Order Code RL32431
CRS Report for Congress
Received through the CRS Web
Particulate Matter (PM ): National Ambient
2.5
Air Quality Standards (NAAQS) Implementation
Updated January 7, 2005
Robert Esworthy
Specialist in Environmental Policy
Resources, Science, and Industry Division
Congressional Research Service ˜ The Library of Congress

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Particulate Matter (PM ): National Ambient
2.5
Air Quality Standards (NAAQS) Implementation
Summary
On January 5, 2005, the U.S. Environmental Protection Agency (EPA)
published a final rule designating geographical areas for the national ambient
(outdoor) air standards for fine particulate matter or “PM ” (particles less than 2.5
2.5
micrometers in diameter). EPA designated 225 counties in 20 states, and the District
of Columbia, as “nonattainment areas;” those areas with (or contributing to) air
quality levels exceeding the annual and 24-hour PM standards, which limit the
2.5
concentration of fine particle levels in the ambient air.
Particulate matter, including PM , is one of the six principal pollutants
2.5
classified as criteria pollutants for which EPA has set National Ambient Air Quality
Standards (NAAQS) under the Clean Air Act (CAA). NAAQS are designed
primarily to protect human health with an adequate margin of safety. After several
years of litigation and other delays, EPA is moving to implement the NAAQS for
PM promulgated in 1997.
2.5
The designation of geographical areas for attainment or nonattainment is a
critical step in the implementation of the PM NAAQS. PM nonattainment areas
2.5
2.5
will require the development of comprehensive implementation plans to meet the
PM standards. Some areas, which have not been designated as nonattainment under
2.5
implementation of other NAAQS, are expected to be designated nonattainment for
the first time.
At the end of June 2004, EPA recommended designating 244 counties in 21
states and the District of Columbia as “nonattainment areas” for the PM NAAQS.
2.5
The agency’s recommendations were in response to submissions received from 18
states and the District of Columbia in mid-February 2004 designating 142 counties
as nonattainment areas. EPA notified each of the affected states regarding their
specific modifications to allow them sufficient opportunity to demonstrate why a
proposed modification is inappropriate. EPA considered states’ responses to the
agency’s proposal in making the final designations.
A number of issues will continue to be the topic of debate as the implementation
of the PM NAAQS progresses. Among the questions and concerns are: when and
2.5
why the standards were established; what criteria were used to determine
nonattainment; how boundaries of the nonattainment area were established; whether
special provisions can be made for areas affected by pollution from upwind; what the
deadline will be for reaching attainment; what grants or other funding might be
available to assist areas in reaching attainment; and how nonattainment designation
might affect economic development and transportation investments in an area.
The ongoing mandated periodic review of PM NAAQS, and currently pending
court challenges that followed the recent release of the 8-hour ozone designations,
could affect PM NAAQS implementation. Legislation affecting various aspects of
2.5
regulating air quality could also potentially alter the implementation process. This
report will be updated as developments warrant.

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Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
The PM Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.5
Geographical Area Designation Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
PM NAAQS Geographical Area Designations . . . . . . . . . . . . . . . . . . . . . . 8
2.5
Demonstrating Attainment: The State Implementation Plan . . . . . . . . . . . . 10
PM NAAQS Implementation Timeline and Delays . . . . . . . . . . . . . . . . . 12
2.5
Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1997 Ozone NAAQS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Boundaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Spatial Averaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Upwind Pollutant Contributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Identifying Sources and Control Measures . . . . . . . . . . . . . . . . . . . . . 15
Economic Impacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Grant Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
EPA’s Review of the 1997 PM Standards . . . . . . . . . . . . . . . . . . . . . . 17
Proposed Legislation and Regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
List of Figures
Figure 1. EPA Estimates of Counties in Nonattainment of PM and
2.5
8-Hour Ozone NAAQS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Figure 2. U.S. Environmental Protection Agency Designations of Attainment
and Nonattainment Areas for the PM National Ambient Air Quality
2.5
Standards (NAAQS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
List of Tables
Table 1. Estimated Schedule for PM NAAQS Implementation . . . . . . . . . . . . 12
2.5

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Particulate Matter (PM ):
2.5
National Ambient Air Quality Standards
(NAAQS) Implementation
Introduction
On December 17, 2004, the U.S. Environmental Protection Agency (EPA)
finalized the designations of geographical areas for attainment or nonattainment1 of
the national ambient (outdoor) air standards for fine particulate matter or “PM ”
2.5
(particles less than 2.5 micrometers
(µm) in diameter). This action
What Is PM ?
2.5
continues EPA’s implementation of
PM can be naturally occurring or
2.5
new National Ambient Air Quality
manmade in the form of solid particles in
Standards (NAAQS) for particulate
soot, smoke, dust, and in some instances is
matter promulgated in 1997 under
in the form of liquid particles. PM can
2.5
authority of the Clean Air Act (CAA),2
come from various residential and
delayed until recently because of court
industrial combustion activities, or they
may result from the reaction of certain gas
challenges and other factors.
emissions with the atmosphere. Sources of
PM include vehicle and equipment
2.5
EPA announced the designation of
exhaust, utility and other industrial plant
all or part of 225 counties3 in 20 states,
emissions, burning wood, and fugitive dust
as well as the District of Columbia, for
emissions from roads or generated by
nonattainment of the PM NAAQS.
2.5
various activities such as construction and
The final designations were based, in
agricultural operations. PM has been
2.5
part, on the EPA’s review and
linked to cardiovascular and respiratory
consideration of recommendations
health problems, and contributes to
previously provided by states and
visibility “haze” and acidic deposition.
tribes.4
The final rule was published in the Federal Register on January 5, 2005 (70
Fed. Reg. 944-1019) and goes into effect April 5, 2005 (90 days from the date of
publication). EPA could withdraw a nonattainment designation prior to this date if
1Areas are identified as “nonattainment” when they violate or contribute to the violation of
National Ambient Air Quality Standards (NAAQS), or “attainment/unclassified” when they
meet the standard or the data are insufficient for making a determination of compliance with
the NAAQS.
262 Federal Register 38652-38896, July 18, 1997.
3Includes 7 cities: Baltimore, MD; St. Louis, MO; Alexandria, VA; Fairfax, VA; Falls
Church, VA; Manassas, VA; and Manassas Park, VA.
4By the end of February 2004, 18 states and the District of Columbia had recommended 142
counties as potential nonattainment areas (see EPA’s “PM Designations” website at
2.5
[http://www.epa.gov/pmdesignations]).

