being relatively new, and are similar to
challenges encountered at the infancy of other large-scale monitoring programs. These
officials cited a need to learn from the experiences of the early implementers of the NATTS
program.
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National and SLT Air Toxics Trends Networks Are Complementary and Jointly
Contribute to What Is Known about the Prevalence of Air Toxics in EPA Region 9.
The NATTS national ambient monitoring program, which includes four sites in EPA
Region 9, gives a broad picture of air toxics trends on a national scale. EPA and SLTs in
the region agree that the NATTS program successfully facilitates the collection of a
consistent national dataset that provides a benchmark of air toxics concentrations across the
United States. Some SLT officials noted that it would be useful to compare data from SLT
monitoring efforts against these national benchmarks to better understand how EPA Region
9 air basins compare to other air basins across the country, although this would require an
assessment of possible differences in sampling and laboratory methods.
Stakeholders at all levels recognize that SLT ambient monitoring networks supplement
national efforts by providing more detailed information on the extent and effects of air
toxics at local and regional scales. These SLT networks collect detailed, long-term data on
air toxics within an air district and provide SLTs the opportunity to identify significant
changes in local air toxics over time. For example, BAAQMD maintains a trends network
which includes 20 air toxics monitoring sites in the San Francisco Bay Area. The density
of sites within the Bay Area provides a rich dataset, which can supplement broader
national-scale monitoring efforts like NATTS. This level of information can contribute to
the development of national air toxics models and trends analyses, although the SLTs
would need to assess how their methods compare to the NATTS methods to conduct such a
comparison.
Difficulties with NATTS Program Start-Up Have Forced Trade-offs across SLT
Program Objectives in the Past, although Future NATTS Implementers Are Likely to
Benefit from Lessons Learned through These Initial Implementations.
The three state and local agencies in EPA Region 9 currently participating in the NATTS
program (ADEQ, BAAQMD, and SCAQMD) noted a number of benefits of participation,
including the ability to use the CAA Section 103 grant funds provided by EPA to purchase
new laboratory equipment, which can also be used for analyzing data from other air toxics
monitoring programs. Moreover, NATTS participation allows agencies to discuss methods
and other technical issues through regularly held conference calls, enhancing agencies'
abilities to share information across air districts. The benefit of NATTS participation is
likely greatest for those SLTs that otherwise would not have been able to monitor for air
toxics but had a strong interest in doing so. SLTs that already had robust air toxics
monitoring programs before joining the NATTS program received the benefit of funding
and communication, but these benefits may not have outweighed the significant difficulties
in having to redesign their systems to conform to national standards.
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Regardless of whether a SLT had an air toxics monitoring program in place or not, a
common challenge for NATTS participants was allocating sufficient budget to meet the
objectives of the program. EPA provided a specific funding amount intended to cover the
costs of the sampling and use the national contract for processing, analysis, validation, and
reporting of air toxics samples. The funding for each NATTS grant recipient also included
approximately $50K in additional funds that could be used at the SLT's discretion. But
SLT officials noted that funding levels were insufficient to support the more intangible
aspects of participating in the NATTS program. For example, there is an array of start-up
costs associated with NATTS participation—such as learning or redesigning laboratory
methods, setting up new equipment, and in some cases, identifying and coordinating with
an external laboratory—which required funding beyond that provided through EPA grants.
Agency officials also reported that certain aspects of the NATTS program design, such as
the use of a 1:6 sampling frequency instead of the 1:12 sampling schedule used by many
SLTs, increased demands on staff time. In addition, agencies participating in the NATTS
program are currently required to monitor for some compounds, such as hexavalent
chromium, that use relatively new laboratory methods. According to agency officials,
newer methods are likely to need small changes in the sampling or laboratory procedures as
they are implemented and further tested, and these changes can demand re-work and extra
cost for the agencies responsible for those procedures. Addressing these challenges
required extra staff time and budget for the participating SLTs in EPA Region 9 resulting in
trade-offs as agencies sought to fulfill national, state, and local objectives in the face of
limited resources.
However, many EPA and SLT officials noted that many of challenges encountered with the
NATTS program are similar to those experienced during implementation of other air
quality programs, and that learning from the current NATTS program participants' efforts
to address these challenges may eliminate or mitigate issues encountered by future program
participants. For example, BAAQMD experienced significant challenges associated with
attaining the MDLs for the TO-15 air toxics method. EPA recently provided BAAQMD
with a gas chromatographer/mass spectrometer that is expected to resolve many of these
challenges. Future NATTS program participants can build on this knowledge by
purchasing this piece of equipment at the onset of NATTS participation or choosing to use
the national contract for laboratory analyses. Also, future NATTS program implementers
are likely to benefit from more stable air toxics methods, as further testing and experience
will improve the stability of these methods. More stable and accepted methods will make
NATTS program implementation easier for agencies that have only NATTS sites and for
those SLTs that have larger air toxics monitoring networks.
EPA and SLT officials also noted that many of the difficulties experienced by EPA Region
9 SLTs during implementation of the NATTS program resulted from challenges associated
with the laboratory analysis of the samples. As new compounds to monitor are added to the
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NATTS program, EPA selects the national monitoring methods for these compounds based
on analysis of existing methods and further research conducted on the air toxics
compounds. SLTs in EPA Region 9 reported that the methods selected by EPA sometimes
differ from those used for their existing monitoring efforts. For example, many SLTs in the
region were using the 'scan' mode on their mass spectrometers, while the national method
called for the use of the 'SIM' mode. While SLT officials agree that data comparability is
affected by the use of different methods or equipment for processing air toxics samples,
there can be substantial costs for SLTs associated with making changes in monitoring
methods to align with new national standards. For agencies that have been tracking
ambient air toxics trends for some time, there is a reluctance to change methods—even if
such changes are improvements—because such a shift can disrupt the temporal
comparability of trends data at the local or state level. In addition, it is generally not
possible to switch a method for one site (i.e., the NATTS site) in a larger network;
therefore, SLTs that have many air toxics monitoring sites are more significantly impacted
by changes in methods. However, EPA officials noted that the difficulties encountered by
some SLTs are due to their choice to build their internal laboratory capacity as part of
participation in the NATTS program, rather than using the national contract for laboratory
analyses, which would eliminate the need to change methods. But, SLT officials noted that
while this may be the case for agencies that manage only NATTS sites, SLTs that have a
larger network of air toxics monitoring sites could sacrifice site comparability if they use
the national contract laboratory for one site and their own laboratory for all their other
sites. In general, it can be seen that SLTs with previous air toxics monitoring programs, a
group that includes all but one Region 9 NATTS participant, bring a wealth of experience
to the NATTS program but also have special implementation challenges.
Several SLT officials indicated that they were not aware of any efforts to analyze or make
use of the NATTS data that has been collected; however EPA officials noted that a portion
of the NATTS budget is devoted to data analysis each year and that there have actually
been significant efforts to analyze national air toxics data. These EPA officials stated that
because the NATTS data is only a portion of the dataset that has been analyzed, sometimes
it may not be clear that the NATTS data is being used for analyses. Four phases of ambient
air toxics data analysis were conducted starting in 1999, and the results of these studies are
available through the EPA AMTIC and Lake Michigan Air Directors Consortium
websites.11 In addition, preliminary results from recent analyses of the UATMP data were
reported at the September 2007 EPA-sponsored Air Toxics Data Analysis Workshop in
Chicago.12 Final results and reports from these analyses are anticipated to be publicly
available in 2008. EPA officials stated that further communication of these and future air
11 The EPA AMTIC website is located at http://www.epa.gov/ttii/amtic/airtoxpg.htinl and the Lake Michigan Air Directors
Consortium website is located at http://www.ladco.org/toxics.htrnl.
12 Presentations from this workshop are located at http://www.epa.gov/ttn/amtic/airtox-daw-2007.html.
Evaluation of Air Toxics Monitoring in EPA Region 9
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toxics data analyses are warranted to ensure that all SLTs are aware of ongoing national
data analysis efforts.
Finding 3: Short-Term and Community-Scale Air Toxics Monitoring Projects Play an
Important Role in Characterizing Air Toxics and Their Health Effects in EPA Region 9, while
Presenting Unique Resource and Management Challenges for SLTs.
SLTs in EPA Region 9 have undertaken a variety of short-term and community-scale air
toxics monitoring projects in addition to participation in broader local, state, tribal, and
national trends monitoring networks. Short-term and community-scale air toxics
monitoring projects greatly contribute to the characterization of air toxics at the local level
and provide a means for performing risk assessments, identifying source "fingerprints",13
and evaluating new monitoring methods. These air toxics monitoring projects provide
unique opportunities for SLTs to collaborate with a variety of community stakeholders and
educate the public on air toxics issues, but can also prompt public scrutiny of agencies'
abilities to diminish air toxics concentrations. Some SLTs fund short-term and community-
scale air toxics monitoring projects through a variety of state, local, and tribal funding
mechanisms, while others receive community-scale air toxics monitoring grants from EPA.
Agencies that have received EPA grants welcome the opportunity they provide to collect
and analyze air toxics data and acknowledge the benefits of the grant program, such as
informing and motivating mitigation strategies. SLTs expressed a desire to use grant funds
to perform further analyses and public communication than has been conducted in previous
grant cycles. These agencies also noted aspects of the community-scale and other short-
term funding structures that can hinder their ability to effectively use the grant funds to
their full benefit.
Short-Term Ambient Monitoring Projects and Community-Scale Monitoring Projects
Contribute to What Is Known about Air Toxics Prevalence, Their Associated Health
Effects, and Effective Methods for Analyzing These Air Toxics.
In addition to monitoring air toxics through long-term national and SLT ambient air trends
networks, a number of EPA Region 9 SLTs have also undertaken short-term ambient
monitoring projects and community-scale projects in order to further characterize air toxics
in areas where long-term ambient monitoring for air toxics is not currently or consistently
conducted. These projects provide a cross-section of toxics occurring in the community,
which may be extrapolated to areas with similar characteristics. For example, Hawaii DOH
established a neighborhood air toxics monitoring site to sample for one year. The results of
this project have provided Hawaii DOH with an indication of air toxics levels in the Pearl
13 For the purpose of this evaluation, a "fingerprint" is defined as the unique combination of elements and compounds
emitted from a source type.
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City neighborhood on Oahu, which, according to agency officials, may also be
representative of other similar neighborhoods on Oahu.
Some SLTs in EPA Region 9 also use the data from short-term ambient monitoring projects
or community-scale projects to perform analyses to support local exposure risk
assessments. For example, SCAQMD completed two successive air toxics exposure studies
in the South Coast Air Basin—MATES and MATES II—and has produced a draft report of
the third iteration of this study, MATES III. SCAQMD measured many of the same
compounds across the MATES studies, which is allowing the agency an opportunity to
develop detailed analyses on the long-term air toxics trends in the basin and to assess the
carcinogenic risks associated with the air quality trends.
In addition, SLTs have successfully used short-term ambient monitoring and community-
scale monitoring projects to attribute emissions to specific sources and identify source
"fingerprints." While source attribution can be difficult in urban areas due to the number
of potential sources present, SLTs are often successful in attributing emissions to specific
sources. For example, ADEQ found that high levels of hydrofluoric acid in the San Luis
area were due to emissions from local brick kilns. This source attribution led to moving
the brick kilns out of town and away from local schools. Source attribution monitoring can
also lead to identification of the "fingerprint" for a specified source type. As a result of
such community-scale monitoring projects in EPA Region 9, agencies are improving
understanding of the air toxics "fingerprints" of source types such as micro-scale chrome
plating businesses, ports, rail yards, and roadways. Source "fingerprint" information could
be used to assist agencies in other air districts to better interpret monitoring data or to
better characterize potential air toxics risks of certain source types without necessitating
costly ambient monitoring.
For several reasons, short-term or community-scale projects are an effective means of
piloting monitoring for specific air toxics compounds or piloting new methods before
monitoring on a broader scale. Pilot monitoring for a compound at a small scale or for a
short period of time is a resource efficient means of developing and testing sampling and
laboratory methods. For example, Nevada DEP received an air toxics grant to support the
development of a process for measuring the deposition of mercury in urban and rural
settings. The results of Nevada DEP's work could be used for future mercury studies
within the state and could also assist other air districts interested in monitoring for
mercury. Another reason to conduct pilot monitoring for a specific air toxics compound is
to identify a baseline for the prevalence of that compound across a region and identify
whether long-term monitoring is useful. For example, CARB conducted pilot monitoring
for several PAHs, but eventually decided to end monitoring for these compounds because
the baseline did not show significant levels of the toxics. A third reason to conduct pilot
monitoring is to identify whether a pollutant should be classified as an air toxic. For
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example, CARB is currently using a network of monitors in agricultural regions to identify
the prevalence of pesticides compounds in those areas. This data will assist the California
DPR in evaluating whether these pesticides should be considered TACs in California.
Table 3 provides a list of some of the air toxics recently piloted by SLTs in EPA Region 9.
Table 3: Example Air Toxics Recently Piloted by One or More Agencies in EPA Region 9
ADEQ CARB Nevada DEP Placer County APCD San Diego APCD
1,3-
Butadiene
1,3- Butadiene
Mercury
Diesel particulate matter
(black carbon and
elemental carbon)
Hexavalent chromium
Cadmium
Acrolein
Acrylonitrile
Naturally-occurring
asbestos
Diesel particulate
matter (black carbon
and elemental
carbon)
Dioxins
Hexavalent
chromium
PAHs
Saccharides (in
wood smoke)
Short-Term and Community-scale Monitoring Projects Provide Unique Opportunities
for Collaboration within Local Communities, and These Interactions Can Also Present
Challenges for SLTs.
SLT officials in EPA Region 9 reported that the narrow scope of many short-term and
community-scale monitoring efforts provides an opportunity for agencies to work closely
with the public and local emission sources. This collaboration can often encourage
stakeholder commitment and lead to voluntary emissions reductions. For example, Placer
County APCD worked with Union Pacific and a group of additional stakeholders to
monitor emissions at the Roseville Rail Yard after receiving a series of public complaints
about pollution from the yard. As a result of the monitoring project, Union Pacific
voluntarily agreed to a mitigation plan that included a 10% reduction in emissions and
provided funds for Placer County APCD to monitor the effects of the mitigation plan.
Although the primary objective of the Roseville Rail Yard monitoring study is to identify
the potential impacts resulting from the yard, the monitoring results will also provide the
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way to verify the performance of the rail yard mitigation plan. After the three-year
monitoring period, if the monitoring results show the original mitigation plan is not as
effective as anticipated, the rail yard has agreed to implement further mitigation measures
to address public concerns. Agency officials reported that community members often view
monitoring results as more accurate than modeled concentration values, and monitoring
efforts like the Roseville Rail Yard project can help allay community concerns about
nearby emission sources.
SLTs noted that it is important to identify at the outset of a project who will use the data
and who will be affected by the actions associated with various monitoring outcomes. This
information can be used to engage various stakeholders to gain a common understanding of
possible outcomes to the monitoring. One benefit of this type of project planning is that it
could provide an exit strategy for SLTs by defining some level of risk that would require
no additional monitoring. In addition, it could prevent monitoring that would result in no
mitigation benefits. Monitoring efforts that do not lead to emissions reductions or facility
closures can lead to frustration and may have the potential to damage an agency's
credibility. For example, CARB and San Diego APCD led an environmental justice
monitoring study on hexavalent chromium emissions from a decorative chrome plater
located near homes in the Barrio Logan neighborhood that showed there were significant
emissions from the facility. Officials from CARB noted that area residents expected the
facility to be shut down due to monitoring outcomes, but because it was not technically
violating emissions regulations, no action could be enforced. The facility eventually shut
down due to an unrelated violation, but, according to San Diego APCD officials, would
otherwise still be operational. In other cases, the regulator agency for a particular source is
the federal government, but the appropriate entities may not be engaged in the monitoring
process or may not be in a position to act on the results of a particular study. Pre-defining
who will use air toxics monitoring data and to what end could help promote positive study
outcomes.
