Order Code RL34057
Ozone Air Quality Standards:
EPA’s 2007 Proposed Changes
Updated October 19, 2007
James E. McCarthy
Specialist in Environmental Policy
Resources, Science, and Industry Division

Ozone Air Quality Standards:
EPA’s 2007 Proposed Changes
Summary
EPA Administrator Stephen Johnson proposed changes to the National Ambient
Air Quality Standard (NAAQS) for ozone on June 20, 2007; the proposal appeared
in the Federal Register July 11. NAAQS are standards for outdoor (ambient) air that
are intended to protect public health and welfare from harmful concentrations of
pollution. If the standard is changed as proposed, EPA would be concluding that
protecting public health and welfare requires lower concentrations of ozone pollution
than it previously judged to be safe. This report discusses the standard-setting
process, the specifics of the ozone standard, and issues raised by the proposal, and
it describes the steps that will follow EPA’s proposal.
The ozone standard affects a large percentage of the population: about half the
U.S. population currently lives in ozone “nonattainment” areas (the term EPA uses
for areas that violate the standard), 144 million people in all. If the standard is
strengthened as a result of the current review, as proposed, more areas would be
affected, and those already considered nonattainment might have to impose more
stringent emission controls.
The proposal would lower the current standard from 0.08 parts per million
(ppm) averaged over 8 hours to something in the range of 0.070 to 0.075 ppm. At
the lower end of that range, 533 counties (83% of all counties with ozone monitors)
would violate the proposed standard using the most recent three years of monitoring
data. Only 104 counties exceed the current standard. Thus, a change in the standard
could have widespread impacts in areas across the country.
The proposal follows a multi-year review of the science regarding ozone’s
effects on public health and welfare. If promulgated in the range proposed, the new
standard will set in motion a long and complicated implementation process that has
far-reaching impacts for public health, for sources of pollution in numerous economic
sectors, and for state and local governments.
A number of issues arise as a result of the proposal, including whether the
agency’s proposed ranges for the primary and secondary standards are backed by the
available science, and, within those ranges, where EPA should set the final standard.
(In general, EPA’s proposed ranges are somewhat weaker than those proposed by an
independent scientific review panel established under the Clean Air Act.) Whether
the standards should lead to stronger federal controls on the sources of ozone
pollution precursors is another likely issue, if the NAAQS is strengthened in the
range proposed. EPA, the states, and Congress may also wish to consider whether
the current monitoring network is adequate to detect violations of a more stringent
standard. Only 639 of the nation’s 3,000 counties have ozone monitors in place.
With most of those monitors showing violations of the proposed standard, questions
arise as to air quality in unmonitored counties.

Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
What Are NAAQS? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
The NAAQS Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
The Ozone Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
The Primary Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
The Secondary Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Controlling Ozone Pollution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Costs and Benefits of Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Next Steps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
List of Figures
Figure 1. Counties with Monitors Violating the Current Primary
Eight-Hour Ozone Standard (0.08 parts per million) . . . . . . . . . . . . . . . . . . . 5
Figure 2. Counties with Monitors Violating Alternate
Eight-Hour Ozone Standards (0.070 and 0.075 parts per million) . . . . . . . . 5

Ozone Air Quality Standards: EPA’s 2007
Proposed Changes
Introduction
On June 20, 2007, the EPA Administrator signed proposed revisions to the
National Ambient Air Quality Standard (NAAQS) for ozone, with final action
expected in March 2008.1 The proposal appeared in the Federal Register July 11,
setting in motion a 90-day public comment period, including public hearings in Los
Angeles, Philadelphia, Houston, Atlanta, and Chicago in late August and early
September. Because it has widespread implications for public health and for the
pollution control measures that will be imposed on sectors of the economy, the
proposal has stirred congressional interest: the Clean Air and Nuclear Safety
subcommittee of the Senate Environment and Public Works Committee held a
hearing on the proposal July 11.
This report provides background on NAAQS, the process used to establish
them, the existing ozone standard, and EPA’s proposal, as well as information
regarding the potential effects of any revision to the standard.
What Are NAAQS?
As defined in Section 109 of the Clean Air Act, NAAQS are standards that
apply to ambient (outdoor) air. The act directs EPA to set both primary and
secondary standards. Primary NAAQS are standards, “the attainment and
maintenance of which in the judgment of the [EPA] Administrator ... are requisite to
protect the public health,” with “an adequate margin of safety.” Secondary NAAQS
are standards necessary to protect public welfare, a broad term that includes damage
to crops, vegetation, property, building materials, etc.2
NAAQS are at the core of the Clean Air Act, even though they do not directly
regulate emissions. In essence, they are standards that define what EPA considers
to be clean air. Once a NAAQS has been set, the agency, using monitoring data and
other information submitted by the states, identifies areas that exceed the standard
and must, therefore, reduce pollutant concentrations to achieve it. After these
1 The schedule was set by a consent decree that settled a lawsuit filed by the American Lung
Association (American Lung Association v. Leavitt, D.D.C., No. 03-778, modified consent
decree approved 12/16/04). EPA agreed that it would propose whether to retain or revise
the ozone standard by June 20, 2007, and take final action by March 12, 2008.
2 The Clean Air Act’s definition of welfare is found in Section 302(h) of the act.