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CRS-2
a state provides 2004 data, by February 22, 2005, suggesting that a change in
designation is appropriate. Because monitoring data for 2004 was not available in
time for EPA to meet its statutory deadline for PM geographical area designations,
2.5
the agency relied on three-year monitoring data from 2001 to 2003 to make the final
designations.
Nonattainment designation begins a process in which states (and tribes) must
develop and adopt emission control programs sufficient to bring air quality into
compliance by an EPA-defined deadline. States are required to submit
“implementation” plans for how they will meet the PM NAAQS by early 2008, and
2.5
must be in compliance by 2010 unless they are granted a five-year extension.
When the NAAQS was promulgated in 1997, EPA estimated that compliance
with the PM NAAQS was expected to result in the prevention of 15,000 premature
2.5
deaths, 75,000 cases of chronic bronchitis, and 10,000 hospital admissions for
respiratory and cardiovascular disease, as well as other benefits. These estimates,
which reflect health effects prevented during a single year, have been the subject of
significant debate and re-analyses. Although some stakeholders continue to question
the substantiation of these benefits, EPA and others contend that more recent analysis
suggest the actual benefits may be larger than the original estimates.5
Designating areas as nonattainment is expected to raise questions and concerns,
particularly for those areas designated nonattainment for the first time. These
questions and concerns include when and why the standards were established; what
criteria were used to determine nonattainment; how boundaries of the nonattainment
area are established; whether special provisions can be made for areas affected by
pollution from upwind; what the deadline will be for reaching attainment; what
grants or other funding might be available to assist areas in reaching attainment; and
how designation might affect economic development and transportation investments
in an area.6
This report provides a brief overview of the NAAQS implementation process
in the context of the PM standards, including links to sources of additional
2.5
information. The report also discusses issues and legislation that could potentially
alter the PM NAAQS implementation process. For a detailed discussion of the
2.5
5 There is extensive and growing literature on the health effects of PM . For relevant EPA
2.5
criteria and technical documents in support of the 1997 promulgation, as well as more
recent analyses, see [http://www.epa.gov/ttn/naaqs/standards/pm/s_pm_index.html]. For a
discussion of estimated premature mortality, see Statement of Jonathan Levy, Harvard
School of Public Health, at “Health Effects of PM Emissions,” Hearing, Senate
2.5
Environment and Public Works Committee, October 2, 2002. Recent research indicates a
correlation between particulate concentrations and infant mortality (The Impact of Air
Pollution on Infant Mortality: Evidence from Geographic Variation in Pollution Shocks
Induced by a Recession, Kenneth Y. Chay and Michael Greenstone, Quarterly Journal of
Economics, Volume 118, Issue 3, August 2003).
6EPA’s April 15, 2004, designation of areas in 32 states and the District of Columbia (474
counties) as “nonattainment areas” for a new ozone air quality standard (promulgated the
same time as the PM NAAQS in 1997) raised similar concerns. See CRS Report
2.5
RL32345, Implementation of EPA’s 8-Hour Ozone Standard.

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CRS-3
history of the PM NAAQS, including an overview of relevant health effects studies
and the status of the statutorily required periodic review, see CRS Report RL31531,
Particulate Matter Air Quality Standards: Background and Current Developments.
Background
NAAQS are a core component of the CAA,7 and the statute requires EPA to set
primary standards at a level “requisite to protect the public health” with an “adequate
margin of safety” (42 U.S.C. 7409(b)(1)), based on a review of the scientific
literature. The CAA also requires setting secondary standards at a level “requisite to
protect the public welfare” as defined by the act (42 U.S.C. 7409(b)(2) and 7602(h)).
EPA has promulgated NAAQS for six principal pollutants classified by the agency
as “criteria pollutants”: sulfur dioxide (SO ), particulate matter (PM and PM ),
2
2.5
10
nitrogen dioxide (NO ), carbon monoxide (CO), ozone, and lead. NAAQS for PM
2
10
(“coarse particulate matter”), which have been in place since 1987, were maintained
with some modification in the final 1997 rule that included adding the PM2.5
standards (see discussion later in this report).
Since they were modified in 1997, the particulate matter standards (also referred
to as the PM NAAQS) issued by EPA have been the source of significant controversy
and national debate, which has led to the delay in their implementation. Congress has
been especially interested in EPA’s promulgation and implementation of these CAA
standards and has held numerous hearings on particulate matter.
EPA is in the process of reviewing the PM standards promulgated in 1997.
Every five years, according to the statute (but less frequently in practice), EPA is
required to review the latest scientific studies and either reaffirm or modify the
NAAQS. EPA’s review of the 1997 PM standards began not long after the current
standards were promulgated.8 As part of the review process, on October 29, 2004,
EPA released the report Air Quality Criteria for Particulate Matter. Referred to as
a “criteria document,” the report will provide the scientific basis for assessments and
policy decisions regarding the adequacy of the existing PM NAAQS. EPA has
targeted December 2005 for publishing its decision on whether or not to propose
changes to the current PM standards.
The PM Standards
2.5
Earlier regulation and monitoring of particulate matter under the CAA,
beginning in 1971, focused primarily on total suspended particles (TSP) and later on,
7Sections 108 and 109 of the Clean Air Act (CAA) govern the establishment, review, and
revisions of NAAQS (42 U.S.C. 7408 and 7409). For an overview of NAAQS and the
standard-setting process, see CRS Report RL30853: Clean Air Act: A Summary of the Act
and Its Major Requirements, and CRS Report 97-722 ENR, Air Quality Standards: The
Decisionmaking Process.
8For EPA’s original plans for reviewing the PM NAAQS, see 62 Federal Register 55201,
October 23, 1997.

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CRS-4
coarse particles equal to or less than 10 micrometers in diameter (PM ).9 After
10
extensive analysis and review, EPA revised the PM standards to provide separate
requirements for fine particulate matter (PM ) based on their link to several types of
2.5
cardiovascular and respiratory health problems, including aggravated asthma and
bronchitis, and links to premature death. EPA also revised the coarse particles
designation (PM ) to include particles larger than 2.5 but smaller than 10
10
micrometers (PM
), so as to explicitly exclude fine particles, and as part of the
10-2.5
1997 rule, promulgated the 8-hour ozone standard.
The primary and the secondary PM NAAQS requirements, which became
2.5
effective September 16, 1997,10 are the same. The PM standards are set at:
2.5
1. an annual maximum concentration of 15 micrograms per cubic meter
(µg/m3) based on the three-year average of arithmetic PM concentrations
2.5
for one or more community-oriented monitors;11 and

