# Air Quality Standards: The Decisionmaking Process

> Briefs, arguments, decisions, and more.

URL: https://www.frixlaw.com/law-library/documents/crs%3A97-722

## Record

- **Collection:** Congressional research report
- **Document type:** CRS Report
- **Published:** April 9, 2002
- **Citation:** 97-722

## Text

Air Quality Standards:
The Decisionmaking Process
(name redacted)
Specialist in Environmental Policy
(name redacted)
Specialist in Energy and Environmental Policy
April 9, 2002

Congressional Research Service
7-....
www.crs.gov
97-722

CRS Report for Congress
Prepared for Members and Committees of Congress

Air Quality Standards: The Decisionmaking Process

Summary
The decisions by the Administrator of the Environmental Protection Agency (EPA) in July 1997
to revise ambient air quality standards (NAAQS) for ozone and particulate matter refocused
attention on the criteria and the process by which these decisions are made. The new standards
were the subject of numerous oversight hearings as well as litigation, which culminated in a
Supreme Court ruling February 27, 2001. The court upheld the NAAQS-setting procedures at
question, in particular definitively rejecting the consideration of costs in setting NAAQS.
However, the court’s ruling also raised questions concerning the implementation of the EPA’s new
ozone standard. With continuing controversy over the PM and ozone standards, along with other
concerns about the Clean Air Act (CAA), the expiration in 1998 of the authorizations for
appropriations in the statute, and the Bush Administration’s proposal for amendments, it is
possible that the Congress may take up amendments to the CAA. If so, the NAAQS
decisionmaking process may command attention, especially with respect to how scientific
evidence is used. Because of the role NAAQS might play in bringing amendments onto the
legislative agenda, this report provides background on the processes and procedures for setting
and revising NAAQS. The basic steps are as follows:
•

EPA identifies a pollutant that is emitted from numerous or diverse mobile or
stationary sources and that endangers public health or welfare.

•

EPA prepares a “criteria document” that summarizes the scientific information
relevant to the pollutant; this document is formally reviewed by a Clean Air
Scientific Advisory Committee (CASAC).

•

EPA prepares a “staff paper” that summarizes the criteria document and lays out
policy options for the Administrator; it is also reviewed by CASAC.

•

Based on the criteria document, the staff paper, and CASAC’s “closure letters,”
the Administrator proposes a NAAQS; this proposal is published in the Federal
Register, a “docket” created, and an opportunity for public review and comment
provided. And,

•

The Administrator’s final decision, “which, in the judgment of the Administrator, ... [is] requisite to protect the public health ... or public welfare.”

The CAA spells out requirements for the criteria document, the CASAC review, the basis on
which the Administrator chooses the standard, and the procedural process for promulgating the
standard. EPA administratively added the preparation of a “staff paper”; in addition, Executive
Order 12866 requires a Regulatory Impact Analysis (RIA), although the economic analysis is
essentially irrelevant to the decision a NAAQS. Other laws also raise regulatory assessment
issues. The Act requires EPA to revisit each NAAQS every 5 years, following the same process.
Several aspects in the NAAQS-setting process have been the foci of attention in the past and
might be revisited: these include the Act’s requirement that NAAQS be set to protect health with
an adequate margin of safety, without consideration of costs; the process for verifying the
scientific underpinnings of a proposed standard; the boundaries on the Administrator’s judgment
in accounting for risk and uncertainty in setting NAAQS; EPA’s responsiveness to public
comments; and the extent to which EPA must respond to requirements exogenous to the CAA that
direct EPA to consider impacts of its regulations.

Congressional Research Service

Air Quality Standards: The Decisionmaking Process

Contents
Introduction ................................................................................................................................1
Background ................................................................................................................................1
Criteria Air Pollutants .................................................................................................................2
National Ambient Air Quality Standards......................................................................................3
Primary Standards.................................................................................................................3
“Margin of Safety”..........................................................................................................4
Secondary Standards .............................................................................................................5
Setting NAAQS ..........................................................................................................................6
Setting and Reviewing NAAQS ............................................................................................6
Criteria Document...........................................................................................................6
Staff Paper ......................................................................................................................7
Clean Air Scientific Advisory Committee........................................................................8
The Administrator’s Decision................................................................................................9
The Evidence ................................................................................................................ 11
The Criteria................................................................................................................... 12
Promulgating NAAQS .............................................................................................................. 16
The Administrative Rulemaking Process ............................................................................. 17
Notice of Proposed Rulemaking .................................................................................... 17
Public Comment ........................................................................................................... 17
Promulgation of the Rule .............................................................................................. 18
Regulatory Impact Assessments .................................................................................... 18
Consultations—Office of Management and Budget; Other Departments and
Agencies .................................................................................................................... 22
Judicial Review................................................................................................................... 22
Congressional Review......................................................................................................... 23

Figures

Appendixes
Appendix A. The NAAQS-Setting Process ................................................................................ 24
Appendix B. Setting NAAQS—A Typical Chronology (Ozone) ................................................ 25

Contacts
Author Contact Information ...................................................................................................... 26

Congressional Research Service

Air Quality Standards: The Decisionmaking Process

Introduction
Decisions in July 1997 by the Administrator of the Environmental Protection Agency (EPA) to
revise the national ambient air quality standards (NAAQS) for ozone and particulate matter (PM)
refocused attention on the criteria and the process by which these decisions are made. The new
standards have been attacked both as overly stringent and as inadequately protective of health; as
ignoring costs and as giving costs too much deference; as going beyond what is scientifically
conclusive; and as failing to be sufficiently precautionary.1 These issues were the subject of
numerous oversight hearings as well as litigation, which culminated in a Supreme Court ruling
February 27, 2001. The court upheld those NAAQS setting procedures at question, in particular
definitively rejecting the consideration of costs in setting NAAQS.
However, the court’s ruling also raised questions concerning the implementation of the EPA’s new
ozone standard. With the court’s decision, continuing controversy over the PM and ozone
standards, along with other concerns about the Clean Air Act (CAA), the expiration in 1998 of the
authorizations for appropriations in the statute, and the Bush Administration’s air quality initiative
that would amend the Act,2 it is possible that the Congress may take up amendments to the CAA.
If so, the NAAQS decisionmaking process may command attention, especially with respect to
how scientific evidence is used – and possibly reopening the question of whether costs should be
considered in setting NAAQS.
Because of discrepancies in views on what transpired—or should have transpired—in EPA’s
development of the 1997 ozone and PM standards, this report provides background on the
processes and procedures for setting and revising NAAQS. It lays out the steps of the decision
process and identifies the statutory criteria established by the Act for NAAQS, to aid the reader’s
understanding of the Act’s policy for NAAQS. It does not evaluate the decisionmaking process
nor assess EPA’s decisions on the ozone and PM NAAQS; nor does it address the several other
categories of pollutants (e.g., hazardous air pollutants) or other standards-setting activities under
the Act.

Background
The process by which EPA sets and revises NAAQS evolved over many years. Initially, federal
air quality law focused on supporting state programs, through the conduct of research (a central,
federal research program was more efficient than 50 state research efforts) and through technical
and financial support (regulation was seen as a state and local matter). By the late 1960s, the
federal research effort, located in the National Center for Air Pollution Control, Public Health
Service, Department of Health, Education, and Welfare (HEW), included the preparation of
“criteria”—a summary of scientific knowledge concerning selected air pollutants—and
“guidelines”—a summary of control technologies. These criteria and guidelines were to support
state programs to control air pollution.

1

See CRS Report 97-8, Air Quality: EPA’s New Ozone and Particulate Matter Standards.
George W. Bush, The White House, “The Clear Skies Initiative,” Feb. 14, 2002. For current information on clean air
legislation, see James McCarthy, Clean Air Act Issues in the 107th Congress, CRS Issue Brief IB10065.
2

Congressional Research Service

1

Air Quality Standards: The Decisionmaking Process

As environmental awareness heightened in the late 1960s, the federal role enlarged. With the
Clean Air Act Amendments of 1970, the federal clean air program was moved to the newly
created EPA3 and reconstituted, with the federal government becoming responsible for
establishing “national ambient air quality standards” for air pollutants endangering public health
or welfare and resulting from numerous or diverse mobile or stationary sources. The states
remained primarily responsible for developing implementation plans to attain and maintain
compliance with those national standards. Major amendments in 1977 and 1990 refined the
NAAQS setting and implementation process. The 1977 amendments formally established the
Clean Air Scientific Advisory Committee (CASAC) and the 5-year review process. The 1990
amendments increased federal guidance to states in implementing existing NAAQS.
Thus the present process for setting and revising NAAQS consists of the statutory steps
incorporated in the CAA over a series of amendments. In addition, several other steps of varying
degrees of import have been added by the EPA, by executive orders, and by subsequent
regulatory reform enactments by the Congress. The steps are depicted in Appendix A; for an
example chronology of the steps, see Appendix B. The documentary language spelling out those
steps, along with explanatory notes, follows.
NOTE: CAA language is in bold; legislative history language, i.e., from
reports on amendments to the CAA, is in bold italics; language from
statutes other than the CAA is in italics.
Citations to ozone or PM standards setting refer to the
documentation for the 1997 ozone and PM NAAQS.