Short-Term and Community-Scale Projects Have Largely Been Successful in
Supporting National and Local Air Toxics Monitoring Objectives, yet SLTs Cite
Difficulties in Coordinating Funding Sources for These Projects.
Many of the SLTs in EPA Region 9 have received community-scale monitoring grants for
air toxics projects, and officials at these agencies report that funds received through the
grant program significantly enhanced their ability to perform short-term, local-scale air
toxics monitoring projects. In addition agencies within Region 9 have undertaken many
independent efforts to characterize local-scale air toxics. However, officials at some SLTs
discussed certain aspects of short-term grant programs that can affect the successful
outcome of a well-designed project. For example, SLT officials noted that some local-
scale projects require a longer period of performance to carry out all phases of the project
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than can be funded through short-term grant programs. For example, JATAP's overall
project plan for their current multi-year air toxics risk assessment effort in the Phoenix
metropolitan area included data collection, laboratory analysis, and extensive data analysis,
modeling, and risk assessment, but their initial community-scale monitoring grant only
covered the air toxics data collection and laboratory analysis and portions of the remaining
phases of the project. While SLTs in EPA Region 9 understand that the community-scale
grant program only allows for short-term grants, they cite difficulties with identifying how
to consolidate larger proposals to fit within the allotted timeframe or in identifying
additional funding mechanisms to cover the remaining project budget. Many local-scale
monitoring efforts involve significant interaction with the public, and SLT officials
reported a need to provide stakeholders with accurate information on the extent and timing
of data analysis associated with a project, which can be difficult when there are
uncertainties about project timelines and funding. For the project described above, JATAP
was awarded an additional community-scale monitoring grant that covered further data
analyses, but EPA and SLT officials noted that this is not always the case. In some other
cases, SLTs have been able to leverage EPA grant funding to get industry, community, or
local agencies to provide additional support. Overall, SLT and EPA officials noted that it
would be useful for SLTs and EPA to share ideas on maximizing funding opportunities for
short-term, local-scale monitoring projects.
Finding 4: The Complex Nature of Air Toxics Monitoring Increases Data Quality and
Cross-Agency Data Comparability Challenges.
EPA, state, local, and tribal agencies all strive to develop and utilize methods and quality
control procedures that will ensure high quality air toxics data that can be used for a variety
of national, state, tribal, and local activities such as rulemaking, modeling, and mitigation
efforts. Because the national air toxics monitoring program is relatively new, fewer time-
tested methods and procedures exist than do for criteria pollutants, and therefore, for
certain pollutants, there is significant variation across sampling and laboratory methods and
QA/QC procedures employed by SLTs in EPA Region 9. EPA has sought to foster
standard approaches for ensuring data quality and comparability through the guidance
provided in the air toxics TAD, TO- and 10- compendiums, and PT testing available to all
agencies, and some EPA Region 9 SLTs have also led methods development efforts to
foster collaboration between SLTs in the region. Despite EPA efforts, individual SLTs
cited difficulties in navigating the available options and balancing national, state, tribal,
and local needs. In addition, some SLTs questioned the need for and value of adhering to
national standard approaches for non-NATTS monitoring sites.
Many EPA and SLT officials interviewed for this report cited the complexity of air toxics
monitoring and laboratory procedures as the root cause of the majority of the data quality
and comparability challenges encountered in EPA Region 9. These officials noted that
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EPA and each SLT in EPA Region 9 can be impacted by the data quality and comparability
challenges encountered by their agency as well as by the challenges encountered by
collaborating SLTs and contractors. EPA is involved in a number of national air toxics
analyses, modeling efforts, and risk assessment activities that can be negatively impacted if
any SLT contributing data to these efforts experiences data quality or comparability
challenges. Similarly, SLTs that analyze data collected by other agencies, such as CARB,
and SLTs that rely on other agencies or contractors for laboratory analyses, such as ADEQ,
can be negatively impacted if these collaborating entities encounter data quality and
comparability challenges.
Due to these potential effects of data quality and comparability challenges, EPA and SLT
officials noted the benefit of clearly defining the issues which have arisen in the past in
order to prompt proactive discussions on air toxics data quality and comparability
challenges, with the goal of continually improving the quality of data used for local and
national analyses, risk assessments, and modeling activities. Figure 1 outlines the major
factors affecting air toxics data quality comparability described in this and subsequent
findings and Appendix M describes an analysis of a selection of 2006 AQS data that
demonstrates some of the data comparability challenges described below.
Figure 1: Factors Affecting Air Toxics Data Quality and Comparability
Sampling
Sampling Schedule
And Frequency
Availability of Raw Data
And Metadata
Reporting
Procedures
Equipment
Field Conditions
Sampling Procedures
Technician
Training
Flagging
Protocols
QA/QC
Procedures
Reporting Limits
Equipment
Methods
Technician
Training
Detection Limits
QA/QC
Procedures
Laboratory
Analysis
Data Analysis
And Reporting
QA/QC
Procedures
Analysis
Methodology
Units Used
For Reporting
Data Quality and
Comparability Issues
The Need for Cross-Agency Data Comparability Differs between EPA and Region 9
SLTs.
EPA officials have expressed a need for cross-agency data comparability to support
national analyses and assessments; however, SLTs in EPA Region 9 had mixed views on
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whether this is a concern for all air toxics monitoring programs. As part of EPA's national
air toxics monitoring program, EPA evaluates national levels and trends, which requires
data comparability at sites across the country. To this end, EPA has established national
requirements that NATTS program sites are expected to meet, and SLTs are encouraged to
follow these guidelines for all air toxics monitoring sites. In contrast, most Region 9 SLTs
compare data only within their local district. While SLT officials expressed an interest in
cross-agency data comparisons, they also expressed doubt that this was a worthwhile
endeavor for SLTs to pursue, noting barriers in accessing quality data in a useable format.
These SLT officials expressed stronger confidence in their ability to share and compare
data within Region 9 than to do so nationally. Within Region 9, SLTs can determine the
quality of data from other agencies. Moreover, numerous agencies within Region 9 are
jointly developing a data acquisition system that will include air toxics, which will make
data formats more standardized across those agencies. Given the inherent difficulties in
national cross-agency data comparability and the lack of clear benefits for SLTs, agency
officials stated that developing, maintaining, and implementing national air toxics
monitoring standards is likely to remain an EPA-driven activity.
EPA and SLT Officials Identified Several Categories of Cross-Agency Data Quality
and Comparability Challenges for Future Discussions.
For those datasets where data comparability is needed, EPA and SLT officials identified the
following four categories of challenges, discussed below, as key topic areas for future air
toxics data quality and comparability discussions. EPA and SLT officials noted that
increased attention to these challenges could result in significant improvements to data
quality and usability, as well as cross-agency data comparability.
1. Further Coordination and Management in the Development of New Monitoring
Methods and in the Modification of Existing Methods.
The monitoring methods used to collect and analyze samples can greatly influence
the quality of the data. A few SLTs in EPA Region 9 have participated in methods
development efforts in the past, although currently CARB is the only SLT in the
region that regularly develops new air toxics methods. The other SLTs in the
region use various sampling and laboratory analysis methods developed by other
agencies or organizations, including EPA and CARB. It is also common for these
SLTs to modify the methods they use in order to better match the equipment and
conditions of their laboratory and to fill any procedural gaps in the method. This
can result in differences in the sampling and analysis methods used by SLTs,
affecting data comparability. For example, appropriate pressurization of canisters
for VOC samplers is an unresolved issue, with some SLTs preparing their canisters
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at sub-ambient levels and others preparing canisters at various levels of
pressurization.
EPA is currently working to organize and assess the utility of available methods for
air toxics compounds through the development of the TO- and 10- compendium
methods, which were originally prepared in the late 1990s. SLTs in EPA Region 9
regularly reference these national standards; however, many SLTs are not confident
that all of the TO- and 10- compendium methods are sufficiently time-tested and
accurate for the region's air toxics monitoring activities. The SLT officials we
interviewed did not typically see significant challenges with the existing TO- and
10- compendium methods; rather, the officials noted small issues, such as the
pressurization example described above, which they hoped could be resolved to
further stabilize the existing methods and decrease the need for each SLT to
research methods options. The challenge of addressing small differences in
methods can be especially difficult for SLTs using outside laboratories for data
analysis, as different laboratories may return different results if different variations
of methods are used. Additionally, in such situations, the laboratories may not
know the field data collection procedures followed (e.g., specifics on canister
pressure, volume, and flow) and therefore may not perform the appropriate QA/QC
on the samples.
EPA officials noted that in general, the methods are meant to be structured but not
overly prescriptive, in order to meet the needs of a broad range of SLTs. These
officials added that they are continually addressing the "option points" in the
existing methods, which are portions of the methods where there is currently more
flexibility, and requested that SLTs discuss any challenges they encounter with
their EPA Regional Officers, who can inform the EPA headquarters team updating
the methods. In addition, EPA encourages SLTs to participate in the air toxics
methods forum that is being initiated by EPA.
SLT laboratory officials also reported that in some cases, they are not able to
achieve the MDLs specified within the national methods. EPA officials noted that
this issue has been brought to their attention and is currently on their list of
challenges to address. SLT officials cited differences in available laboratory
equipment as a major factor in MDL discrepancies, although procedural challenges
may also be a factor.
Changes within recommended methods for data collection and analysis can affect
data interpretation. For certain reasons, such as new scientific knowledge or
additional testing of a method, it is necessary for EPA to alter the TO- and 10-
compendium methods. Although method changes are not common, SLT officials
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noted that agencies in EPA Region 9 with existing long-term trends networks and
special studies underway, such as CARB, BAAQMD, SCAQMD, and San Diego
APCD, can be negatively affected by a change in methods if it disrupts long-term
trends analyses. Moreover, SLTs may not see the benefit to adopting a revised or
new method if they have not been involved in the process of selecting the method.
Lack of a fluid dialogue between EPA and SLTs to address potential impacts from a
shift in methods can exacerbate these data comparability challenges.
In addition, for those SLTs in EPA Region 9 actively involved in air toxics methods
development, it can be a challenge to balance local needs with national methods
development efforts. For example, CARB is a national leader in methods
development and often develops methods for locally prevalent compounds that are
not currently addressed at the national level. CARB officials stated that difficulties
can arise if EPA identifies different TO- or 10- compendium methods for those
compounds at a later date, and noted a preference for collaborative EPA/CARB
methods development efforts that result in methods useful at national and local
levels. For example, officials from EPA, CARB, and other air districts in
California recently collaborated on methods development for acrylonitrile, an effort
that was seen as beneficial by all parties. However, officials who participated in
previous collaborative methods development discussions between EPA and SLTs
caution that difficulties can arise when the parties involved significantly disagree
and that an agreed-upon decision-making framework must be in place prior to such
discussions.
SLT and EPA officials also noted that further communication would be beneficial
in instances where multiple agencies are developing and testing methods for the
same compound. For example, a number of SLTs within EPA Region 9—such as
CARB, Placer County APCD, and BAAQMD—previously participated in or are
currently involved in studies measuring diesel particulate matter. Because diesel
particulate matter cannot be directly monitored, methods development efforts for
this air toxic focus on surrogates such as elemental carbon or black carbon. SLT
officials noted that further inter-agency collaboration on diesel particulate matter
methods would be especially beneficial given the complexity of monitoring for this
pollutant.
2. Further Clarity on Guidelines for Detection and Reporting Limits and AQS
Flagging Procedures for Air Toxics Compounds.
Standardization of detection and reporting limits is important for producing
comparable datasets across air districts. The 2004 version of EPA's TAD provides
guidelines on the standardization of detection and reporting limits, and for flagging
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data in relation to these limits in the AQS database. Several officials from EPA
Region 9 SLTs reported that there are information gaps in the TAD, and noted that
identifying and addressing these gaps can be time consuming and costly for
individual agencies. However, since our interviews were conducted, EPA prepared
an updated version of data management section of the TAD, which addresses many
of the SLTs questions on guidelines for detection and reporting limits and data
flagging procedures for the AQS database. Additionally, the challenges
surrounding MDL determination will be addressed on future methods focus group
calls for the NATTS program.
An additional challenge is that some SLTs that can achieve the detection limits
documented in the air toxics TAD choose not to use these detection limits in order
to be consistent with the detection limits they have used in the past. EPA officials
noted that SLTs that do not receive funding from EPA are not required to follow the
procedures laid out in the TAD, but that the use of different detection limits may
produce data that may not be comparable with datasets from other air districts,
limiting the usefulness of the data for national and regional trends analyses.
Similarly, agencies that operate non-NATTS sites may choose not to use EPA's
flagging guidelines, thus affecting cross-agency data comparability. As noted
earlier, SLTs generally don't undertake cross-agency data comparison to the same
degree as EPA and so these issues are likely to be more concerning to EPA than to
SLTs.
3. Further Standardization in QA/QC Procedures.
Standardization of QA/QC procedures for air toxics sampling, analysis, and
reporting contributes to cross-agency data comparability. Officials from all SLTs
in EPA Region 9 reported that they follow rigorous QA/QC procedures for
sampling and laboratory analysis. However, agency officials reported that
variations in QA/QC procedures between air districts do exist, and are likely due to
a variety of factors including financial constraints, lack of cross-agency
communication, and training deficiencies.
In addition to regular calibration and maintenance of sampling and laboratory
equipment, EPA Region 9 SLTs regularly perform internal audits of their
equipment and procedures through the use of audit samples. Agency officials
reported that they have purchased audit samples from a variety of consultants and
organizations in the past. However, the National Institute of Standards and
Technology (NIST) audit samples are widely considered the gold standard for
internal audits, and most agency officials reported that they prefer to use these audit
samples over other options. Several agency officials noted that one benefit of NIST
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audit samples is the consistency between the level of air toxics compounds found in
the samples and the average level at which those compounds occur in the region.
However, agency officials noted that the cost of NIST samples can be prohibitive
and that samples are not available for all air toxics compounds currently monitored
in EPA Region 9.
In addition, some SLTs participate in the national PT audit program which focuses
on compounds monitored through the NATTS program. This audit program
provides further comparison of how individual laboratories measure against other
laboratories across the nation and can be used to identify data comparability
concerns. Several SLT officials noted that the first round of PT audits included
audit samples that contained significantly higher levels of some air toxics
compounds than regularly occur in their region, which caused unexpected issues
with some agencies' equipment. However, EPA officials reported that due to
feedback on this initial round of audits, the PT audit samples are now prepared at
lower levels. The PT testing program has been effective at helping agencies identify
problems, which has led to greatly improved data quality for participating agencies.
For example, San Diego APCD, which does not currently maintain NATTS sites,
follows the NATTS program methods and procedures. Agency officials noted the
benefits of the PT audit program and NATTS program Technical System Audit in
identifying necessary refinements to agency procedures. However, EPA officials
noted that some of the SLTs in EPA Region 9 choose not to participate in the PT
audit program, which can diminish the effectiveness of this data comparability tool.