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“nonattainment” areas are identified, state and local governments have three years to
produce State Implementation Plans which outline the measures they will implement
to reduce the pollution levels and attain the standards. Depending on the severity of
the pollution, ozone nonattainment areas have anywhere from 3 to 20 years to
actually attain the standard.
EPA also acts to control many of the NAAQS pollutants wherever they are
emitted, through national standards for products that emit them (particularly mobile
sources, such as automobiles) and emission standards for new stationary sources,
such as power plants. Thus, establishment or revision of a NAAQS sets in motion
a long and complicated implementation process that has far-reaching impacts for
public health, for sources of pollution in numerous economic sectors, and for states
and local governments.
The pollutants to which NAAQS apply are generally referred to as “criteria”
pollutants. The act defines them as pollutants that “endanger public health or
welfare,” and whose presence in ambient air “results from numerous or diverse
mobile or stationary sources.”3 Six pollutants are currently identified as criteria
pollutants: ozone, particulates, carbon monoxide, sulfur dioxide, nitrogen oxides, and
lead. The EPA Administrator can add to this list if he determines that additional
pollutants meet the act’s criteria, or delete them if he concludes that they no longer
do so.
The act requires the agency to review each NAAQS every five years. That
schedule is rarely met, but it often triggers lawsuits that force the agency to undertake
a review. In the case of ozone, the last review of the NAAQS was completed in 1997.
As noted earlier, the American Lung Association filed suit over EPA’s failure to
complete a review in 2003, and a consent decree established the schedule EPA is
following.4
The NAAQS Process
Reviewing an existing NAAQS is a long process that is described elsewhere in
more detail.5 To summarize briefly, EPA scientists review the scientific literature
published since the last NAAQS revision, and summarize it in a report known as a
Criteria Document. The review process for ozone identified 1,700 scientific studies
on topics as wide-ranging as the physics and chemistry of ozone in the atmosphere;
3 Authority to establish NAAQS comes from both Sections 108 and 109 of the act; this
definition of criteria pollutants is found in Section 108. The authority and procedures for
controlling the sources of criteria pollutants are found throughout Titles I, II, and IV of the
act. Pollutants that are less widely emitted are generally classified as “hazardous air
pollutants” and are regulated under a different section of the act (Section 112).
4 See footnote 1.
5 For a discussion of the process, and of changes to it that EPA is now implementing, see
CRS Report RL33807, Air Quality Standards and Sound Science: What Role for CASAC?,
by James E. McCarthy.

