Order Code RL32431
CRS Report for Congress
Received through the CRS Web
Particulate Matter (PM ): National Ambient
2.5
Air Quality Standards (NAAQS) Implementation
June 15, 2004
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
By December 31, 2004, the U.S. Environmental Protection Agency (EPA)
intends to finalize the designations of 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). Particulate matter, including PM , is one of the six
2.5
principal pollutants classified as criteria pollutants for which the agency has set
National Ambient Air Quality Standards (NAAQS) under the Clean Air Act (CAA).
NAAQS are designed primarily to protect human health by providing 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
National PM air quality data have been collected for three years or more. The
2.5
next step in the process is the designation of geographical areas for attainment or
nonattainment. Areas with air quality levels exceeding the annual and 24-hour PM2.5
standards, which limit the concentration of fine particle levels in the ambient air, will
be designated “nonattainment areas.” Many areas that have not been designated as
nonattainment under implementation of other NAAQS are expected to be designated
nonattainment for the first time with the implementation of the PM NAAQS.
2.5
The designation process is a cooperative federal-state/tribe process in which
states/tribes provide initial designation recommendations to EPA for consideration.
EPA ultimately makes the decision on the final designations. PM nonattainment
2.5
areas will require the development of comprehensive implementation plans to meet
the PM standards.
2.5
EPA is currently reviewing the state/tribe attainment designation
recommendations, and plans to notify the states/tribes of any modifications by June-
July 2004. A preliminary review of the submissions indicates that 18 states and the
District of Columbia have recommended 145 counties as potential nonattainment
areas. The agency is expected to use its discretion to expand the size and number of
nonattainment areas, including designation of additional counties because of their
contribution to nonattainment in a defined metropolitan statistical area.
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 are 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 nonattainment designation
might affect economic development and transportation investments in an area.
Actions following the recent release of the 8-hour ozone designations will likely
affect certain decisions and the schedule regarding PM NAAQS implementation.
2.5
Legislation currently being considered could also potentially alter the implementation
process. This report will be updated as developments warrant.

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Contents
Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
The PM Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.5
Geographical Area Designation Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
PM Implementation Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.5
Demonstrating Attainment: The State Implementation Plan . . . . . . . . . . . . . 7
PM NAAQS Implementation Timeline and Delays . . . . . . . . . . . . . . . . . . 8
2.5
Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Boundaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Spatial Averaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Upwind Pollutant Contributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Identifying Sources and Control Measures . . . . . . . . . . . . . . . . . . . . . 12
Economic Impacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Grant Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Proposed Legislation and Regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
List of Figures
Figure 1. EPA Estimates of Counties in Nonattainment of PM and
2.5
8-Hour Ozone NAAQS (based on 2000-2002 data) . . . . . . . . . . . . . . . . . . . 6
List of Tables
Table 1. Estimated Schedule for PM NAAQS Implementation . . . . . . . . . . . . . 9
2.5

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Particulate Matter (PM ):
2.5
National Ambient Air Quality Standards
(NAAQS) Implementation
Background
By December 31, 2004, the U.S. Environmental Protection Agency (EPA)
intends to finalize the designations of geographical areas for attainment or
nonattainment1 of the national ambient (outdoor) air standards for fine particulate
matter or “PM ” (particles less than
2.5
2.5 micrometers (µm) in diameter).
What Is PM ?
2.5
This action continues EPA’s
PM can be naturally occurring or
2.5
implementation of new National
manmade in the form of solid particles in
Ambient Air Quality Standards
soot, smoke, dust, and in some instances is
(NAAQS) for particulate matter
in the form of liquid particles. PM can
2.5
promulgated in 1997 under authority of
come from various residential and
the Clean Air Act (CAA),2 delayed
industrial combustion activities, or they
may result from the reaction of certain gas
until recently because of court
emissions with the atmosphere. Sources of
challenges and other factors.
PM include vehicle and equipment
2.5
exhaust, utility and other industrial plant
NAAQS are a core component of
emissions, burning wood, and fugitive dust
the CAA,3 and the statute requires that
emissions from roads or generated by
EPA set primary standards at a
various activities such as construction and
level,”requisite to protect the public
agricultural operations. PM has been
2.5
health” with an “adequate margin of
linked to cardiovascular and respiratory
safety” (42 U.S.C. 7409(b)(1)), based
health problems, and contributes to
on a review of the scientific literature.
visibility “haze” and acidic deposition.
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
2
2.5
and PM ), nitrogen dioxide (NO ), carbon monoxide (CO), ozone, and lead. Every
10
2
five years, according to the statute (but less frequently in practice), EPA is required
1Areas will be 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.
3Sections 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, see CRS
Report RL30853: Clean Air Act: A Summary of the Act and Its Major Requirements.