2. a 24-hour concentration of 65 µg/m3, based on the three-year average
of the 98th percentile of 24-hour PM concentrations at each population-
2.5
oriented monitor12 within the area.
In requiring both the annual and the 24-hour PM standards, EPA reportedly
2.5
considered the “combined effect of the standards rather than an approach that
weighed short- and long-term exposure evidence, analyses, and standards
independently.”13 EPA considers the annual standard the primary requirement for
reducing total PM risk. The 24-hour standard is intended to provide supplemental
2.5
protection for days with peak PM concentrations, localized “hot spots,” and PM
2.5
2.5
risks arising from seasonal emissions.
EPA changed the “form” of the 24-hour standards to a concentration-based
percentile form, indicating the percent of the time that a monitoring station can
exceed the standard. For instance, a 99th percentile 24-hour standard indicates that
a monitoring station can exceed the standard 1% of the time, or 3.65 days a year, if
monitoring occurs every day. The previous form was known as the “one-expected-
exceedance” form; monitoring stations could exceed the 24-hour PM NAAQS only
once, averaged over three years. Although the limits of PM remained the same, the
10
form of the PM 24-hour standard was changed to be based on a three-year average
10
of the 99th percentile of 24-hour PM concentrations.
10
9See 52 Federal Register 24640, July 1, 1987.
1062 Federal Register 38652-38896, July 18, 1997.
11Community oriented monitoring zones are defined as “an optional averaging area with well
established boundaries such as county or census block” (40 CFR Part 58 Subpart A).
12Population-oriented monitoring (or sites) applies to “residential areas, commercial areas,
recreational areas, industrial areas, and other areas where a substantial number of people
may spend a significant fraction of their day” (40 CFR Part 58 Subpart A).
13U.S. EPA Fact Sheet: EPA’s Revised Particulate Matter Standards, July 17, 1997.

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Geographical Area Designation Process
The designation of geographical areas failing to comply with the NAAQS based
on monitoring and analysis of relevant air quality data is a critical step in NAAQS
implementation. The CAA establishes a process for designating nonattainment areas
and setting their boundaries, but it allows the EPA Administrator some discretion in
determining what the final boundaries of the areas will be. According to EPA’s 2003
Trends Report, there were 124 areas designated as nonattainment for at least one of
the six criteria pollutants (including particulate matter) and approximately 126
million people living in these areas, as of September 2002.14 The number of
nonattainment areas and associated population have increased since the 2003 Trends
Report; the April 15, 2004, 8-hour ozone designated nonattainment areas alone
include 159 million people.15
The designation process is intended as a cooperative federal-state/tribe process
in which states/tribes provide initial designation recommendations to EPA for
consideration. Tribes are not required, but were encouraged, to submit
recommendations.16 In Section 107(d)(1)(A) (42 U.S.C. 7407), the statute states that
governors shall submit a list to EPA of all areas in the state, “designating as ...
nonattainment, any area that does not meet (or that contributes to ambient air quality
in a nearby area that does not meet)” an air quality standard (emphasis added).
PM attainment or nonattainment designations are to be made primarily on the
2.5
basis of three-year federally referenced PM monitoring data.17 At the time the new
2.5
NAAQS were being finalized, EPA also developed methods for monitoring fine
particles. Using funding specifically authorized for this purpose in EPA
appropriations FY1998-FY2000,18 the agency worked closely with states and tribes
to initiate the deployment of a portion of the network of 1,200 monitors in January
1999. The majority of the monitors were not in place until January 2000.
States/tribes were expected to rely on data collected during 2000-2002 for their
14U.S. EPA, National Air Quality Trends Report: 2003 Special Studies, Chapter 4, pp. 59-61,
September 2003, at [http://www.epa.gov/airtrends/pm.html].
15The EPA “Greenbook” lists areas of the country where air pollution levels persistently
exceed the national ambient air quality standards and may be designated as nonattainment.
For current information on the location of NAAQS nonattainment areas, visit EPA’s website
[http://www.epa.gov/oar/oaqps/greenbk.html].
16The area designation requirements under the CAA (section 107) are specific with respect
to states, but not tribes. EPA plans to follow the same designation process for tribes per
sections 110(o) and 301(d) of the CAA and pursuant to the 1988 Tribal Authority Rule,
which specifies that tribes shall be treated as states in selected cases (40 Code of Federal
Regulations Part 49). Six tribes have participated in the PM designation recommendation
2.5
process to date (see [http://www.epa.gov/pmdesignations]).
17A federally referenced monitor is one that has been accepted for use by EPA for
comparison of the NAAQS by meeting the design specifications, and certain precision and
bias (performance) specifications (40 Code of Federal Regulations Part 58).
18Appropriations for monitoring averaged roughly $50 million per year, P.L. 105-65, P.L.
105-226, P.L. 106-74.

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CRS-6
recommendations. EPA considered the 2001-2003 data to make the final
designations.
In its guidance document,19 the EPA identified several factors that states/tribes
and the agency would consider for determining attainment with the PM NAAQS,
2.5
and also specified data and conditions that would not be acceptable. The EPA’s
nonbinding guidance also includes a recommendation that states/tribes consider using
the same boundaries for nonattainment for both the PM and 8-hour ozone standards,
2.5
to facilitate consistency in future implementation plans. Many of the PM2.5
nonattainment areas are expected to overlap with the 8-hour ozone designations.
Figure 1 (below) shows EPA’s estimates for violations of the PM and 8-hour ozone
2.5
NAAQS based on 2000-2002 monitoring data, and indicates the potential overlap of
the two NAAQS. These data show at least one monitor measuring concentrations
exceeding the PM NAAQS in 120 counties. Final PM designation areas were
2.5
2.5
determined based on 2001-2003 monitoring data. Also, the map in Figure 1 only
shows those counties with monitoring results above the standards; however, final
nonattainment designation areas include other counties within a defined metropolitan
statistical area.
Figure 1. EPA Estimates of Counties in Nonattainment of
PM and 8-Hour Ozone NAAQS
2.5
(based on 2000-2002 data)
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2.5
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19See EPA’s NAAQS website at [http://www.epa.gov/ttn/naaqs/pm/pm25_guide.html].