Several California agencies have also used through-the-probe audits to check the
accuracy of their equipment and methods. In this type of audit, a sample of known
quantity is inserted into an air toxics sampling device. The laboratory staff
members, who are not aware that the sample is an audit, process the sample
according to their standard procedures and their results are compared to the known
quantity in the sample to identify any equipment or method problems.
CARB has also led several California agencies in cross-agency laboratory audits.
In the annual Whole Air Toxic Audit, CARB uses a modified toxics sampler to
simultaneously collect multiple canister samples from a single location.
Participating laboratories analyze the sample and report values for each air toxics
compound. Using the reported values that fall between established minimum and
maximum values, CARB calculates the mean reported value and prepares a
comparison of individual laboratory results with this mean value. In addition,
CARB leads an annual "round robin" audit where NIST cylinders are distributed to
participated laboratories for analysis. CARB compares the results of each
laboratory and identifies whether they fall within an acceptable range of the actual
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quantities of air toxics within the NIST cylinders. EPA Region 9 officials
acknowledged the benefit of cross-agency precision and accuracy audits like those
that CARB leads, but noted that SLTs outside of California likely do not have the
connectivity or infrastructure to perform similar audits.
Additionally, SLT officials in EPA Region 9 noted that one deficiency in available
QA/QC resources is the lack of low-level calibration standards for agency
equipment. These officials noted a concern with the stability of currently available
low-level calibration cylinders and cited a need for consistently reliable standards,
which would provide better calibration than diluting cylinders with higher levels of
toxics.
4. Further Guidance and Tools for SLTs Using Outside Laboratories to Process
Their Samples.
Several SLTs within EPA Region 9 rely on other agencies or contractors to perform
the laboratory analysis on their samples. Agency officials reported that in the past,
these collaborations have led to unnecessary errors and re-work for SLTs if
expectations were not clearly communicated from the onset. For example, the
entity performing the laboratory analysis and the agency conducting the sampling
may have different expectations for a variety of factors including the format for
reporting the data, the detection and reporting limits for the air toxics compounds,
and which agency is responsible for ensuring the validity of the sample. SLT
officials noted that up-front and ongoing communication would prevent most of
these issues. Agency officials also attributed continued difficulties with using
outside laboratories to a lack in standard procedures or templates for agencies, lack
of standardization in the criteria for handling samples, challenges with defining
ownership of the sample, lack of communication on QA/QC audits performed at the
laboratory, and few venues for agencies to discuss best practices.
Finding 5: Agencies across EPA Region 9 Expressed Strong Interest in Expanding Cross-
Agency Communication, Information Sharing, Collaboration, and Training Related to Air
Toxics Monitoring.
EPA Region 9 SLTs expressed an interest in enhancing communication and collaboration
related to air toxics monitoring priorities, methods, results, and trends within their region
and within the larger national framework. Currently existing communication and
collaboration forums address some of the region's needs but there is a desire for a more
cohesive collaboration strategy that consolidates and enhances the current systems.
Specifically, Region 9 SLTs see a need for improvements to the available guidance and
resources, enhancements to the current set of national and regional communication forums,
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and improvements to training tools. SLT officials noted the important role for EPA
headquarters and EPA Region 9 at both the national and regional levels to provide
leadership and foster coordination among agencies engaged in air toxics monitoring. At the
same time, EPA and SLT officials observed that there are opportunities for SLTs in Region
9 to enhance communication and information sharing among peers.
A Patchwork of Forums Is Available for Agencies in EPA Region 9 to Share
Information Related to Air Toxics Monitoring, but There Is Not Currently Systemic
Coordination and Collaboration Across Agencies.
EPA Region 9 and SLTs in the region collaborate through a variety of venues. SLT and
EPA Region 9 officials reported that they currently participate in a variety of conference
calls and meetings targeted towards the air toxics community (see Table 4), although not all
agencies participate in all forums. In addition, SLT officials noted that they regularly
reference tools made available by EPA on the TTN AMTIC website and sometimes
reference other SLT websites to learn more about others' monitoring approaches. Some
SLT officials also reported having regular communications and collaboration with other
agencies or academic institutions, but that the ability to set up and maintain this type of ad-
hoc communication path varies widely among Region 9 agencies. For example, several
officials in the region reported that they employ former graduates or professors from local
universities, and that this has allowed their agency to build ties to academic institutions.
Overall, this breadth of venues available in EPA Region 9 creates a solid infrastructure for
communication and collaboration, although EPA Region 9 and SLT officials noted that
each agency participates in collaboration efforts to a different extent. The EPA
headquarters, EPA Region 9, and SLT officials we interviewed for this evaluation
described a number of improvements to the existing communication and collaboration
venues available to agencies in the region which would be beneficial if resources are
available for these upgrades and enhancements.
In addition, many SLT officials in EPA Region 9 indicated interest in receiving a broader
range of information on air toxics monitoring studies than what is currently available
through existing venues. For example, many agency officials cited difficulty in obtaining
information on the breadth of current air toxics monitoring activities across the United
States, particularly on those monitoring projects not funded by EPA. SLT officials also
noted that they would be interested in having more information on current and past air
toxics studies categorized by source types, such as near-roadway effects or ports, as well as
detailed information from past studies, including study methodologies, relevant metadata,
and any data analysis. A few SLT officials also noted that access to reference materials,
such as peer reviewed academic reports, templates, example QA plans, methods, and
standard operating procedures developed by SLTs, and best practices guides, would
enhance their ability to design and manage effective air toxics monitoring projects. Some
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of this type of information is currently available through EPA's TTN AMTIC website,
although EPA and SLT officials noted that the current set of information could be enhanced
to better meet all parties' needs. Similarly, SLT officials indicated that they could work
together in linking intra-regional air toxics monitoring activities on each other's websites.
In addition, some SLTs indicated interest in a message board for collaborating on
monitoring issues, but acknowledged that other SLTs may not be able to answer their
questions and suggested that this sort of collaboration forum would only be useful if air
toxics experts could regularly monitor the message board and respond to questions.
EPA Region 9 officials and personnel from most SLTs in the region participate in
collaborative committees to discuss air toxics issues or attend national meetings where air
toxics topics are included on the agenda (see Table 4). For example, managers with
responsibility for air toxics monitoring from most agencies in California participate in
California Air Pollution Control Officers Association (CAPCOA) meetings each year,
which frequently address air toxics issues. For example, the focus of a 2007 meeting was
"Health Impacts of Air Pollution on Communities." In addition, some agency officials
stated that EPA's Air Toxics Data Analysis Workshops and National Air Monitoring
Conferences are beneficial for sharing information on monitoring related activities and
issues. For example, several presentations on updates to national programs, results of
recent community-scale monitoring efforts, and results of national data analysis efforts
were discussed at the 2007 workshop in Chicago. However, several EPA Region 9 and
SLT officials noted that agendas for the communication forums listed in Table 4 do not
always sufficiently focus on air toxics monitoring, and suggested consolidation and
improvements to agendas may be warranted in the future.
Table 4: EPA Region 9 Communication Forums
Air Monitoring Technical Advisory Committee
(AMTAC)
National Air Toxics Trends Stations (NATTS)
conference calls
Air Toxics Risk Assessment (ATRA)
conference calls
National Association of Clean Air Agencies (NACAA)
Air Toxics Committee
California Air Pollution Control Officers
Association (CAPCOA)
Regional Air Toxics Coordinators (RATC) conference
calls
EPA Air Toxics Data Analysis Workshops
Western States Air Resources Council (WESTAR)
Technical Committee
EPA National Air Monitoring Conferences
Building on the idea of consolidation of air toxics communication and collaboration
forums, several SLT and EPA Region 9 officials cited a need for a more focused and
cohesive regional air toxics communication and collaboration strategy. These officials
noted that there are few forums focusing specifically on air toxics monitoring or
technically-oriented interactions about air toxics monitoring issues, needs, and methods.
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We found that SLTs in EPA Region 9 currently collaborate in a number of ways—
including informal consulting and advising, collaborative monitoring projects, sharing or
loaning equipment, and sharing laboratory, analysis, and auditing services—but that nearly
all such collaboration occurs within state boundaries. For example, the Roseville Rail Yard
project was a collaborative monitoring effort between several agencies including CARB,
SCAQMD, EPA, and Placer County APCD. Placer County APCD managed the majority of
the project components including development of the methodology and collection of the
data, and managed the day-to-day project activities. CARB and SCAQMD provided a
variety of in-kind services including modeling, participation on the project advisory board,
and laboratory and auditing services, in addition to loaning Placer County APCD much of
the sampling equipment for the project, and EPA provided Placer County APCD a
community-scale monitoring grant and participated on the project advisory board. Several
agency officials involved in the Roseville Rail Yard project and other collaborative
monitoring efforts suggested that a regionally-focused air toxics meeting targeted towards a
technical audience would greatly enhance regional collaboration, communication, and
coordination opportunities, and could especially encourage collaboration across state
boundaries.
EPA and SLT Officials Cite a Need for Improved Air Toxics Data Sharing.
As part of the national air toxics monitoring program, EPA accesses and compares data
from numerous sites across the nation. In comparison, SLTs tend to focus most of their
efforts on data from their own air toxics networks, although EPA Region 9 SLT officials
expressed an interest in occasionally sharing and comparing data with other agencies.
However, EPA and SLT officials noted that there is not a streamlined mechanism for
accessing and comparing data from numerous agencies. While the AQS database serves as
an effective repository for air toxics data that has been collected, SLT officials in EPA
Region 9 reported difficulty with accessing comprehensive raw air toxics data and trends
information. The AQS database currently provides the best means for retrieving data
collected by SLTs across the nation, but several SLT officials indicated that certain aspects
of AQS's data entry requirements and user interface often deter them from using the
database for this function (see Table 5). A common concern among agency officials is the
lack of metadata associated with the data points in the AQS database. For example, several
SLT officials noted that they hesitate to compare their data to other air districts' data
without a full report on any potential data quality issues. These officials noted that AQS
provides a limited ability to report this information, primarily through the use of data flags,
but that more detailed information is lacking. EPA and SLT officials also noted that some
air districts do not report data from their community-scale air toxics monitoring projects to
AQS, particularly when these projects are not funded through EPA grants, limiting the
extent of data available in the database. In addition, several SLT officials reported
difficulty with the AQS user interface, citing specifically that limited guidance is available
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to set-up and interpret data reports and that data reports cannot easily be incorporated into
local applications, such as spreadsheets. Overall, SLT and EPA officials cited the
complexity of air toxics data as the key contributor to continued data sharing challenges.
Because air toxics data is more complex to collect and analyze than criteria pollutant data,
there are many unique challenges with reporting air toxics data that are not present in
criteria pollutant monitoring programs.
Table 5: Common Reported Issues with Using the AQS Database and User Interface
Report formats are difficult to integrate with local
applications (e.g., spreadsheets and databases)
The user interface for AQS is not easy to
navigate and it is easy to misinterpret the data
reports and what information they contain
Users in different screening groups cannot report
data for the same monitor so sometimes
agencies and their contractors are forced to set
up two monitors in AQS for a single monitor in
their network
There is no standard way to pull NATTS data
from the AQS database, as this data is combined
with other HAPs data
There are conflicting opinions on whether zeros
should be entered when data is not available or
if the field should be left blank
The user interface for data entry is confusing
and data entry can be time-consuming
During preparation of this evaluation, we also encountered difficulties with interpreting and
using data reports from AQS, but found that EPA has a number of more user-friendly
interfaces for the public to access air quality information including AirData, AirExplorer,
AirNOW, and AQS Discoverer.14 The AirData, AirExplorer, and AirNOW interfaces are
targeted towards less technical audiences, and likely do not provide access to the level of
information needed by SLTs in EPA Region 9; however, they do provide examples of other
types of user interfaces for retrieving air quality data. The AQS Discoverer application
provides access to all the data available in the AQS database and allows any user with an
AQS account to prepare customized data reports that can be easily exported to common
spreadsheet applications. However, there is a significant learning curve associated with use
of the AQS Discoverer application, due to the complexity of developing the customized
data reports.
SLT officials also noted that they regularly reference the CARB ADAM database to
retrieve California air toxics data primarily because of its user-friendly interface. In
addition, CARB publishes an annual air quality DVD that allows users access to an
interactive interface for querying California air quality data, including air toxics data. For
example, the 2007 DVD includes data from 1980-2005. These DVDs allow the user to
create custom printable reports or tables in DBF, TXT, or DAT formats.
14 AirData is located at http://www.epa.gov/air/data/, AirExplorer is located at http://www.epa.gov/airexplorer/, AirNOW
is located at http://www.airnow.gov/, and AQS Discoverer is located at http://www.epa.gov/ttii/airs/airsaqs/aqsdiscover/.
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Agencies Cite a Need for Additional Training Opportunities and Training Tools.
A few SLT officials in EPA Region 9 noted that past training events led by EPA in New
York and California provided good opportunities for local agency staff, but that many
agencies cannot send staff to training events outside of their locale. Because most training
occurs within SLTs, officials indicated a need for additional guidance and mentoring for
training new staff, and noted that the guidance should address the specific needs of field
and laboratory staff. Many of the SLTs we interviewed observed that they had adequate in-
house procedures for training laboratory staff, but that gaps exist in training procedures for
field staff. Whereas laboratory staff members tend to have similar academic and
professional backgrounds, field staff members often have a mix of professional
backgrounds and may require a broader scope of training. Several SLT officials suggested
that a regional training event with modules geared towards different types of staff could
help improve consistency between agencies and provide a forum to deliberate technical
issues and concerns. Other officials suggested that regional coordination that includes
mentoring could be another effective means of training. In addition, SLT officials at
agencies which use outside laboratories cited a need for training specific to their situation,
including procedures for verifying the validity of collected samples and best practices for
reviewing the laboratory's results to identify any QA/QC or transcription errors.
Finding 6: Air Toxics Monitoring Data Is Being Used and Analyzed to Varying Degrees
across EPA Region 9, and There Is a General Sense that Increased Attention Is Needed to
Effectively Expand the Use of the Data for Program Planning and Accountability.
Much attention over the past decade has focused on expanding efforts to monitor ambient
air toxics concentrations, and there is a general sense that greater attention is needed for
analyzing and using air toxics monitoring data. SLTs undertake varying levels of data
analysis and EPA has had a national monitoring effort underway for the past several years.
EPA and SLT officials generally asserted that additional efforts are needed to maximize the
value of monitoring data. At the state and local level, agencies in California have
substantial experience in analyzing, using, and reporting ambient air toxics data for
purposes of program accountability and planning. Other SLTs are generally at the early
stages of beginning to analyze and use collected data. EPA and SLT officials noted that
any efforts to further analyze air toxics data at the national and regional levels will likely
be led by EPA and a select number of SLTs in the region.
Significant Variation Exists within EPA Region 9 in How SLTs Are Using Air Toxics
Monitoring Data to Inform Program Accountability and Planning.
At the state and local level, California is a clear leader in using ambient monitoring data for
purposes of program accountability and planning. Ambient monitoring data is routinely
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analyzed to prepare an annual assessment of air toxics issues and trends in California.
Since 1999, CARB has published the annual California Almanac of Emissions and Air
Quality.15 The 2007 Almanac presents an overview of emission and air quality information
on TACs. It also provides summaries of statewide emissions, annual average
concentrations (calculated as an average of the monthly means), and estimated health risks
for ten selected TACs.16 The 2007 Almanac also provides similar information for
California's five most populous air basins: the South Coast, the San Francisco Bay Area,
the San Joaquin Valley, San Diego County, and the Sacramento Valley air basin.