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CRS-2
to review the latest scientific studies and either reaffirm or modify the NAAQS. The
most recent changes, a strengthening of the PM standards and ozone, were
promulgated in 1997.
A critical step in NAAQS implementation is the designation of geographical
areas failing to comply with the NAAQS following extensive monitoring and
analysis of relevant air quality data. Earlier this year, on April 15, 2004, EPA
designated areas in 32 states and the District of Columbia as “nonattainment areas”
(474 counties) for a new ozone air quality standard.4 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.
It is expected that some of the areas being considered under implementation of
the PM standards have not previously been designated nonattainment for any other
2.5
NAAQS. This has raised questions and concerns about the process in these areas,
including when and why the standards were established; what criteria are 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.
This report provides a brief overview of the NAAQS implementation process,
including links to sources of additional information. The report also discusses issues
and legislation that could potentially alter the implementation process.
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,
coarse particles equal to or less than 10 micrometers in diameter (PM ). 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.5
4See CRS Report RL32345, Implementation of EPA’s 8-Hour Ozone Standard.
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
brief summary indicating some dimensions of the estimated premature mortality, see
Statement of Jonathan Levy, Harvard School of Public Health, at “Health Effects of PM2.5
Emissions,” Hearing, Senate Environment and Public Works Committee, October 2, 2002.
More 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).

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CRS-3
The NAAQS for PM became effective September 16, 1997.6 The primary and
2.5
the secondary PM NAAQS requirements are the same. As part of the promulgation
2.5
of the PM NAAQS, EPA revised the coarse particles designation (PM ) to particles
2.5
10
larger than 2.5 but smaller than 10 micrometers (PM
), so as to explicitly exclude
10-2.5
fine particles, and also promulgated the 8-hour ozone NAAQS. The PM standards
2.5
are set at:
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;7 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 monitor8 within the area.
In requiring both PM standards (24-hour and annual), EPA reportedly considered
2.5
the “combined effect of the standards rather than an approach that weighed short- and
long-term exposure evidence, analyses, and standards independently.”9 EPA
considers the annual standard the primary requirement for reducing total PM risk.
2.5
The 24-hour standard is intended to provide supplemental protection for days with
peak PM concentrations, localized “hot spots,” and PM risks arising from seasonal
2.5
2.5
emissions.
Geographical Area Designation Process
The CAA establishes a process for designating nonattainment areas10 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 2002.11 The number of nonattainment
662 Federal Register 38652-38896, July 18, 1997.
7Community oriented monitoring zones are defined as “.an optional averaging area with well
established boundaries such as county or census block” (40 Code of Federal Regulations
Part 58 Subpart A).
8Population-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 Code of Federal Regulations Part 58
Subpart A).
9U.S. EPA Fact Sheet: EPA’s Revised Particulate Matter Standards, July 17, 1997.
10The 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].
11U.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].