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CRS-7
PM designations do not include nonattainment classifications based on
2.5
severity as is the case with PM and ozone, which has seven classifications. The
10
1990 CAA Amendments include classifications of nonattainment based on the extent
to which the NAAQS is exceeded, and establish specific pollution controls and
attainment dates for each classification.20 EPA interprets that those classification
provisions in the act regarding particulate matter21 explicitly apply to PM , but not
10
PM , NAAQS implementation. PM implementation is governed by the general
2.5
2.5
nonattainment planning requirements of Title I of the act.22
EPA recognized that determining the geographic extent of nearby source areas
that contribute to nonattainment would be complicated. The CAA is not specific
regarding requirements to combine neighboring counties within the same
nonattainment area, but it does require the use of metropolitan statistical area
boundaries in the more severely polluted areas (Section 107(d)(4)(A)(iv)). Echoing
this requirement, and similar to the 8-hour ozone approach, EPA recommended that
Metropolitan Statistical Areas or Consolidated Metropolitan Statistical Areas23 serve
as the “presumptive boundary” for nonattainment areas under the PM standards.
2.5
Metropolitan areas are generally treated as units, even where part of the area lies
in a separate state or where part of the area does not have readings exceeding the
standards. In the latter case, even though a specific county may not exceed the
standards, the pollution generated there is likely to influence PM levels elsewhere
2.5
in the metropolitan area. In addition, including the entire metropolitan area avoids
the creation of additional incentives for sprawl development on the fringes of urban
areas. For rural areas in violation of the PM standards, EPA’s guidance presumes
2.5
that the full county would be designated a nonattainment area.
Following state/tribe designation submissions, the EPA Administrator has
discretion to make modifications, including to the area boundaries. As required by
statute,24 the agency must notify the states/tribes regarding any modifications,
allowing them sufficient opportunity to demonstrate why a proposed modification is
inappropriate, but the final determination rests with EPA.
20These requirements can be found in Title I Part D Sections 171-193 of the act.
21Under subpart 4 of the CAA, PM nonattainment designations are either “moderate” or
10
“serious,” and each of these categories is subject to specified control requirements.
Moderate areas require permits for new and modified major stationary sources of PM and
10
must impose reasonably available control measures (RACM). Serious areas must impose
best available control measures (BACM) and reduce definition of a major source of PM10
from 100 tons per year to 70 tons per year. For areas designated moderate, the deadline for
attainment is six years after designation; for serious areas, the deadline is ten years after
designation (Section 188 of Part D subpart 4 of Title I in the CAA; 42 U.S.C. Sec. 7513).
22CAA Title I Part A, and Part D subpart 1.
23As defined by the Office of Management Budget. For more information on the definitions
of metropolitan areas, see [http://www.census.gov/population/www/estimates/metroarea].
24CAA section 107(d)1(B)(ii).

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CRS-8
Detailed information regarding EPA’s guidance for PM designation can be
2.5
obtained from EPA’s PM Implementation website at [http://www.epa.gov/ttn/
2.5
naaqs/pm/pm25_index.html] and its Policy and Guidance website at [http://www.
epa.gov/ttn/oarpg].
PM NAAQS Geographical Area Designations
2.5
By the end of February 2004, 18 states and the District of Columbia had
recommended 142 counties as potential nonattainment areas.25 After completing its
review of the state/tribe attainment designation recommendations, EPA
recommended modifications resulting in nonattainment designations for 244 counties
in 21 states and the District of Columbia at the end of June 2004. As required by
statute, the EPA notified each of the affected states regarding their specific
modifications to allow sufficient opportunity to provide new information and
demonstrate why a proposed modification is inappropriate. Some states responding
to the EPA’s proposal continued to support their original recommendations.
EPA’s final designations of 225 counties in 20 states, and the District of
Columbia, reflect minor modifications to its June 2004 proposal. The modifications
are primarily the result of removing 19 counties from the list of nonattainment areas,
and redefining other counties by designating only specified geographical locations
(“partial”) within the county as nonattainment. Taking into consideration factors
defined in the agency’s guidance in conjunction with the additional information
provided by the states, in some cases EPA determined that only those portions of a
county that contained the significant sources of emissions should be considered as
contributing to the violations. In other cases, the agency determined that if emissions
from a large identifiable source in a county were contributing to the violations in a
nearby area, the portion of the county where the source was located would be
designated nonattainment, even if it is not contiguous with the remainder of the
designated area. The boundaries for these “noncontiguous” portions are based on
legally recognized government boundaries, such as townships, tax districts, or census
blocks.
The designated nonattainment areas are primarily concentrated in the central,
mid-Atlantic, and southeastern states east of the Mississippi River, as well as in
California, which has established its own PM standards.26 The map in Figure 2 on
2.5
the next page, obtained from EPA’s website ([http://www.epa.gov/pmdesignations/
nonattaingreen.htm]), highlights the PM nonattainment designation areas. More
2.5
than 2,900 counties were designated as attaining compliance for the PM NAAQS
2.5
or as unclassifiable. Some public interest groups maintain that at least 150 additional
25For EPA’s proposed PM geographical designation recommendations and those from
2.5
individual states and tribes, see EPA’s “PM Designations” website at [http://www.epa.gov/
2.5
pmdesignations].
26For more information regarding California’s PM standards, see CRS Report RL31531,
2.5
Particulate Matter Air Quality Standards: Background and Current Developments (p. 28-
29), or visit the California Air Resources Board website at [http://www.arb.ca.gov/pm/
pmmeasures/pmmeasures.htm] (visited November 16, 2004).

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CRS-9
counties warranted nonattainment designations on the basis of emission sources
within those areas.27
Figure 2. U.S. Environmental Protection Agency Designations of
Attainment and Nonattainment Areas for the PM National
2.5
Ambient Air Quality Standards (NAAQS)
Based on 2001-2003 monitoring data.
Source: U.S. Environmental Protection Agency, December 17, 2004 ([http://www.epa.gov/
pmdesignations/nonattaingreen.htm]).
Some states and stakeholders continue to contend that several counties should
not be designated nonattainment, particularly when taking into account 2004 PM2.5
monitoring data. EPA’s final designations are based on monitoring data for the
three-year period 2001-2003. Monitoring data for 2004 were not available in time
for EPA to meet its statutory deadline (see discussion later in this report) for PM2.5
geographical area designations. The final PM designation rule allows states to
2.5
submit no later than February 22, 2005, certified, quality-assured 2004 monitoring
data that suggests a change in designation is appropriate for consideration (70 Fed.
Reg. 948). A nonattainment designation could be withdrawn if the EPA agrees that
the additional data warrants such a change.
27American Lung Association, December 17, 2004, press release, “No One Should Have to
Breathe Unsafe Air,” available at [http://www.lungusa.org].

