Septembers, 1998
EPA-SAB-COUNCIL-ADV-98-003
Honorable Carol M. Browner
Administrator
U.S. Environmental Protection Agency
401 M Street, SW
Washington, DC 20460
RE: Advisory Council on Clean Air Compliance Analysis (COUNCIL) Advisory
on the Clean Air Act Amendments (CAAA) of 1990 Section 812
Prospective Study: Overview of Air Quality and Emissions Estimates
Modeling, Health and Ecological Valuation Issues Initial Studies.
Dear Ms. Browner:
Pursuant to requirements of the Clean Air Act Amendments (CAAA of 1990,
Section 812 (CAAA-1990, Pub. Law 101-549, November 15, 1990, 104 Stat. 2399), the
Advisory Council on Clean Air Compliance Analysis ("the Council") has reviewed
various issues and initial studies related to the Prospective Study of Benefits and
Costs of the 1990 Clean Air Act Amendments. The Council held a public meeting on
February 5-6, 1998. This followed public meetings of the Air Quality Models
Subcommittee (AQMS) of the Council on January 22-23, 1998 (which addressed both
air quality modeling and emissions issues) and Health and Ecological Effects
Subcommittee (HEES) of the Council on January 29-30, 1998. Following final approval
by the Council, the reports of these Subcommittees will also be transmitted to you.
The following charge questions were provided by the Agency staff, consistent
with the review responsibilities of the Council as defined in Section 812 of the CAAA90
and are as follows:
a) Are the input data used for each component of the analysis sufficiently
valid and reliable for the intended analytical purpose?
b) Are the models, and the methodologies they employ, used for each
component of the analysis sufficiently valid and reliable for the intended
analytical purpose?, and
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c) If the answers to either of the two questions above is negative, what
specific alternative assumptions, data or methodologies does the Council
recommend the Agency consider using for the first prospective analysis?
While the above charge defines the general scope of the advice requested from the
Council, specific questions and issues are also identified for individual analytical
components in the briefing slides and discussion papers provided to the Council for the
February 5 and 6, 1998 meeting.
The Council's answers to questions a) and b) above are generally in the
affirmative. Indeed, we wish to congratulate the Agency on doing an admirable job in
carrying out what is an inherently difficult task. To answer the issues raised in the
briefings of February 5 and 6, 1998, the Council provides advice on four important
issues concerning the development of the EPA's Prospective Study: 1) Scope and
Objectives of the Study; 2) Measurement of Costs; 3) Measurement and Valuation of
Ecological Benefits, and 4) Measurement and Valuation of Health and Welfare
Benefits. (See items 4-6, below).
We also wish to underscore in this letter several issues raised by the Council's
AQMS in their deliberations (these issues are addressed in detail in their forthcoming
report). Specifically, we urge that the Agency address the apparent inconsistency
between modeled and actual trends in particulate matter (both PM10 and PM2.5) which
may undermine the credibility of the Prospective Study. As noted in our letter of
September 9, 19971, modeled PM10 emissions in both the pre-CAAA and post-CAAA
scenarios are predicted to increase between 2000 and 2010. This is also true of
ambient concentrations. This predicted increase is in stark contrast to actual ambient
PM trends, which have shown a decline ranging from 33 to 17 percent between 1988
and 1994. Although the differences in PM10 concentrations between the pre-CAAA and
post-CAAA scenarios may be accurate, the PM levels do not appear to be correct, and
this inconsistency will likely undermine the credibility of the study. This issue is
especially important in view of the key role that PM plays in calculating the benefits of
the CAAA.
1. Scope and Objectives of the Study
1.1 Objectives of the Study
In terms of the scope and objectives of the study, the Council is in general
U.S. EPA/SAB/COUNCIL, Council/Air Quality Modeling Subcommittee (AQMS) Letter
Report in Review of CAAA90 Section 812 Prospective Study Emissions Modeling and
Associated Air Quality Modeling Issues, EPA-SAB-COUNCIL-LTR-97-012, September 9,
1997.