California has also included air toxics in the state's broader environmental indicators
initiative to assess environmental quality trends, enhance accountability of government
environmental programs, and guide future government action. The Environmental
Protection Indicators for California (EPIC) Project was established in statute in 2003, 17
requiring the development and routine reporting of a set of environmental indicators for
California.18 EPIC is a collaborative effort of the California Environmental Protection
Agency, the Resources Agency, the Department of Health Services, and an external
advisory group, and is led by the California OEHHA. Progress reports on EPIC pilot
projects show that the consideration of indicators in the development and implementation
of environmental protection programs has been important in evaluating program
effectiveness.
EPIC has identified three air toxics indicators for development. These include:
¦ Total emissions of toxic air contaminants.
¦ Community-based cancer risk from exposure to TACs.
¦ Cumulative exposure to toxic air contaminants that may pose chronic or acute
health risks.
These indicators are categorized as "Type II" indicators, meaning that they will require
additional data and effort to develop. As of 2007, these indicators had not been fully
implemented in the EPIC project. The first indicator, total emissions of toxic air
contaminants, will rely on emissions inventory data. The second indicator, community-
based cancer risk from exposure to TACs, will utilize data collected from air monitors and
dispersion modeling to estimate ambient concentrations of air toxics throughout California.
These estimated concentrations will be used to calculate excess cancer risk for each toxic
13 The 2007 Almanac is located at http://www.arb.ca.gov/Aqd/almaiiac/almaiiac.htm
16 The TACs addressed ill the 2007 Almanac represent the ten TACs known to have the greatest health risk in California,
based primarily on ambient air quality data, including: acetaldehyde, benzene, 1,3-butadiene, carbon tetrachloride,
hexavalent chromium, para-dichlorobenzene, formaldehyde, methylene chloride, perchloroethylene, and diesel particulate
matter.
17 EPIC was established under AB 1360.
18 Further information is located at http://www.oehha.org/multimedia/epic/.
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air contaminant, and a cumulative risk will be calculated by adding estimated risk values
for the toxic air contaminants in an air basin or community. The results will be overlaid by
demographic data using a GIS-based program. Additional demographic data, such as
average income or ethnic background may also be utilized to address environmental justice
issues. The third indicator, cumulative exposure to toxic air contaminants that may pose
chronic or acute health risks, would utilize air monitoring data and dispersion modeling to
estimate ambient concentrations of air toxics throughout California. Particular attention
will be paid to the main air basins known to have the highest air levels of TACs in
California (South Coast, San Diego County, San Joaquin Valley, San Francisco Bay Area,
and Sacramento Valley). The data on long-term ambient air concentrations of TACs are
being compiled and will be presented in a future indicator for chronic non-cancer risk.
Officials from California OEHHA have noted that the collection of acute TAC exposure
data is more resource intensive since it requires hourly ambient concentration data. The
acute non-cancer risks posed by TACs may be presented in a future indicator, as more
complete data on hourly levels of TACs is collected.
Several of the local air agencies in California also publish analyses of air toxics trends,
drawing at least in part on ambient monitoring data. For example, BAAQMD prepares and
publishes a Toxic Air Contaminant Control Program Annual Report, which provides the
public with information regarding BAAQMD's programs to reduce ambient concentrations
of TACs.19 The report summarizes the current focus and direction of the programs that are
used to identify and control TACs from stationary sources (Volume I), and contains
summaries of the TAC emissions inventory and ambient monitoring network (Volume II).
At present, there is a substantial lag in time for publication of the report. The most recent
report that is publicly available is for 2003. In addition, SCAQMD published the results of
it MATES I and MATES II studies. The MATES II study report provides comprehensive
information including the data monitoring results, an updated emissions inventory for the
South Coast Air Basin, and summarizes a modeling effort which characterizes the health
risk due to air toxics in the Basin.
Outside of California, the availability of information and analyses of air toxics monitoring
trends and performance measures is limited but increasing. For example, ADEQ publishes
an Air Quality Annual Report,20 which has included references to JATAP in recent years.
In addition, EPA requires agencies receiving community-scale monitoring grants to
develop final project reports, 21 which document the monitoring effort methodology,
participants, analysis, and results.
19 The BAAQMD annual reports are located at http://www.baaqmd.gov/pmt/air_toxics/annual_reports/index.htm.
20 ADEQ's 2006 Air Quality Annual Report is located at http://www.azdeq.gov/function/forms/download/2006/aqd.pdf.
21 Information on past and current community-scale grant projects can be located at
http://yosemite.epa.gov/oar/CommunityAssessment.nsf/Community%20Assessment%20ListlOpenForm and the final grant
reports are located at http://www.epa.gov/ttn/amtic/local.html.
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SLTs in EPA Region 9 Cite a Strong Interest in Expanding and Improving the Use of
Air Toxics Monitoring Data for Program Planning and Accountability Purposes.
SLT officials in EPA Region 9 generally agreed that air toxics monitoring data is not being
used to the extent that is possible or desired to inform program planning and assess
program performance. Opportunities for improving the availability, accessibility, and
analysis of ambient data were identified at multiple levels, including regional trends data,
national trend data (e.g., NATTS) and local-scale monitoring project data. SLT officials
identified several types of hurdles to the effective use of air toxics monitoring data for
program planning and assessment. First, delays in the availability and reporting of ambient
monitoring data can hinder the ability to analyze and compare data and to assess trends.
Second, the user-friendliness of information system tools can affect the ability and ease of
accessing and analyzing ambient monitoring data. Third, limited availability of funding
and staff resources often mean that the collection of ambient monitoring data is prioritized
over analysis of monitoring data.
During our interviews with SLT officials, we found a general sentiment that analysis and
use of ambient air toxics data should increase over the next few years in order to meet air
toxics program objectives. Agency officials indicated that as ambient data is accumulating,
and data comparability issues are being addressed, it will be increasingly important to focus
attention on the analysis and communication of air toxics monitoring data, trends, and
issues. Several officials noted that failure to make this shift will undermine future
monitoring efforts, particularly if there is a perception that ambient monitoring investments
are not providing commensurate benefits for program accountability and planning. These
officials also noted that public interest and attention will likely grow related to air toxics,
and that the ability of government to help the public understand and address the health risks
from air toxics will be increasingly important.
In addition, SLT officials noted the need for further collaboration in developing unit risk
factors. Unit risk factors, such as those developed by EPA and California OEHHA, are
important inputs for risk evaluations and models. CARB officials noted that it would be
helpful to receive input from external agencies during periodic updates to their unit risk
factors.
Air Toxics Monitoring Data Is Playing a Small but Increasingly Important Role in
Assessing the Performance and Accountability of the National Air Toxics Program.
In the past decade, ambient air toxics monitoring data has not played a major role in the
national assessment of air toxics programs or of the extent to which these programs are
meeting established goals and desired outcomes. The air toxics program performance
measures and indicators compiled by EPA in 2007 indicate that most short-term and long-
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term air toxics program outcome measures are currently constructed using data from the
NEI and the NATA, which model ambient air toxics concentrations and public exposure
using emissions inventory data.
Recent EPA efforts to improve program performance measurement have focused on better
accounting for program outcomes in addition to program outputs, in part driven by the
GPRA and OMB 's PART evaluation. As emphasis has shifted towards improving
measures of program outcomes and results, increased attention has focused on using
ambient air toxics monitoring data as an alternative or supplement to information from the
NATA and the NEI. Ambient concentrations of pollutants assessed through monitoring are
typically viewed, particularly by the public, as more direct and accurate indicators of public
exposure to air toxics than modeled concentration values.
Concurrent with the development of the NATTS network, EPA has sought to use ambient
air toxics monitoring data in efforts to assess the performance of the national air toxics
program. For example, in the ambient air toxics data MIP, EPA proposed transitioning
from the existing toxicity-weighted emission inventory measure to a measure that uses
ambient monitoring of air toxics as a surrogate for population exposure and compares these
values with health benchmarks to predict risks. EPA has proposed to use data from the
NATTS sites for development of this measure, but EPA officials noted that increased
management attention and resources will likely be needed.
Some EPA and SLT officials in EPA Region 9 suggested that national-scale trends data
may have important, but limited, utility in assessing national air toxics program
performance. The primary issue involves challenges associated with capturing a
representative picture of ambient conditions and public exposures from the limited number
of NATTS sites. Local factors such as geography, topography, meteorology, and source
locations can dramatically affect the value of measured ambient concentrations in an area,
making it difficult to find a representative site for a location despite rigorous siting criteria
and methods. In its MIP for ambient air toxics data, EPA acknowledged that the current
proposed measure is designed to only capture widespread risk estimates and that it may not
address local-scale risks or hot spots. EPA suggested that in the future the technical
approach for developing the measure could be modified to potentially account for local hot
spots and variations. EPA and SLT officials also noted that the accuracy and comparability
of NATTS data is an important factor in determining the usefulness of this dataset for
program accountability.
The national air toxics program is driven by the CAA requirements to address specific
source categories, and therefore EPA headquarters officials noted that ambient monitoring
data may not always play a prominent role in program planning efforts. However, EPA
headquarters and SLT officials in the region recognized the importance of using ambient
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monitoring data for national program planning and accountability purposes, to the extent
possible. Monitored ambient concentration data can help tell important stories about air
toxics trends and issues and the extent to which program activities are affecting exposure
outcomes. Several EPA and SLT officials indicated that the optimal approach is to have a
collection of measures, drawn from ambient monitoring data and modeled emissions
inventories, to address the status of both broad-scale ambient conditions and local
"hotspots." For example, a few SLT officials in EPA Region 9 noted that the UATMP has
been a useful vehicle for analyzing and disseminating the results of ambient monitoring
data, such as the 2005 UATMP report that focused on national trends in ambient
concentrations of hexavalent chromium. The findings from such national-scale studies
based on monitoring data can both inform national-scale policy making as well as state,
local, and tribal efforts to better understand how these national trends may be playing out
within specific communities.
EPA Officials Cite a Need to Enhance Performance Measures Addressing Air Toxics
Monitoring Program Implementation and the Tracking and Communication of These
Measures at the National Level.
While annual program goals and performance measures are being set by EPA for air quality
programs, including air toxics monitoring, program performance measures are not being
tracked, reported, and communicated in a manner that informs or drives results-based
management. As part of its Annual Commitment System, EPA OAQPS and EPA Regional
Air Offices develop annual tables of goals, performance measures, and activities, outputs,
and targets for achieving and demonstrating progress towards goals outlined in EPA's
National Monitoring Strategy. The identified activities, outputs, and targets include those
sought from EPA's national program office and EPA Regional offices, as well as from
SLTs. Several EPA officials, however, suggested that this effort is largely a planning
exercise and that progress towards these specific program goals and targets are not
consistently tracked, reported, or communicated in a manner that is useful for management
of national and regional air toxics monitoring programs.
EPA officials identified a number of performance measures that could be useful in
assessing the progress of national and regional air toxics program implementation. These
include the timeliness or completeness of SLT air toxics data reporting to AQS and
participation rates in the PT testing program and Technical System Audit program. Several
EPA officials noted that improved measurement, reporting, and communication of progress
in regional and national air toxics monitoring program implementation could be useful for
sustaining inter-agency attention and commitment to strengthening air toxic monitoring
programs. Several officials also indicated that the recent process change to allow for
annual state-level review and comment on the national goals, activities, and targets is a
welcome addition. They noted, however, that a more collaborative process would likely be
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needed to enhance buy-in from SLTs and to enable better alignment of program priorities at
the federal, regional, state, and local levels.
Conclusions
There is a significant amount of air toxics monitoring activity occurring within EPA
Region 9 which supports EPA's dual emphasis on national- and local-scale air toxics
monitoring. Overall, there is a strong degree of consistency in the air toxics monitoring
objectives articulated by EPA and the SLTs in EPA Region 9, and the monitoring efforts
currently underway in the region address these objectives. Each SLT within the region has
different needs, priorities, and abilities, resulting in a patchwork of monitoring activity
across EPA Region 9. Despite this patchwork, there is evidence that monitoring efforts
have contributed to significant advances in understanding and addressing regional, state,
tribal, and local air toxics issues and associated public health risks. In particular, agencies
in EPA Region 9 have pioneered local-scale monitoring activities that are improving
understanding of air toxics risks and mitigation options associated with sources such as
near-roadway locations, rail yards, and ports. In addition, data collected from local- and
regional-scale trends networks in EPA Region 9 complement results from national-scale
trends networks, providing a richer picture of air toxics concentration and exposure issues.
Furthermore, the extent of progress made in establishing the diverse array of air toxics
monitoring activities is impressive given the complexity of the task and the limited
resources and staffing available at EPA and SLTs to support these activities, particularly
when compared with criteria pollutant programs. At the same time, however, there are
important opportunities to improve air toxics monitoring activities in the region and to
enhance the usefulness of the resulting data to address program objectives.
It appears that air toxics monitoring activities are approaching a key juncture at the national
and regional level: many SLTs have air toxics monitoring programs that are maturing, the
NATTS program is becoming firmly established, and numerous local-scale monitoring
projects, including EPA's community-scale air toxics monitoring grant program, have been
completed. At this point there is an important window of opportunity to consider and share
lessons learned, continue efforts to improve data quality and comparability, enhance the
analysis and communication of monitoring results and trends for measuring program
performance and informing planning, and identify future directions for air toxics
monitoring activities at all levels.
First, there are opportunities to strengthen and connect air toxics monitoring activities
across air districts in EPA Region 9. EPA Region 9 SLTs represent a spectrum of air toxics
monitoring experience, which ranges from agencies that have managed air toxics
monitoring networks for over two decades to agencies that began air toxics monitoring as
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recently as 2006. As a result, agencies' needs and abilities cannot be generalized as a
whole, but must be categorized between agencies with significant air toxics monitoring
experience and agencies newer to this type of monitoring. Agencies with significant
monitoring experience have a wealth of experience and technical expertise that can be
leveraged by other SLTs and EPA, and require less outside expertise and direction to
continue to grow their air toxics monitoring programs. Agencies with less air toxics
monitoring experience can benefit from the mentorship, tools, and best practices of more
experienced agencies, all of which can help readily improve their air toxics monitoring
capabilities. While there is a significant amount of interaction among air toxics monitoring
program managers in California, there are important opportunities to deepen the level of
staff contacts within the state and to broaden interactions to include other interested
agencies in Region 9. It is clear that Region 9 SLTs can play a vital role in mentoring each
other and other SLTs nationwide.
SLT officials in EPA Region 9 view EPA as fulfilling a vital leadership role in fostering
communication, coordination, and collaboration related to air toxics monitoring. This role
is important to strengthen and connect air toxics monitoring activities both within the
region and nationally. Region 9 has the benefit of having a number of agencies with
substantial air toxics monitoring experience. The continued ability of EPA headquarters,
EPA Region 9, and SLTs in the region to engage in a productive partnership will enhance
the efficacy of air toxics monitoring program activities regionally and nationally. In
conducting this evaluation, however, we were left with a sense of missed opportunity
resulting from the limited communication and collaboration between EPA and Region 9
SLTs with significant air toxics monitoring experience, and among regional SLTs. While
there is undoubtedly a rich history that accounts for this, the potential benefits of closer
communication, coordination, and collaboration struck us as profound.
Second, there are continued opportunities to improve both the comparability and usefulness
of air toxics monitoring data. There is a strong need to collaborate around and address the
data quality and comparability issues which have come to light through the NATTS
program implementation and through other SLT air toxics monitoring efforts. Despite the
general agreement around air toxics monitoring program objectives among EPA and SLTs,
not all agencies see the benefit in adopting national standard approaches to facilitate
national data comparability at non-NATTS sites. In addition, several factors have been
identified that can undermine the ability to compare data in a manner that supports
effective air toxics program planning and accountability within EPA Region 9 and at the
national program level. As described in Figure 1, there are a variety of factors that affect
data quality and comparability which could be addressed to more fully realize the value of
collected air toxics monitoring data in EPA Region 9.