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CRS-10
Demonstrating Attainment: The State Implementation Plan
Following designation of an area as nonattainment, the state where the area is
located must develop a State Implementation Plan (SIP) that demonstrates how
attainment with the PM standards will be achieved. Under Section 110 of the CAA,
2.5
the states must submit their SIPs to EPA within three years of designation. To be
approved, a SIP must demonstrate that the area will reach attainment of the standards
by a specified deadline. SIPs include pollution control measures that will be
implemented by federal, state, and local governments, and rely on models of the
impact on air quality of projected emission reductions to demonstrate attainment.
EPA plans to propose an “implementation” rule later in 2005 that will establish the
planning and control requirements for PM for those areas designated as
2.5
nonattainment.
EPA has concluded that in many cases, PM attainment will be reached as the
2.5
result of implementing strategies developed under the 1999 visibility protection
regulations (“Regional Haze Rule”28); voluntary diesel engine retrofit programs; new
federal standards on cars, light trucks, and heavy duty diesel engines that are
scheduled to be implemented between 2004 and 2010; and the 1998 regional strategy
to reduce nitrogen oxides from eastern states referred to as the “NOx SIP Call.”29
Although primarily designed to meet the ozone NAAQS, EPA predicts the NOx SIP
call will also provide benefits in terms of reduced levels of nitrate fine particles.
According to a December 2004, EPA report, The Particle Pollution Report:
Current Understanding of Air Quality and Emissions through 2003, monitored
concentrations of PM have decreased 10 percent, and PM have decreased 7 percent
2.5
10
since 1999, primarily in areas with the highest concentrations.30 EPA attributes a
large portion of these decreases to the Acid Rain Program.
Other, proposed, legislation (not enacted) and EPA regulations for controlling
coal-fired electric power plants’ emissions, such as “Clear Skies”/multi-pollutant
legislation and the proposed “Clean Air Interstate Rule” (CAIR, also referred to as
the Interstate Air Quality (IAQ) Rule),31 to be implemented between 2004 and 2015,
are also expected to contribute national and regional measures for attaining PM2.5
standards. The EPA predicts that, of an estimated 120 eastern counties out of
compliance with PM NAAQS in 2002, the Clean Air Interstate Rule would bring
2.5
28 more counties into compliance in addition to the 58 counties predicted to come
2864 Federal Register 35714, July 1, 1999. EPA recently published a proposal revising the
regional haze rule, intended to provide guidelines for state and tribal air quality agencies to
use in determining how to set air pollution limits (69 Federal Register 25184, May 5, 2004).
2964 Federal Register 35714, October 27, 1998.
30U.S. Environmental Protection Agency, EPA 454-R-04-002, December 2004. Revised
report posted on EPA’s website at [http://www.epa.gov/airtrends/pm.html],December 23,
2004.
3169 Federal Register 4572, January 30,2004.

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CRS-11
into compliance under existing programs.32 The extent of pollution reduction that is
projected as a result of these proposals has been the subject of considerable debate
among stakeholders, and some Members of Congress.
If new, or revised, SIPs for PM attainment establish or revise a transportation-
2.5
related emissions allowance (“budget”), or add or delete transportation control
measures (TCMs), they will trigger “conformity” determinations. Transportation
conformity is required by the Clean Air Act, Section 176(c) (42 U.S.C. 7506(c)), to
ensure that federal funding and approval are given to highway and transit projects
that are consistent with (“conform to”) the air quality goals established by a SIP, and
will not cause new air quality violations, worsen existing violations, or delay timely
attainment of the national ambient air quality standards.33 The initial conformity rule
was promulgated by EPA November 24, 1993 (58 Federal Register 62188), and has
subsequently been amended several times. The most comprehensive amendments,
clarifying and streamlining the 1993 rule, were published August 15, 1997 (62
Federal Register 43780).
Transportation conformity, under EPA’s previous rules, applied to ozone, PM ,
10
CO, and NOx, but did not include PM . On July 1, 2004, EPA published a final
2.5
rule34 making transportation conformity regulations explicitly applicable to PM2.5
nonattainment areas, and including criteria and procedures for the new PM and 8-
2.5
hour ozone NAAQS. Conformity determinations must be submitted to EPA within
one year of the effective date designating an area as nonattainment. Since the
transportation conformity requirements could apply in PM nonattainment areas
2.5
prior to the availability of SIP emission budgets, EPA included provisions in the rule
for interim emissions tests for conformity determinations.35

Given the complexities associated with the final conformity rule, EPA provided
guidance to accompany the rule. The guidance, entitled Companion Guidance for the
July 1, 2004, Final Transportation Conformity Rule: Conformity Implementation in
Multi-Jurisdictional Nonattainment and Maintenance Areas for Existing and New
Air Quality Standards,36 expands on the final conformity rule by including additional
detailed examples, and interpretations for generic scenarios that are present in the
field and that are expected to occur under the new standards. EPA has provided other
32For a further discussion, see CRS Report RL31779, Air Quality: Multi-Pollutant
Legislation in the 108th Congress; and CRS Report RL32273, Air Quality: EPA’s Proposed
Interstate Air Quality Rule.
33For additional information on conformity, see CRS Report RL32106, Transportation
Conformity Under the Clean Air Act: In Need of Reform?
3469 Federal Register 40004. The final rule was signed on June 14, 2004. EPA uses the
Federal Register publication date when referring to a rule for information purposes.
35See 69 Federal Register 40014-40015. July 2004.
36U.S. Environmental Protection Agency, July 2004, EPA420-B-04-012. Transportation and
Regional Programs Division, Office of Transportation and Air Quality. Available at
[http://www.epa.gov/otaq/transp/conform/420b04012.pdf], viewed November 22, 1004.

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CRS-12
fact sheets and summary tables, and is conducting training sessions for implementers,
to further assist understanding of the requirements of the rule.37
PM NAAQS Implementation Timeline and Delays
2.5
Due to legal challenges, lack of a national monitoring network, and other
factors, implementation of the new standards has been delayed since they were
promulgated. The timeline presented in Table 1 reflects the most recent key
milestone dates for PM implementation. The current implementation schedule is
2.5
based primarily on statutory requirements. An initial milestone schedule was
outlined in an April 21, 2003, memorandum to EPA Regional Administrators, which
also provides the non-binding guidance for implementation of the PM2.5
designations.38 Recognizing there may be potential efficiencies associated with states
and tribes being able to harmonize future control strategies, the initial PM schedule
2.5
was intended to be similar to the 8-hour ozone program.
Table 1. Estimated Schedule for PM NAAQS Implementation
2.5
Date
PM NAAQS Milestones
2.5
February 2004 (completed)
State/tribal area designation recommendations
(based on 2000-2002 monitoring data)
June-July 2004 (completed)
EPA notifies states/tribes regarding modifications
to states/tribes’ recommendations
January 5, 2004 (completed)
EPA promulgates final area designations (required
(published in the 70 Fed. Reg. 944)
1 year after states/tribes’ recommendations)
February 2005
EPA proposes PM implementation rule
2.5
January 5, 2006 (1 year after the
States must submit transportation conformity
final designation effective date)
determination within one year of the effective date
of nonattainment designation (per EPA’s final
“conformity rule,” published July 1, 2004)
Early 2006
EPA promulgates final PM implementation rule
2.5
January 2008 (3 years after final area
States/tribes submit revised implementation plans
designations)
(SIPS) to achieve PM compliance in
2.5
nonattainment areas
2010-2015 (5-10 years after final
NAAQS statutory compliance deadline for
area designations)
attainment
Source: Prepared by the Congressional Research Service based on U.S. Environmental Protection
Agency fact sheets and guidance documents, and relevant Federal Register Notices.
37For EPA fact sheets, Q&As, training and training material, regarding the July 2004
conformity rule, see EPA’s Office of Transportation and Air Quality website
[http://www.epa.gov/otaq/transp/conform/2004training.htm], viewed November 22, 2004.
38EPA memorandum, April 21, 2003, from EPA’s Office of Air and Radiation Assistant
Administrator Jeffrey R. Holmstead to EPA Regional Administrators, available on EPA’s
NAAQS website at [http://www.epa.gov/ttn/naaqs/pm/pm25_guide.html].