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agreement with the goals of the Prospective Study, as articulated by the Agency, but
wishes to elaborate upon them. The Agency correctly states that the study should
benefit future research and policy making, as well as providing a greater understanding
of the benefits and costs of the 1990 CAAA. The Council wishes to emphasize that the
analysis: a) should serve as an example of the best practice of benefit-cost analysis as
it is applied to evaluating environmental programs; and b) should yield, to the extent
practicable, insights into the efficiency of key provisions of the 1990 CAAA. Such
insights would serve to place future legislative efforts with respect to air pollution
control on a more sound economic footing, as well as providing benefits for focusing
future research and policy making.
1.2 Scope of the Study
In work to date, emphasis has been placed on estimating the benefits and costs
of all titles of the 1990 CAAA in the aggregate. In previous letters we have
recommended that analyses of benefits and costs be disaggregated whenever
possible, to provide a better guide to regulation. The Agency is now considering
options for disaggregating the Prospective analysis by title, or supplementing the
aggregate analysis by studying additional pollution controls beyond the 1990 CAAA.
Each approach has its merits. Disaggregating the benefits and costs of the 1990 CAAA
by title would suggest to the Agency which portions of the 1990 Amendments pass the
benefit-cost test and which do not. This could suggest areas in which further pollution
controls are warranted and areas in which they are not. For the purposes of informing
future legislation it would, however, be more useful to analyze additional controls
beyond the 1990 amendments.
The Council recommends that the following supplemental analyses be
undertaken, as resources permit: a) an additional 50% reduction in S02 emissions by
electric utilities beyond Title IV requirements, together with a further reduction in NOX
emissions; b) additional NOX and VOC controls on highways vehicles; and c) items a)
and b) combined.
1.3 Presentation of Results
In presenting the results of the study, the Council recommends that benefit and
cost figures be presented in as disaggregated a form as possible, even if resources do
not permit separate benefit-cost analyses of each title of the 1990 CAAA. Cost
estimates have been generated for each title of the amendments and should be
presented by title. Disaggregation of benefits by title is more difficult because of
nonlinearities in pollution creation. Nevertheless, the Council recommends that benefit
estimates be presented by pollutant (for example, premature mortality avoided due to
reductions in PM).
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1.4 Discussion of Choice of Regulatory Assumptions on Study Results
The choice of regulatory assumptions will have a significant impact on the
study's results. The Prospective Study, which was begun in 1993, of necessity ignores
the impact of the recent PM and ozone standards on the control (with-CAAA) and no-
control (without-CAAA) scenarios. The same is true of developments that may occur
before 2010 (the last year of the analysis), such as controls to reduce C02. The fact
that a program was not mandated by the 1990 CAAA does not imply that it would have
the same impact on with-CAAA and without-CAAA emissions, and no effect on
abatement costs. A program to reduce C02 emissions, for example, would alter the
costs of achieving provisions of the 1990 CAAA.
The Council believes that there should be a clear discussion of programs and
regulations that affect emissions of the criteria air pollutants but are not being
examined in the Prospective Study. These include the recent PM and ozone
standards, any programs to reduce greenhouse gas emissions, and the Forest
Service's prescribed burning program. It is perfectly defensible not to analyze such
programs, but some discussion is essential as to how the programs might alter the
conclusions of the Prospective Study.
2. Measurement of Costs
The measurement of costs is also a major issue. The Council is aware of the
tremendous difficulty involved in estimating the costs of complying with regulations to
be issued under the 1990 CAAA and wishes to commend the Agency on the excellent
job it has done in estimating direct costs. In general, the Council agrees with the
Agency's estimates of the direct costs of complying with the various titles of the 1990
CAAA. We note, however, that the estimate of the costs of Inspection and
Maintenance (IM) programs appear to be at some variance from estimates in the
literature. For instance, IM estimates do not appear to include the opportunity cost of
owner's time, which is a legitimate component of cost. We recommend a focus on
reconciliation of the costs of IM programs.
2.1 Presentation of Cost Estimates
In presenting cost estimates, we believe that it is important to discuss the degree
of uncertainty in the various cost estimates and, when possible, to show the sensitivity
of cost estimates to underlying assumptions. The credibility of the Prospective Study
will be greatly enhanced if the cost estimates, when presented to the public, are
accompanied by a discussion of the modeling options available and some rationale for
the options chosen. It is also important that the reader be given a sense of which are
the key assumptions; i.e., of the assumptions that, if changed, would generate the
largest change in the cost estimates. If possible, some sensitivity analysis should be
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presented showing how much costs change when assumptions change.