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As air toxics monitoring activities in EPA Region 9 expand and mature, there is a greater
need and opportunity to invest in the analysis, use, and communication of data for air
toxics program planning and accountability purposes. Efforts to improve awareness and
understanding of air toxics issues, from regional trends to "hotspots" linked to specific
sources, will both enhance the usefulness of existing air toxics monitoring data and the
demand for future monitoring.
Recommendations
The following five recommendations, based on the findings in this report and from a
January 31, 2008 meeting between EPA headquarters, EPA Region 9, and Region 9 SLT
officials, provide ideas for improving air toxics monitoring communication, collaboration,
and coordination in EPA Region 9 and nationally. These recommendations do not reflect
critical improvements to the national air toxics monitoring program or SLT air toxics
monitoring efforts. Rather, these recommendations are presented as ideas that can be used
to inform EPA headquarters' ongoing improvements to the national air toxics monitoring
program and can also be used by EPA Region 9 and SLTs to improve intra-regional air
toxics monitoring communication, collaboration, and coordination.
Recommendation 1: Enhance Opportunities for Regional and National Information
Sharing, Communication, and Coordination on Air Toxics Monitoring Methods and
Results.
Enhanced communication opportunities within EPA Region 9 would provide SLTs an
opportunity to share ideas and best practices and to coordinate with EPA on air toxics
monitoring methods. Specifically, a regional technical air toxics committee could greatly
enhance SLTs' abilities to collaborate and coordinate on air toxics topics. At the January
31, 2008 meeting, EPA and regional SLTs discussed formation of such a committee
structured in the following ways:
¦ EPA Region 9 program officials would coordinate initial formation of the
committee, which would include representatives from regional SLTs and EPA
Region 9.
¦ The committee would hold quarterly conference calls and call agendas would be set
by the committee members.
¦ The committee would meet in-person once a year.
¦ Responsibility for hosting, organizing, or presenting on specific conference calls or
at in-person meetings would rotate among SLTs.
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¦ Conference calls and meetings would be used to share information on past or future
air toxics studies within the region and to discuss technical topics, such as methods.
¦ Some or all conference calls would be web broadcast, allowing officials from SLTs
across the nation to join the discussions and learn from Region 9's experience.
¦ An EPA headquarters liaison would either attend the quarterly conference calls and
meetings or would be briefed by the EPA Region 9 representative following the
discussions.
Potential discussion topics for the regional technical air toxics committee could include:
¦ Sampling and laboratory analysis challenges for specific air toxics (e.g., acrolein or
diesel particulate matter).
¦ Integration of regional information collection and storage systems (e.g., integration
of Laboratory Information Management Systems with other data management
systems).
¦ Information sharing mechanisms for air toxics data, methods, and study results
(e.g., websites, databases, clearinghouses, message boards, and blogs).
¦ National, regional, state, local, and tribal objectives and priorities for air toxics
monitoring (see Recommendation 2).
¦ Scoping and innovative funding opportunities for community-scale air toxics
monitoring projects (see Recommendation 3).
¦ Data comparability needs and solutions to common data comparability challenges
(see Recommendation 4).
¦ Air toxics data analysis and use (see Recommendation 5).
In addition, EPA could support Region 9's communication and information sharing efforts
through enhancements to the EPA Region 9 and TTN AMTIC websites. For example, EPA
could consider the following website improvement ideas to help disseminate air toxics
information to SLTs in Region 9 and nationally:
¦ More clearly articulate national and regional air toxics monitoring objectives and
provide ready access to detailed information on EPA-funded monitoring efforts, the
data collected through these efforts, and resulting final reports and analyses.
During these enhancements, EPA could consider adding more explanatory text to
the main pages of the websites, so that users can access summary information
without downloading large reports.
¦ Improve ability to access information by air toxics themes (e.g., pollutants or
source types) or to search EPA websites by common air toxics key words.
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¦ Improve access to the data contained in the AQS database. This could be achieved
through continued improvements to current user interfaces such as AQS Discoverer.
¦ Provide access to user-friendly spreadsheet tools that enable SLTs to benchmark
their air toxics monitoring data against annual averages from other SLTs and/or
NATTS locations.
¦ Identify and provide contact information for air toxics experts (e.g., representatives
from EPA, Northeast States for Coordinated Air Use Management (NESCAUM),
academia, and EPA Region 9 SLTs).
¦ Add training resources (e.g. audio and visual presentations on air toxics topics).
In addition, officials from EPA and SLTs in EPA Region 9 could coordinate to help
develop agendas for future national Air Toxics Data Analysis Workshops and National Air
Monitoring Conferences. Many SLTs in the region are involved in innovative air toxics
monitoring projects and could use their experience to help inform agenda planning for
these meetings.
Recommendation 2: Increase Communication and Alignment of Regional Air Toxics
Monitoring Program Objectives and Elevate Importance of Linking Air Toxics
Monitoring to Emissions Reductions.
Further communication about air toxics monitoring program objectives could help SLTs in
EPA Region 9 better understand regional priorities and could facilitate completion of
monitoring activities that address these priorities. For example, many Region 9 SLTs have
indicated interest in more consistently identifying the links between air toxics monitoring
efforts and actual emission reductions within air districts, and in communicating these
achievements to the public. Region 9 SLTs could discuss this and other enhancements to
regional priorities at the quarterly meetings of the EPA Region 9 technical air toxics
committee.
In addition, regional SLTs could work with EPA Region 9 to better understand the
connections between the national air toxics monitoring program objectives and regional
objectives. The National Air Toxics Program Logic Model could be used as a tool for
understanding the connections between each agency's objectives and anticipated
monitoring program outcomes, and to better understand the national objectives specific to
the NATTS program and the community-scale monitoring grant program. These
discussions of objectives could help Region 9 SLTs and EPA better understand future
directions for air toxics monitoring programs and identify any needed enhancements to
regional or national objectives.
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Recommendation 3: Enhance Scoping of Local-Scale Air Toxics Monitoring Efforts
and Communication about These Activities to Improve Alignment with National,
Regional, State, Local, and Tribal Objectives.
Further scoping and preparation for local-scale air toxics monitoring efforts could help
SLTs in EPA Region 9 focus their activities to better reflect national, regional, state, local,
and tribal objectives. For example, SLTs could further scope their local-scale monitoring
efforts by clearly identifying the extent of monitoring that will be conducted, the objectives
of the monitoring effort, the anticipated impacts of the monitoring on the local community,
and how that community will be involved in the monitoring process and any mitigation
efforts that may result from the monitoring. It may also be important for SLTs to more
clearly articulate the links between the monitoring effort and actual air toxics reductions.
For example, SLTs could identify key stakeholders—such as regulators and source
representatives—as part of their scoping efforts and describe the ways in which these
parties could contribute to air toxics mitigation efforts if monitoring shows evidence of
significant levels of toxics emissions. SLTs could also more clearly articulate the levels of
risk at which mitigation or other actions are needed, as well as the levels at which
monitoring will conclude. In some cases the regulators or stakeholders may be the federal
government, and engaging the appropriate federal Branch and Division early in the scoping
process may help align expectations and maximize mitigation opportunities. To better
involve local sources and encourage voluntary mitigation efforts, SLTs could also consider
broader incorporation of source attribution studies (e.g., through the use of local emissions
inventories and receptor modeling) as part of their local-scale monitoring efforts.
Enhancements to EPA's current community-scale air toxics monitoring grant program
could further focus SLT air toxics monitoring efforts on identified air toxics monitoring
objectives. For example, new applicants during a given grant cycle could be encouraged
to focus on particular themes that tie directly to current national objectives for problem
identification, trends analysis, and science support, while giving equal weight to the review
of applications that aim to complete activities outside the selected themes. Potential
themes could be developed around specific source types or monitoring and methods
development for specific air toxics. These themes could include near-roadway effects,
goods movement, micro-scale chrome platers, diesel particulate matter, hexavalent
chromium, acrolein, and naturally-occurring asbestos. In addition, EPA could help SLTs
further scope their community-scale monitoring efforts by more clearly articulating
national objectives for community-scale monitoring activities and how these may differ
from objectives of other air toxics monitoring programs (e.g., the NATTS and PAMS
programs) in the grant program guidelines.
Further communication about local-scale monitoring activities could also enhance Region
9's ability to meet identified air toxics monitoring objectives. For example, regional SLTs
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and EPA Region 9 could collaborate to share the results of regional local-scale monitoring
projects through agency websites by posting documentation on study designs, objectives,
and results. Adding key word searches to these websites would also facilitate access to
information on past air toxics monitoring studies. In addition, SLTs could increase public
communication efforts at the conclusion of air toxics monitoring efforts to further enhance
the public's understanding of the results of the monitoring efforts and any mitigation
measures resulting from the monitoring. EPA could also enhance the distribution of EPA-
funded monitoring study results by providing communication links to other federal
agencies and offices concerned with air toxics, such as the Federal Highway Administration
and EPA Office of Transportation and Air Quality.
Additionally, EPA Region 9 and SLTs within the region could collaborate to enhance
SLTs' abilities to conduct future local-scale air toxics monitoring studies. For example,
these agencies could open a regional dialogue aimed at understanding funding options for
local-scale air toxics monitoring projects. Officials from these agencies could share ideas
for funding opportunities from all available sources—including federal, state, local, tribal,
and private options—and discuss best practices for securing funding for mid-term
community-scale monitoring projects. In addition, SLTs could optimize these discussions
by identifying potential collaborative projects that could distribute resource needs between
several agencies.
Recommendation 4: Collaborate to Identify Solutions to Common Data Quality and
Comparability Problems and Develop Tools to Enhance Data Usability.
EPA Region 9 and SLTs in the region could use the regional technical air toxics committee
to discuss the common data comparability issues documented in this report, including
methods, detection limits, QA/QC procedures, and other technical topics relevant to air
toxics of concern in the region (including those compounds currently outside the scope of
the NATTS program). For example, at the January 31, 2008 meeting EPA and SLT
officials from Region 9 expressed interest in discussing standard approaches for setting
MDLs for specific compounds, differences in AQS reporting procedures for agencies with
higher or lower MDLs, seasonal issues affecting data comparability, co-located data
reporting precision, needs for future round robin and through-the-probe audits, and
common series of data flags for AQS reporting. It may also be necessary for the
participants in these technical committee discussions to agree on a decision-making
framework to use during these meetings so that all parties follow the same process when
there are disagreements on methods development or other technical issues.
EPA and Region 9 SLTs could also open a broader dialogue on the differences in data
comparability needs at national, regional, and local levels. For example, EPA headquarters
representatives could join a Region 9 technical air toxics committee meeting to discuss
Evaluation of Air Toxics Monitoring in EPA Region 9
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national needs for data comparability and how these may differ from the needs of some
SLTs. This dialogue could help EPA and SLTs understand objectives and priorities at
varying levels and identify priority data comparability challenges to address. While data
quality issues are of great importance to both EPA and SLTs, EPA should remain sensitive
to the fact that data comparability across districts is generally a higher priority to EPA than
SLTs. The following three options for national data comparability were identified during
the January 31 meeting:
1. Find consensus from all agencies on a consistent set of national standards for air
toxics monitoring and implement these standards at all agencies;
2. Rely solely on NATTS data for establishing national trends; or
3. Conduct in-depth data analysis that assesses data quality and comparability of each
site prior to inclusion in trends analyses.
SLTs in EPA Region 9 expressed an interest in working towards uniform monitoring
methods but cannot currently commit to following national standards at non-NATTS sites;
therefore, option 1 should be considered a potential goal that cannot yet be implemented.
In the meantime, options 2 and 3 remain viable alternatives that have little direct impact on
SLTs. This dialogue between EPA and SLTs on data comparability could also provide an
opportunity to discuss methods requirements for major air toxics programs, such as
NATTS, PAMS, and PM speciation studies. Considering these programs together could
provide opportunities for resource savings.
In addition, EPA and Region 9 SLTs could discuss needs for an air toxics laboratory
certification program. At the January 31, 2008 meeting, SLT officials in EPA Region 9
suggested that all laboratories should meet EPA's National Environmental Laboratory
Accreditation Program standards, and expressed a desire to open a conversation with EPA
on extending this accreditation standard as a national air toxics grant requirement.
EPA could support Region 9's efforts to address common data comparability challenges by
continuing to support national air toxics data analysis and providing SLTs with tools to
assist in data comparability challenges. For example, EPA could consider the following
ideas:
¦ Enhance efforts to further analyze the national air toxics datasets and share this
information with SLTs (e.g., via teleconference or webcast). This analysis could be
conducted and documented in a method similar to the analysis conducted by EPA
contractors on the UATMP data.
¦ Develop and provide access to user-friendly tools that enable SLTs to benchmark
their air toxics monitoring data against annual averages from other SLTs. For
Evaluation of Air Toxics Monitoring in EPA Region 9
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example, provide training on AQS Discoverer specifically tailored for air toxics
staff or user-friendly spreadsheet tools.
¦ Expand the availability of online training resources.
¦ Assist SLTs with accessing NIST standards and/or develop a national stockpile of
these standards.
Recommendation 5: Explore Methods for Using Air Toxics Monitoring Data to
Evaluate Programs and Their Ability to Address Monitoring Objectives.
Data analysis and use could be highlighted during Region 9 technical air toxics committee
discussions. In particular, EPA and Region 9 SLTs could discuss how each agency
currently uses air toxics data, how they would like to use data in the future, how data is
being used by other SLTs across the nation, best practices for data analysis, common
QA/QC challenges associated with data analysis, best practices for benchmarking and
comparing datasets, and potential changes to current practices or mechanisms that could
facilitate further data analysis and use in the future. The SLTs in EPA Region 9 could use
these meetings to highlight analysis of compounds prevalent in the region, and could web
broadcast their discussions to assist other SLTs nationwide. In addition, regional SLTs
could work with EPA to identify important national data analysis efforts and provide web
broadcasts on these topics.
EPA could also support broader use of air toxics data on a national level by continuing to
explore approaches for using air toxics monitoring data to evaluate national air toxics
programs and their results, and to respond to the 2004 air toxics program PART
assessment. For example, EPA could enhance efforts to fully implement the Measure
Implementation Plan for using air toxics monitoring data to develop a risk-weighted
performance measure. EPA could also use the annual goal-setting and performance
measure process that is part of EPA's Annual Commitment System to support a more
collaborative process of tracking and communicating air toxics monitoring program
implementation. EPA's Air Toxics Monitoring Program Logic Model could be used to
inform the development of program implementation performance measures.
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Appendix A: Quality Assurance Plan
This appendix describes the Quality Assurance Plan that was developed for this air toxics
monitoring program evaluation prior to the start of the evaluation.
Quality Assurance Plan
Title: EPA Region 9 Air Toxics Monitoring Program Evaluation
Contractor: Ross & Associates Environmental Consulting, Ltd. (Ross & Associates),
subcontractor to Industrial Economics, Incorporated (lEc)
Plan Summary: EPA's National Center for Environmental Innovation (NCEI), located in
the Office of Policy, Economics, and Innovation (OPEI), promotes new ways to achieve
better environmental results. As part of its effort to encourage the effective use of
program evaluations throughout the Agency, NCEI's Evaluation Support Division (ESD)
has collaborated with the Office of Planning, Accountability and Analysis in EPA's Office
of the Chief Financial Officer (OCFO), to promote program evaluation through a Program
Evaluation Competition. This competition is part of an ongoing, long-term effort to help
build the capacity of EPA headquarters and regional offices to evaluate activities and to
improve measures of program performance. A project to evaluate the EPA Region 9 Air
Toxics Monitoring Program (R9 ATMP) was selected in the 2006 Program Evaluation
Competition.