Criteria Air Pollutants
The pollutants for which NAAQS are set are often called “criteria pollutants.” This term reflects
the evolution of the process. Before there were NAAQS, the Air Quality Act of 1967 (a
predecessor of the CAA) required the Federal government to list air pollutants and to prepare
“criteria”—a report summarizing scientific evidence concerning their health effects. The states
then set standards. Thus the air pollutants for which NAAQS were later set were originally air
pollutants for which the Office of Air Quality in HEW prepared “criteria.” The current language
specifying the listing of “criteria” air pollutants, as modified by the 1970 and 1977 amendments
to the CAA, is as follows:
The Administrator shall ... publish, and shall from time to time thereafter revise, a list
which includes each air pollutant—(A) emissions of which, in his judgment, cause or
contribute to air pollution which may reasonably be anticipated to endanger public
health or welfare; [and] (B) the presence of which in the ambient air results from
numerous or diverse mobile or stationary sources .... [CAA §108(a)(1)]

With the Clean Air Act Amendments of 1970, the EPA became responsible for determining
national ambient air quality standards for the “criteria pollutants”—those of such national scope
in release or effect that national standards are appropriate. Also, EPA was to assist states in

3

EPA was created by Reorganization Plan No. 3 in 1970, reprinted as 42 U.S.C. §4321 note; the Agency went into
operation December 2 of that year.

Congressional Research Service

2

Air Quality Standards: The Decisionmaking Process

attaining these standards through grants and technical assistance,4 and could impose sanctions on
states for failures to fulfill their obligations. At present, six pollutants are designated “criteria
pollutants” for which NAAQS have been set: particulate matter5 (PM), ozone (O3, a key measure
of smog), nitrogen dioxide (NO2,, or, inclusively, nitrogen oxides, 6 NOx), sulfur oxides (SOx, or,
specifically, SO2), carbon monoxide (CO), and lead (Pb).

National Ambient Air Quality Standards
The Administrator ... shall publish ... regulations prescribing a national primary
ambient air quality standard and a national secondary ambient air quality standard for
each air pollutant for which air quality criteria have been issued .... [CAA
§109(a)(1)(A)]

A NAAQS is a uniform, national standard establishing the maximum permissible concentration of
an air pollutant in the ambient air—the “portion of the atmosphere, external to buildings, to which
the general public has access.”7 The CAA directs the Administrator to set a NAAQS at a level that
provides protection from adverse effects on the public health and welfare. The Act provides for
“primary standards” to protect health with a margin of safety and for “secondary standards” to
protect welfare.

Primary Standards
National primary ambient air quality standards ... shall be ambient air quality
standards the attainment and maintenance of which in the judgment of the
Administrator, based on such criteria and allowing an adequate margin of safety, are
requisite to protect the public health. [CAA §109(b)(1)]
An ambient air quality standard ... should be the maximum permissible ambient air level
of an air pollution agent or class of such agents (related to a period of time) which will
protect the health of any group of the population. [Senate Report No. 91-1196, p. 10]

As stated in §109, a NAAQS defines the acceptable concentration of an air pollutant in the
ambient air necessary to protect health. As discussed later, costs are not considered in setting
primary standards. Areas—defined as air quality control regions—complying with the standard
4

For example, in conjunction with setting NAAQS, the CAA requires EPA to prepare information on air pollution
control technologies:
Simultaneously with the issuance of criteria ..., the Administrator shall, after consultation
with appropriate advisory committees and Federal departments and agencies, issue to the
States and appropriate air pollution control agencies information on air pollution control
technologies, which information shall include data relating to the cost of installation and
operation, energy requirements, emission reduction benefits, and environmental impact of
the emission control technology. [CAA, §108(b)(1)]
The preparation of these “guidance documents,” as they are known, is not reviewed in this report.
5
The original PM NAAQS was for “Total Suspended Particulates”; the standard was later focused on particles smaller
than 10 microns (PM10) and in 1997 EPA proposed that a standard be added for particles smaller than 2.5 microns
(PM2.5).
6
The NAAQS is for NO2; nitrogen gases that are ozone precursors are referred to as NOx.
7
CFR §50.1(e). Air within workplaces is subject to regulation by the Occupational Health and Safety Administration.

Congressional Research Service

3

Air Quality Standards: The Decisionmaking Process

are designated “attainment areas” and areas in which the pollutant exceeds the standard are
designated “nonattainment areas.” An area can be in attainment for one air pollutant and out of
attainment for another.
Although a primary NAAQS has a federally enforceable deadline, a NAAQS does not itself
establish what to do when concentrations exceed the standard (nor how to protect clean air in
attainment areas). Other provisions of the CAA lay out the process of implementation
(specifically, §110). For nonattainment areas, this includes monitoring ambient air quality to
determine compliance; requiring states to prepare state implementation plans (SIPs) to bring areas
not in compliance into compliance; and requiring states to implement their plans to achieve and
maintain the NAAQS by a specified deadline (Title I, Part D of the Act). Federal measures to
protect air quality include new source performance standards (§111), which are national standards
on specified categories of new sources of selected air pollutants, and mobile source emission
standards (§202). Also, the federal government continues to prepare “guidance documents”
spelling out available control measures for the NAAQS pollutants. Finally, in attainment areas
where the air is cleaner than NAAQS, the CAA establishes a program for new source permitting
to “maintain” that clean air quality (Title I, Part C).

“Margin of Safety”
... [A]llowing an adequate margin of safety .... [CAA §109(b)(1)]
In setting such [national ambient air quality] standards the [Administrator] should
consider and incorporate not only the results of research summarized in air quality
criteria documents, but also the need for margins of safety. Margins of safety are essential
to any health-related environmental standards if a reasonable degree of protection is to be
provided against hazards which research has not yet identified. [Senate Committee on
Public Works, Report No. 91-1196 (1970), pp. 9-10]

The phrase, “margin of safety,” has been central to several debates.
The phrase seems to imply that NAAQS are based on thresholds—that there is a concentration of
a pollutant below which adverse health effects do not occur. In this view, the Administrator
determines the “no effect” threshold for the pollutant from the scientific evidence in the “criteria
document” and then adds a safety factor. From this perspective, the issue is how large the margin
of safety should be. In a report on automobile emissions in 1974, a panel of the National
Academy of Sciences observed that “the safety factors provided by the air standards are much
smaller than is usual in regulating other environmental pollutants such as radioactivity....”8 This
could be interpreted as suggesting the need for tighter standards,9 thus providing a larger margin
of safety.
In fact, scientists find that there seem not to be clear thresholds for air pollutants. The 1974
National Academy of Sciences panel on auto emissions observed that—

8

National Academy of Sciences, Air Quality and Automobile Emission Control, Vol. 1 (September 1974), p. 6.

9

U.S. Congress, House, Committee on Interstate and Foreign Commerce, Clean Air Act Amendments of 1977, House
Rept. No. 95-294, to accompany H.R. 6161 (95th Congress, 1st session) (Washington, D.C.: U.S. Govt. Print. Off.,
1977), p. 182.

Congressional Research Service

4

Air Quality Standards: The Decisionmaking Process

... in no case is there evidence that the threshold levels have a clear physiological meaning, in
the sense that there are genuine adverse health effects at and above some level of pollution,
but no effects at all below that level. On the contrary, evidence indicates that the amount of
health damage varies with the upward and downward variations in the concentration of the
pollutant, with no sharp lower limit.10

The 1996 reviews of the ozone and PM standards likewise concluded that no threshold of adverse
effects could be found for either pollutant.
The inability of scientists to find a threshold has led to contention in the setting of NAAQS. Some
argue that if there is no threshold, then there cannot be a margin of safety and as a result the
whole NAAQS process of necessity becomes a risk management decision—that is, one in which
the Administrator balances risks with costs to decide where to set the standard. Others argue that
the lack of a threshold justifies the tightest possible standards.
Another, related debate comes from the view that only in adding a “margin of safety” does the
administrator layer a policy judgment onto an objective, scientifically determined NAAQS. Some
argue that this judgmental aspect means that the “margin of safety” phrase implicitly endorses the
consideration of costs in setting NAAQS; as discussed later, the lead industry sued EPA over lead
standards on the basis that the “margin of safety” required EPA to take costs into account in
setting NAAQS, but the court ruled that the statute and its legislative history are against that
interpretation (Lead Industries Association v. Environmental Protection Agency, 647 F.2d 1130
(D.C. Cir. 1980)).
The legislative history of the CAA only briefly touches on the “margin of safety” phrase. The
Senate Report 90-1196 (accompanying legislation that became the Clean Air Amendments of
1970), quoted at the beginning of this section, clearly indicates that the “margin of safety” is
designed to protect against the potential for adverse effects to occur at pollutant concentrations
below those known to cause harm. Thus, regardless of the existence of a threshold, the margin of
safety is a factor the Administrator would consider in making choices involving uncertainties
embedded in the definitions of which vulnerable population groups to protect and of what effects
are adverse health effects: these issues are discussed later. Similarly, House Report 95-294
(accompanying legislation that became the Clean Air Act Amendments of 1977), after quoting the
National Academy of Sciences about the “smaller than usual” safety factor in NAAQS and about
the lack of evidence for thresholds, suggested “greater not lesser control of emissions are likely
to be needed.”11 The precautionary premise of the act seems manifest in the phrase “margin of
safety” regardless of the existence of thresholds; and the inference that the phrase calls for
consideration of costs has been consistently rejected.