Regarding uncertainty in the cost estimates, we recognize that a formal
uncertainty analysis is likely to be impossible. Nevertheless, it would be desirable to
indicate qualitatively the degree of uncertainty in various categories of cost estimates;
i.e., which estimates are the most uncertain.
2.2 Direct versus Indirect Costs
In presenting the estimates of compliance costs, it is important to indicate that
what is estimated are the direct costs of compliance; that is, the costs of pollution
abatement to firms undertaking such abatement. A growing body of economic research
indicates that these costs may significantly understate the full economic costs of
pollution abatement. We believe that the indirect costs of pollution abatement merit
discussion in the text of the Prospective Study.
Recent research shows that, by raising production costs and output prices,
environmental regulations reduce the returns to factors of production such as labor and
capital. The reduction in factor returns (both in the regulated industry and in other
industries) introduces efficiency losses over and above the firm-level costs of
compliance. For example, if a fall in the real wage accompanies increased pollution
control costs, this will increase the dead weight loss associated with labor (i.e., income
taxes). These additional efficiency losses are larger the higher the pre-existing tax
rates on factors of production. Published studies on this subject indicate that when
these factor-market efficiency costs are taken into account, the overall economic costs
will be 25-75 percent higher than the firm-level compliance costs.
The Council believes that the Prospective Study should make clear the
distinction between compliance costs and overall economic costs, and that the overall
cost assessment should include reference to the potential range of additional costs
associated with regulation-induced factor market distortions.
3. Measurement and Valuation of Ecological Benefits
3.1 Scope of Ecological Benefits
The impacts of air pollution on the functioning of ecosystems involve complex
interactions that are difficult to measure and to value in dollar terms. In view of the
complexity of these relationships, and the difficulty in valuing them, the Agency has
focused on the impacts of air pollution on the commercial services flows generated by
ecosystems, such as timber, crops and fish. While the Council understands the need
to limit the categories of ecological benefits quantified during the first Prospective
Study, we hope that economists within the Agency will work with ecologists to better
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define and measure the broader ecosystem benefits of air pollution control.
We urge the Agency to develop a comprehensive framework for consideration of
ecological effects before making decisions about which effects to quantify and value.
Such a framework should be developed along the following lines:
a) For each major type of ecosystem, identify the major stressors originating
from air emissions subject to control under the CAAA90. Major types of
ecosystems considered might include: forests subject to commercial
harvest; other forest ecosystems; grasslands; managed agriculture;
freshwater aquatic systems; marine aquatic systems; and wetlands.
b) For each ecosystem type and stressor, identify the possible impacts of
such things as community structure, species richness, net primary
productivity, other major ecosystem functions, and the flows of ecosystem
services to people. This could provide a basis for identifying those
impacts that for which quantification might be possible.
c) Note that not all ecosystem changes are necessarily adverse. Consider
criteria for identifying adverse changes. The criterion that emerges from
economics focuses on changes that result in reductions in service flows to
people. Which of the stressors and changes identified above are likely to
lead to the largest reductions in valued service flows? The answers to
this question can be used to: 1) select service flows for valuation; and 2)
identify research priorities.
3.2 Validity of Existence Values for Ecosystems
The ability to better describe and quantify ecosystem improvements should help
economists measure the existence values people place on these improvements. The
Council acknowledges that people are willing to pay for ecological improvements based
solely on the knowledge that these improvements exist. The Council agrees that
existence values for ecological improvements are a legitimate source of benefits that
should be discussed in the text of the final report. We believe, however, that the state
of the art may not be sufficient to provide a comprehensive set of existence values.
However, there are some studies that measure existence values reasonably accurately.
3.3 Inappropriateness of Avoided Costs as a Method of Valuing Ecological
Benefits
Because of the difficulty in quantifying and valuing the benefits of reduced
environmental damage to ecosystems, it is sometimes suggested that an avoided cost
approach be used. To illustrate, one of the benefits of the 1990 CAAA is reduced
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nitrogen deposition in lakes. The avoided cost approach would look at the cost of other
methods of reducing nitrogen deposition (e.g., the cost of other regulations to reduce
nitrogen deposits), and value the reductions achieved by the C AAA using these costs.