Under this work assignment, Ross & Associates will assist EPA in evaluating the R9
ATMP. The objectives of this program evaluation are to (1) characterize air toxics
monitoring programs across EPA Region 9, including identifying State and local network
member objectives as well as those of EPA Region 9; (2) assess the network's design
and the extent to which it meets stated objectives; (3) distinguish ways in which EPA
Region 9's monitoring program contributes to the objectives of the national Air Toxics
Monitoring Program and areas for improvement; and (4) identify potential performance
metrics for evaluating air toxics monitoring programs at national and regional levels.
Ross & Associates collaborated with EPA OPEI, the EPA Office of Air Quality Planning
and Standards (OAQPS), and EPA Region 9 in designing this evaluation. Key points of
agreement include:
¦ Data Sources: Key data sources include: (1) the Air Quality System (AOS) and
California Air Resources Board (CARB) air quality information databases; (2)
interviews with officials from EPA OAQPS, EPA Region 9, and EPA Region 5; (3)
interviews with officials from the eleven State and local air toxics monitoring
programs EPA set within the scope of the evaluation22; and (4) publicly available
22 The eleven State and local air toxics monitoring programs EPA set within the scope of the evaluation are: Arizona
Department of Environmental Quality; Bay Area Air Quality Management District; California Air Resources Board; Clark
Evaluation of Air Toxics Monitoring in EPA Region 9
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information from the websites of the eleven programs set within the evaluation
scope and EPA Region 9.
¦ Design: Ross & Associates designed its data collection and analysis in the
context of the overarching evaluation questions and national Air Toxics
Monitoring Program logic model provided by EPA.
¦ Consistency: Ross & Associates collaborated with EPA to develop an
evaluation methodology document and interview guide for this project. Please
refer to these documents for further information on how Ross & Associates will
achieve consistency in data collection and analysis.
¦ Audience: Key audiences for the evaluation report include: EPA Region 9 Air
Division; EPA OAQPS; EPA Air Toxics Monitoring Advisory Committee; and
Region 9 State and local air toxics monitoring programs.
EPA Office: Office of Policy, Economics, and Innovation
EPA Project Leaders:
¦ Michelle Mandolia, OPEI
¦ Meredith Kurpius, Region 9
EPA Quality Manager: Michelle Mandolia, OPEI
County, Nevada; Hawaii State Department of Health; Joint Air Toxics Assessment Project; Nevada Division of
Environmental Protection; Placer County Air Permit Control District; San Diego County Air Pollution Control District;
South Coast Air Quality Management District; and Washoe County, Nevada.
Evaluation of Air Toxics Monitoring in EPA Region 9
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Appendix C: List of Evaluation Contributors
This appendix lists the EPA officials, SLT officials, and additional contributors who
provided input to this evaluation.
Name Affiliation
Leonard Montenegro
ADEQ ,
Marnie Greenbie
ADEC
Michael Sundblom
ADEQ
Randy Sedlacek
ADEQ
Sandra Wardwell
A
Steve Peplau
ADEQ
Eric Stevenson
BAAQMD
Jim Hesson
BAAQMD
Scott Lutz
BAAQMD
Karen Magliano
CARE
Ken Stroud
CARE
Lynn Baker
CARE
Mena Shah
CARE
Mike Poore
CARE
Dennis Mikel
EPA OAC
James Hemby
EPA OAC
Mike Jones
EPA OAC
Ted Palma
EPA OAC
Christina Kakoyannis
EPA OPE
Michelle Mandolia
EPA OPE
Carl Nash
EPA Region 5
Motria Caudill
EPA Region 5
John Brock
EPA Region 9
Matt Lakin
EPA Region 9
Meredith Kurpius
EPA Region 9
Mike Bandrowski
EPA Region 9
Sean Hogan
EPA Region 9
Wilfred Nagamine
Hawaii D(
Leroy Williams
JATAP
Mehrdad Khabiti
JATAP
Tom Christofk
Placer County AP
Yu-Shuo Chang
Placer County AP
Janet Cawyer
San Diego APCD
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Mike Kaszuba
San Diego APCD
Philip Fine
SCAQMD
Rudy Eden
SCAQMD
Mae Gustin
University of Nevada
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Appendix D: SLT Interview Questions
This appendix lists the interview questions which were distributed to the participating SLT
officials and referenced during interviews with these officials. Not all SLT officials were
asked all questions, but the question list served as a guide for the interviews.
1. Characterization of Air Toxics Monitoring Programs
a. Air Monitoring Program Objectives
i. What are the stated objectives of your agency's air toxics monitoring
program?
ii. If there are tribal lands within your State or local boundaries, are you familiar
with the Tribe(s) stated objectives for air toxics monitoring? If so, what are
they?
b. Air Toxics Monitoring Network and Information Collection
i. Please describe your agency's medium- to long-term air toxics monitoring
efforts (efforts which will last at least one year).
a. What are the purposes and/or objectives for these efforts?
b. What monitoring sites are associated with each of these efforts?
c. What approaches are used for each of these monitoring efforts?
a. Which air toxics are measured?
b. At what detection levels/thresholds are these air toxics
measured?
c. What methods/tools are used for sampling and analysis?
d. What is the frequency and duration of sampling?
e. What quality assurance processes are used?
ii. Please describe any short-term air toxics monitoring studies underway in your
jurisdiction (studies which will last less than one year).
iii. What are your future objectives for air toxics monitoring?
c. Data Management, Analysis, and Reporting
i. Please describe the information systems you use to store and manage air
toxics monitoring information.
ii. What is the process for making air toxics monitoring information available in
EPA's Air Quality System (AQS)?
iii. Does your agency make air toxics monitoring data and/or information
available to the public or others outside of the agency? If so, what
information to whom?
iv. What analyses, if any, are conducted using the air toxics monitoring data
collected?
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v. Does your agency prepare any reports based on air toxics monitoring data? If
so, what are the purpose, scope, format, frequency, and audience for these
reports?
vi. How could EPA assist or enhance your agency's air toxics data management,
analysis, and reporting activities?
d. Sources of Program Support
i. What non-EPA monetary and other contributions (e.g., lab equipment, staff
time) do your agency and/or monitoring site staff use for air quality
monitoring efforts?
2. Reflections on Air Toxics Monitoring Program Implementation
a. Program Objectives and Monitoring Design/ Implementation
i. Is the air toxics monitoring program in your agency's jurisdiction, as
currently designed and implemented, capable of meeting the stated program
objectives? If not, how could the program be modified to meet the stated
program objectives?
ii. What can you do with the data being generated and what are the data
limitations?
iii. Do you have a need to use data from other jurisdictions? What are the
limitations associated with this?
b. Assessing Risks and Health Effects
i. Does the monitoring program address priority source categories and priority
geographic locations (risk drivers)?
ii. What activities are underway in your agency's jurisdiction to improve
understanding of the human health risks associated with exposure to air
toxics? What outcomes have you seen from these activities?
iii. Are there any activities underway or planned to better understand the effects
of air toxics on ecological conditions using monitoring data?
c. Communication, Coordination, and Collaboration in EPA Region 9
i. Are there any efforts you are aware of to foster communication, coordination,
and/or collaboration related to air toxics monitoring between agencies in your
state or in EPA Region 9?
ii. What type of communication, coordination, and/or collaboration would you
like to see in the future?
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Appendix E: List of Documents and Websites
Referenced During Development of This Report
The following tables provide a list of the websites and additional documents referenced as
background materials during development of this evaluation report.
Table 6: EPA and SLT Websites
Arizona Department of
Environmental Quality
Air Quality Monitoring webpage:
http://www.azdeq.gov/environ/air/monitoring/index.html
Air Quality Annual Reports:
http://www.azdeq.gov/function/forms/reports.html
Bay Area Air Quality
Management District
Main webpage: http://www.baaqmd.gov/
Toxic Air Contaminant Control Program Annual Reports:
http://www.baaqmd.gov/pmt/air_toxics/annual_reports/index.htm
California Air Resources
Board
Air Toxics Program: http://www.arb.ca.gov/toxics/toxics.htm
ADAM database: http://www.arb.ca.gov/adam/welcome.html
Department of Pesticide Regulation: http://www.cdpr.ca.gov/
California Almanac of Emissions and Air Quality:
http://www.arb.ca.gov/aqd/almanac/almanac.htm
Environmental Protection
Agency
EPA Region 9 main webpage: http://www.epa.gov/region09/
EPA Technology Transfer Network Ambient Monitoring Technology
Information Center: http://www.epa.gov/ttn/amtic/
EPA Technology Transfer Network Air Toxics Website:
http://www. epa. gov/ttn/atw/
Office of Air and Radiation grants and funding webpage:
http://www.epa.g0v/air/grants/#cl0sed
Air Quality System website: http://www.epa.gov/ttn/airs/airsaqs/
Community-based Air Toxics Projects webpage:
http://yosemite.epa.gov/oar/CommunityAssessment.nsf/Community%
20Assessment%20List!OpenForm
AirData webpage: http://www.epa.gov/air/data/
AirExplorer webpage: http://www.epa.gov/airexplorer/
AirNOW webpage: http://airnow.gov/
AQS Discoverer webpage:
http://www.epa.gov/ttn/airs/airsaqs/aqsdiscover/
Urban Air Toxics Monitoring Program webpage:
http://www. epa. gov/ttn/amt ic/uatm. htm 1
PAMS program website: http://www.epa.gov/oar/oaqps/pams/
Hawaii Department of
Health
Main webpage: http://www.hawaii.gov/doh
Joint Air Toxics
Assessment Project
Main webpage: http://www4.nau.edu/jatap/
Nevada Division of
Environmental Protection
Main webpage: http://ndep.nv.gov/
Placer County Air Pollution
Control District
Roseville Rail Yard Air Quality Study:
http://www.placer.ca.gov/Departments/Air/railroad.aspx
San Diego Air Pollution
Control District
Air toxics webpage: http://www.sdapcd.org/toxics/air_toxics.html
South Coast Air Quality
Management District
Main webpage: http://www.aqmd.gov/
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Table 7: Additional Documents and Websites Referenced in Development of This Evaluation
Document
Website Location or Source
2001 EPA Pilot City Air Toxics
Measurement Summary
http://www.epa.gov/ttnamti1/files/ambient/airtox/toxics2
a.pdf
2002 EPA Air Toxics Research Stratejy
http://www. epa. gov/ord/htm/docum ents/Air_T oxics. pdf
2004 Air Toxics Component of the
National Monitoring Strategy
http://www.epa.gov/ttnamti1/files/ambient/airtox/atstrat8
04.pdf
2004 Analysis of Air Toxics Monitoring
Data Work Plan
http://www.ladco.org/toxics/reports/Work%20Plan%20fo
r%20toxics%20data%20analysis%20-%20WP2.pdf
2004 Measurement Implementation Plan
for the air toxics program
Provided by EPA
2004 Technical Assistance Document for
the National Ambient Air Toxics Trends
and Assessment Program
http://www.epa.gov/ttnamti1/files/ambient/airtox/toctad0
4.pdf
2005 Draft National Ambient Air
Monitoring Strategy
http://epa.gov/air/particlepollution/pdfs/naam strategy
20051222.pdf
2005 EPA Office of Inspector General
Evaluation Report
http://www.epa.gov/oig/reports/2005/20050302-2005-P-
00008.pdf
2005 Mercury Pollution in Northeast
Nevada Air report
http://www.theminingnews.org/pubs/ICLHginNVair.pdf
2006 United States Government
Accountability Office air toxics program
report
http://www.gao.gov/new.items/d06669.pdf
2006-2011 EPA Strategic Plan
http://www.epa.gov/ocfo/plan/2006/entire_report.pdf
2007 Inventory of Measures, Indicators,
and Data for Air Toxics
Provided by EPA
April 2007 State of Nevada news release
http://ndep.nv.gov/pio/file/05-
2006_mercury_research.pdf
California Office of Environmental Health
Hazard Assessment Environmental
Indicators for California
http://www.oehha.org/multimedia/epic/
December 2007 National Air Toxics
Trends Stations Work Plan Template
Provided by EPA
Logic model for EPA's Air Toxics
Monitoring Program
Provided by EPA
Mercury Deposition Network
http://nadp.sws.uiuc.edu/mdn/
Office of Management and Budget
Program Assessment and Rating Tool air
toxics report
http://www.whitehouse.gOv/omb/expectmore/summary/1
0000226.2004.html
Evaluation of Air Toxics Monitoring in EPA Region 9
64
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Appendix F: Federal Hazardous Air Pollutants
This appendix lists the federal HAPs. This list was compiled by accessing the original list
of federal HAPs and removing the three compounds (methyl ethyl ketone, caprolactam, and
hydrogen sulfide) which EPA de-listed following publication of the list in 1990. The list of
original HAPs and modifications to this list was accessed through the EPA website23 on
November 20, 2007.
