Ozone Air Quality Standards: EPA’s March 2008 Revision

Ozone Air Quality Standards: EPA’s March

2008 Revision

name redacted

Specialist in Environmental Policy

April 18, 2008

Congressional Research Service

7-....

www.crs.gov

RL34057

CRS Report for Congress

Prepared for Members and Committees of Congress

Ozone Air Quality Standards: EPA’s March 2008 Revision

Summary

EPA Administrator Stephen Johnson signed final changes to the National Ambient Air Quality

Standard (NAAQS) for ozone on March 12, 2008; the proposal appeared in the Federal Register

on March 27. NAAQS are standards for outdoor (ambient) air that are intended to protect public

health and welfare from harmful concentrations of pollution. By changing the standard, EPA has

concluded 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 new standard, and issues raised by the Administrator’s choice, and it describes

the steps that will follow EPA’s promulgation.

The ozone standard affects a large percentage of the population: nearly half the U.S. population

currently lives in ozone “nonattainment” areas (the term EPA uses for areas that violate the

standard), 140 million people in all. As a result of the standard’s strengthening, more areas will be

affected, and those already considered nonattainment may have to impose more stringent

emission controls.

The revision lowers the primary (health-based) and secondary (welfare-based) standards from

0.08 parts per million (ppm) averaged over 8 hours to 0.075 ppm averaged over the same time.

Using the most recent three years of monitoring data, 345 counties (54% of all counties with

ozone monitors) would violate the new standards. Only 85 counties exceeded the pre-existing

standards. Thus, the change in standards will have widespread impacts in areas across the country.

(The 345 counties that would exceed the standard are shown in Figure 2 of this report.)

The revision follows a multi-year review of the science regarding ozone’s effects on public health

and welfare. The new standards 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. The first step, designation of

nonattainment areas is expected to take place in 2010, with the areas so designated then having 3

to 20 years to reach attainment.

The new standards raise a number of issues, including whether the choices for the primary and

secondary standards are backed by the available science. Not only are the Administrator’s choices

weaker than those proposed by his scientific advisers, but the administrative record makes clear

that, in part, they were dictated by the White House over the objections of EPA. Whether the

standards should lead to stronger federal controls on the sources of pollution is another likely

issue. Current federal standards for cars, trucks, power plants, and other pollution sources are not

strong enough to bring all areas into attainment, thus requiring local pollution control measures in

many cases. 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 half of those monitors showing

violations of the new standards, questions arise as to air quality in unmonitored counties.

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Ozone Air Quality Standards: EPA’s March 2008 Revision

Contents

Introduction ................................................................................................................................1

What Are NAAQS?.....................................................................................................................1

The NAAQS Process ..................................................................................................................2

The Ozone Standard....................................................................................................................3

The Primary Standard ...........................................................................................................3

The Secondary Standard........................................................................................................5

Controlling Ozone Pollution........................................................................................................6

Costs and Benefits of Control......................................................................................................7

Issues..........................................................................................................................................8

Figures

Figure 1. Counties with Monitors Violating the 1997 Eight-Hour Ozone Standard (0.08

parts per million)......................................................................................................................4

Figure 2. Counties with Monitors Violating the New Eight-Hour Ozone Standard (0.075

parts per million)......................................................................................................................5

Contacts

Author Contact Information ...................................................................................................... 10

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Ozone Air Quality Standards: EPA’s March 2008 Revision

Introduction

On March 12, 2008, the EPA Administrator signed revisions to the National Ambient Air Quality

Standards (NAAQS) for ozone. The revisions appeared in the March 27, 2008 issue of the

Federal Register.1 Because they have widespread implications for public health and for the

pollution control measures that will be imposed on sectors of the economy, the revisions (released

in proposed form in June 2007) have stirred congressional interest and led many Members of

Congress and state and local officials to comment on the Administrator’s proposal. The Clean Air

and Nuclear Safety subcommittee of the Senate Environment and Public Works Committee held a

hearing on the proposal July 11, 2007. The House Oversight and Government Reform Committee

plans a hearing April 24, 2008.

This report provides background on NAAQS, the process used to establish them, the pre-existing

ozone standard, and EPA’s revisions, as well as information regarding the revisions’ potential

effects.

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 “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 farreaching 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

1

2

73 Federal Register 16436.

The Clean Air Act’s definition of welfare is found in Section 302(h) of the act.