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CRS-13
The PM requirement of three years of monitoring data to determine whether
2.5
or not areas are meeting the established limits is one factor responsible for delaying
implementation. Comprehensive monitoring data sufficient to make this
determination and the attainment designations were not available in 1997.
Recognizing this dilemma, in the 1998 Transportation Equity Act for the 21st
Century (TEA-21),39 Congress revised the statutory deadline requirements for the
new NAAQS, predicated on a previously released EPA Interim Implementation
Policy. TEA-21 required states to submit designation recommendations within one
year after receipt of three years of data meeting defined federal protocols, and EPA
to promulgate designations within one year after state recommendations are due but
not later than December 31, 2005.
As discussed earlier, operation of the network of monitors was phased in from
1999 through 2000, making three-year monitoring data available at different points
depending on area location. Rather than a staggered designation schedule which
would likely result in hampering cross-coordination of implementation plans, the
EPA proposed a single date for state/tribal recommendations and final EPA
designations.
In addition to the delay in establishing a monitoring network, the NAAQS
standards were challenged in District Court by the American Trucking Associations,
the U.S. Chamber of Commerce, and several other state and business groups. An
initial May 1999 opinion by the District Court partially in favor of the plaintiffs, was
reversed by the Supreme Court in February 2001.40
Whether the EPA has exceeded its authority by extending deadlines for existing
nonattainment areas, and whether the statutory requirements should be made more
flexible has been an issue of recent debate.41 In its “Clear Skies” bill (H.R. 999/ S.
485) and in its regulatory guidance, the Administration proposed additional flexibility
for areas designated nonattainment beyond what exists currently in the CAA.
Congress amended the CAA in the FY2004 omnibus appropriations (P.L.108-199)
mandating the current PM deadlines of February 15, 2004, for Governors to submit
2.5
their PM designation recommendations, and December 31, 2004, for EPA to
2.5
promulgate designations for each state.
39P.L. 105-178, Title VI.
40United States Court of Appeals for the District of Columbia Circuit, argued December 17,
1998; decided May 14, 1999 (No. 97-1440). American Trucking Associations, Inc., et al.,
Petitioners v. United States Environmental Protection Agency; Whitman v. American
Trucking Associations, U.S. Supreme Court, No. 99-1257 and No. 99-1426, February 27,
2001 (121 S. Ct. 903). See CRS Report RS20860, The Supreme Court Upholds EPA
Standard Setting Under the Clean Air Act: Whitman v. American Trucking Assn’s.
41See CRS Report RS21611, Ozone and Particulate Air Quality: Should the Deadline for
Attainment Be Extended? for detailed discussion of scheduling issues regarding NAAQS for
PM and 8-hour ozone.
2.5

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CRS-14
Issues
1997 Ozone NAAQS. The final PM NAAQS was signed by the EPA
Administrator at the same time as new NAAQS for ground-level ozone, on July 16,
1997. The two NAAQS were jointly published on July 18, 1997 (62 Federal Register
38652-38896). Generally referred to as the 8-hour ozone standard, the new standard
for ground-level ozone requires a more stringent concentration limit (0.08 parts per
million vs. the previous 0.12), but it averages the ozone concentrations measured
over 8 hours rather than the previous 1 hour. (See CRS Report RL32345:
Implementation of EPA’s 8-Hour Ozone Standard).
Following their joint promulgation in 1997, both the ozone and the PM
NAAQS were the subject of many of the same challenges and litigation, including
a Supreme Court decision in 2001 (see discussion earlier in this report).
Implementation of the 8-hour ozone standard currently precedes the PM NAAQS
implementation. On April 15, 2004, EPA designated areas in 32 states and the
District of Columbia (474 counties in all) as “nonattainment areas” for the new ozone
air quality standard (69 Fed. Reg. 23857-23951). The EPA designations, and the new
implementation rule (69 Fed. Reg. 23951-24000) that accompanied the designations,
have been challenged for being too lenient by several states and various public
interest groups, and too restrictive by industry groups.
Although the two are parallel, PM implementation is not expected to generate
2.5
the level of controversy associated with the recent 8-hour ozone action. A number
of general issues, such as cost and interpretation of boundaries, are expected to be
similar, but the CAA requirements regarding PM are deemed by the EPA to be less
2.5
complicated, relative to ozone requirements. The PM implementation rule will be
2.5
new rather than a transformation of an existing one, as in the case of 8-hour ozone.
In addition, fewer areas have been designated PM nonattainment areas than were
2.5
designated under the 8-hour ozone NAAQS. Implementation of the 8-hour ozone
NAAQS, as well as associated challenges or other delays, will likely impact the
implementation of the PM NAAQS.
Boundaries. Some states/tribes disagree with EPA’s final designations. EPA
has generally used its discretion to expand the size of nonattainment areas, or to
combine areas that a state listed as separate areas into a single larger unit. In
implementing other NAAQS, for example, EPA has combined nonattainment
counties across state lines into the same nonattainment area, if the counties are part
of the same metropolitan area. Pursuant to the statutory requirements for working
with states, EPA staff in the regions and the agency’s Office of Air Quality Planning
and Standards have been made available for assistance and consultation throughout
the designation process according to the agency.
Spatial Averaging. Some concern has been raised regarding the option
available to states to use spatial averaging of monitoring data to determine attainment
for the annual standard.42 Spatial averaging allows calculation of the average
42Spatial averaging applies only to the annual standard, and does not apply the 24-hour
(continued...)