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environmental concentrations, patterns, and exposure; dosimetry and animal-to-
human extrapolation; toxicology; interactions with co-occurring pollutants;
controlled human exposure studies; epidemiology; effects on vegetation and
ecosystems; effects on UVB exposures and climate; and effects on man-made
materials. A second document that EPA prepares, the Staff Paper, summarizes the
information compiled in the Criteria Document and provides the Administrator with
options regarding the indicators, averaging times, statistical form, and numerical
level (concentration) of the NAAQS.
To ensure that these reviews meet the highest scientific standards, the 1977
amendments to the Clean Air Act required the Administrator to appoint an
independent Clean Air Scientific Advisory Committee (CASAC). CASAC has seven
members, largely from academia and from private research institutions. In
conducting NAAQS reviews, their expertise is supplemented by panels of the
nation’s leading experts on the health and environmental effects of the specific
pollutants that are under review. These panels can be quite large. The current ozone
review panel, for example, has 23 members. CASAC and the public make
suggestions regarding the membership of the panels on specific pollutants, with the
final selections made by EPA. The panels review the agency’s work during
NAAQS-setting and NAAQS-revision, rather than conducting their own independent
reviews.
The Ozone Standard
The ozone standard affects a larger percentage of the population than any of the
other NAAQS. About half the U.S. population lives in ozone nonattainment areas,
144 million people in all.6 If the standard is strengthened as a result of the current
review, as many expect, more areas would be affected, and those already considered
nonattainment might have to impose more stringent emission controls.
The Primary Standard
The current primary (health-based) standard, promulgated in 1997, is set at 0.08
parts per million (ppm), averaged over an 8-hour period. Allowing for rounding,
EPA considers areas with readings as high as 0.084 to have attained the standard.
The current review has found evidence of health effects, including mortality, at
levels of exposure below the current standard. As a result, both EPA staff and the
Clean Air Scientific Advisory Committee (CASAC) have recommended
strengthening the standard. According to CASAC, “There is no scientific
justification for retaining the current primary 8-hr NAAQS....”7 The panel
6 For information on the nonattainment areas, including maps and population data, see
EPA’s “Green Book” at [http://www.epa.gov/oar/oaqps/greenbk/index.html].
7 Letter of Rogene Henderson, Chair, Clean Air Scientific Advisory Committee, to Hon.
Stephen L. Johnson, EPA Administrator, October 24, 2006, available at
(continued...)

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unanimously recommended a range of 0.060 to 0.070 ppm for the primary 8-hour
standard.
EPA staff also recommended strengthening the standard, in wording not quite
so direct. The staff stated, “The overall body of evidence on ozone health effects
clearly calls into question the adequacy of the current standard.” They recommended
“considering a standard level within the range of somewhat below 0.080 parts per
million (ppm) to 0.060 ppm.”8
Based on these recommendations, and his own judgment regarding the strength
of the science, the Administrator proposed to tighten the primary standard to a level
within the range of 0.070-0.075 ppm. Doing so would likely add a large number of
counties to those showing nonattainment. As shown in Figure 1, using 2003-2005
data (the latest available), 104 counties have monitors showing violation of the
current 0.08 ppm primary standard. Figure 2 shows what happens if the standard is
strengthened as proposed (again using 2003-2005 data). If the standard were changed
to 0.075 ppm, 398 counties would exceed it. If it were changed to 0.070, 533
counties would be in violation.
EPA notes that nonattainment designations will not actually be made until 2010,
and will use data for the period 2006-2008. Given the trend toward cleaner air in
recent years, and regulations on both mobile and stationary sources that will be taking
effect in the next few years, the agency expects the number of counties exceeding the
standard to be less than indicated by these projections. Nevertheless, because a
strengthening of the standard would result in some (perhaps a substantial number of)
additional areas being designated nonattainment, and would mean that current
nonattainment areas might have to adopt additional pollution control measures in
order to reach attainment, numerous industry groups are reported to have challenged
the scientific conclusions in meetings with Administration officials.9 EPA’s response
to this challenge was apparently to make clear that it would also entertain comments
on a wider range of primary standards, anything from 0.060 to retention of the current
standard.
7 (...continued)
[http://www.epa.gov/sab/pdf/casac-07-001.pdf].
8 “Review of National Ambient Air Quality Standards for Ozone Final Staff Paper, Human
Exposure and Risk Assessments and Environmental Report,” Fact Sheet, at
[http://www.epa.gov/ttn/naaqs/standards/ozone/data/2007_01_finalsp_factsheet.pdf].
9 “Activists, Industry Offer Competing Data as EPA Ozone Deadline Nears,” InsideEPA
Clean Air Report
, June 14, 2007.



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Figure 1. Counties with Monitors Violating the Current Primary
Eight-Hour Ozone Standard
(0.08 parts per million)
Figure 2. Counties with Monitors Violating Alternate Eight-
Hour Ozone Standards
(0.070 and 0.075 parts per million)

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The Secondary Standard
As part of its current review, EPA has also assessed the secondary (public
welfare) NAAQS for ozone, which is currently identical to the primary standard.
Ozone affects both tree growth and crop yields, and the damage from exposure is
cumulative over the growing season. In order to provide protection against ozone’s
adverse impacts, EPA staff recommended a new seasonal (3-month) average for the
secondary standard that would cumulate hourly ozone exposures for the daily 12-hour
daylight window (termed a “W126 index”). The staff recommended a standard in a
range of 7 - 21 parts per million-hours (ppm-hrs). CASAC’s ozone panel agreed
unanimously that the form of the secondary standard should be changed as the staff
suggested, but it did not agree that the upper bound of the range should be as high as
21 ppm-hours. The panel recommended that the upper bound be no higher than 15
ppm-hours.10 The Administrator’s proposal is in line with the staff recommendation,
7 - 21 ppm-hrs.