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Ozone Air Quality Standards: EPA’s March 2008 Revision

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

previous review of the NAAQS was completed in 1997. The American Lung Association filed

suit over EPA’s failure to complete a review in 2003, and a consent decree established the

schedule EPA ultimately followed. 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; 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 ozone review panel, for example, had 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.

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

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.

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 (name redacted).

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The Ozone Standard

The ozone standard affects a larger percentage of the population than any of the other NAAQS.

Nearly half the U.S. population currently lives in ozone nonattainment areas, 140 million people

in all.6 Since the standard has been strengthened as a result of the current review, more areas will

be affected, and those already considered nonattainment may have to impose more stringent

emission controls.

The Primary Standard

The pre-existing primary (health-based) standard, promulgated in 1997, was set at 0.08 parts per

million (ppm), averaged over an 8-hour period. Allowing for rounding, EPA considered areas

with readings as high as 0.084 ppm (84 parts per billion) to have attained the standard.

The review just completed found evidence of health effects, including mortality, at levels of

exposure below the 0.08 ppm standard. As a result, both EPA staff and the Clean Air Scientific

Advisory Committee (CASAC) recommended strengthening the standard. According to CASAC,

“There is no scientific justification for retaining the current [0.08 ppm] primary 8-hr NAAQS....”7

The panel 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 in June 2007, and ultimately chose to finalize the standard at 0.075 ppm (75 parts per

billion).9 The revision will add a large number of counties to those showing nonattainment. As

shown in Figure 1, using 2004-2006 data (the latest available), 85 counties had monitors showing

violation of the 0.08 ppm primary standard. Figure 2 shows what happens when the standard is

strengthened to 0.075 ppm, again using 2004-2006 data: under the new standard, 345 counties,

more than four times as many, show violations.

EPA notes that nonattainment designations will not actually be made until 2010 at the earliest,

and will use data for the period 2006-2008. Given the trend toward cleaner air in recent years, and

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 http://yosemite.epa.gov/sab/sabproduct.nsf/

AB290E0DB8B72A33852572120055858F/$File/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

All of EPA’s references to the standard are expressed as parts per million (e.g., 0.075 ppm), but many references in

the press convert this to a more readable parts per billion (i.e., 75 parts per billion). In order to avoid confusion when

quoting from EPA sources, this report generally uses the more cumbersome parts-per-million form.

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Ozone Air Quality Standards: EPA’s March 2008 Revision

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 will result in some

(perhaps a substantial number of) additional areas being designated nonattainment, and will mean

that current nonattainment areas may 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.10

Figure 1. Counties with Monitors Violating the 1997 Eight-Hour Ozone Standard

(0.08 parts per million)

(Based on 2004-2006 Air Quality Data)

Source: U.S. EPA.

1 85 monitored counties violate.

2 Monitored air quality data can be obtained from the AQS system at http://www.epa.gov/ttn/airsaqa/

3 The 1997 national ambient air quality standard (NAAQS) for ozone of 0.08 ppm is effectively expressed as

0.084 ppm when data handling conventions are applied.

10

“EPA Target of Intensive Lobbying Over Forthcoming Ozone Decision,” Daily Environment Report, March 10,

2008, p. A-3, and “Energy Industry Presents Case to Preserve Existing Air Quality Standard for Ozone,” Daily

Environment Report, February 6, 2008, p. A-9.

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Figure 2. Counties with Monitors Violating the New Eight-Hour Ozone Standard

(0.075 parts per million)

(Based on 2004-2006 Air Quality Data)

Source: U.S. EPA.

Note: Estimates are based on the most recent data (2004-2006). EPA will not designate areas as nonattainment

on these data, but likely on data from 2006-2008 or later, which we expect to show improved air quality.

1 345 monitored counties violate the 2008 8-hour ozone standard of 0.075 parts per million (ppm).

2 Monitored air quality data can be obtained from the AQS system at http//www.epa.gov/ttn/airsaqs/

The Secondary Standard

As part of its recent review, EPA also assessed the secondary (public welfare) NAAQS for ozone,

which was identical to the previous 0.08 ppm 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 (3month) 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.11 The Administrator’s June

2007 proposal was in line with the staff recommendation, 7-21 ppm-hrs, but his final March 2008

11

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://yosemite.epa.gov/sab/sabproduct.nsf/

FE915E916333D776852572AC007397B5/$File/casac-07-002.pdf.