Secondary Standards
Any national secondary ambient air quality standard ... shall specify a level of air
quality the attainment and maintenance of which in the judgment of the Administrator,
based on such criteria, is requisite to protect the public welfare from any known or

10

National Academy of Sciences, Air Quality and Automobile Emission Control, Vol. 1 (September 1974), p. 17.

11

U.S. Congress, House, Committee on Interstate and Foreign Commerce, Clean Air Act Amendments of 1977, House
Rept. No. 95-294, to accompany H.R. 6161 (95th Congress, 1st session) (Washington, D.C.: U.S. Govt. Print. Off.,
1977), p. 182.

Congressional Research Service

5

Air Quality Standards: The Decisionmaking Process

anticipated adverse effects associated with presence of such air pollutant in the ambient
air. [CAA §109(b)(2)]
All language referring to effects on welfare includes, but is not limited to, effects on
soils, water, crops, vegetation, man-made materials, animals, wildlife, weather,
visibility, and climate, damage to and deterioration of property, and hazards to
transportation, as well as effects on economic values and on personal comfort and wellbeing, whether caused by transformation, conversion, or combination with other air
pollutants. [CAA §302(h)]

Secondary NAAQS define the concentration of an air pollutant in the ambient air necessary to
protect the “public welfare.” Secondary standards are implemented in the same manner as
primary NAAQS, with the key difference that there is no federally enforceable specified deadline
for attainment. Most secondary NAAQS have been set at the same level as the primary NAAQS,
but they can be set at levels more or less stringent if justified by available evidence.

Setting NAAQS
Setting and Reviewing NAAQS
The process for setting a NAAQS is a multistage one, and repeats regularly as the CAA requires
each NAAQS to be reviewed every 5 years using the same process, to ensure that each NAAQS is
based on the most recent scientific information. The CAA is quite specific on certain steps of the
process: in particular, on the preparation of a “criteria document” summarizing the scientific
information, on the review of that document by an independent scientific committee, on the
criteria to be used by the Administrator in deciding on the final standard, and on the procedural
process for promulgating the standard. In addition, EPA has administratively added a key step, the
preparation of a “staff paper” that summarizes the criteria document and lays out policy options;
and Executive Order 12866 requires a Regulatory Impact Analysis (RIA), although the economic
analysis it contains is legally irrelevant to the actual decision on the standard. Finally, there are a
number of regulatory assessment requirements in law that impinge on the process—but have
limited substantive impact on the decision itself. These stages are discussed below (see also
Appendix A).

Criteria Document
The Administrator shall issue air quality criteria for [each] air pollutant ... included ...
[on the] list .... [CAA §108(a)(2)]

The “criteria document” precedes the NAAQS both in its appearance in air pollution control law
and in the process of setting NAAQS. In the early stages of the evolution of Federal air pollution
control law, the Federal role focused primarily on research and on providing financial and
technical advice to states. This role was exemplified in the requirement that the Public Health
Service (which was responsible for Federal air pollution activities before EPA) prepare a “criteria
document.”
“Air quality criteria [documents] are an expression of the scientific knowledge of the
relationship between various concentrations of pollutants in the air and their adverse
effects on man, animals, vegetation, materials, visibility, and so on.

Congressional Research Service

6

Air Quality Standards: The Decisionmaking Process

“Air quality criteria can and should be used in developing air quality standards. Criteria
and standards are not synonymous. Air quality criteria are descriptive; that is, they
describe the effects that can be expected to occur whenever and wherever the ambient air
level of a pollutant reaches or exceeds a specific figure for a specific time period.” [Dr.
Middleton, Director, National Center for Air Pollution Control, Public Health Service,
quoted in Senate Committee on Public Works Report 403 on the Air Quality Act of 1967, p.
26.]
Air quality criteria for an air pollutant shall accurately reflect the latest scientific
knowledge useful in indicating the kind and extent of all identifiable effects on public
health or welfare which may be expected from the presence of such pollutant in the
ambient air, in varying quantities. [CAA, §108(a)(2)]

In 1970, when the Clean Air Amendments of 1970 established the federal role in setting NAAQS,
the “criteria document” became the basic technical underpinning of the standards-setting process.
Explicitly, the preparation, review, and use of the “criteria document” was to be objective and
scientifically validated. It is scientifically peer reviewed by an advisory committee—established
by statute in the 1977 amendments—and by other federal departments and agencies. Much of the
review process is open to the public, and the final criteria document is made public:
The issuance of air quality criteria ... shall be announced in the Federal Register and
copies shall be made available to the general public. [CAA, §108(d)]

The criteria document is prepared in the Office of Research and Development by EPA scientists
(with the advice of and review by a scientific advisory committee, described below). Reviewing
the scientific literature for all studies relevant to the air pollutant, the preparers consolidate
information pertinent to indicating the kinds and magnitudes of effects resulting from the
pollutant’s presence in ambient air, assess the robustness of the studies, endeavor to resolve
inconsistencies, and evaluate findings. Key components of the scientific evidence include
epidemiological studies that examine the relationships between ambient pollutant levels and
public health and welfare; clinical studies that examine human responses to controlled levels of
pollutants, for example in air chambers; and animal studies. Typically, the studies included have
undergone peer review and been published in the open literature, but on occasion some other
studies, such as preliminary reports on ongoing research, may be included if they meet other
standards of scientific reporting.
Criteria documents are major undertakings: the 1996 ozone criteria document contains over 1,500
pages and evaluates nearly 190 scientific studies; the 1996 PM criteria document contains 2,400
pages and evaluates some 80 studies. Each document took about one year to draft; review and
revisions took another year to come to closure.

Staff Paper
This [staff paper] assessment is intended to help bridge the gap between the scientific review
contained in the [criteria document] and the judgments required of the Administrator in
setting ambient standards for PM. Thus, emphasis is placed on identifying those conclusions
and uncertainties in the available scientific literature that the staff believes should be
considered in selecting particulate pollutant indicators, forms, averaging times, and levels for
the primary (health) and secondary (welfare) standards. [EPA, Particulate Matter Staff Paper
(1996), p. I-1]

Congressional Research Service

7

Air Quality Standards: The Decisionmaking Process

Based on the criteria document, EPA scientists and policy experts prepare a staff paper. It is
developed in the Office of Air Quality Planning and Standards of the Office of Air and Radiation.
This document is not required by the CAA; it is an administrative step designed to facilitate the
EPA Administrator’s decision. It lays out options for a NAAQS standard—e.g., whether to set a
standard, at what level(s) it might be set, and methods for measuring compliance—along with
justifications from the criteria document. Like the criteria document, the staff paper is reviewed
by the scientific advisory committee.

Clean Air Scientific Advisory Committee
The Administrator shall appoint an independent [clean air] scientific review committee
[CASAC] composed of seven members including at least one member of the National
Academy of Sciences, one physician, and one person representing State air pollution
control agencies.
... [T]he [clean air scientific advisory] committee ... shall ... review ... the criteria
published under section 108 and the national primary and secondary ambient air
quality standards promulgated under this section and shall recommend to the
Administrator any new national ambient air quality standards and revisions of existing
criteria and standards as may be appropriate ....
Such committee shall also (i) advise the Administrator of areas in which additional
knowledge is required to appraise the adequacy and basis of existing, new, or revised
national ambient air quality standards, (ii) describe the research efforts necessary to
provide the required information, (iii) advise the Administrator on the relative
contribution to air pollution concentrations of natural as well as anthropogenic activity,
and (iv) advise the Administrator of any adverse public health, welfare, social,
economic, or energy effects which may result from various strategies for attainment
and maintenance of such national ambient air quality standards. [CAA, §109(d)(2)]

The 1967 Air Quality Act required the Secretary of HEW to consult with “appropriate advisory
committees” (along with Federal departments and agencies) when preparing criteria documents.
The Secretary established a National Air Quality Criteria Advisory Committee, having a
membership broadly representative of industry, universities, conservation interests, and all levels
of government. This committee actively participated in the rewriting of the Sulfur Oxides Criteria
Document published in 1969, and in the preparation of subsequent criteria documents. This
general requirement for consultation was replaced in 1977 by the specific requirements creating
CASAC, with its responsibilities for reviewing the scientific basis of the Administrator’s
decisions on NAAQS. The legislative history concerning the CASAC provision emphasizes its
independence:
This committee is intended to assist the Administrator, but it is also intended to have
complete independence. This independence will help provide an outside mechanism for
evaluating whether any pollutant may reasonably be anticipated to endanger public health
or environment, for evaluating the scientific and medical data which bear on this question,
and for reviewing gaps in the available data and recommending additional needs for
research. [Committee on Interstate and Foreign Commerce, House Rept. No. 95-294 (1977),
p. 182]

The seven-member CASAC creates a panel to review each NAAQS. This panel consists of the
members of CASAC plus consultant members to assure full coverage of the expertises needed to