Acetaldehyde
Hydrazine
Acetamide
Hydrochloric acid
Acetonitrile
Hydrogen fluoride (Hydrofluoric acid)
Acetophenone
Hydroquinone
2-Acetylaminofluorene
Isophorone
Acrolein
Lindane (all isomers)
Aery lam ide
Maleic anhydride
Acrylic acid
Methanol
Acrylonitrile
Methoxychlor
Allyl chloride
Methyl bromide (Bromomethane)
4-Aminobiphenyl
Methyl chloride (Chloromethane)
Aniline
Methyl chloroform (1,1,1-Trichloroethane)
o-Anisidine
Methyl hydrazine
Asbestos
Methyl iodide (lodomethane)
Benzene (including benzene from gasoline)
Methyl isobutyl ketone (Hexone)
Benzidine
Methyl isocyanate
Benzotrichloride
Methyl methacrylate
Benzyl chloride
Methyl tert butyl ether
Biphenyl
4,4-Methylene bis(2-chloroaniline)
Bis(2-ethylhexyl)phthalate (DEHP
Methylene chloride (Dichloromethane)
Bis(chloromethyl)ether
Methylene diphenyl diisocyanate (MDI)
Bromoform
4,4-i-Methylenedianiline
1,3-Butadiene
Naphthalene
Calcium cyanamide
Nitrobenzene
Captan
4-Nitrobiphenyl
Carbaryl
4-Nitrophenol
Carbon disulfide
2-Nitropropane
Carbon tetrachloride
N-Nitroso-N-m ethyl urea
Carbonyl sulfide
N-Nitrosodimethylamine
23 http://www. epa. gov/ttn/atw/pollsour.html
Evaluation of Air Toxics Monitoring in EPA Region 9
65
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Catechol
N-Nitrosomorpholine
Chloramben
Parathion
Chlordane
Pentachloronitrobenzene (Quintobenzene)
Chlorine
Pentachlorophenol
Chloroacetic acid
Phenol
2-Chloroacetophenone
p-Phenylenediamine
Chlorobenzene
Phosgene
Chlorobenzilate
Phosphine
Chloroform
Phosphorus
Chloromethyl methyl ether
Phthalic anhydride
Chloroprene
Polychlorinated biphenyls (Aroclors)
Cresols/Cresylic acid (isomers and mixture)
1,3-Propane sultone
o-Cresol
beta-Propiolactone
m-Cresol
Propionaldehyde
p-Cresol
Propoxur(Baygon)
Cumene
Propylene dichloride (1,2-Dichloropropane)
2,4-D, salts and esters
Propylene oxide
DDE
1,2-Propylenimine (2-Methyl aziridine)
Diazomethane
Quinoline
Dibenzofurans
Quinone
1,2-Dibromo-3-chloropropane
Styrene
Dibutylphthalate
Styrene oxide
1,4-Dichlorobenzene(p)
2,3,7,8-Tetrachlorodibenzo-p-dioxin
3,3-Dichlorobenzidene
1,1,2,2-Tetrachloroethane
Dichloroethyl ether (Bis(2-chloroethyl)ether)
Tetrachloroethylene (Perchloroethylene)
1,3-Dichloropropene
Titanium tetrachloride
Dichlorvos
Toluene
Diethanolamine
2,4-Toluene diamine
N,N-Diethyl aniline (N,N-Dimethylaniline)
2,4-Toluene diisocyanate
Diethyl sulfate
o-Toluidine
3,3-Dimethoxybenzidine
Toxaphene (chlorinated camphene)
Dimethyl aminoazobenzene
1,2,4-T richlorobenzene
3,3'-Dimethyl benzidine
1,1,2-Trichloroethane
Dimethyl carbamoyl chloride
Trichloroethylene
Dimethyl formamide
2,4,5-T richlorophenol
1,1-Dimethyl hydrazine
2,4,6-T richlorophenol
Dimethyl phthalate
Triethylamine
Dimethyl sulfate
Trifluralin
4,6-Dinitro-o-cresol, and salts
2,2,4-T rimethylpentane
2,4-Dinitrophenol
Vinyl acetate
Evaluation of Air Toxics Monitoring in EPA Region 9
66
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2,4-Dinitrotoluene
Vinyl bromide
1,4-Dioxane (1,4-Diethyleneoxide)
Vinyl chloride
1,2-Diphenylhydrazine
Vinylidene chloride (1,1 -Dichloroethylene)
Epichlorohydrin (l-Chloro-2,3-epoxypropane)
Xylenes (isomers and mixture)
1,2-Epoxybutane
o-Xylenes
Ethyl acrylate
m-Xylenes
Ethyl benzene
p-Xylenes
Ethyl carbamate (Urethane)
Antimony Compounds
Ethyl chloride (Chloroethane)
Arsenic Compounds (inorganic including arsine)
Ethylene dibromide (Dibromoethane)
Beryllium Compounds
Ethylene dichloride (1,2-Dichloroethane)
Cadmium Compounds
Ethylene glycol
Chromium Compounds
Ethylene imine (Aziridine)
Cobalt Compounds
Ethylene oxide
Coke Oven Emissions
Ethylene thiourea
Cyanide Compounds
Ethylidene dichloride (1,1 -Dichloroethane)
Glycol ethers
Formaldehyde
Lead Compounds
Heptachlor
Manganese Compounds
Hexachlorobenzene
Mercury Compounds
Hexachlorobutadiene
Fine mineral fibers
Hexachlorocyclopentadiene
Nickel Compounds
Hexachloroethane
Polycylic Organic Matter
Hexamethylene-1,6-diisocyanate
Radionuclides (including radon)
Hexamethylphosphoramide
Selenium Compounds
Hexane
Evaluation of Air Toxics Monitoring in EPA Region 9
67
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Appendix G: National Air Toxics Trends Stations
Compounds
This appendix lists the air toxics compounds currently measured through the NATTS
program. This list was drawn from the December 3, 2007 version of the NATTS Work
Plan Template.
1,2- dichloropropane
dichloromethane
1,3- butadiene
formaldehyde
acetaldehyde
hexavalent chromium (TSP)
acrolein
lead
arsenic compounds (PM10)
manganese compounds (PM10)
benzene
napthalene
benzo(a)pyrene
nickel compounds (PM10)
beryllium
perchloroethylene (tetrachloroethylene)
cadmium compounds (PM10)
trichloroethylene
carbon tetrachloride
vinyl chloride
chloroform
Evaluation of Air Toxics Monitoring in EPA Region 9
68
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Appendix H: Photochemical Assessment Monitoring
Stations Compounds
This appendix lists the hydrocarbons and carbonyls currently included on the list of
PAMS program compounds. This list was drawn from the PAMS program website24
on January 21, 2008.
Table 8: Hydrocarbons Monitored Through the PAMS Program
Ethylene
2-methylpentane
n-Octane
Acetylene
3-Methylpentane
Ethylbenzene
Ethane
2-Methyl-1 -Pentene
m&p-Xylenes
Propylene
n-hexane
Styrene
Propane
Methylcyclopentane
o-Xylene
Isobutane
2,4-dimethylpentane
n-Nonane
1 -Butene
Benzene
Isopropylbenzene
n-Butane
Cyclohexane
n-Propylbenzene
t-2-Butene
2-methylhexane
m-Ethyltoluene
c-2-Butene
2,3-dimethylpentane
p-Ethyltoluene
Isopentane
3-methylhexane
1,3,5-T rimethylbenzene
1 -Pentene
2,2,4-trimethylpentane
o-Ethyltoluene
n-Pentane
n-Heptane
1,2,4-trimethylbenzene
Isoprene
Methylcyclohexane
n-Decane
t-2-pentene
2,3,4-trimethylpentane
1,2,3-trimethylbenzene
c-2-pentene
Toluene
m-Diethylbenzene
2,2-Dimethylbutane
2-methylheptane
p-Diethylbenzene
Cyclopentane
3-methylheptane
n-Undecane
2,3-dimethylbutane
Table 9: Carbonyls Monitored Through the PAMS Program
Formaldehyde
Acetone
Acetaldehyde
24 The PAMS program website is located at http://www.epa.gov/oar/oaqps/pams/.
Evaluation of Air Toxics Monitoring in EPA Region 9
69
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Appendix J: Air Toxics Monitored by State and Local
Agencies in EPA Region 9
This appendix lists the air toxics monitored in several of the trends networks and long-term
special studies referenced throughout this evaluation. These lists were collected during
interviews with state and local agency officials that took place during July-September
2007.
Bay Area Air Quality Management District
Table 10: Air Toxics Monitored through the BAAQMD Trends Network
1,1,2 Trichlorotrifluoroethane
Methyl chloroform
1,3-Butadiene
Methyl ethyl ketone
Acetone
Methyl tertiary-butyl ether
Benzene
Methylene chloride
Carbon tetrachloride
O-Xylene
Chloroform
Perchloroethylene
Ethylbenzene
Toluene
Ethylene dibromide
Trichloroethylene
Ethylene dichloride
T richlorofluoromethane
M/P Xylei
Vinyl chloride
California Air Resources Board
Table 11: Air Toxics Monitored through the CARB Trends Network
1,3-Butadiene
Coba
Perchloroethylene
Acetaldehyde
Copper
Phosphorus
Acetone
Ethyl Benzene
Potassium
Acetonitrile
Formaldehyde
Rubidium
Acrolein
Hexavalent Chromium
Selenium
Acrylonitrile
Iron
Silicon
Aluminum
Lead
Strontium
Antimony
Manganese
Styrene
Arsenic
Mercury
Sulfur
Barium
meta/para-Xylene
T
Benzene
Methyl Chloroform
Titanium
Bromine
Methyl Ethyl Ketone
Toluene
Evaluation of Air Toxics Monitoring in EPA Region 9
73
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Calcium
Methylene Chloride
Trichloroethylene
Carbon Disulfide
Molybdenum
Vanadium
Carbon Tetrachloride
Nickel
Zinc
Chlorine
ortho-Dichlorobenzene
Zirconium
Chloroform
ortho-Xylene
Chromium
para-Dichlorobenzene
Table 12: Pesticides Monitored by CARB
Acephate
Chloropicrin
Linuron
Oxydemeton-m ethyl
Acrolein
Chlorothalonil
Malathion
Paraquat
Alachlor
Chlorpyrifos
Mancozeb
Permethrin
Aldicarb
Cycloate
Metam-sodium/MITC
Phorate
Amitraz
D
Methamidophos
Propargite
Atrazine
Diazinon
Methidathion
Simazine
Azinphos-methyl
Dichloropropene
Methomyl
Sodium arsenite
Benomyl
Endosulfan
Methyl bromide
Sulfuryl fluoride
Bifenthrin
E
Methyl parathion
Ziram
Bromoxynil
Ethoprop
Molinate
Captan
Ethyl parathion
Monocrotophos
Carbofuran
Fenamiphos
NalO' I
Hawaii Department of Health
Table 13: Air Toxics Monitored at the Pearl City Site
1,2-Dichloropropane
Formaldehyde
1,3-Butadiene
Lead
Acetaldehyde
Methylene Chloride
Benzene
Manganese
Beryllium
Nickel
Cadmium
Tetrachloroethene
Carbon Tetrachloride
Trichloroethylene
Chloroform
Vinyl Chloride
Chromium
Evaluation of Air Toxics Monitoring in EPA Region 9
74
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San Diego Air Pollution Control District
Table 14: Pollutants Monitored at Community-scale Monitoring Sites
Acetaldehyde
1,4-Dichlorobenzene
Nickel
Acetone
1,1 -Dichloroethane
Selenium
Arsenic
1,2-Dichloroethane
Styrene
Benzene
1,1 -Dichloroethene
1,1,2,2-Tetrachloroethane
Beryllium
cis-1,2-Dichloroethene
Tetrachloroethene
Bromoform
trans-1,2-Dichloroethene
Toluene
Bromomethane
Dich lorodif I uorom ethane
1,2,4-T richlorobenzene
1,3-Butadiene
1,2-Dichloropropane
1,1,1-Trichloroethane
Cadmium
cis-1,3-Dichloropropene
1,1,2-Trichloroethane
Carbon Tetrachloride
trans-1,3-Dichloropropene
1,2,4-T rimethylbenzene
Chlorobenzene
Dichlorotetrafluoroethane
1,3,5-T rimethylbenzene
Chloroethane
Ethylbenzene
Trichloroethene
Chloroform
formaldehyde
T richlorofluoromethane
Chloromethane
Hexachlorobutadiene
T richlorotrifluoroethane
Chromium
Lead
Vinyl Chloride
Copper
Manganese
m-Xylene
1,2-Dibromoethane
Methylene Chloride
o-Xylene
1,2-Dichlorobenzene
Methyl Ethyl Ketone (2-Butanone)
p-Xylene
1,3-Dichlorobenzene
2-Methoxy-2-methylpropane
Table 15: Additional Pollutants that will be Monitored at Community-scale Monitoring
Sites Starting in 2008
Acrolein
Chlorine
Antimony
Acrylonitrile
Coba
Silicon
Hexavalent Chromium
Iron
Tin
Organic Carbon
Mercury
Titanium
Elemental Carbon
Potassium
Uranium
Aluminum
Molybdenum
Vanadium
Barium
Phosphorus
Yttrium
Bromine
Rubidium
Zinc
Calcium
Sulfur
Evaluation of Air Toxics Monitoring in EPA Region 9
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South Coast Air Quality Management District
Table 16: Pollutants Monitored during MATES II
1,3- butadiene
Dichlorobenzene (ortho- & para)
PAHs
Acetaldehyde
Dichloroethane [1,1]
Perchloroethylene
Acetone
Elemental carbon
Selenium
Arsenic
Ethyl benzene
Styrene
Benzene
Formaldehyde
Toluene
Carbon tetrachloride
Hexavalent chromium
Trichloroethylene
Chloroform
Lead
Vinyl chloride
Chloromethane
Methylene chloride
Xylene (m-, p-, o-)
Chromium (total)
Nickel
Zinc
Copper
Organic carbon
Table 17: Air Toxics Monitored during MATES III
1,3-Butadiene
Dichlorobenzene
Organic Carbon
Acetaldehyde
Dichloroethane
PAHs
Acetone
Elemental Carbon
Perchloroethylene
Arsenic
Ethylbenzene
P7
Benzene
Formaldehyde
PM2.5
Beryllium
Hexavalent Chromium
Styrene
Cadmium
Lead
Toluene
Carbon Tetrachloride
Manganese
Trichloroethylene
Chloroform
Methylene Chloride
Vinyl Chloride
Chloromethane
Naphthalene
Xylene
Copper
Nickel
Zinc
Evaluation of Air Toxics Monitoring in EPA Region 9
76
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Appendix K: Arizona Hazardous Air Pollutants
This appendix lists the compounds considered to be HAPs in Arizona. This list was
accessed from the ADEQ website26 on December 4, 2007.