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CRS-15
arithmetic mean over three years using data from multiple monitoring sites within a
monitoring planning area, versus data from a single monitor. There is concern that
by allowing averaging of locations well below the PM annual standard with
2.5
locations substantially above, spatial averaging could potentially lead to a designation
of attainment in the defined area while failing to provide adequate health protection.
On the other hand, it has been suggested that spatial averaging is consistent with
epidemiological studies used in the determination of the PM standards and could
2.5
reflect a better characterization of area-wide exposure in some circumstances. In
addition, states have stressed the need for flexibility given the variability in the nature
and sources of PM .
2.5
As a means of protecting against inappropriate use of spatial averaging, certain
criteria must be met and conditions demonstrated.43 Monitors must be specifically
designated in monitoring plans prior to data collection and analysis, and sufficient
opportunity for public comment must be provided in advance of final approval.44
Upwind Pollutant Contributions. One of the more frequently raised issues
in nonattainment areas is whether any special consideration can be given to areas
whose air quality is adversely affected by pollution from upwind areas. Unlike the
larger coarse particles which generally settle more rapidly and fall near their source
of emission, the smaller PM particles frequently remain in the atmosphere longer
2.5
and can travel significant distances from their original source. The transport of PM2.5
can contribute to, and in some cases be the primary cause of nonattainment, in areas
downwind of the emission source.
Recent EPA attempts to extend the deadlines for ozone attainment in an effort
to provide additional time for areas affected by upwind pollution (seven areas
regulated for ozone under Subpart 2), have been overturned by court decisions in
three separate circuits.45 Subpart 1 of the CAA which allows EPA to “classify the
area for the purpose of applying an attainment date” and consider such factors as
“the availability and feasibility of pollution control measures,” may provide more
flexibility. In another recent effort by the EPA, the proposed Clean Air Interstate
Rule (CAIR)46 is intended to address interstate transport of pollutants that are
hindering attainment of PM and 8-hour ozone NAAQS in downwind states.
2.5
Identifying Sources and Control Measures. Determining sources
contributing to emission of fine particles in order to identify the appropriate actions
for compliance with the PM standards, as required for future designated geographic
2.5
42(...continued)
standard intended to protect against peak or seasonal levels. See Appendix N of 40 Code
of Federal Regulations Part 50. Also, see discussion of spatial averaging in the final rule for
particulate matter NAAQS 62 Federal Register 38671-38674.
4340 Code of Federal Regulations Part 58.
44See 40 Code of Federal Regulations Part 58.20(f) and 58.26(e) regarding public
notification and public comment associated with spatial averaging.
45The cases involved St. Louis, Washington, D.C., and Beaumont-Port Arthur, Texas.
4669 Federal Register 4572.

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CRS-16
nonattainment areas including surrounding areas, is expected to be complicated.
EPA has been conducting several technical studies in an effort to develop extensive
guidance to assist states in identifying appropriate control measures in their SIPs for
specific parameters and conditions.
Economic Impacts. Another concern of areas facing nonattainment
designation, particularly of local businesses and governments, is that it will have
potential negative impacts on an area’s economic development. Nonattainment
designation does require new major sources of pollution to offset their pollution by
equivalent or greater emission reductions from existing sources, and requires
highway and transit planners to demonstrate that new projects “conform” to the
area’s SIP.47 Although EPA has not analyzed the potential economic impact of
designating areas as nonattainment for particulate matter, a recent EPA analysis48
found that ozone nonattainment designations had no net negative impact on those
areas. Specifically, 6.5 million jobs were created in ozone nonattainment areas from
1990 to 1998, and “over 55 percent of ozone nonattainment areas had average annual
employment growth rates greater than that of their region of the country.” Personal
income growth in these nonattainment areas essentially matched the national average
between 1990 and 1998, according to EPA (38.5% vs. 38.9%).
Grant Programs. Although EPA does not have a grant program designed to
assist nonattainment areas, the agency does provide grants to state air pollution
agencies in support of their programs. Many nonattainment areas have benefitted in
the past from a program administered by the Department of Transportation: the
Congestion Mitigation and Air Quality Improvement program (CMAQ).49 Although
CMAQ’s purpose is to reduce emissions from highway travel as a means of assisting
states in complying with the NAAQS, providing grants for PM attainment activities
2.5
would require amending the program.
CMAQ funds are distributed based on a formula that takes into account
population and severity of pollution. The structure of the current formula does not
include any funding factors for PM (or PM
). States with new nonattainment
2.5
10-2.5
areas designated under the PM NAAQS would not receive CMAQ funds without
2.5
revisions to the statutory formula.
Reauthorization legislation was introduced in the House and Senate in the 108th
Congress, but was not enacted. The Administration’s proposal, the Safe,
Accountable, Flexible, and Efficient Transportation Equity Act of 2003 (SAFETEA)
was introduced by request as H.R. 2088 and S. 1072, and a third bill, the
Transportation Equity Act: A Legacy for Users (TEA-LU) was introduced as H.R.
47For additional information on conformity, see CRS Report RL32106, Transportation
Conformity Under the Clean Air Act: In Need of Reform?
48 U.S. EPA, Office of Air and Radiation, “The Historical Record: Nonattainment Status and
Economic Growth,” February 26, 2002.
49The CMAQ program, funded by the Highway Trust Fund, was established by Congress
under the Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA, P.L. 102-240).
In enacting the Transportation Equity Act for the 21st Century (TEA-21, P.L. 105-178)
Congress authorized another $8.1 billion for continuing it from FY1998 through FY2003.

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CRS-17
3550. Section 1611 of the bill passed by the Senate, S. 1072, would have amended
the statutory funding formula for determining how CMAQ funds would be
distributed among the states to include factors for new nonattainment areas that did
not meet the NAAQS for PM .50 H.R. 3550, passed by the House, would not have
2.5
done so. The Senate bill would have also provided a substantial increase in CMAQ
funding, to $13.4 billion over the six years FY2004-FY2009, a $5.3 billion (65%)
increase above the previous authorization. The House bill would have provided a
smaller increase, to $9.4 billion (16%). Both bills would have expanded the types of
projects eligible for assistance, although in different ways. (For a more detailed
discussion of CMAQ and relevant legislation see CRS Report RL32057, Highway
and Transit Program Reauthorization: Environmental Protection Issues and
Legislation).
EPA’s Review of the 1997 PM Standards. EPA’s review of the 1997 PM
standards, which began not long after the current standards were promulgated, is
ongoing. As discussed previously in this report, the CAA requires the criteria
document for each criteria pollutant to be reviewed and, if appropriate, the NAAQS
revised, every five years. If EPA decides to tighten the PM standard again based on
the results of its review, more areas could be classified as nonattainment and would
need to implement new controls on PM. Given the simultaneity of this review and
the ongoing implementation of the current standards, outcomes and challenges
associated with the review could potentially affect the implementation schedule.
As the implementation of the 1997 PM standards has been delayed, so too has
the review. Through a consent decree, approved by the District Court of the District
of Columbia July 31, 2003,51 EPA and the parties to a previous lawsuit reached an
agreement that included the establishment of deadlines for issuance of the criteria
document by July 30, 2004, a preliminary decision regarding revisions to the PM
standards by March 31, 2005, and final revised standards (if deemed appropriate) by
December 20, 2005. On July 12, 2004, EPA filed an opposed motion for a further
extension of the PM criteria document until October 29, 2004, which was granted by
the court. On August 13, 2004, EPA submitted a proposal for extending the
remaining PM deadlines to the court as part of a negotiation with the parties of the
consent agreement.52
EPA announced the availability of the updated criteria document, Air Quality
Criteria for Particulate Matter, in the October 29, 2004, Federal Register (69 FR
63111). The criteria document, a critical step in the NAAQS review process, is the
result of a rigorous evaluation of information relevant to PM NAAQS criteria
50The structure of the current formula is based on classifications of nonattainment under the
previous 1-hour ozone standard, and S. 1072 would amend the formula to include
comparable classification for the designation of new 8-hour ozone nonattainment areas.
51Consent Agreement, July 2003, C.A. No. 03-778 (ESH). American Lung Association, et
al. v. the U.S. Environmental Protection et al. (EPA), U.S. District Court for the District of
Columbia.
52Joint Status Report, August 2004,C.A. No. 03-778 (ESH). American Lung Association,
et al. v. the U.S. Environmental Protection et al. (EPA), U.S. District Court for the District
of Columbia.