The Council urges that the Agency refrain from using the avoided cost approach
to value reduced ecosystem damages. The main difficulty with the approach is that it
does not value the damages themselves, but measures the cost of alternative ways of
reducing the damages. There are some circumstances under which the avoided cost
approach may legitimately capture environmental benefits but these requirements,
while easily established, are generally unmet (i.e., difficult to achieve).
The key requirement is that there be a direct link between the: a) the
implementation of the Federal environmental regulation; and b) the abandonment of a
(costly) environmental regulatory program by some other agency (e.g., a state-level
environmental authority), where this abandonment resulted because the Federal
regulatory effort made similar efforts at the local or state level redundant and
unnecessary. In this case the benefit from the Federal environmental program is the
avoided regulatory cost at the local or state level, plus the value of the net improvement
(if any) in environmental quality between a) the quality level that results after the
Federal regulatory effort and b) the quality level that would have resulted through
efforts at the state or local level. Note that if Federal environmental clean-up exactly
substitutes for clean-up that otherwise would have been brought about by state or local
agencies, then the benefit of the Federal program is simply the avoided state or local
regulatory cost, since in this case the Federal program leads to no net improvement in
the environment.
The Council believes that it is generally very difficult to establish the requirement
described above, and that in most cases it will be inadvisable to employ avoided costs
in connection with the assessment of benefits.
4. Measurement and Valuation of Health Outcomes
4.1 Measurement of Human Health and Welfare Benefits
The Council was also asked for advice on the measurement of health and
agricultural outcomes associated with air pollution, as well as for advice on appropriate
methods to value these outcomes. In almost all cases the Council agreed with the
Agency's suggestions regarding the appropriate method for measuring impacts and the
appropriate valuation techniques. Items that required further comment are discussed
below.
The Agency has suggested that measures of willingness-to-pay for
environmental improvements be adjusted upward to account for the expected increase
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in real income over the period 1990-2010. In principle, such adjustments should be
made provided there are reliable estimates of the income elasticities of willingness-to-
pay for the relevant endpoints. The Council is not confident that there is an adequate
empirical basis for estimating these income elasticities at the present time, but it is
willing to examine proposals from the Agency staff.
4.2 Valuation of Mortality Risk Reductions
The mortality risk reductions associated with reducing exposures to particulate
concentrations and their subsequent valuation were the driving forces behind the
Retrospective Study2 and can be expected to be similarly important for the Prospective
Study. Thus, the Council wishes to emphasize that an exemplary and comprehensive
treatment of these effects and their monetized benefits is of the utmost importance to
making the study credible.
The Council believes that the conceptually correct measure of the value of
reductions in mortality risk is what an individual would pay today for a shift in that
person's survival curve, which describes the chances that the individual will survive to
each future age. The shift in the survival curve captures precisely changes in a
person's life expectancy and the timing of these changes. Furthermore, the shift in the
survival curve is the way in which a change in air pollution affects mortality in the Pope
et al (1995)3 study, which forms the basis for measuring the physical impacts of a
change in air pollution on premature mortality.
The Council acknowledges, however, that no reliable empirical estimates exist of
the value of shifts in survival curves. We therefore recommend, for the purposes of
completing the Prospective Study, that the same approach to valuing mortality risk
reductions be used as was employed in the Retrospective Study. Statistical lives
saved should be valued using the same Value of a Statistical Life (VSL) as in the
Retrospective Study, and the value of the corresponding life-years saved should also
be presented.
The Council urges, however, that the Agency review the studies as well as the
alternative methods of valuing changes in mortality risks and discuss these in an
U.S. EPA, "77)e Benefits and Costs of the Clean Air Act, 1970 to 1990, "Prepared for U.S.
Congress by U.S. Environmental Protection Agency, Office of Air and Radiation, October
1997.
Pope, C.A. Ill; Thun, M.J.Namboodiri, M.; Dockery, D.W.; Evans, J.S.; Speizer, F.E., and
Heath, C.W., Jr. Particulate Air Pollution is a Predictor of Mortality in a Prospective Study
of U.S. Adults. Am. J. Respir. Care Med., Vol. 151, March 1995, pp.669-674.
8
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Appendix to the Prospective Study. Specifically, the Council recommends that
alternative measures of mortality risk reductions, including VSL, be discussed and
compared to one-another for their appropriateness in capturing the types of effects
estimated in the Pope eŁa/.(1995)3 study. These measures would include changes in
life expectancy, changes in risk of dying, changes in life-days per person (or life-years
in the aggregate) and changes in statistical lives lost (both age-adjusted and age-
unadjusted).