Congressional Research Service

8

Air Quality Standards: The Decisionmaking Process

assess fully the issues involved. For the ozone review, a panel of 15 was convened; for the PM
review, the panel consisted of 21.
The panel members meet to review each criteria document and staff paper as it is prepared,
recommend improvements, and after further meetings and reviews sign off only when they are
convinced that each accurately reflects the status of the science. CASAC panel meetings are open
to the public. 12 These “closure documents” become part of the record for rulemaking. Thus—
The independent, scientific review committee’s recommendations on these issues will not
only aid the Administrator and the Congress, but also the courts in judicial review of any
national ambient air quality standard or of the Administrator’s failure or refusal to set or
revise such a standard with respect to any pollutant. [Committee on Interstate and Foreign
Commerce, House Rept. No. 95-294 (1977), p. 182]

What the closure letter means is that the CASAC panel members agree that the criteria document
and the staff paper provide an adequate scientific basis for regulatory decisionmaking. Using
formulaic sentences, a closure letter for a criteria document typically reads:
At the September 1995 meeting the Panel came to closure on the Criteria Document. It was
the consensus of the Panel members that the Criteria Document provides an adequate review
of the available scientific data and relevant studies of ozone and related photochemical
oxidants. The document is quite comprehensive and will provide an adequate scientific basis
for regulatory decisions on ozone and related photochemical oxidants based on available
information. [CASAC Closure on the Air Quality Criteria for Ozone and Related
Photochemical Oxidants, letter, from Dr. George T. Wolff, Chair, to Honorable Carol M.
Browner, Administrator, EPA (November 28, 1995)]

A closure letter for a staff paper typically says:
It was the consensus of the Panel that although our understanding of the health effects of
ozone is far from complete, the document provides an adequate scientific basis for making
regulatory decisions regarding a primary ozone standard. [CASAC Closure on the Primary
Standard Portion of the Staff Paper for Ozone, letter, from D. George T. Wolff, Chair, to
Honorable Carol M. Browner, Administrator, EPA (November 30, 1995)]

The Administrator’s Decision
... [I]n the judgment of the Administrator .... [CAA, §109(b)(1)]

The CAA specifies that the Administrator shall use her “judgment ..., based on [the] criteria
[document] and allowing an adequate margin of safety” to determine the NAAQS “requisite
to protect the public health” [CAA, §109(b)(1)]. Thus the decision involves weighing of the
scientific evidence, collected and analyzed in the criteria document, of the policy options laid out
in the staff paper, and of the comments of CASAC—following the criteria dictated in the CAA.
EPA’s interpretation of the criteria has been the subject of various challenges. One key issue arose
from litigation that actually concerned another part of the CAA; the dispute led to amendments in
1977 that clarified provisions relating to NAAQS. This landmark case concerning the appropriate
12

CASAC is subject to the Federal Advisory Committee Act (5 U.S.C. App. 2) which governs public accessibility to
committee meetings and products.

Congressional Research Service

9

Air Quality Standards: The Decisionmaking Process

criteria for air quality regulatory judgments is Ethyl Corp. v. EPA. A 3-judge panel, voting 2-1,
invalidated the Administrator’s regulation of lead in fuels based on § 211 (regulation of fuels) of
the CAA [No. 73-2205 (D.C. Cir. Jan. 28, 1975)]. The decision hinged on the burden of proof the
Administrator had to meet in order to justify the proposed standard, with the majority holding that
the Administrator had to show actual harm rather than the threat or risk of harm. Subsequently,
the initial decision was vacated and the U.S. Court of Appeals granted a rehearing en banc; the
full court upheld the Administrator’s regulations on a 5-4 vote, holding that §211 states a merely
precautionary standard—i.e., does not require actual harm.
Even though vacated, the initial Ethyl decision raised issues affecting all clean air standards
setting that were directly addressed in the 1977 Amendments to the CAA.13 In its report on the
bill amending the CAA, the House Committee on Interstate and Foreign Commerce identified six
issues raised by the case that “required further congressional clarification”:
(1) whether the Administrator could “act to prevent harm before it occurs or should he be
authorized to regulate an air pollutant only if he finds actual harm has already occurred”;
(2) whether the Administrator could assess risks or only “make findings of past fact”;
(3) whether the Administrator could consider the cumulative risk of a pollutant from multiple
sources, or only the risk from the single class of sources being regulated;
(4) whether different standards of proof apply to different sources;
(5) whether “protection of public health” referred only to healthy normal adults or included
“susceptible individuals within the exposed population”; and
(6) whether a “Court’s standard of review of informal rulemaking by the Administrator to
protect public health be whether he has relied on conclusive or indisputable facts or whether he
has reached reasonable conclusions which are rationally justified.”
To resolve these issues, the Committee added language amending the act, using “a standardized
basis for future rulemaking to protect the public health: the Administrator may regulate a
pollutant, emissions of ‘which in his judgment cause or contribute to air pollution which may
reasonably be anticipated to endanger public health or welfare.’ This same basic formula” was
used in the several standards-setting provisions of the Act, including sections 108 (criteria for
NAAQS), 111 (new source performance standards), 112 (hazardous air pollutants), 202 (motor
vehicle emission standards), 211 (regulation of fuels and fuel additives), and 231 (aircraft
emissions), as well as subtitle B of Title I (ozone and stratospheric protection).
In using this language in amending the act, as discussed in the report on the bill, the Committee
intended—
(1) To emphasize the preventative or precautionary nature of the act, i.e., to assure that
regulatory action can effectively prevent harm before it occurs ...;

13
This discussion, including the quotations, are from U.S. Congress, House, Committee on Interstate and Foreign
Commerce, Clean Air Act Amendments of 1977, House Rept. No. 95-294, to accompany H.R. 6161 (95th Congress, 1st
session) (Washington, D.C.: U.S. Govt. Print. Off., 1977), pp. 43-51.

Congressional Research Service

10

Air Quality Standards: The Decisionmaking Process

(2) To authorize the Administrator to weigh risks and make reasonable projections of future
trends ...;
(3) To assure consideration of the cumulative impact of all sources of a pollutant in setting
ambient and emission standards, not just the extent of the risk from the emissions from a single
source or class of sources of the pollutant; ...
(4) To provide the same standard of proof for regulation of any air pollutant ...;
(5) To assure that the health of susceptible individuals, as well as healthy adults, will be
encompassed in the term ‘public health,’ regardless of the section of the act under which the
Administrator proceeds; and
(6) To reflect awareness of the uncertainties and limitations in the data which will be available
to the Administrator in the foreseeable future to enable him to execute his rulemaking duties
under this act, because of the limitations on research resources and the fact that
decisionmaking about the risks to public health from air pollution falls on ‘the frontiers of
scientific and medical knowledge.’
In short, “the committee language is intended to emphasize the necessarily judgmental element
in the task of predicting future health risks of present action and to confer upon the
Administrator the requisite authority to exercise such judgment.”
This is not, however, a blank check: “... the committee does not intend this language as a license
for ‘crystal ball’ speculation. The Administrator’s judgment must, of course, remain subject to
restraints of reasoned decisionmaking.”

The Evidence
...[B]ased on such criteria [document] ... [CAA, §109(b)(1)]
Air quality criteria for an air pollutant shall accurately reflect the latest scientific
knowledge useful in indicating the kind and extent of all identifiable effects on public
health or welfare which may be expected from the presence of such pollutant in the
ambient air, in varying quantities. The criteria for an air pollutant, to the extent
practicable, shall include information on—
(A) those variable factors (including atmospheric conditions) which of themselves or in
combination with other factors may alter the effects on public health or welfare of such
air pollutant;
(B) the types of air pollutants which, when present in the atmosphere, may interact
with such pollutant to produce an adverse effect on public health or welfare; and
(C) any known or anticipated adverse effects on welfare. [CAA, §108(a)(2)]
Each agency shall base its [regulatory] decisions on the best reasonably obtainable scientific,
technical, economic, and other information concerning the need for, and consequences of,
the intended regulation. [Executive Order 12866]

The evidence for a NAAQS decision ultimately resides in the criteria document, the staff paper,
and the CASAC letters of closure, plus materials submitted during the public comment period.

Congressional Research Service

11

Air Quality Standards: The Decisionmaking Process

Ancillary information is included in the Regulatory Impact Analysis (discussed below).
Summaries are included in the proposed and final rules as published in the Federal Register. In
setting NAAQS, the generic direction of E.O. 12866 to regulatory agencies to base their
“decisions on the best reasonably obtainable scientific, technical, economic, and other
information....” is constrained by the CAA, which specifies that health protection is to be the
criterion in determining the standard.

The Criteria
Health
Health is the sole criterion for setting the primary NAAQS. (For a discussion of the issue of
considering costs, see below.)
Beside the technical information underlying a health standard,14 the Administrator must consider
several crucial policy issues: These include (1) defining whose health the standard is to protect,
given that some people will be more susceptible to pollution than others; (2) defining which
health effects of pollution are adverse health impacts to be protected against; (3) evaluating
exposure and characterizing risk; and (4) considering what factors to take into account in
providing “an adequate margin of safety.” The statute and legislative history provide some
guidance on these questions. As they are key elements of the judgment that the Administrator
makes in deciding the standard, these questions are more or less explicitly posed in the staff
paper.
Sensitive populations. For answering the first question, about whose health a primary standard
should protect, the Senate Report on the Clean Air Act Amendments of 1970 provided explicit
guidance:
In requiring that national ambient air quality standards be established at a level necessary
to protect the health of persons, the Committee recognizes that such standards will not
necessarily provide for the quality of air required to protect those individuals who are
otherwise dependent on a controlled internal environment such as patients in intensive
care units or newborn infants in nurseries. However, the Committee emphasizes that
included among those persons whose health should be protected by the ambient standard
are particularly sensitive citizens such as bronchial asthmatics and emphysematics who in
the normal course of daily activity are exposed to the ambient environment. In establishing
an ambient standard necessary to protect the health of these persons, reference would be
made to a representative sample of persons comprising the sensitive group rather than to a
single person in such a group.

