Ozone Air Quality Standards: EPA’s Proposed Revisions

Ozone Air Quality Standards:

EPA’s Proposed Revisions

name redacted

Specialist in Environmental Policy

December 21, 2010

Congressional Research Service

7-....

www.crs.gov

R41062

CRS Report for Congress

Prepared for Members and Committees of Congress

Ozone Air Quality Standards: EPA’s Proposed Revisions

Summary

On December 8, 2010, the Environmental Protection Agency (EPA) announced that it will delay

issuing revised ambient air quality standards for ozone until July 2011 so that it can consider

further recommendations from an independent panel of scientific advisers. The agency proposed

changes to the National Ambient Air Quality Standards (NAAQS) for ozone on January 19, 2010,

with an expected promulgation date of August 2010. The December announcement marks the

third time that the agency has postponed issuing the revised standards.

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 would be

concluding that protecting public health and welfare requires lower concentrations of ozone

pollution than it previously judged to be safe. Under the January 2010 proposed standards, as

many as 96% of the counties that currently monitor ozone might need to take action to reduce

emissions. The proposal would also, for the first time, set a separate standard for public welfare,

the principal effect of which would be to call attention to the negative effects of ozone on forests

and agricultural productivity.

The ozone standard affects a large percentage of the population: as of September 2010, 119

million people (nearly 40% of the U.S. population) lived in areas classified “nonattainment” for

the primary ozone NAAQS. As a result of the standard’s strengthening, more areas would likely

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

emission controls.

The proposed revision would lower the primary (health-based) standard from 0.075 parts per

million—75 parts per billion (ppb)—averaged over 8 hours to somewhere in the range of 70 to 60

ppb averaged over the same time. Using the most recent three years of monitoring data, 515

counties (76% of all counties with ozone monitors) would violate the new standard at 70 ppb; 650

counties (96% of those with monitors) would be in nonattainment if the standard is set at 60 ppb.

By comparison, only 85 counties have monitors showing exceedance of the currently

implemented 1997 standard. (The counties that might exceed the proposed standard are shown in

Figure 3 of this report.)

The proposed standards, now expected to be finalized in July 2011, will set in motion a long and

complicated implementation process that has far-reaching impacts. The first step, designation of

nonattainment areas, is expected to take place within a year of the new standards’ promulgation;

the areas so designated would then have 3 to 20 years to reach attainment.

The proposed standards raise a number of issues, including whether they should lead to stronger

federal controls on the sources that contribute to ozone pollution. Current federal standards for

cars, trucks, nonroad vehicles and engines, power plants, and other stationary pollution sources

are not strong enough to bring many 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

675 of the nation’s 3,000 counties have ozone monitors in place.

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.

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Ozone Air Quality Standards: EPA’s Proposed Revisions

Contents

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

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

The NAAQS Process ....................................................................................................................... 3

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

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

The Secondary Standard ............................................................................................................ 7

Controlling Ozone Pollution ............................................................................................................ 9

Costs and Benefits of Control .......................................................................................................... 9

Issues.............................................................................................................................................. 10

Figures

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

(0.08 parts per million) ................................................................................................................. 5

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

in 2008 (0.075 parts per million) .................................................................................................. 6

Figure 3. Counties With Monitors Violating Proposed Primary 8-hour Ground-level

Ozone Standards, 0.060-0.070 parts per million .......................................................................... 7

Figure 4. Counties With Monitors Violating Proposed Secondary Seasonal Ground-Level

Ozone Standards, 7–15 parts per million-hours............................................................................ 8

Contacts

Author Contact Information........................................................................................................... 12

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Ozone Air Quality Standards: EPA’s Proposed Revisions

Introduction

On January 19, 2010, the Environmental Protection Agency (EPA) proposed revisions to the

National Ambient Air Quality Standards (NAAQS) for ozone.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 have stirred congressional interest and caused a variety of

reactions among state and local officials. EPA held three public hearings (in Arlington, VA,

Houston, TX, and Sacramento, CA) during the first week of February 2010, and accepted public

comments in writing until March 22. The agency received more than 5,000 unique comments.