5. Valuation of Morbidity Outcomes
5.1 Adjustment of Cost-of-lllness Estimates
Agency Staff discussed the possibility of adjusting cost-of-illness estimates of
the benefits of reduced morbidity to account for the fact that the cost-of-illness under-
estimates total willingness-to-pay to avoid the effect. They concluded that there is not
a sufficient empirical basis for making these adjustments at this time. The Council
agrees with this conclusion, but suggests that the report include some illustrative
calculations to show the sensitivity of total benefits to the range of possible adjustments
to cost-of-illness estimates.
5.2 Health Benefits of Reducing Stratospheric Ozone Depletion
To estimate the health benefits of reducing stratospheric ozone depletion, the
Agency is proposing to base its analysis of the benefits of Title VI on the Regulatory
Impact Analysis (RIA) prepared in 1992 for compliance with Section 604. The Council
was not briefed on the methods used in the RIA. But, it appears that the benefits of
reducing ultraviolet (UV) radiation were calculated by estimating the reductions in the
incidence of melanomas that would result. This assumes that people have not altered
their behavior in response to the increase in UV radiation by, for example, spending
less time in the sun, wearing protective clothing, or using sunscreen. Such behavioral
changes are referred to as averting behavior. The Agency needs to address the issue
of averting behavior and its impact on estimated benefits associated with Title VI.
Further, if UV-B effects are discussed for stratospheric ozone, they should also be
discussed in terms of substitution risks associated with reduced ambient ozone
concentrations.
The report should also include at least a qualitative discussion of the benefits to
aquatic and terrestrial ecosystems that might be expected with a decrease in UV
radiation.
6. Valuation of Materials Damage
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The Council questions the continued use of the valuation function for household
soiling taken from the New York State Externality Cost Study to value materials
damage. That function is based primarily on data from two household surveys
conducted in 1970 and 1972-3 and on the observed relationship between cleaning
expenditures/activities and Total Suspended Particulate (TSP) levels. We believe that
the use of these data for the Retrospective Study was defensible, but we question
whether values derived for TSP using 25-year-old behavioral data can be applied to
value changes in PM10and PM25 over the time period 1990-2010.
7. Concluding Remarks
We believe that, overall, the Agency is doing an admirable job of answering what
are inherently difficult questions: what are the human health and ecological damages
avoided by the 1990 CAAA? ... and ... what is the dollar value of these damages? The
effort required to generate credible benefit and cost estimates is enormous, and the
Agency is to be congratulated on its accomplishments. We believe that, subject to the
above caveats, the Agency has made appropriate choices regarding the models used
for each component of the analysis and has chosen appropriate data for use in these
models. We must however, note our particularly strong concerns over the modeled PM
emission trends. We suggest that the AQMS provide a consultation on new PM
emission projections as soon as they become available. Also, we urge the Agency's
economists to confer with ecologists to better define and measure the broader
ecosystem benefits of air pollution control, and to develop a comprehensive framework
for consideration of ecological effects before making decisions about which effects to
quantify and value. Such a framework should be developed along the lines outlined
above.
We thank the Agency for the opportunity to be of service in review of the various
building blocks which will lead to the Prospective Study: Report to Congress, and look
forward to continuing productive dialogue on this important topic to the nation.