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CRS-4
areas and associated population have increased since this report; the April 15, 2004,
8-hour designated nonattainment areas alone include 159 million people.
The designation process is 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.12 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.13 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-FY2000,14 the agency worked closely with states and tribes
to initiate the deployment of a portion of the network of 1,200 monitors in January
of 1999. The majority of the monitors were not in place until January of 2000.
States/tribes were expected to rely on data collected during 2000-2002 for their
recommendations. EPA plans to consider the 2001-2003 data to make the final
designations. The agency has specified data and conditions that will not be
acceptable, but there are several other factors that states/tribes and the agency will
consider as described in EPA’s guidance.15 The agency’s nonbinding guidance
recommends that states/tribes consider using the same boundaries for nonattainment
for both the PM and 8-hour ozone standards, to facilitate consistency in future
2.5
implementation plans.
PM designations will 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.16 EPA interprets that those classification
12The 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). Currently, six tribes have participated in the PM designation
2.5
recommendation process, recommending designations of attainment/unclassified (see
[http://www.epa.gov/pmdesignations]).
13A 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).
14Appropriations for monitoring averaged roughly $50 million per year, P.L. 105-65, P.L.
105-226, P.L. 106-74.
15See EPA’s NAAQS website at [http://www.epa.gov/ttn/naaqs/pm/pm25_guide.html].
16These requirements can be found in Title I Part D Sections 171-193 of the act..

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CRS-5
provisions in the act regarding particulate matter 17 explicitly apply to PM , but not
10
PM NAAQS implementation. PM implementation is governed by the general and
2.5
2.5
nonattainment planning requirements of Title I of the act.18
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 Areas19 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,20 the agency will notify the states/tribes regarding any modifications allowing
sufficient opportunity to demonstrate why a proposed modification is inappropriate,
but the final determination rests with EPA.
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].
17Under 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).
18CAA Title I Part A, and Part D subpart 1.
19As 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.
html].
20CAA section 107(d)1(B)(ii).

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CRS-6
PM Implementation Status
2.5
EPA is currently reviewing the state/tribe attainment designation
recommendations, and plans to notify the states/tribes of any modifications by June-
July 2004, followed by the final PM implementation rule in late 2004 or early 2005,
2.5
and final designations by the December 31, 2004 date. A preliminary review of the
submissions indicates that 18 states and the District of Columbia have recommended
145 counties as potential nonattainment areas.21
Many of these PM areas are expected to overlap with the 8-hour ozone
2.5
designations. As an indication of the potential overlap of the two new NAAQS,
Figure 1 shows EPA’s estimates for violations of PM and 8-hour ozone based on
2.5
2000-2002 monitoring data. The data show at least one monitor measuring
concentrations exceeding the PM NAAQS in 120 counties. Final PM designation
2.5
2.5
areas will be 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 will 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)
Count
oun i
t e
i s W
s
it
i h
t M
h
oni
o t
ni o
t r
o s
r E
s
xc
x e
c edi
d ng t
i
h
ng t e
h Ozon
o e
n
and
an PM
d
NAA
A Q
A S in
i 200
n
2
2.5
Ozon
Ozo e
n Non
No a
n tt
t ai
t n
ai men
m
t
en (226 Counti
ount e
i s)
PM
Nonatt
t a
t inm
i
e
nm nt
n (49 Counti
ount e
i s)
2.5
Bot
o h
t N
h
onatt
t a
t inm
i
e
nm nt (
t 71 Counti
unt e
i s)
21For PM geographical designation recommendations from individual states and tribes, see
2.5
EPA’s “PM Designations” website at [http://www.epa.gov/pmdesignations].
2.5

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CRS-7
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 expects most PM SIPs will focus primarily on local control measures to
2.5
reduce emissions. The most common local measures affect motor vehicles, fuels,
and stationary sources of pollution. In addition, because of the significant
contribution of PM to visibility impairment (“haze”), and the frequent tendency of
2.5
PM emissions to be transported across geographic boundaries, regional planning to
2.5
address sources inside and outside nonattainment areas is also expected to be a
critical component of PM SIPs.
2.5
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 may 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.22 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 current rules, applies to ozone, PM ,
10
CO, and NOx, but does not include PM . On November 5, 2003, EPA published a
2.5
proposed rule (68 Federal Register 62690) that would make transportation
conformity regulations explicitly applicable to PM nonattainment areas, and
2.5
includes criteria and procedures for the new PM and 8-hour ozone NAAQS.
2.5
Conformity determinations must be submitted to EPA within one year of the
effective date designating an area as nonattainment. Recognizing that the
transportation conformity requirements could apply in PM nonattainment areas
2.5
prior to the availability of SIP budgets, EPA included options in the proposed rule
regarding interim emissions tests for conformity determinations.23 EPA anticipates
promulgating a final rule in late June-July 2004.
22For additional information on conformity, see CRS Report RL32106, Transportation
Conformity Under the Clean Air Act: In Need of Reform?
23See 68 Federal Register 62697-62699.