14

Controversy about the science underlying the 1997 NAAQS standards contributed to later legislation. A key concern
focused on the availability of raw data to assess the scientific robustness of a study of health effects of air pollution in
several cities and of the conclusions drawn. This led to a provision added to P.L. 105-277 regarding public availability
of data; see (name redacted) and (name redacted), Public access to data from federally funded research: OMB
Circular A-110 and issues for Congress (November 18, 1999), CRS Report RL30376, pp. 3-4. Relatedly, a provision
was included in P.L. 106-554 to ensure and maximize the integrity of information used by agencies, and to require
agencies to provide “mechanisms allowing affected persons to seek and obtain correction of information ...”; see John
E. Blodgett, Environmental Reauthorizations and Regulatory Reform: From the 104th Congress through the 106th
(December 27, 200), CRS Report 96-949 ENR, p. 6.

Congressional Research Service

12

Air Quality Standards: The Decisionmaking Process

Ambient air quality is sufficient to protect the health of such persons whenever there is an
absence of adverse effect on the health of a statistically related sample of persons in
sensitive groups from exposure to ambient air. [Senate Committee on Public Works, Report
No. 91-1196 (1970), p. 10]

Also, as discussed earlier, the Committee on Interstate and Foreign Commerce, in its report
language discussing amendments relating to the basis for administrative standards, expressly
noted its intent to “assure that the health of susceptible individuals, as well as healthy adults, will
be encompassed in the term ‘public health,’ regardless of the section of the act under which the
Administrator proceeds.”
Adverse health effect. The Clean Air Act does not define the adverse health effects against which
NAAQS must protect, nor does the legislative history of the CAA contain much discussion of
what constitutes an adverse health effect. The National Commission on Air Quality15 noted
proposals that the Act contain greater specificity, but observed:
any attempt to identify specific types of health effects could inhibit identification of
unanticipated effects that should be considered. In addition, most air pollutants affect public
health in more than one way. To carry out its responsibilities under the Act, EPA, before
making a final decision to set or revise an air quality standard, must have all relevant and
reliable scientific information on the full range of possible health effects of a pollutant.16

Indications of what constitutes an adverse health effect can be found in the distinction between
primary and secondary standards and in the definition of hazardous air pollutants. While a
primary NAAQS protects health, a secondary NAAQS protects welfare, which includes, by
definition, “personal comfort and well-being.” Thus, pollution effects that involve only “personal
comfort and well-being” are not health effects that primary standards are directed toward. The
definition of a hazardous air pollutant in the 1970 Act is “an air pollutant ... which ... may cause,
or contribute to, an increase in mortality or an increase in serious irreversible, or incapacitating
reversible, illness.” Unquestionably, “increase in mortality,” “irreversible” and “incapacitating”
signal health effects. Are bouts of coughing or decreased lung functioning adverse health effects?
If they are irreversible or incapacitating, the answer would seem clearly “yes.” As a practical
matter, if an effect necessitates medical intervention or leads to curtailed activity, such as missing
school or work, the answer would seem “yes.” The question of whether an effect is an adverse
health effect can be difficult to answer, particularly if the effect appears minor but may cumulate
over a lifetime.
Exposure evaluation and risk assessment.
In order to emphasize the precautionary or preventive purpose of the act (and, therefore,
the Administrator’s duty to assess risks rather than wait for proof of actual harm), the
committee not only retained the concept of endangerment to health; the committee also
added the words ‘may reasonably be anticipated’. ...
By its use of the words ‘cause or contribute to air pollution’, the committee intends to
require the Administrator to consider all sources of the contaminant which contribute to
15

The National Commission on Air Quality was created by the Clean Air Act Amendments of 1977, §323, to review
the Act and to report to the Congress the effects of the Act, alternative ways of controlling air pollution, and any
recommended midcourse corrections.
16
National Commission on Air Quality, To Breathe Clean Air (Washington, D.C.: 1981), p. 3.1-2.

Congressional Research Service

13

Air Quality Standards: The Decisionmaking Process

air pollution and to consider all sources of exposure to the contaminant—food, water, air,
etc.—in determining health risk.
Finally, the term ‘in the judgment of the Administrator’ is intended to modify both the
‘cause and contribute to’ phrase and the ‘reasonably may be anticipated’ phrase.
[Committee on Interstate and Foreign Congress, Clean Air Act Amendments of 1977, Report
95-294 (1970), p. 51.]

As indicated in the previous discussions of the Ethyl and Lead Industries v. EPA cases, and as
emphasized in House Report 95-294, the Administrator may promulgate a NAAQS in
“reasonable” anticipation of public health endangerment. The practical effect of this criterion is to
allow a “weight of evidence” approach to be used in setting a NAAQS17; EPA need not prove that
adverse health effects have already occurred, nor that the air-borne form of the pollutant solely
caused the harm.
Margin of safety. On the question of what constitutes a “margin of safety,” EPA’s Staff Paper on
Particulate Matter summarizes the situation as follows:
The U.S. Court of Appeals for the District of Columbia Circuit has held that the requirement
for an adequate margin of safety for primary standards was intended to address uncertainties
associated with inconclusive scientific and technical information available at the time of
standard setting. It was also intended to provide a reasonable degree of protection against
hazards that research has not yet identified (Lead Industries Association v. EPA, 647 F.2d
1130, 1154 (D.C. Cir. 1980), cert. denied, 101 S. Ct. 621 (1980); American Petroleum
Institute v. Costle, 665 F.2d 1176, 1177 (D.C. Cir. 1981), cert. denied, 102 S. Ct. 1737
(1982)). Both kinds of uncertainties are components of the risk associated with pollution at
levels below those at which human health effects can be said to occur with reasonable
scientific certainty. Thus, by selecting primary standards that provide an adequate margin of
safety, the Administrator is seeking not only to prevent pollution levels that have been
demonstrated to be harmful but also to prevent lower pollutant levels that she finds may pose
an unacceptable risk of harm, even if the risk is not precisely identified as to nature or
degree.
In selecting a margin of safety, the EPA considers such factors as the nature and severity of
the health effects involved, the size of the sensitive population(s) at risk, and the kind and
degree of the uncertainties that must be addressed. Given that the “margin of safety”
requirement by definition only comes into play where no conclusive showing of adverse
effects exists, such factors which involve unknown or only partially quantified risks have
their inherent limits as guides to action. The selection of any particular approach to providing
an adequate margin of safety is a policy choice left specifically to the Administrator’s
judgment (Lead Industries Association v. EPA, supra, 647 F.2d at 1161-62). [EPA,
Particulate Matter Staff Paper (1996), pp. II-1 - II-2]

EPA’s view, then, is that the “margin of safety” allows the Administrator to take into account the
dimensions of the decision that scientific data cannot resolve. This view has also been voiced by
17

In rejecting objections to the ozone NAAQS, the D.C. Circuit Court observed: “One final aspect of EPA’s discussion
of the primary NAAQS level is relevant here: The Agency’s response to certain comments questioning its reliance on
specific field, epidemiological, and clinical studies. According to EPA, the comments ‘did not reflect an integrative
assessment of the evidence – the approach CASAC has historically urged [the Agency] to follow – but rather a
piecemeal look at each individual study’ [Ozone NAAQS, 62 Fed. Reg. 38,868]. EPA therefore dismissed the
comments, arguing that such an incremental critique ‘tends to miss the strength of the entire body of evidence taken
together’ [Ibid]. American Trucking Association, Inc. v. EPA, 2002 Westlaw 452092 (D.C. Cir. Mar. 26, 2002).

Congressional Research Service

14

Air Quality Standards: The Decisionmaking Process

the Courts. For example, concerning the ozone NAAQS, the D.C. Circuit Court of Appeals
observed, “... EPA must err on the side of caution, just as it did here – setting the NAAQS at
whatever level it deems necessary and sufficient to protect the public health with an adequate
margin of safety, taking into account both the available evidence and the inevitable scientific
uncertainties.” American Trucking Association, Inc. v. EPA, 2002 Westlaw 452092 (D.C. Cir. Mar.
26, 2002).