Sincerely,
Dr. Maureen L. Cropper, Chair
Advisory Council on Clean Air Compliance
Analysis
10
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U. S. ENVIRONMENTAL PROTECTION AGENCY
SCIENCE ADVISORY BOARD (SAB)
ADVISORY COUNCIL ON CLEAN AIR COMPLIANCE ANALYSIS
(THE COUNCIL)
CHAIR:
Dr. Maureen L. Cropper, Principal Economist, The World Bank, Washington, DC
MEMBERS:
Dr. Ronald G. Cummings, Professor of Economics and Noah Langdale, Jr. Professor of
Environmental Policy, Policy Research Center, Georgia State University, Atlanta, GA
Dr. A. Myrick Freeman, Professor, Department of Economics, Bowdoin College, Brunswick,
ME (Also Vice-Chair of the Health and Ecological Effects Subcommittee, HEES of the
Council)
Dr. Lawrence H. Goulder, Associate Professor, Department of Economics & Institute for
International Studies, Stanford University, Stanford, CA
Dr. Jane V. Hall, Professor of Economics, Department of Economics and Institute for
Economic and Environmental Studies, California State University, Fullerton, CA
Dr. Paul Lioy, Deputy Director-EOSHI & Director Exposure Measurement & Assessment
Division, Environmental & Occupational Health Sciences Institute, Robert Wood Johnson
School of Medicine, Piscataway, NJ (Also Chair of the Health and Ecological Effects
Subcommittee, HEES of the Council)
Dr. Paulette Middleton, Deputy Director, RAND Center for Environmental Sciences & Policy,
Boulder, CO (Also Chair of the Air Quality Models Subcommittee, AQMS of the Council)
Dr. Richard Schmalensee, Deputy Dean, Sloan School of Management, Massachusetts
Institute of Technology, Cambridge, MA
Dr. Thomas H. Tietenberg, Professor, Dept. of Economics, Colby College, Waterville, ME
CONSULTANTS:
Dr. Alan J. Krupnick, Senior Fellow, Resources for the Future, Washington, DC
SAB COMMITTEE LIAISON:
Dr. William H. Smith, Professor of Forest Biology, School of Forestry & Environmental
Studies, Yale University, New Haven, CT (Liaison from the Environmental Processes and
Effects Committee)
SCIENCE ADVISORY BOARD STAFF:
Dr. K. Jack Kooyoomjian, Designated Federal Officer, Science Advisory Board (1400), U.S.
Environmental Protection Agency, Washington, DC 20460
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Mrs. Diana L. Pozun, Management Assistant, Science Advisory Board (1400), U.S.
Environmental Protection Agency, Washington, DC 20460
NOTICE
This report has been written as part of the activities of the Science Advisory
Board, a public advisory group providing extramural scientific information and advice to
the Administrator and other officials of the Environmental Protection Agency. The
Board is structured to provide a balanced, expert assessment of scientific matters
related to problems facing the Agency. This commentary has not been reviewed for
approval by the Agency and, hence, the contents of this report do not necessarily
represent the views and policies of the Environmental Protection Agency, nor of other
agencies in the Executive Branch of the federal government, nor does mention of trade
names or commercial products constitute endorsement or recommendation for use.
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GLOSSARY OF TERMS AND ACRONYMS
ADV
AQMS
CAA
CAAA
CAAA90
C02
EPA
HEES
IM
LTR
NOX
PM
PM2.5
PM10
Pub.
ORD
RIA
SAB
S02
Stat.
TSP
U.S.
UV
UV-B
VOC
VSL
Advisory
Air Quality Models Subcommittee (of the Council)
Clean Air Act
Clean Air Act Amendments
Clean Air Act Amendments of 1990
Carbon Dioxide
U.S. Environmental Protection Agency (U.S. EPA)
Health and Ecological Effects Subcommittee (U.S. EPA/SAB/
Council)
inspection and Maintenance
Letter Report
Oxides of Mtrogen
Particulate Matter
Particulate Matter (2.5 microns in diameter)
Particulate Matter (10 microns in diameter)
Public
Office of Research and Development (U.S. EPA/ORD)
Regulatory impact Analysis
Science Advisory Board (U.S. SAB/EPA)
Sulfur Dioxide
Statute
Total Suspended Particulate
LJnited States
ytra Violet (radiation)
ytra Violet - Beta (radiation)
Volatile Organic Compounds
Value of a Statistical Life
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DISTRIBUTION LIST
Deputy Administrator
Assistant Administrators
EPA Regional Administrators
EPA Laboratory Directors
Office of the Administrator:
Office of Cooperative Environmental Management
Deputy Assistant Administrator for Air and Radiation:
Director, Office of Policy Analysis and Review (OPAR)
Director, Office of Air Quality Planning and Standards (OAQPS)
Deputy Assistant Administrator for Policy, Planning and Evaluation (OPPE):
Director, Office of Economy and Environment (OEE)
Director, Office of Policy Analysis (OPA)
Director, Office of Regulatory Management and Evaluation (ORME)
Director, Office of Strategic Planning and Environmental Data (OPED)
Deputy Assistant Administrator for Research and Development
EPA Headquarters Libraries
EPA Regional Libraries
National Technical Information Service (NTIS)
Library of Congress
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