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CRS-8
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”24); 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.”25
Although primarily designed to meet the ozone NAAQS, EPA predicts the NOx SIP
call will also provide some benefits in terms of reduced levels of nitrate fine
particles.
Other, proposed, legislation and EPA regulations for controlling coal-fired
electric power plants’ emissions, such as, “Clear Skies”/multi-pollutant legislation
and the proposed “Interstate Air Quality Rule”(IAQ) to be implemented between
2004 and 2015,26 are also expected to contribute national and regional measures for
attaining PM standards. The EPA predicts that, of an estimated 120 eastern
2.5
counties out of compliance with PM NAAQS in 2002, the Interstate Quality Rule
2.5
will bring 28 more counties into compliance in addition to the 58 counties predicted
to come into compliance under existing programs.27
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 current implementation schedule is 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 PM designations.28 Recognizing there may be
2.5
potential efficiencies associated with states and tribes being able to harmonize future
control strategies, the initial PM schedule was intended to be similar to the 8-hour
2.5
ozone program. The timeline presented in Table 1 reflects the most recent key
milestone dates for PM implementation.
2.5
2464 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).
2564 Federal Register 35714, October 27, 1998.
26For 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.
27CRS Report RL32273, Air Quality: EPA’s Proposed Interstate Air Quality Rule.
28EPA 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-9
Table 1. Estimated Schedule for PM NAAQS Implementation
2.5
Date
PM NAAQS Milestones
2.5
February 2004 (completed)
State/tribal area designation recommendations
(can be based on 2000-2002 monitoring data)
June-July 2004
EPA notifies states/tribes regarding modifications
to states/tribes’ recommendations
August-September 2004
EPA proposes PM implementation rule
2.5
Late 2004- Early 2005
EPA promulgates final PM implementation rule
2.5
December 31, 2004 (required
EPA promulgates final area designations
one year after states/tribes’
recommendations)
December 31, 2005, or one year
States must submit transportation conformity
after the final designation
determination within one year of the effective date
effective date
of nonattainment designation of an area, assuming
EPA’s proposed “conformity rule” is promulgated
December 2007-January 2008
States/tribes submit revised implementation plans
(three years after final area
(SIPS) to achieve PM compliance in
2.5
designations)
nonattainment areas
2010-2015 (5-10 years after
NAAQS statutory compliance deadline for
final area designations)
attainment
Source: Prepared by Congressional Research Service based on U.S. Environmental Protection Agency
fact sheets and guidance documents, and relevant Federal Register Notices.
The PM requirement of three years of monitoring data to determine whether
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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),29 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.
29P.L. 105-178, Title VI.