Final standards were expected to be issued by the end of August 2010, but EPA has delayed

promulgation, first to October, then to December, and now to July 2011. The delays have allowed

the agency to analyze the information it received during the public comment period. Having done

so, the agency says that it intends to seek additional advice from the Clean Air Scientific

Advisory Committee (CASAC), a panel of outside experts who review agency decision-making

regarding the setting of NAAQS. Specifically, the agency intends to take the following steps:

During December 2010 and January 2011, EPA intends to prepare a set of questions for

CASAC and provide them for CASAC’s review. The questions are expected to request

additional advice focused on the scientific evidence and other information before the

Administrator. EPA anticipates that CASAC will hold a public meeting in February 2011 to

discuss their response, and anticipates that CASAC will provide its additional advice to the

Agency by letter shortly thereafter. The CASAC process includes an opportunity for the

public to submit comments to CASAC and EPA. EPA intends to issue a final decision on the

reconsideration by July 29, 2011.2

The final decision will be subject to interagency review under Executive Order No. 12866 before

being promulgated.

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

ozone standards, and EPA’s proposed 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.3

1

75 Federal Register 2938.

Declaration of Regina McCarthy, Assistant Administrator for Air and Radiation, Environmental Protection Agency,

December 8, 2010, State of Mississippi v. EPA, Document 1281979, D.C. Cir. No. 08-1200.

3

The Clean Air Act’s definition of welfare is found in Section 302(h) of the act (42 U.S.C. 7602).

2

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Ozone Air Quality Standards: EPA’s Proposed Revisions

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 up

to 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

ambient air “results from numerous or diverse mobile or stationary sources.”4 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 she determines that

additional pollutants meet the act’s criteria, or delete them if she 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

American Lung Association filed suit over EPA’s failure to complete a review in 2003, and a

consent decree established a schedule under which the Bush Administration’s EPA promulgated

revisions to the NAAQS in March 2008.5 Numerous parties petitioned the courts for a review of

that standard,6 and, with the change of Administrations, EPA itself concluded that it had concerns

whether the 2008 standards “satisfy the requirements of the Clean Air Act.” Thus, in September

2009, the agency suspended implementation of the 2008 standards and set a schedule for their

review under which the January 2010 proposal was released. EPA is also in the process of

reviewing several other NAAQS. For more information, see the “Air Quality Standards” section

of CRS Report R40145, Clean Air Issues in the 111th Congress.

4

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).

5

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.

6

Mississippi v. EPA, D.C. Cir., No. 08-1200, notice filed 9/16/09.

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The NAAQS Process

Reviewing an existing NAAQS is generally a long process. To begin the process, EPA scientists

review the scientific literature published since the last NAAQS revision, and summarize it in a

report known as a Criteria Document or Integrated Science Assessment. The review that

culminated in the 2008 ozone revision identified 1,700 scientific studies on topics as wideranging 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 or Policy Assessment,

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 rather large. The review panel for the 2008 ozone standard,

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.

The Ozone Standard

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

As of September 2010, 39% of the U.S. population lived in areas designated nonattainment under

the 1997 standard for ozone, 119 million people in all.7 Since the standard has been strengthened

as a result of a review completed in 2008 and the Administrator is now proposing a further

strengthening, more areas will be affected, and those already considered nonattainment may have

to impose more stringent emission controls.

The Primary Standard

The 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 completed in 2008 found evidence of health effects, including mortality, at levels of

exposure below the 0.08 ppm standard. As a result, both EPA staff and CASAC recommended

7

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.

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strengthening the standard. According to CASAC, “There is no scientific justification for

retaining the current [0.08 ppm] primary 8-hr NAAQS.”8 The panel unanimously recommended a

range of 0.060 to 0.070 ppm (60 to 70 parts per billion) 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.”9

Based on these recommendations, and his own judgment regarding the strength of the science,

Stephen Johnson, the Bush Administration’s last EPA Administrator, chose to finalize the standard

at 0.075 ppm (75 parts per billion).10 That revision has not yet been implemented, however: the

designation of nonattainment areas has not been completed, and the Obama Administration’s EPA

announced in September 2009 that it would undertake a further review of the NAAQS before

completing the designations.11

As shown in Figure 1, using 2004-2006 data, 85 counties had monitors showing violation of the

old 0.08 ppm primary standard. Figure 2 shows what happens when the standard is strengthened

to 0.075 ppm (75 ppb), again using 2004-2006 data: under the 0.075 ppm standard, 345 counties,

more than four times as many, showed violations. Figure 3, using more recent monitoring data,

shows the number of counties that would exceed a standard in the range of 0.060 to 0.070 ppm.