Costs
The question of whether costs or technical feasibility should be taken into account in setting
NAAQS has been an enduring debate. The National Commission on Air Quality explained the
principle as follows:
The statutory basis for setting national ambient air quality standards does not take economic
factors into account. In the Act, Congress recognized that while the levels of air pollution at
which public health is affected generally do not vary among different locations, the costs of
meeting a specific standard can vary substantially from area to area, depending upon the
severity of the pollution. Thus, if a national air quality standard were based in part on the
costs of complying with it, the high costs of meeting the standard in a few heavily polluted
areas could result in the standard’s being set at a less protective level than is achievable in a
reasonable, economic fashion in other areas. The health benefits of good air quality and the
economic, social, energy, and other costs of meeting health-based standards can be balanced
more effectively and appropriately when control programs are established for particular areas
than when national primary standards are set.18

The concept of deferring cost considerations until the implementation of standards, rather than
incorporating them in standards-setting, arose early in the evolution of the CAA. The Senate
Report on the Air Quality Act of 1967 affirmed the primacy of health protection in setting
NAAQS:
Considerations of technology and economic feasibility, while important in helping to
develop alternative plans and schedules for achieving goals of air quality, should not be
used to mitigate against protection of the public health and welfare. [Senate Committee on
Public Works, Report No. 403 (1967), pp. 28-29]

Subsequently, in bringing to the floor the Senate bill that became the Clean Air Act Amendments
of 1970, Senator Muskie repeated that language and called it a “warning” that had been ignored
by those who sought to compromise health standards because of costs:
That warning ... has been on the books of this committee for 3 years, for all to read.
Contrary to this intent, these [cost and feasibility] considerations have been used as
arguments to compromise the public health. Therefore, the committee has made explicit in
this bill what is implicit to standards designed to protect our health. That concept and that
philosophy are behind every page of the proposed legislation.
The first responsibility of Congress is not the making of technological or
economic judgments—or even to be limited by what is or appears to be

18

National Commission on Air Quality, To Breathe Clean Air (Washington, D.C.: 1981), p. 3.1-2.

Congressional Research Service

15

Air Quality Standards: The Decisionmaking Process

technologically feasible. Our responsibility is to establish what the public interest
requires to protect the health of persons.
[Senator Muskie, debate on the National Air Quality Standards Act of 1970 (Congressional
Record, September 21, 1970, pp. 32901-02)]

The question of taking costs into account in setting NAAQS was litigated in the case of the lead
NAAQS. The D.C. Circuit Court’s decision was unambiguous:
... [T]he statute and its legislative history make clear that economic considerations play no
part in the promulgation of ambient air quality standards under Section 109.
... Section 109(b) speaks only of protecting the public health and welfare. Nothing in its
language suggests that the Administrator is to consider economic or technological feasibility
in setting ambient air quality standards.
The legislative history of the Act also shows the Administrator may not consider economic
and technological feasibility in setting air quality standards; the absence of any provision
requiring consideration of these factors was no accident; it was the result of a deliberate
decision by Congress to subordinate such concerns to the achievement of health goals. [Lead
Industries Association v. Environmental Protection Agency, 647 F.2d 1130 (D.C. Cir. 1980)]

The issue of costs recurred following the 1997 ozone and PM2.5 NAAQS. Among the many
comments submitted on the proposed rules were objections that the EPA had not considered costs.
EPA responded to these comments at some length, arguing that costs should not be considered in
setting the NAAQS.19 EPA’s position was challenged in court, and again the D.C. Circuit Court
was explicit:
As this court long ago made clear, in setting NAAQS under §109(b) of the Clean Air Act,
the EPA is not permitted to consider the cost of implementing those standards. [American
Trucking Associations v. U.S. E.P.A., 175 F.3d 1027 (D.C. Cir. 1999)]

This holding was among those appealed to the Supreme Court, which unanimously upheld the
D.C. Circuit Court’s ruling on this point. The Supreme Court stated:
Section 109(b) does not permit the Administrator to consider implementation costs in setting
NAAQS. [Whitman v. American Trucking Associations, Inc. 531 U.S. 457 (2001).

Promulgating NAAQS
The procedural steps for promulgating or revising NAAQS are set forth in the CAA itself—not,
as is usual elsewhere, in the Administrative Procedure Act. 20 Affecting this process to varying
degrees are several other statutory requirements affecting regulations, notably the Regulatory
19

See, for example, EPA, “Cost Considerations,” National Ambient Air Quality Standards for Ozone; Final Rule, 62
Federal Register 38878-38883 (July 18, 1997).
20
The Clean Air Act Amendments of 1977, adding §307 to the CAA: the reasons for the changes from the
Administrative Procedures Act and their intent are discussed at length in U.S. Congress, House, Committee on
Interstate and Foreign Commerce, Clean Air Act Amendments of 1977, House Rept. No. 95-294, to accompany H.R.
6161 (95th Congress, 1st session) (Washington, D.C.: U.S. Govt. Print. Off., 1977), pp. 318-325.

Congressional Research Service

16

Air Quality Standards: The Decisionmaking Process

Flexibility Act, the Unfunded Mandates Reform Act, and the Small Business Regulatory
Enforcement Fairness Act. Also affecting the process are executive mandates, notably Executive
Order 12866, Regulatory Planning and Review, and Executive Order 12848, Federal Actions to
Address Environmental Justice in Minority Populations and Low-Income Populations.

The Administrative Rulemaking Process
For numerous CAA rulemakings, including the process for promulgating or revising CAA rules,
§307 of the CAA modifies the procedures of the Administrative Procedure Act governing
rulemaking. The process is codified at 42 U.S.C. 7607(d). In general, the procedures require EPA
to establish a “docket” that contains all the crucial elements of the rulemaking, that is open to
public inspection, and that represents all the information available for the Administrator’s
decision. (An additional provision allows evidence not in the docket to be considered in certain
cases when the omission was “reasonable.”) The key steps of the rulemaking include: (1) notice
of the proposed rulemaking, (2) a period available for public comment, (3) promulgation of the
rule, which shall include responses to significant comments on the proposal, and (4) an
opportunity for judicial review and challenges to the procedural determinations.

Notice of Proposed Rulemaking
... [T]he Administrator shall publish, simultaneously with the issuance of such criteria
[document] and information, proposed national primary and secondary ambient air
quality standards .... [CAA, §109(a)(2)]
... [N]otice of proposed rulemaking shall be published in the Federal Register, ... shall
be accompanied by a statement of its basis and purpose and shall specify the period
available for public comment .... The notice of proposed rulemaking shall also state the
docket number, the location ... of the docket, and the times it will be open to public
inspection. [CAA §307(d)(3)]

As an illustration of the process, on June 12, 1996 EPA published an “Advance Notice of
Proposed Rulemaking (ANPR) for National Ambient Air Quality Standards for Ozone and
Particulate Matter” (61 Federal Register 29719-2925). This ANPR outlined the basis for EPA
having to make the decision, identified the key documents, and indicated the major options under
consideration. The Proposed Rules on ozone and PM were released November 27, 1996, and
published December 13 (61 Federal Register 65638-65872). Each laid out the proposed decision,
requested public comment generally and on specific options, told where and how to access the
docket, and provided for a 60-day public comment period (later extended 21 days, until March
12, 1997).

Public Comment
... [A]fter a reasonable time for interested persons to submit written comments thereon
.... [CAA, §109(a)(1)(B)]
In promulgating a [NAAQS], ... (i) the Administrator shall allow any person to submit
written comments, data, or documentary information; (ii) the Administrator shall give
interested persons an opportunity for the oral presentation of data, views, or arguments
.... [CAA, §307(d)(5)]

Congressional Research Service

17

Air Quality Standards: The Decisionmaking Process

In the case of the ozone and particulate matter NAAQS proposed by EPA in December 1996, the
Agency received over 25,000 comments during the public comment period. Also, EPA held 4
public hearings.

Promulgation of the Rule
...[A]fter a reasonable time for interested persons to submit written comments thereon
(but no later than 90 days after the initial publication of such proposed standards) [the
Administrator] shall by regulation promulgate such proposed national ambient air
quality standards with such modifications as he deems appropriate. [CAA,
§109(a)(1)(B)]
(A) The promulgated rule shall be accompanied by (i) a statement of basis and purpose
... and (ii) an explanation of the reasons for any major changes in the promulgated rule
from the proposed rule. (B) The promulgated rule shall also be accompanied by a
response to each of the significant comments, criticisms, and new data submitted in
written or oral presentations during the comment period. [CAA, §307(d)(6)]

The ozone and particulate matter final decisions were signed by the Administrator on July 16,
1997 and published on July 18, 1997 (62 Federal Register 38652-38896). Each final rule
contained lengthy discussions of issues raised by commentators and the EPA’s final disposition of
them.

Regulatory Impact Assessments
Costs and Benefits—Executive Order 12866
Each agency shall assess both the costs and the benefits of the intended regulation ....
For ... a significant regulatory action ... the agency shall ... provide ... (i) An assessment,
including the underlying analysis, of benefits anticipated from the regulatory action (such as,
but not limited to, the promotion of the efficient functioning of the economy and private
markets, the enhancement of health and safety, the protection of the natural environment, and
the elimination or reduction of discrimination or bias) together with, to the extent feasible, a
quantification of those benefits; (ii) An assessment, including the underlying analysis, of
costs anticipated from the regulatory action (such as, but not limited to, the direct cost both
to the government in administering the regulation and to businesses and others in complying
with the regulation, and any adverse effects on the efficient functioning of the economy,
private markets (including productivity, employment, and competitiveness), health, safety,
and the natural environment, together with, to the extent feasible, a quantification of those
costs; and (iii) An assessment, including the underlying analysis, of costs and benefits of
potentially effective and reasonably feasible alternatives to the planned regulation....
[Executive Order 12866, 58 FR 51735 (4 October 1993)]

EPA has concluded that NAAQS reviews are “significant” regulatory actions21 requiring
preparation of a Regulatory Impact Analysis (RIA). However, EPA also explicitly states that
21

E.O. 12866 defines “significant regulatory action” to include a rule that may “have an annual effect on the economy
of $100 million or more ....”