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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 2001.30
Whether the agency 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.31 In its “Clear Skies” bill (H.R. 999/
S. 485) and in its regulatory guidance, the Administration proposed additional
flexibility for 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 their PM
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designation recommendations, and December 31, 2004, for EPA to promulgate
designations for each state.
Issues
Although the two are parallel, PM implementation is not expected to generate
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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 agency to be
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less complicated, relative to ozone requirements, and the PM will be a new
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implementation rule rather than a transformation of an existing one, as in the case of
8-hour ozone. In addition, fewer areas are expected to be designated PM2.5
nonattainment areas than were designated under the 8-hour ozone NAAQS.
Boundaries. Some states/tribes may disagree with EPA’s final designations.
The agency 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.
30United 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 Ass’ns.
31See 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.
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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.32 Spatial averaging allows calculation of the average
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
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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
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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 .
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As a means of protecting against inappropriate use of spatial averaging, certain
criteria must be met and conditions demonstrated.33 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.34
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
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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.35 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 Interstate Air Quality
(IAQ) rule36 is intended to address interstate transport of pollutants that are hindering
attainment of PM and 8-hour ozone NAAQS in downwind states.
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32Spatial averaging applies only to the annual standard, and does not apply the 24-hour
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.
3340 Code of Federal Regulations Part 58.
34See 40 Code of Federal Regulations Part 58.20(f) and 58.26(e) regarding public
notification and public comment associated with spatial averaging.
35The cases involved St. Louis, Washington, D.C., and Beaumont-Port Arthur, Texas.
3669 Federal Register 4572.

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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
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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 identify 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.37 Although EPA has not analyzed the potential economic impact of
designating areas as nonattainment for particulate matter, a recent EPA analysis38
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 the agency (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).39 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
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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
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areas designated under the PM NAAQS would not receive CMAQ funds without
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revisions to the statutory formula.
37For additional information on conformity, see CRS Report RL32106, Transportation
Conformity Under the Clean Air Act: In Need of Reform?
38 U.S. EPA, Office of Air and Radiation, “The Historical Record: Nonattainment Status and
Economic Growth,” February 26, 2002.
39The 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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Reauthorization legislation has been introduced in the House and Senate. 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. 3550. Section 1611 of the bill passed by the
Senate, S. 1072, would amend the statutory funding formula for determining how
CMAQ funds are distributed among the states to include factors for new
nonattainment areas that do not meet the NAAQS for PM .40 H.R. 3550, passed by
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the House, would not do so. The Senate bill would also provide 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
provide a smaller increase, to $9.4 billion (16%). Both bills would also expand the
types of projects eligible for assistance, although in different ways. (For a more
detailed discussion of CMAQ and relevant pending legislation see CRS Report
RL32057, Highway and Transit Program Reauthorization: Environmental
Protection Issues and Legislation).
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.41
Legislative attempts have generally been attached to larger pieces of legislation, and
(with the exception of amendments clarifying the schedule for implementation) have
not been enacted.
The Administration has 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). In Section 3, Clear Skies would allow EPA to avoid designating
8-hour ozone and PM areas as nonattainment until 2016, provided that the area
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demonstrates that it will attain the standards by December 31, 2015. Areas fitting
into this new “transitional” category could avoid 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 Interstate Air Quality (IAQ) rule in December 2003 primarily
to address the interstate transport of pollutants (SO and NOx) that are hindering
2
downwind states from attaining the 8-hour ozone and PM NAAQS.42 The proposed
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rule, covering 29 states in the eastern United States and the District of Columbia,
40The 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.
41See CRS Issue Brief IB10107, Clean Air Act Issues in the 108th Congress.
42Proposed Interstate Air Quality (IAQ) Rule, 69 Federal Register 4572.

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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.43
Conclusion
PM standards are expected to affect numerous areas that have not previously
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been designated nonattainment for a NAAQS. This has raised concern in these areas
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 recent Congressional
hearing,44 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 agency’s predictions regarding the relative magnitude of
the emission reductions associated with existing and proposed air quality controls.
Actions following the release of the 8-hour ozone designations will likely affect
certain decisions and the schedule regarding PM . EPA’s PM implementation plan
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(like many EPA rules) may be challenged in the courts. As discussed earlier, the
agency’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. It would not be surprising if
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interested parties returned to the courts in the months ahead as the agency attempts
to implement new versions of its implementation plans. Thus, the final form of PM2.5
implementation or its effects may not be known for some time.
43See CRS Report RL32273 Air Quality: EPA’s Proposed Interstate Air Quality Rule.
44U.S. Senate Committee on Environment and Public Works hearing on: The Environmental
Protection Agency FY2005 Budget, March 10, 2004 (transcript to be published).

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