At 0.070 ppm, 515 counties (76% of those with monitors) exceeded the standard. At 0.060 ppm,

650 counties—virtually every county with a monitor—exceeded the proposed standard.

EPA notes that nonattainment designations will not actually be made until at least 2011, and will

likely use data for the period 2008-2010. Given the trend toward cleaner air in recent years, and

regulations on both mobile and stationary sources that have taken effect in the intervening 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 were reported to have challenged the scientific

conclusions in meetings with Bush Administration officials before the 2008 review was

completed.12 Some of the same concerns have surfaced in the public comment period on the 2010

revision.13 Members of Congress have been among those commenting on EPA’s proposed

8

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.

9

“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.

10

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.

11

See “Fact Sheet: EPA to Reconsider Ozone Pollution Standards,” September 16, 2009, at http://www.epa.gov/

groundlevelozone/pdfs/O3_Reconsideration_FACT%20SHEET_091609.pdf.

12

“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.

13

See, for example, “Chemical, Oil, Gas Industries Criticize EPA Ozone Proposal at Hearing in Houston,” Daily

(continued...)

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revision: on August 6, 2010, a bipartisan group of seven Senators wrote the EPA Administrator,

asking her to maintain the current (2008) standards, noting that “the Agency has not presented

new data or evidence to justify its course of action.”14

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.

Notes: (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.

(...continued)

Environment Report, February 4, 2010, p. A-5.

14

Letter of Senator George V. Voinovich et al., to EPA Administrator Lisa Jackson, August 6, 2010.

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

Promulgated in 2008 (0.075 parts per million)

(Based on 2004-2006 Air Quality Data)

Source: U.S. EPA.

Note: Estimates were based on the most recent data at the time of promulgation (2004-2006). 345 monitored

counties violated the 2008 8-hour ozone standard of 0.075 parts per million (ppm), based on those data.

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

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Figure 3. Counties With Monitors Violating Proposed Primary 8-hour

Ground-level Ozone Standards, 0.060-0.070 parts per million

(Based on 2006–2008 Air Quality Data)

Source: U.S. EPA

Notes: (1) No monitored counties outside the continental U.S. violate. (2) EPA is proposing to determine

compliance with a revised primary ozone standard by rounding the three-year average to three decimal places.

The Secondary Standard

As part of the review completed in 2008, 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 (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-hours). 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 ppmhours, suggesting that the upper bound be no higher than 15 ppm-hours.15 The Administrator’s

June 2007 proposal was in line with the staff recommendation, 7-21 ppm-hours, but his final

March 2008 choice was to duplicate the primary standard he promulgated at that time. He set a

15

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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secondary standard at 0.075 ppm averaged over 8 hours, rejecting the advice of both CASAC and

his staff.

Figure 4. Counties With Monitors Violating Proposed Secondary Seasonal GroundLevel Ozone Standards, 7–15 parts per million-hours

(Based on 2006 –2008 Air Quality Data)

Source: U.S. EPA

Notes: No monitored counties outside the continental U.S. violate.

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), but there was substantial disagreement between the Bush Administration EPA and the

White House over the form in which this standard should be set. (For a discussion, see archived

CRS Report RL34057, Ozone Air Quality Standards: EPA’s March 2008 Revision.)

The new (January 2010) proposal would adopt the W126 index and would set the secondary

standard at 7-15 ppm-hours, in line with CASAC’s recommendations. As shown in Figure 4,

nonattainment with the proposed secondary standard could be widespread: based on the latest

available (2006-2008) data at the time of proposal, 196 counties would be nonattainment if the

secondary standard were set at 15 ppm-hours, and 579 counties (86% of all counties with

monitors) would be nonattainment under a 7 ppm-hours standard. As discussed further below,

however, few rural counties have ozone monitors, so the true extent of nonattainment with the

secondary standard is unknowable. EPA has proposed additional ozone monitoring requirements

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for both urban and non-urban areas and expects to issue a final monitoring rule in coordination

with the final ozone standards.16

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. In general, ozone is a summertime pollutant. 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.