Congressional Research Service

18

Air Quality Standards: The Decisionmaking Process

“Because judicial decisions make clear that cost cannot be considered in setting NAAQS, the
results of the draft RIA have not been considered in developing this proposal” [National Ambient
Air Quality Standard for Ozone: Proposed Decision, pp. 157-158].
The 1996 ozone and PM NAAQS proposals are the first NAAQS rulemakings undertaken since
enactment of the Unfunded Mandates Reform Act (UMRA) and the Regulatory Flexibility Act
(RFA). While EPA concluded that the proposals were “significant regulatory actions” as defined
by E.O. 12866, EPA concluded that the proposals do not trigger the regulatory analysis provisions
of UMRA or RFA.

Unfunded Mandates—Unfunded Mandates Reform Act
Unless otherwise prohibited by law, before promulgating any general notice of proposed
rulemaking that is likely to result in promulgation of any rule that includes any Federal
mandate that may result in the expenditure by State, local, and tribal governments, in the
aggregate, or by the private sector, of $100,000,000 or more (adjusted annually for
inflation) in any 1 year, and before promulgating any final rule for which a general notice of
proposed rulemaking was published, the agency shall prepare a written statement
containing—
... a qualitative and quantitative assessment of the anticipated costs and benefits of the
Federal mandate, including the costs and benefits to State, local, and tribal governments or
the private sector, as well as the effect of the Federal mandate on health, safety, and the
natural environment and ... a description of the extent of the agency’s prior consultation with
elected representatives ... of the affected State, local, and tribal governments .... [Unfunded
Mandates Reform Act of 1995, §202(a)]

On the issue of unfunded mandates, EPA concluded:
As indicated previously, EPA cannot consider in setting a NAAQS the economic or
technological feasibility of attaining ambient air quality standards, although such factors may
be considered to a degree in the development of State plans to implement the standards.
Accordingly, EPA has determined that the provision of sections 202, 203, and 205 of the
UMRA do not apply to this proposed [NAAQS] decision. The EPA acknowledges, however,
that any corresponding revisions to associated State implementation plan requirements and
air quality surveillance requirements, 40 CFR part 51 and 40 CFR part 58, respectively,
might result in such effects. Accordingly, EPA will address unfunded mandates as
appropriate when it proposes any revisions to 40 CFR parts 51 and 58. [Proposed Decision:
Particulate Matter, 61 FR 65670 (December 13, 1996)]

However, in its PM RIA, EPA does prepare a governmental entities analysis. According to EPA,
“This ... is not an unfunded mandates analysis, but provides estimates of the potential budgetary
impact of the control measures used in the control strategy-cost analysis affecting State and local
government agencies.” EPA notes that it “will be useful in guiding future implementation
activities....” [PM RIA, p. 8-20]
EPA’s denial that it had to prepare an unfunded mandates analysis (regulatory impact statement)
was challenged in court as part of American Trucking Associations v. U.S. E.P.A. The D.C. Circuit
Court noted, however, that the Unfunded Mandates Reform Act explicitly states that a failure to
prepare an impact analysis “shall not be used as a basis for staying, enjoining, invalidating or
otherwise affecting [an] agency rule” [UMRA, § 1571]. Further, the court held that “the failure to
prepare a regulatory impact statement does not render the NAAQS arbitrary and capricious.”

Congressional Research Service

19

Air Quality Standards: The Decisionmaking Process

[American Trucking Associations v. U.S. E.P.A., 175 F.3d 1027 (D.C. Cir. 1999), modified on
other grounds, 195 F.3d 4 (D.C. Cir. 1999). This issue was not addressed in the appeal to the
Supreme Court, see 531 U.S. 457 (2001).]

Small Business—Regulatory Flexibility Act
Whenever an agency is required ... to publish general notice of proposed rulemaking for any
proposed rule, the agency shall prepare and make available for public comment an initial
regulatory flexibility analysis. Such analysis shall describe the impact of the proposed rule
on small entities.... [5 U.S.C. §603(a)]
When an agency promulgates a final rule ..., after being required ... to publish a general
notice of proposed rulemaking, the agency shall prepare a final regulatory flexibility
analysis.... [5 U.S.C. §604(a)]
Sections 603 and 604 of this title shall not apply to any proposed or final rule if the head of
the agency certifies that the rule will not, if promulgated, have a significant economic impact
on a substantial number of small entities. [5 U.S.C. §605(b)]

On the issue of assessing the impact of regulations on small businesses, EPA said the ozone and
PM proposed NAAQS—
will not have a significant economic impact on small entities within the meaning of the RFA.
Instead, it will establish a standard of air quality that other Act provisions will call on states
(or in case of state default, the federal government), to achieve by adopting implementation
plans containing specific control measures for that purpose. In other words, state (or federal)
regulations implementing the NAAQS might establish requirements applicable to small
entities, but the NAAQS itself would not. For these reasons, the Administrator certifies that
this proposed rule will not have a significant economic impact on a substantial number of
small entities.” [National Ambient Air Quality Standard for Ozone: Proposed Decision, pp.
163-164].

EPA nevertheless concedes interest in the “potential impact” of the NAAQS and notes that
discussion of those impacts are included in the RIA. In the RIAs, EPA performs a “Screening
Analysis” to “evaluate small entity impacts.” This identifies impacts on industries classified by
SIC codes.
Prior to publication of an initial regulatory flexibility analysis which a covered agency is
required to conduct by this chapter—
(1) a covered agency shall notify the Chief Counsel for Advocacy of the Small Business
Administration and provide the Chief Counsel with information on the potential impacts of
the proposed rule on small entities and the type of small entities that might be affected;
(2) not later than 15 days after the date of receipt of the materials described in paragraph
(1), the Chief Counsel shall identify individuals representative of affected small entities for
the purpose of obtaining advice and recommendations from those individuals about the
potential impacts of the proposed rule;
(3) the agency shall convene a review panel for such rule consisting wholly of full time
Federal employees of the office within the agency responsible for carrying out the proposed
rule, the Office of Information and Regulatory Affairs within the Office of Management and
Budget, and the Chief Counsel;

Congressional Research Service

20

Air Quality Standards: The Decisionmaking Process

(4) the panel shall review any material the agency has prepared in connection with this
chapter, including any draft proposed rule, collect advice and recommendations of each
individual small entity representative identified by the agency after consultation with the
Chief Counsel....
(5) not later than 60 days after the date a covered agency convenes a review panel pursuant
to paragraph (3), the review panel shall report on the comments of the small entity
representatives and its findings ...; and
(6) where appropriate, the agency shall modify the proposed rule, the initial regulatory
flexibility analysis or the decision on whether an initial regulatory flexibility analysis is
required. [Small Business Regulatory Enforcement Fairness Act of 1996, §244]

On the same basis that it decided the Unfunded Mandates and the Regulatory Flexibility Act
requirements did not apply when setting NAAQS, EPA concludes “that the small-entity
provisions in Section 244 of the Small Business Regulatory Enforcement Fairness Act (SBREFA)
do not apply.” [National Ambient Air Quality Standard for Ozone: Proposed Decision, p. 164]
And similarly, EPA says it “intends to fulfill the spirit of SBREFA on a voluntary basis” by
working with the Small Business Administration to hold panel exercises to solicit comments and
advice from representatives of small entities.
As part of American Trucking Associations v. U.S. E.P.A., this certification that SBREFA did not
apply was challenged. However, the D.C. Circuit Court found “incontestable” EPA’s argument
that setting a NAAQS has no direct impact on small businesses because the states, through the
SIP plan process, determine what sources will be affected. Thus the court concluded that “EPA
properly certified that its NAAQS would not have a significant impact on a substantial number of
small entities.” [American Trucking Associations v. U.S. E.P.A., 175 F.3d 1027 (D.C. Cir. 1999),
modified on other grounds, 195 F.3d 4 (D.C. Cir. 1999). This issue was not addressed in the
appeal to the Supreme Court, see 531 U.S. 457 (2001).]

Other Regulatory Impact Assessments
Besides the regulatory impact assessments required by the statutes discussed above, provisions of
the Paperwork Reduction Act may be triggered by reporting requirements. In the ozone and PM
proposed rules, EPA said that this issue would arise only in implementation.
Also, Executive Order 12848, Federal Actions To Address Environmental Justice in Minority
Populations and Low-Income Populations, requires each federal agency to identify and address,
as appropriate, disproportionate adverse health and environmental impacts of programs, policies,
and activities on minorities and low-income populations. Again, EPA indicates that analysis of
effects on minorities and low-income populations would be appropriately examined in
preparation of RIAs in the implementation process.22

22

RIA for Proposed Particulate Matter Ambient Air Quality Standard (December 1996), p. 8-26.