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choice was to duplicate the new primary standard. He set a secondary standard at 0.075 ppm

averaged over 8 hours, rejecting the advice of both CASAC and his staff.

The secondary standard carries no deadline for attainment and has never been the subject of

penalties or sanctions for areas that failed to meet it (unless they also violated a primary

standard). Nevertheless, there appears to have been substantial disagreement between EPA and

the White House over the form in which this standard should be set. The preamble to the final

regulation repeats the arguments for a new form of standard (the W126 index), concluding:

The CASAC, based on its assessment of the same vegetation effects science, agreed with the

Criteria Document and Staff Paper and unanimously concluded that protection of vegetation

from the known or anticipated adverse effects of ambient O3 [ozone] “requires a secondary

standard that is substantially different from the primary standard in averaging time, level,

and form,” i.e. not identical to the primary standard for O3 (Henderson, 2007).12

The preamble also cites comments the agency received from the National Park Service that “...

the NPS supports both the conclusion that a seasonal, cumulative metric is needed to protect

vegetation, and that the W126 is a more appropriate metric ...,” and it adds “EPA agrees with

these comments.”13

Nevertheless, the agency appears to have lost this argument. The preamble states that:

On March 11, 2008, the President “concluded that, consistent with Administration policy,

added protection should be afforded to public welfare by strengthening the secondary ozone

standard and setting it to be identical to the new primary standard, the approach adopted

when ozone standards were last promulgated. This policy thus recognizes the

Administrator’s judgment that the secondary standard needs to be adjusted to provide

increased protection to public welfare and avoids setting a standard lower or higher than is

necessary.”14

The statement that the policy “recognizes the Administrator’s judgment” is not EPA’s wording. It

is a direct quotation from the White House Office of Management and Budget.15

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

12

73 Federal Register 16498.

Ibid., p. 16499.

14

Ibid., p. 16497.

15

Letter from Susan E. Dudley, Administrator, Office of Management and Budget, to Stephen L. Johnson,

Administrator, U.S. EPA, March 13, 2008, at http://www.regulations.gov/fdmspublic/component/

main?main=DocketDetail&d=EPA-HQ-OAR-2005-0172, item 7178. Note: the date on the letter is apparently

incorrect, as the letter was received March 12, 2008.

13

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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.

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 for

the final standards on March 14; the major conclusions regarding benefits and costs were also

included in text slides dated March 12 that were posted on the agency’s website. 16 The RIA shows

a wide range of estimates for benefits, from a low of $2 billion annually to a high of $19 billion

annually in 2020. Costs of implementing the standard were estimated to range from $7.6 billion

to $8.8 billion annually, also in 2020. The benefit range is so wide that it is difficult to reach any

general conclusions regarding whether projected benefits exceed costs or vice versa.

The public health 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.17 An

EPA Fact Sheet that accompanied the standards states that the benefits of an 0.075 ppm primary

standard might include the avoidance of 260 to 2,300 premature deaths annually in 2020.18 Other

annual benefits in 2020 would include preventing the following:

•

380 cases of chronic bronchitis

•

890 nonfatal heart attacks

•

1,900 hospital and emergency room visits

•

1,000 cases of acute bronchitis

16

The RIA is at http://www.epa.gov/ttn/ecas/ria.html. The text slides are at http://www.epa.gov/groundlevelozone/pdfs/

2008_03_text_slides.pdf.

17

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/6-ozoneriachapter6.pdf.

18

“Final Revisions to the National Ambient Air Quality Standards for Ozone,” Fact Sheet, at http://www.epa.gov/

groundlevelozone/pdfs/2008_03_factsheet.pdf, pp. 2-3.

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•

11,600 cases of upper and lower respiratory symptoms

•

6,100 cases of aggravated asthma

•

243,000 days when people miss work or school

•

750,000 days when people must restrict their activities.

In the RIA, the agency notes that, “There are significant uncertainties in both cost and benefit

estimates.”19 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.