Controlling Ozone Pollution
Controlling ozone pollution is more complicated than controlling many other
pollutants, because ozone is not emitted directly by pollution sources. Rather, it
forms in the atmosphere when volatile organic compounds (VOCs) react with
nitrogen oxides (NOx) in the presence of sunlight. The ozone concentration is as
dependent on the temperature and amount of sunshine as it is on the presence of the
precursor gases. Ozone is a summertime pollutant, in general. Other factors being
equal, a cool, cloudy summer will produce fewer high ozone readings than a warm,
sunny summer.
There are also complicated reactions that affect ozone formation. In general,
lower emissions lead to less ozone, particularly lower emissions of VOCs. But under
some conditions, higher emissions of NOx lead to lower ozone readings. This makes
modeling ozone air quality and predicting attainment more difficult and contentious
than the modeling of other air pollutants.
Most stationary and mobile sources are considered to be contributors to ozone
pollution. Thus, there are literally hundreds of millions of sources of the pollutants
of concern and control strategies require implementation of a wide array of measures.
Among the sources of VOCs are motor vehicles (about 40% of total emissions),
industrial processes, particularly the chemical and petroleum industries, and any use
of paints, coatings, and solvents (about 40% for these sources combined). Service
stations, pesticide application, dry cleaning, fuel combustion, and open burning are
other significant sources of VOCs. Nitrogen oxides come overwhelmingly from
motor vehicles and fuel combustion by electric utilities and other industrial sources.
10 Letter of Rogene Henderson, Chair, Clean Air Scientific Advisory Committee, to Hon.
Stephen L. Johnson, EPA Administrator, March 26, 2007, p. 3, available at
[http://www.epa.gov/sab/pdf/casac-07-002.pdf].

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Costs and Benefits of Control
EPA is prohibited from taking cost into account in setting NAAQS, but to
comply with an executive order, the agency generally produces a Regulatory Impact
Analysis (RIA) analyzing in detail the costs and benefits of new or revised NAAQS
standards. The agency released an RIA August 2, 2007, which showed a wide range
of estimates for both costs and benefits.11 The ranges are so wide that it is difficult
to reach any general conclusions regarding whether projected benefits exceed costs
or vice versa. The conclusions one reaches will depend on the assumptions one
makes.
The benefits of setting a more stringent ozone standard are the monetized value
of such effects as fewer premature deaths, fewer hospital admissions, fewer
emergency room visits, fewer asthma attacks, less time lost at work and school, and
fewer restricted activity days.12 Monetizing these effects, the benefits of setting an
0.075 standard were estimated to range from $1.5 billion annually to $22 billion
annually in 2020 depending on the methodology used, whereas projected costs
ranged from $5.5 billion to $8.8 billion annually. There were five separate estimates
of benefits calculated. If the midpoint of each of the five separate estimates was
used, benefits exceeded costs in each case, by as little as $1 billion or by as much as
$8 billion.13
For the more stringent 0.070 standard, there was again a wide range of benefits
estimates, from as low as $4.3 billion annually in 2020 to as high as $33 billion.
Costs were estimated to range from $10 billion to $22 billion annually. Using
midpoints of the benefit and cost estimates, benefits exceeded costs in three of the
five cases. For an 0.065 standard, both the benefit and cost estimates were higher;
the midpoint benefits again outweighed costs in three of five scenarios, while lagging
in the other two.
The agency noted that, “There are significant uncertainties in both cost and
benefit estimates.”14 Among the uncertainties are unquantified benefits (the effects
of reduced ozone on forest health and agricultural productivity, for example) and
unquantified disbenefits (reduced screening of UVB radiation and reduced nitrogen
fertilization of forests and cropland). The benefits will also vary, depending on
which of the precursor pollutants nonattainment areas choose to control.
In some of the scenarios, the agency assumed no premature mortality due to
ozone exceedances, despite the growing scientific consensus that a link exists. In
11 U.S. EPA, Office of Air Quality Planning and Standards, Regulatory Impact Analysis of
the Proposed Revisions to the National Ambient Air Quality Standards for Ground-Level
Ozone
, available at [http://www.epa.gov/ttn/ecas/ria.html#ria2007].
12 For a full discussion of these variables and their monetized values, see Chapter 6 of the
RIA at [http://www.epa.gov/ttn/ecas/regdata/RIAs/ozoneriachapter6.pdf].
13 These estimates, as well as those in the next two paragraphs, can be found in the RIA’s
Executive Summary at [http://www.epa.gov/ttn/ecas/regdata/RIAs/ozoneriaexecsum.pdf].
14 Ibid., p. ES-11.