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CRS-18
development from pertinent literature that has become available between 1996 and
April 2002. The information in the report will serve as the scientific basis for further
assessment by EPA technical staff in developing options to be considered in
assessing the adequacy of the current PM NAAQS promulgated in 1997. The
ultimate determination by the EPA Administrator whether changes to the existing
PM NAAQS are necessary is not expected until late 2005 or early 2006.
EPA’s previous review and establishment of PM standards was the subject of
litigation and challenges, including a Supreme Court decision in 2001. It would not
be surprising if interested parties return to the courts or initiate challenges in the
months ahead, including initiating challenges under the 2000 Data Quality Act (also
referred to as the Information Quality Act),53 as the EPA continues its review of the
PM NAAQS. These challenges could affect the implementation schedule as well.
Proposed Legislation and Regulations
Concerns regarding the potential impacts of the new ozone and particulate
standards have led to several attempts to modify the implementation requirements.54
Legislative attempts during the 108th Congress were generally attached to larger
pieces of legislation, such as the proposed multi-pollutant (H.R. 999/S. 485, “Clear
Skies”) and energy (H.R. 6) bills. With the exception of amendments clarifying the
schedule for implementation in the FY2004 omnibus appropriations (P.L.108-199),
the proposed legislation has not been enacted.
The Administration proposed an additional modification of the requirements for
areas not meeting the new ozone and fine particle standards in its Clear Skies bill
(H.R. 999/S. 485) introduced during the 108th Congress. In Section 3, Clear Skies
would have allowed EPA to avoid designating 8-hour ozone and PM areas as
2.5
nonattainment until 2016, provided that the area demonstrates that it will attain the
standards by December 31, 2015. Areas fitting into this new “transitional” category
could have avoided additional regulatory controls, including the requirement to
demonstrate conformity, if they could demonstrate that attainment would be achieved
through the imposition of federal controls on utilities, diesel engines, automobiles,
and other sources. The Senate Environment and Public Works Committee,
Subcommittee on Clean Air, Climate Change and Nuclear Safety, held a series of
hearings regarding S. 485 during the first session of the 108th Congress.
EPA proposed the Clean Air Interstate Rule (CAIR) in December 2003,55
primarily to address the interstate transport of pollutants (SO and NOx) that are
2
hindering downwind states from attaining the 8-hour ozone and PM NAAQS. The
2.5
53Enacted in December 2000 as Section 515 of the Treasury and General Government
Appropriations Act for Fiscal Year 2001 (P.L. 106-554) (44 U.S.C. 3504(d)(1) and 3516).
Intended to ensure quality, objectivity, utility, and integrity of information, the act provides
a process for those who have submitted public comment but dissatisfied with how their
correction requests were handled through the Administrative Procedures Act process, to
appeal the EPA’s decision.
54See CRS Issue Brief IB10107, Clean Air Act Issues in the 108th Congress.
55Interstate Air Quality (IAQ) Rule as proposed, 69 Federal Register 4572, January 30,2004.

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CRS-19
proposed rule, covering 29 states in the eastern United States and the District of
Columbia, uses a cap and trade approach to reduce the target pollutants by up to 70%.
As discussed earlier, the proposal is predicted to have a greater impact on PM2.5
attainment than on 8-hour ozone attainment.56
Conclusion
PM standards are expected to affect a number of areas, including some that
2.5
have not previously been designated nonattainment for a NAAQS. This has raised
concerns regarding the potential impacts, and triggered numerous questions regarding
the specifics of the implementation process.
EPA projects that federal measures, such as recent auto and truck emission
standards and controls on power plants, will be sufficient to demonstrate attainment
in a large portion of monitored nonattainment counties by 2015, prior to the
development and implementation of local measures. At a March 2004 Congressional
hearing,57 EPA Administrator Leavitt stated that “EPA projects that adopted and
proposed regulatory measures, combined with existing federal and state programs,
will bring well over half of the areas of the country into attainment with fine particles
and ozone standards between now and 2015.” Some Members of Congress, and
others, have questioned the EPA’s predictions regarding the relative magnitude of the
emission reductions associated with existing and proposed air quality controls.
The final form of PM implementation or its effects may not be known for
2.5
some time. Some states and other stakeholders are in disagreement with EPA’s PM2.5
nonattainment area designations, and suggest fewer counties should have been
designated. Other stakeholder groups contend EPA should have included additional
counties. The agency’s PM implementation rule, which has yet to be proposed, may
2.5
be challenged (like many EPA rules) in the courts. As discussed earlier, EPA’s first
attempt at an implementation plan was among the issues remanded by the Supreme
Court in a 2001 decision that addressed a number of issues related to the setting of
the PM and the 8-hour ozone standard. The recent challenges following the release
2.5
of the 8-hour ozone designations could also affect certain decisions and the schedule
regarding PM . The EPA’s ongoing review of the current PM standards, and the
2.5
potential changes that could result, may also face challenges that could affect
implementation the PM standards.
2.5
Many critical milestones are scheduled to be completed in the coming months,
and PM will likely remain an area of focus for many stakeholders and Congress
2.5
throughout 2005.
56See CRS Report RL32273 Air Quality: EPA’s Proposed Interstate Air Quality Rule.
57U.S. Senate Committee on Environment and Public Works, hearing on: The Environmental
Protection Agency FY2005 Budget, March 10, 2004, testimony. Available on the committee
website at [http://epw.senate.gov/hearings.cfmo](visited December 6, 2004).

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