Congressional Research Service

21

Air Quality Standards: The Decisionmaking Process

Consultations—Office of Management and Budget; Other Departments and
Agencies
The drafts of ... rules submitted by the Administrator to the Office of Management and
Budget for any interagency review process ..., all documents accompanying such drafts,
and all written comments thereon by other agencies and all written responses to such
written comments by the Administrator shall be placed in the docket .... [CAA,
§307(d)(4)(B)(ii)]
To the extent permitted by law, OMB ... shall be the entity that reviews individual
regulations ....[Executive Order 12866]

EPA’s NAAQS decisions are subject to this OMB review: “In view of its important policy
implications, this proposal has been judged to be a ‘significant regulatory action’ within the
meaning of the Executive Order, and EPA has submitted it to OMB for review. Changes made in
response to OMB suggestions or recommendations will be documented in the public docket and
made available for public inspection....” [National Ambient Air Quality Standard for Ozone:
Proposed Decision, p. 157]. Apparently no changes were made on this basis, however.
Likewise, drafts of the proposed and final rule are circulated for review to other departments and
agencies. In cases of substantive controversy, as with the ozone and PM2.5 NAAQS, the issue may
go to the White House for final adjudication.

Judicial Review
A petition for review of action of the Administrator in promulgating any national
primary or secondary ambient air quality standard, ... may be filed only in the United
States Court of Appeals for the District of Columbia. ... Any petition for review ... shall
be filed within sixty days from the date notice of such promulgation ... appears in the
Federal Register .... [CAA, §307(b)(1)]

EPA’s NAAQS rulemaking is subject to several statutory procedural requirements, compliance
with which is subject to judicial review. The basic framework is spelled out in the CAA, §307(d),
[42 U.S.C. §7607(d)] and details the requirements for public notice and participation in the
process. The final rule cannot be based, in whole or part, on any information or data which have
not been placed in the rulemaking docket as of the date of its final promulgation. The final rule
must be accompanied by a statement of basis and purpose which includes a summary of the
factual data upon which the rule is based, the methodology used in obtaining and analyzing the
data, the major legal interpretations, and policy considerations underlying the remaking decision.
The statement must also contain the agency’s response to each of the significant comments,
criticisms, and new data submitted in written and oral presentations during the comment period.
Courts have also indicated that they will look at the alternatives the agency considered (or
believes it should have considered) in assessing necessary compliance. On appeal the court may
reverse the rulemaking action if it finds it to be “arbitrary, capricious, an abuse of discretion or
otherwise not in accordance with law,” a standard by which the courts assess the rule’s
reasonableness and rationality based on review of the rulemaking record taken as a whole.
The first suits challenging the ozone and PM NAAQS were filed in the D.C. Circuit Court of
Appeals on July 18, 1997, the day the final rules appeared in the Federal Register. During 1997 a
total of 38 suits were filed for judicial review of various aspects of the ozone and PM NAAQS.

Congressional Research Service

22

Air Quality Standards: The Decisionmaking Process

These suits were consolidated in American Trucking Associations v. U.S. E.P.A., argued
December 17, 1998, and decided May 14, 1999 [175 F.3d 1027 (D.C. Cir. 1999)]. Various parts of
that decision were then appealed to the U.S. Supreme Court, argued November 7, 2000, and
decided February 27, 2001 [Whitman, Administrator of Environmental Protection Agency, et al. v.
American Trucking Associations, Inc., et al., 531 U.S. _______ (2001)]. While the Supreme Court
decided several aspects of the case – including that the CAA constitutionally delegated authority
to EPA and that costs could not be taken into account in setting NAAQS, it remanded the question
of the validity of the standards to the D.C. Circuit Court. The Circuit Court issued its ruling on
March 26, 2002, upholding EPA’s particulate and ozone standards.
For any rule subject to this chapter, a small entity that is adversely affected or aggrieved by
final agency action is entitled to judicial review of agency compliance with the requirements
of sections 601, 604, 605(b) [... if the head of the agency certifies that the rule will not, if
promulgated, have a significant economic impact on a substantial number of small entities],
608(b), and 610 in accordance with chapter 7. [5 U.S.C. §611(a)(1)]

EPA’s decisions that requirements of the Small Business Regulatory Enforcement Fairness Act,
the Regulatory Flexibility Act, and the Unfunded Mandates Act do not apply to the ozone and PM
NAAQS were challenged. These were among the suits consolidated in American Trucking
Associations v. U.S. E.P.A. As previously noted, the D.C. Circuit Court of Appeals upheld EPA’s
position.

Congressional Review
Before a rule can take effect, the Federal agency promulgating such rule shall submit to
each House of the Congress ... a report ....
A rule shall not take effect ..., if the Congress enacts a joint resolution of disapproval .... [5
U.S.C. §801(a)(1)(A), (b)(1)]

EPA’s publication of its final decisions on the ozone and PM NAAQS on July 18, 1997, triggered
the Congressional Review of Agency Rulemaking provision of SBREFA. Under this provision,
Congress could consider a joint resolution of disapproval, with special procedures in the Senate to
ensure floor consideration within 60 legislative days. While the procedure was not invoked, bills
to delay the new standards were introduced, including H.R. 1984 and S. 1084, with a hearing held
on the latter. No bill to rescind the new NAAQS was reported from committee, however.

Congressional Research Service

23

Air Quality Standards: The Decisionmaking Process

Appendix A. The NAAQS-Setting Process

Source: Adapted from National Commission on Air Quality, To Breathe Clean Air (1981), based on EPA Information.

CRS-24

Air Quality Standards: The Decisionmaking Process

Appendix B. Setting NAAQS—A Typical
Chronology (Ozone)
August 1992

Ozone NAAQS review initiated

Summer/Fall 1993

Workshops

Spring 1994

Draft Criteria Document available to public and CASAC

July 20 and 21, 1994

CASAC meetings to review draft Criteria Document

March 20 and 21, 1995

CASAC meetings to review revised draft of Criteria Document; also to
review draft sections of Staff Paper

September 19 and 20, 1995

CASAC closure on Criteria Document; also closure on primary
standard section of Staff Paper

November 28, 1995

CASAC closure letter on Criteria Document sent to Administrator

November 30, 1995

CASAC closure letter on primary standard section of Staff Paper sent
to Administrator

March 21, 1996

CASAC subpanel meeting on secondary standard section of Staff Paper

April 4, 1996

CASAC closure letter on secondary standard section of Staff Paper sent
to Administrator

June 12, 1996

EPA publishes Advance Notice of Proposed Rulemaking (ANPR) for
Ozone & PM NAAQS

July 25 and August 8, 1996

Public meetings on ANPR

November 27, 1996/
December 13, 1996

Proposed Decision announced/published in Federal Register; public
comment period begins

January 14 and 15, 1997

Public Meetings in four cities on proposal

March 12, 1997

End of public comment period on proposal

Winter/Spring 1997

Congressional hearings on the proposed NAAQS

June 25, 1997

President Clinton endorses the proposed ozone & PM NAAQS, with
some modifications

late June 1997

EPA submits proposed final standards to OMB

July 16, 1997

Administrator signs off on final Ozone & PM NAAQS

July 18, 1997

Final NAAQS published in Federal Register

July 18, 1997

First suit challenging the final standards filed in the U.S. Court of
Appeals for the D.C. District

September 16, 1997

Ozone & PM rules become effective

December 17, 1998

American Trucking Associations v. U.S. E.P.A. argued before D.C. Circuit
Court of Appeals

May 14, 1999

D.C. Circuit Court of Appeals issues decision

October 29, 1999

D.C. Circuit Court of Appeals (en banc) denies petition for rehearing

May 22 and 29, 2000

Supreme Court accepts cert. on appeals by EPA and the U.S. Chamber
of Commerce

November 7, 2000

Oral arguments on American Trucking Associations v. U.S. E.P.A. before the
U.S. Supreme Court

Congressional Research Service

25

Air Quality Standards: The Decisionmaking Process

February 27, 2001

U.S. Supreme Court issues decision, which among other findings
unanimously concluded that costs may not be considered in setting
NAAQS, remands issue of adequacy of science for standards to Circuit
Court

March 26, 2002

D.C. Circuit Court of Appeals issues decision, basically upholding EPA’s
particulate and ozone standards

Author Contact Information
(name redacted)
Specialist in Environmental Policy
[redacted]@crs.loc.gov, 7-....

Congressional Research Service

(name redacted)
Specialist in Energy and Environmental Policy
[redacted]@crs.loc.gov, 7-....

26

EveryCRSReport.com
The Congressional Research Service (CRS) is a federal legislative branch agency, housed inside the
Library of Congress, charged with providing the United States Congress non-partisan advice on
issues that may come before Congress.
EveryCRSReport.com republishes CRS reports that are available to all Congressional staff. The
reports are not classified, and Members of Congress routinely make individual reports available to
the public.
Prior to our republication, we redacted names, phone numbers and email addresses of analysts
who produced the reports. We also added this page to the report. We have not intentionally made
any other changes to any report published on EveryCRSReport.com.
CRS reports, as a work of the United States government, are not subject to copyright protection in
the United States. Any CRS report may be reproduced and distributed in its entirety without
permission from CRS. However, as a CRS report may include copyrighted images or material from a
third party, you may need to obtain permission of the copyright holder if you wish to copy or
otherwise use copyrighted material.
Information in a CRS report should not be relied upon for purposes other than public
understanding of information that has been provided by CRS to members of Congress in
connection with CRS' institutional role.
EveryCRSReport.com is not a government website and is not affiliated with CRS. We do not claim
copyright on any CRS report we have republished.

---

Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/crs%3A97-722. Public record. Not legal advice.