Costs and Benefits of Control

EPA is prohibited from taking cost into account in setting NAAQS, but to comply with an

executive order (E.O. 12866) and guidance from the Office of Management and Budget, the

agency generally produces a Regulatory Impact Analysis (RIA) analyzing in detail the costs and

benefits of new or revised NAAQS standards. The agency produced an RIA for its 2008 ozone

NAAQS, and it released an 89-page supplement to that RIA in conjunction with the January 2010

proposal. The major conclusions regarding benefits and costs were also included in a Fact Sheet

posted on the agency’s website.17 The analysis shows a wide range of estimates for benefits, from

a low of $13 billion annually to a high of $100 billion annually in 2020. EPA estimates of the

costs of implementing the standard also range widely, from $19 billion to $90 billion annually in

2020.

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,

16

See “Fact Sheet: Proposal to Revise the National Ambient Air Quality Standards for Ozone,” p. 4, at

http://www.epa.gov/air/ozonepollution/pdfs/fs20100106std.pdf.

17

The supplement and the Fact Sheet can be accessed at http://www.epa.gov/air/ozonepollution/actions.html#jan10s.

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fewer asthma attacks, less time lost at work and school, and fewer restricted activity days.18 The

Fact Sheet accompanying the proposed standards states that the benefits of a 0.070 ppm primary

standard would include the avoidance of 1,500 to 4,300 premature deaths annually in 2020,

whereas the more stringent 0.060 ppm standard would avoid 4,000 to 12,000 premature deaths

annually.19 Other benefits in 2020 would include preventing the following, annually20:

•

880 to 2,200 cases of chronic bronchitis

•

2,200 to 5,300 nonfatal heart attacks

•

6,700 to 21,000 hospital and emergency room visits

•

2,100 to 5,300 cases of acute bronchitis

•

44,000 to 111,000 cases of upper and lower respiratory symptoms

•

23,000 to 58,000 cases of aggravated asthma

•

770,000 to 2.5 million days when people miss work or school

•

2.6 million to 8.1 million days when people must restrict their activities.

In the supplement, the agency notes that “there are significant uncertainties in both cost and

benefit estimates for the full range of standard alternatives.” 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.”21 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.”22 Benefits, meanwhile, will remain difficult to

quantify, in part because of the difficulty of quantifying and valuing lives lost prematurely and

other adverse health effects due to exposure to pollution.

Issues

The major issues raised by the proposed standards concern whether the Administrator has made

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

by the scientific studies). Unlike the choices made by Administrator Johnson in 2008, both the

18

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.

19

“Fact Sheet: Supplement to the Regulatory Impact Analysis for Ozone,” at http://www.epa.gov/air/ozonepollution/

pdfs/fs20100106ria.pdf.

20

In each case, the low end of the range represents EPA’s estimate of the benefit from a 0.070 ppm standard; the high

end of the range represents the benefit of a 0.060 ppm standard.

21

Supplement to the RIA for Ozone, p. S-9.

22

Ibid., p. S-12.

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primary and secondary standards proposed by Administrator Jackson reflect the range of values

and the statistical form recommended by the agency’s independent science advisers, CASAC.

Other issues have been raised as affected industries, state environmental agencies, public interest

and environmental groups, and Members of Congress review what EPA has proposed, 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 Mercury Rule, 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 projects that 99 counties in 19 states (counties that include

some of the nation’s biggest cities) would violate the 70 ppb standard in 2020. If the final

standard is set at 60 ppb, 451 counties in 44 states are projected to be in nonattainment.23

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

most, the deadline will likely be 2015 or 2018 (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: whether the current monitoring

network is adequate to detect violations of a more stringent standard. Only 675 of the nation’s

3,000 counties have ozone monitors in place. With as many as 650 of them (96%) showing

violations of the most stringent proposed standard, using current data, how confident is the

agency that the 2,350 counties without monitors would all be in attainment? 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 new form of the secondary NAAQS proposed by EPA suggests a need for

additional monitoring in rural areas to detect impacts on forests and agricultural production.

The agency has, in a separate rulemaking, proposed changing the minimum monitoring

requirements for both urban and non-urban areas.24 That proposal would require that each state

operate at least three ozone monitors in non-urban areas. It would also require at least one ozone

monitor in each urban area with a population between 50,000 and 350,000.

23

For a map showing the 2020 projections, see map 4 in EPA’s briefing materials at http://www.epa.gov/air/

ozonepollution/pdfs/20100104maps.pdf.

24

74 Federal Register 34525, July 16, 2009.

Congressional Research Service

11

Ozone Air Quality Standards: EPA’s Proposed Revisions

Author Contact Information

(name redacted)

Specialist in Environmental Policy

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

Congressional Research Service

12

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