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other scenarios, the agency assumed that as many as 2,300 premature deaths a year
from ozone exposure would be avoided and as many as 6,800 additional premature
deaths annually would be avoided because of the co-benefit of reducing particulate
matter when standards are tightened for ozone.15 The agency said, “EPA has
requested advice from the National Academy of Sciences on how best to quantify
uncertainty in the relationship between ozone exposure and premature mortality in
the context of quantifying benefits,” but did not state when it expected a response.16
“Of critical importance to understanding these estimates of future costs and
benefits,” according to the agency, “is that they [are] not intended to be forecasts of
the actual costs and benefits of implementing revised standards.”17 If past experience
is any guide, this is likely to mean that costs will not be as great as they are projected
to be. In the agency’s words, “Technological advances over time will tend to
increase the economic feasibility of reducing emissions, and will tend to reduce the
costs of reducing emissions.”18 Benefits, meanwhile, will remain difficult to
quantify, in part because of the difficulty of quantifying and valuing lives lost
prematurely due to exposure to pollution.
Issues
The major issues raised by the proposal concern whether the Administrator has
made appropriate choices, i.e., whether his proposed ranges for the primary and
secondary standards are backed by the scientific studies, and, within the ranges he has
chosen, where the final standard should be set. In general, the proposed ranges seem
somewhat weaker than those proposed by CASAC. The range of secondary
standards includes an upper bound number that is substantially weaker, and the
proposed range for the primary standard has almost no overlap with CASAC’s
recommendation: the most stringent end of the Administrator’s range for the primary
standard just matches the least stringent end of CASAC’s range. So, depending on
the Administrator’s final choice, there may or may not be a conflict with the
scientific judgment of the agency’s independent scientific advisors.
In explaining the Administrator’s proposal for the primary standard, agency
briefers stressed that the Administrator felt there was too much scientific uncertainty
at levels below a standard of 0.070 ppm. At 0.080 ppm and immediately below it,
they maintained, a standard would be supported both by clinical studies of the effects
of a given ozone concentration on lung function in individuals, and by
epidemiological studies showing overall effects on large populations. At levels
below 0.070, a standard would be based almost entirely on epidemiological studies,
15 RIA Chapter 6, previously cited, pp. 6-33, 6-37.
16 RIA Executive Summary, previously cited, p. ES-11.
17 Ibid.
18 Ibid., p. ES-12.