The RIA also states, “Of critical importance to understanding these estimates of future costs and

benefits is that they [are] not intended to be forecasts of the actual costs and benefits of

implementing revised standards.”20 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.”21 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 new standards concern whether the Administrator has made

appropriate choices, i.e., whether his choices for the primary and secondary standards are backed

by the scientific studies. The Administrator’s choice for the primary standard is weaker than any

part of the range proposed by CASAC. The secondary standard does not follow the form that

CASAC unanimously recommended.

In explaining the Administrator’s choice for the primary standard, the preamble stresses the

uncertainty that the Administrator found at lower levels of ozone exposure:

The Administrator noted that at exposure levels below 0.080 ppm there is only a very limited

amount of evidence from clinical studies, indicating effects in some healthy individuals at

levels as low as 0.060 ppm. The great majority of the evidence concerning effects below

0.080 ppm is from epidemiological studies. The epidemiological studies do not identify any

bright-line threshold level for effects. At the same time, the epidemiological studies are not

in and of themselves direct evidence of a causal link between exposure to O3 and the

occurrence of the effects.22

Thus, he concluded that within his proposed range of 0.070 to 0.075 ppm, the choice was

essentially a policy judgment.

19

RIA Executive Summary, p. ES-9, at http://www.epa.gov/ttn/ecas/regdata/RIAs/0-ozoneriaexecsum.pdf.

Ibid.

21

Ibid., p. ES-10.

22

73 Federal Register 16476, March 27, 2008.

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Taking into account the uncertainties that remain in interpreting the evidence from available

controlled human exposure and epidemiological studies at very low levels, the Administrator

notes that the likelihood of obtaining benefits to public health with a standard set below

0.075 ppm O3 decreases, while the likelihood of requiring reductions in ambient

concentrations that go beyond those that are needed to protect public health increases. The

Administrator judges that the appropriate balance to be drawn, based on the entire body of

evidence and information available in this review, is a standard set at 0.075.23

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 healthprotective 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.24

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.25 It would not be

surprising if the new ozone standard is also challenged.

In setting the secondary standard, as described earlier, the Administrator’s choice also disregarded

the advice of CASAC, and apparently EPA’s staff as well. The preamble contains EPA statements

both opposing and supporting the final form of the standard, and it appears to indicate substantial

involvement by the White House Office of Management and Budget in the final days before

promulgation.

Other issues will undoubtedly be raised as affected industries, state environmental agencies,

public interest and environmental groups, and the Congress review what EPA has promulgated,

including the potential impacts of the new standards 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 28 counties in 10 states (counties that include some of

the nation’s biggest cities) would violate the 0.075 standard in 2020.26 Furthermore, most

23

Ibid., p. 16483.

Letter of Dr. Rogene Henderson, Chair, CASAC, to EPA Administrator Stephen L. Johnson, October 24, 2006, at

http://yosemite.epa.gov/sab/sabproduct.nsf/AB290E0DB8B72A33852572120055858F/$File/casac-07-001.pdf, pp. 3-4.

25

For additional information on the particulate NAAQS, see CRS Report RL33254, Air Quality: EPA’s 2006 Changes

to the Particulate Matter (PM) Standard, by (name redacted) and (name redacted).

26

For a map showing the 2020 projections, see EPA’s briefing materials at http://www.epa.gov/groundlevelozone/pdfs/

20070621_maps.pdf.

24

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nonattainment areas will not be given until 2020 to attain the standards: for most, the deadline

will be 2013 or 2016 (based on the degree to which pollutant concentrations exceed the new

standard). This suggests a mismatch between the full impact of federal regulations on specific

categories of emission sources and the requirement that local areas demonstrate attainment. This

mismatch could support a case for stronger federal controls on the sources of ozone precursors or

a reexamination of the attainment deadlines.

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. With 345 of them (54%) showing violations of the

new standard, using current data, how confident is the agency that the 2,400 counties without

monitors would all be in attainment? For the past three years, the President’s budget has requested

significant reductions in grants to states and local governments for air quality management, which

includes funding for monitoring.27 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. In addition to the potential

health impacts of ozone in rural areas, the controversy over the setting of the secondary ozone

NAAQS might suggest a need for additional monitoring in rural areas.

Author Contact Information

(name redacted)

Specialist in Environmental Policy

[redacted]@crs.loc.gov, 7-....

27

For additional information, see CRS Report RL34011, Interior, Environment, and Related Agencies: FY2008

Appropriations, by (name redacted) et al.

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