Acetaldehyde
1,2-Dichloroethane
Nickel Acetate
Acetic Acid
1,1 -Dichloroethane
Nitric Acid
Acetone
1,2-Dichloroethane
Nitrobenzene
Acetonitrile
Dichloromethane
Nitrogen Oxide
Acetophenone
1,2-Dichloropropane
2-Nitropropane
Acrolein
2,4-Dichlorophenol
N-Nitrosodiethylamine
Aery lam ide
Dichlorosilane
N-Nitrosodimethylamine
Acrylic Acid
Dicofol
N-Nitrosopyrrolidine
Acrylonitrile
Dieldrin
N-Nitroso-di-nbutylamine
Aldrin
Diethylene Glycol Monobutyl
Ether Acetate
Octane
Aliphatic Naptha
Diethylene Glycol Monobutyl
Ether
Oxoheptyl Acetate
Allyl Alcohol
Diethylene Triamine
Oxohexyl Acetate
Aluminum Oxide
Diethyl Phthalate
Pentachlorobenzene
Ammonia
Diethyl Telluride
Pentachloronitrobenzene
Aniline
Dimethoate
Pentachlorophenol
Antimony
Dimethylnitrosoamine
Pentanal
Arsenic
Di-n-butyl Phthalate
Pentane
Arsenic Pentoxide
Di-n-Octyl Phthalate
2-Pentanone
Arsenic Trioxide
2,4-Dinitrophenol
Phenol
Arsine
2,4-Dinitrotoluene
p-Phenylenediamine
Azinphos
1,4-Dioxane
Phenylmercuric Acetate
Barium
Diphenylamine
Phosmet
Barium Oxide
1,2-Diphenylhydrazine
Phosphamidon
Barium Sulfate-td
N,N-Dipropyl-4-trifluro methyl-
2,6-Dinitroaniline
Phosphine
Barium Sulfate-rf
Dithane
Phosphoric Acid
Benzene
Endosulfan
Phosphorous Pentafluoride
Benzidine
Endrin
Phosphorous Pentadsulfide
Benz(a)anthracene
Epichlorohydrin
Phosphorous Pentoxide
Benzo(a)Pyrene
Ethanol
Polychlorinated Biphenyls
[PCBx]
26 http://www.azdeq.gov/eiiviroii/air/moiiitoriiig/haz.html
Evaluation of Air Toxics Monitoring in EPA Region 9
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Benzyl Chloride
2-Ethoxy Ethyl Acetate
Potassium Carbonate
Beryllium
Ethyl Acetate
Potassium Fluoride
Bis(2-chlorethyl) Ether
Ethylbenzene
Potassium Hydroxide
Bis(chloromethyl) Ether
Ethyl-3-Ethoxy Propionate
Propane-asphyxiant
Bis(2-ethylhexyl) Phthalate
Ethylene Glycol Dimethyl Ether
n-Propanol
Bismuth Oxide
Ethylene Glycol
Pronamide
Borates
Monopropyl Ether
Propionic Acid
Boron
Ethylene Oxide
n-Propyl Acetate
Boron Oxide
Ethyl Parathion
Propylene Gylcol Monomethyl
Ether
Boron Trichloride
Fiberglass
Propylene Oxide
Boron Trifluoride
Fluorine
Pyridine
Bromodchlorom ethane
Formaldehyde
Selenium
Bromoform
Formic Acid
Silane
Bromomethane
Glycerol
Silica-amorphous fumed
1,3-Butadiene
Glycol Monobutylether Acetate
Silver
n-Butanol
Heptachlor
Sodium Aluminofluoride
2-Butoxyethanol
Heptachlor Epoxide
Sodium Fluoride
1 -Butyl Acetate
2-Heptanone
Sodium Hydroxide
n-Butyric Acid
n-Heptane
Sodium Sulfate
Cadium
Hexchlorobenzene
Strychnine
Calcium Carbonate-td
Hexachlorobutadine
Styrene-includes dimers
Calcium Carbonate-rf
Hexchlororcyclohexane (all
isomers)
Sulfuric Acid
Calcium Fluoride
Hexachlorocyclopentadine
T
Calcium Oxide
Hexachloroethane
1,2,4,5-Tetrachlorobenzene
Captan
n-Hexane
2,3,7,8-Tetrachlorodibenzo-p-
Dioxin
Carbaryl
Hydrofluoric Acid
1,1,2,2-Tetrachloroethane
Carbon Black
Hydrogen Chloride
Tetrachloroethene
Carbon Disulfide
Hydrogen Cyanide
Tetraethyl Lead
Carbon Tetrachloride
Hydrogen Sulfide
Tetrafluoromethane
Carbonyl Fluoride
1 -Hydroxy-2-Propanone
Thallium
Carbonyl Sulfide
Iron Compounds-soluble
Thorium
Cellulose Nitrate-td
Iron Compounds -insoluble
Titanium Dioxide-td
Cellulose Nitrate-rf
Iron (II) Chloride
Titanium Dioxide-rd
Chlorine
Iron illl i Chloride
Toluene
Chlorobenzene
Iron ill. Illi Oxide
Toxaphene
2-Chloro-1,3-butadiene
Iron (III) Oxide
1,2,4-T richlorobenzene
Chlorodane
Isobutyl Acetate
1,1,1-Trichloroethane
Chloroform
Isobutyl Alcohol
1,1,2-Trichloroethane
Evaluation of Air Toxics Monitoring in EPA Region 9
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Chloromethane(Methyl
Chloride)
Isobutyl Isobutyrate
Trichloroethene
3-Chloropropene
Isopropanol
T richlorofluoromethane
Chlorothalonil
Isopropyl Acetate
2,4,5-T richlorophenol
Chromic Oxide
Magnesium Fluoride
2,4,6-T richlorophenol
Chromium
Magnesium Oxide-td
T richlorotrifluoroethane
Chromium VI
Magnesium Oxide-rf
Triethylenetetramine
Copper-Fume
Magnesium Silicate
1,2,4 Trimethylbenzene
Cresols
Manganese - metal, fume
1,3,5 Trimethylbenzene
Cuprous Chloride
Manganese Dioxide
2,2,4 Trimethyl-1,3-pentanediol
Isobutyrate
Cuprous Oxide
Malathion
Tungsten Trioxide
Cupric Chloride
Mercury
Uranium 238-soluble
Cupric Oxide
Methanol
Uranium 238-insoluble
Diacetone Alcohol
Methomyl
Vanadium
Dichloeodiphenyl-
trichloroethane (DDT)
Methoxychlor
Vinyl Chloride
DDD
1-Methoxy-2-Propanol Acetate
Xylenes-mixed isomers
DDE
Methyl n-Butyl Ketone
Xylene (meta)
Diazinon
3-Methylcholanthrene
Xylene (ortho)
Dibenzo(a,h)anthracene
Methyl Ethyl Ketone [2-
Butanone]
Xylene (para)
Diborane
4,4'-Methylene-bis-2-
chloroanaline
Zinc Chloride
Dibromochlorom ethane
Methylhydrazine
Zinc Oxide-fume
1,2-Dibromo-3-chloropropane
Methyl Parathion
Zinc Oxide-rd
1,2-Dibromoethane
a-Methylstyrene
Zinc Oxide-td
1,2-Dichlorobenzene
Methyldenum Trioxide
Zinc Stearate
1,4-Dichlorobenzene
Myclobutanil
Zirconium
1,4-Dichlorodifluoromethane
Napthalene
Zirconium Carbide
1,1 -Dichloroethane
Nickel-metal, fume
Zirconium Oxide
Evaluation of Air Toxics Monitoring in EPA Region 9
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Appendix L: California Toxic Air Contaminants
This appendix lists the compounds considered to be TACs in California. This list was
accessed from the CARB website27 on November 20, 2007.
Acetaldehyde
Fine mineral fibers
Acetamide
Formaldehyde
Acetonitrile
Glycol ethers
Acetophenone
Heptachlor
2-Acetylaminofluorene
Hexachlorobenzene
Acrolein
Hexachlorobutadiene
Aery lam ide
Hexachlorocyclopentadiene
Acrylic acid
Hexachloroethane
Acrylonitrile
Hexamethylene-1,6-diisocyanate
Allyl chloride
Hexamethylphosphoramide
4-Aminobiphenyl
Hexane
Aniline
Hydrazine
o-Anisidine
Hydrochloric acid
Antimony compounds
Hydrogen fluoride (Hydrofluoric acid)
Inorganic Arsenic and Arsenic compounds
(inorganic including arsine)
Hydroquinone
Asbestos [asbestiform varieties of serpentine
(chrysotile), riebeckite (crocidolite),
cummingtonite-grunerite (amosite), tremolite,
actinolite, and anthophyllite]
Isophorone
Benzene (including benzene from gasoline)
Inorganic Lead and Inorganic lead
compounds (includes elemental lead)
Benzidine
Lead and compounds (does not include elemental
lea> li
Benzotrichloride
Lindane
Benzyl chloride
Maleic anhydride
Beryllium Compounds
Manganese and compounds
Biphenyl
Mercury and compounds
Bis(chloromethyl)ether
Methanol
Bis(2-ethylhexyl)phthalate (DEHF
Methoxychlor
Bromoform
Methyl bromide (Bromomethane)
1,3-Butadiene
Methyl chloride (Chloromethane)
Cadmium and cadmium compounds (metallic
cadmium and cadmium compounds)
Methyl chloroform (1,1,1-Trichloroethane)
27 http://www.arb.ea.gov/toxics/quickref.htm
Evaluation of Air Toxics Monitoring in EPA Region 9
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Calcium cyanamide
Methyl ethyl ketone (2-Butanone)
Caprolactam
Methyl hydrazine
Captan
Methyl iodide (lodomethane)
Carbaryl
Methyl isobutyl ketone (Hexone)
Carbon disulfide
Methyl isocyanate
Carbon tetrachloride (Tetrachloromethane)
Methyl methacrylate
Carbonyl sulfide
Methyl tertiary butyl ether (MTBE
Catechol
4,4'-Methylene bis(2-chloroaniline)
Chloramben
Methylene chloride (Dichloromethane)
Chlordane
4,4-Methylenedianiline
Chlorinated dibenzo-p-dioxins and dibenzofurans
Methylene diphenyl diisocyanate (MDI)
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCD
Naphthalene
Chlorine
Nickel and compounds (metallic nickel &
inorganic nickel compounds)
Chloroacetic acid
Nitrobenzene
2-Chloroacetophenone
4-Nitrobiphenyl
Chlorobenzene
4-Nitrophenol
Chlorobenzilate
2-Nitropropane
Chloroform
N-Nitroso-N-m ethyl urea
Chloromethyl methyl ether
N-Nitrosodimethylamine
Chloroprene
N-Nitrosomorpholine
Chromium and Compounds
Parathion
Chromium VI (Hexavalent chromium)
Particulate emissions from diesel-fueled engines
Cobalt Compounds
Pentachloronitrobenzene (Quintozene)
Coke Oven Emissions
Pentachlorophenol
Cresols/Cresylic acid (isomers and mixture)
Perchloroethylene (Tetrachloroethylene)
m-Cresol
Phenol
o-Cresol
p-Phenylenediamine
p-Cresol
Phosgene
Cumene
Phosphine
Cyanide compounds
Phosphorus
2,4-D, salts and esters
Phthalic anhydride
DDE (p,p-Dichlorodiphenyldichloroethylene)
Polychlorinated biphenyls (PCBs)
Diazomethane
Polycyclic organic matter (POM)
Dibenzofuran
Benzo[a]pyrene
1,2-Dibromo-3-chloropropane (DBCP
1,3-Propane sultone
Dibutylphthalate
beta-Propiolactone
1,4-Dichlorobenzene (p-Dicholorobenzene)
Propionaldehyde
3,3'-Dichlorobenzidene
Propoxur (Baygon)
Dichloroethyl ether (Bis(2-chloroethyl) ether)
Propylene dichloride (1,2-Dichloropropane)
Evaluation of Air Toxics Monitoring in EPA Region 9
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1,3-Dichloropropene (Telone)
Propylene oxide
Dichlorvos (DDV
1,2-Propylenimine (2-Methyl aziridine)
Diethanolamine
Quinoline
N,N-Diethyl aniline (N,N-Dimethylaniline)
Quinone
Diethyl sulfate
Radionuclides (including radon)
3,3'-Dimethoxybenzidine
Selenium and compounds
4-Dimethyl aminoazobenzene
Styrene
3,3-Dimethyl benzidine (o-Tolidine)
Styrene oxide
Dimethyl carbamoyl chloride
1,1,2,2-Tetrachloroethane
Dimethyl formamide
Titanium tetrachloride
1,1-Dimethyl hydrazine
Toluene
Dimethyl phthalate
2,4-Toluene diamine (2,4-Diaminotoluene)
Dimethyl sulfate
Toluene-2,4- diisocyanate
4,6-Dinitro-o-cresol, and salts
o-Toluidine
2,4-Dinitrophenol
Toxaphene (Chlorinated camphene)
2,4-Dinitrotoluene
1,2,4-T richlorobenzene
1,4-Dioxane (1,4-Diethyleneoxide)
1,1,2-Trichloroethane
1,2-Diphenylhydrazine
Trichloroethylene
Epichlorohydrin (1 -Chloro-2,3-epoxypropane)
2,4,5-T richlorophenol
1,2-Epoxybutane
2,4,6-T richlorophenol
Ethyl acrylate
Triethylamine
Ethyl benzene
Trifluralin
Ethyl carbamate (Urethane)
2,2,4-T rimethylpentane
Ethyl chloride (Chloroethane)
Vinyl acetate
Ethylene dibromide (1,2-Dibromoethane)
Vinyl bromide
Ethylene dichloride (1,2-Dichloroethane)
Vinyl chloride
Ethylene glycol
Vinylidene chloride (1,1 -Dichloroethylene)
Ethylene imine (Aziridine)
Xylenes (isomers and mixture)
Ethylene oxide (1,2-Epoxyethane)
m-Xylene
Ethylene thiourea
o-Xylene
Ethylidene dichloride (1,1 -Dichloroethane)
p-Xylene
Evaluation of Air Toxics Monitoring in EPA Region 9
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Appendix M: Analysis of AQS Data for the Six Core
NATTS Pollutants
This appendix describes the distribution of the six core NATTS pollutants—acrolein, PMio
arsenic, benzene, 1, 3- butadiene, formaldehyde, and hexavalent chromium— across EPA
Region 9 in 2006, based on data accessed from the AQS database on November 23, 2007.
This appendix is not intended to provide a full analysis of the data, but rather, is intended
to provide a snapshot of the core NATTS pollutants data submitted by state and local
agencies in EPA Region 9. A description of the methodology used in preparing this
analysis is listed below.
Methodology for Preparing AQS Data Analysis
Step 1: Data Collection
¦ On November 23, 2007, we downloaded a 'raw data report' (AMP 350) from the
AQS database. This report included the following specifications:
o Geographic range: states of Arizona, California, Hawaii, and Nevada,
o Compounds: acrolein (43505), PMio arsenic (82103), benzene (45201), 1, 3-
butadiene (43218), formaldehyde (43502), and hexavalent chromium (12115).
o Timeframe: January 1, 2006 through December 31, 2006.
o Type of data: reported.
¦ In addition, on November 23, 2007, we downloaded an 'extract raw data report'
(AMP501) from the AQS database. This report included the following
specifications:
o Geographic range: states of Arizona, California, Hawaii, and Nevada,
o Compounds: acrolein (43505), PMio arsenic (82103), benzene (45201), 1, 3-
butadiene (43218), formaldehyde (43502), and hexavalent chromium (12115).
o Timeframe: January 1, 2006 through December 31, 2006.
Step 2: Analysis of Reported Mean Concentrations
¦ We prepared a table of the reported mean concentrations of each of the six
compounds for each monitor and the units these concentrations were reported in,
based on the AMP 350 report. Monitors were considered to belong to the agency
listed as the "support agency" in these reports, and all data from agencies not
participating in this evaluation was excluded from the analysis.
¦ We used three different methods for defining the yearly mean concentration of the
air toxics compounds at each monitoring site:
o For the majority of monitoring sites, the AMP 350 report provided a yearly
mean concentration of each compound. In these cases, we used that value in the
analysis.
Evaluation of Air Toxics Monitoring in EPA Region 9
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o For some monitoring sites, the AMP 350 report provided monthly mean
concentrations for each month the compound was monitored. In these cases, we
averaged the monthly means to estimate the yearly mean for the analysis,
o For most of the monitoring sites reporting hexavalent chromium data, the AMP
350 report provided quarterly mean concentrations of the compound. In these
cases, we averaged the quarterly means to estimate the yearly mean for the
analysis.
¦ We rounded all values to three decimal places.
¦ Using the table of mean concentrations, we prepared box and whisker charts
demonstrating the range of mean concentrations found across monitoring sites.
¦ Note that no state or local agency in EPA Region 9 reported PMio arsenic data in
2006, so the analysis which follows does not include this compound.
Step 3: Analysis of Data Completeness
¦ We prepared a table of the number of days in 2006 that non-null values were
reported for each compound at each monitor. We used two different methods to
define the number of non-null values reported:
o For the majority of monitors, the AMP 350 report provided the number of days
in 2006 that non-null values were reported. In these cases, we used that value
in the analysis.
o For some monitors, the AMP 350 report provided the number of times that non-
null values were reported each month. In these cases, we manually counted the
number of days that non-null values were reported.
¦ Using the table of the number of days in 2006 that non-null values were reported
for each compound at each site, we prepared bar charts comparing these data points.
Step 4: Analysis of Reported Methods and MDLs
¦ We prepared a table of the methods and associated MDLs reported for each
monitor.
o We used the method code identified for each monitor in the AMP 350 report to
determine the method followed at each site,
o We defined the reported MDL for each monitor in two different ways:
¦ For the majority of monitors, the AMP 350 report identified the MDL for
2006. In these cases, we used that value in the analysis.
¦ For those monitors where more than one MDL were reported in 2006, the
AMP 350 report did not list the MDLs. In these cases, we referenced the
AMP 501 report to identify the set of MDLs reported throughout the year.
¦ We used the December 3, 2007 version of the National Air Toxics Trends Stations
Work Plan Template to identify the EPA recommended MDLs for each compound,
and converted units using standard conversions provided by EPA.
¦ Using the methods and MDLs reported by state and local agencies and the EPA
recommended MDLs, we prepared tables comparing these data points.
Evaluation of Air Toxics Monitoring in EPA Region 9
84
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