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and would not be as well supported, they maintain.19 CASAC, in a letter to the
Administrator dated October 24, 2006, appeared to disagree with this conclusion.
The letter states:
Furthermore, we have evidence from recently reported controlled clinical studies
of healthy adult human volunteers exposed for 6.6 hours to 0.08, 0.06, or 0.04
ppm ozone, or to filtered air alone during moderate exercise (Adams, 2006).
Statistically-significant decrements in lung function were observed at the 0.08
ppm exposure level. Importantly, adverse lung function effects were also
observed in some individuals at 0.06 ppm (Adams, 2006). These results indicate
that the current ozone standard of 0.08 ppm is not sufficiently health-protective
with an adequate margin of safety. It should be noted these findings were
observed in healthy volunteers; similar studies in sensitive groups such as
asthmatics have yet to be conducted. However, people with asthma, and
particularly children, have been found to be more sensitive and to experience
larger decrements in lung function in response to ozone exposures than would
healthy volunteers.20
In past years, the Administrator has generally chosen standards within CASAC’s
ranges, but not always — a recent example being the NAAQS for particulate matter
promulgated in October 2006. That standard is currently being challenged in the
D.C. Circuit Court of Appeals.21
Many other issues will undoubtedly be raised as affected industries, state
environmental agencies, public interest and environmental groups, and the Congress
review what EPA has proposed, including the potential impacts of the proposal on
public health and on the economy. In looking at potential impacts, EPA projected
air quality to the year 2020, incorporating the expected reductions in emissions from
a slew of federal regulations, including the Clean Air Interstate Rule (CAIR), the
Clean Air Visibility Rule, the Tier 2 auto and light truck emission standards, several
rules affecting diesel engines, and some state and local measures. Even with these
controls, the agency projected that 82 counties (including many of the nation’s
biggest cities) would violate the weakest of the proposed standards (0.075) in 2020.
If the standard were set at 0.070 ppm, 203 counties are projected to exceed it. About
200 other counties fell into a category for which the agency said it could not project
future levels at this time, so some of them might also violate the standard.22 This
widespread failure to attain could support a case for stronger federal controls on the
sources of ozone precursors if the NAAQS is strengthened in the range proposed.
19 Briefing on the June 2007 Proposal to Revise the National Ambient Air Quality Standards
for Ground-Level Ozone for staff of the Senate Committee on Environment and Public
Works, June 21, 2007.
20 Letter of Dr. Rogene Henderson, Chair, CASAC, to EPA Administrator Stephen L.
Johnson, October 24, 2006, at [http://www.epa.gov/sab/pdf/casac-07-001.pdf], pp. 3-4.
21 For additional information on the particulate NAAQS, see CRS Report RL33254, Air
Quality: EPA’s 2006 Changes to the Particulate Matter (PM) Standard
, by Robert Esworthy
and James E. McCarthy.
22 For a map showing the 2020 projections, see EPA’s briefing materials at
[http://www.epa.gov/groundlevelozone/pdfs/20070621_maps.pdf].

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Another issue arises from a close inspection of EPA’s maps: i.e., whether the
current monitoring network is adequate to detect violations of a more stringent
standard. Only 639 of the nation’s 3,000 counties have ozone monitors in place. If
533 of them (83%) show violations of a proposed standard, using current data, how
confident is the agency that the 2,400 counties without monitors would all be in
attainment? EPA has recently proposed budget cuts, including reductions in funding
for the monitoring network. For FY2007 and FY2008, the President’s budget
requested significant reductions in grants to states and local governments for air
quality management, which includes funding for monitoring.23 Given these
reductions, increasing the number of monitors would appear to be a task that the
agency views as falling on state and local government resources.
The current monitors are generally found in urban areas, because of the larger
population potentially affected, and because most of the sources of ozone precursor
emissions are located in such areas. But, as noted earlier, ozone is not emitted
directly by polluters. It forms in the atmosphere downwind of emission sources.
Thus, rural areas can have high ozone concentrations, unless they are located a
substantial distance from any urban area.
Next Steps
Section 307(d) of the Clean Air Act sets out the procedures for proposal and
promulgation of NAAQS. It requires the establishment of a rulemaking docket; it
requires that the notice of proposed rulemaking in the Federal Register be
accompanied by a statement of the proposal’s basis and purpose, including a
summary of the factual data on which the proposed rule is based, the methodology
used in obtaining and analyzing the data, and the major legal interpretations and
policy considerations underlying the proposed rule. The statement is required to set
forth or summarize and provide a reference to any pertinent findings,
recommendations, and comments by CASAC and the National Academy of Sciences,
and, if the proposal differs in any important respect from any of these
recommendations, provide an explanation of the reasons for such differences. The
act also requires that any drafts of proposed and final rules submitted by the
Administrator to the Office of Management and Budget (OMB) prior to proposal or
promulgation, all documents accompanying those drafts, and all written comments
thereon and EPA responses to such comments, be placed in the docket no later than
the date of proposal.
Publication in the Federal Register, July 11, set in motion a public comment
period of 90 days, which has included public hearings in Los Angeles and
Philadelphia on August 30, and Atlanta, Houston, and Chicago September 5. Upon
completion of the public comment period, the agency reviews and summarizes the
public comments and the Administrator makes a final choice regarding the standard.
Under the consent agreement between EPA and the American Lung Association, the
Administrator is required to do so by March 12, 2008.
23 For additional information, see CRS Report RL34011, Interior, Environment, and Related
Agencies: FY2008 Appropriations
, coordinated by Carol Hardy Vincent, p. 52.