CRS Report: 97-8 - Air Quality: EPA's Proposed New Ozone and Particulate Matter Standards

John E. Blodgett, Larry B. Parker, and James E. McCarthy
Environment and Natural Resources Division

On June 25, 1997, President Clinton announced his decision to support revisions of national ambient air quality standards (NAAQS) for ozone and particulate matter (PM) similar to those proposed by the Environmental Protection Agency (EPA) in November 1996. The announcement ended a debate within the Administration and made it virtually certain EPA will issue final standards by a July 19 deadline. While the approved standards are slightly less stringent than EPA's original proposals, the President's action is widely viewed as endorsing EPA's intent to tighten controls on air pollution and as rejecting criticisms that the proposed standards are too stringent and will harm the economy.

As approved by the President, the ozone standard would be 0.08 parts per million measured over 8 hours, with the annual fourth highest concentration averaged over a 3-year period determining whether an area is out of compliance. This is somewhat more stringent than the existing 1-hour, 0.12 ppm ozone standard with 3 exceedences. The existing PM10 standard that regulates particles less than 10 microns in diameter will remain at a maximum annual concentration of 50 micrograms per cubic meter (µg/m3) and 24-hour concentration of 150 µg/m3; but a revised method for calculating compliance that permits averaging will reduce its stringency. A new PM2.5 standard will regulate particles less than 2.5 microns in diameter; it sets an annual limit of 15 µg/m3 and a 24-hour standard of 65 µg/m3 and will likely lead to further controls on utilities and industrial sources of precursor gases that make up very fine particles.

Issuance of the standards will be followed by monitoring to determine compliance. Nonattainment triggers a state planning process that could result in new air pollution controls on industry, utilities, the service sector, and transportation. This process will be lengthy: EPA expects the deadline for ozone attainment to extend to 2007, and for PM2.5 to extend to 2015.

Whether the benefits of the proposed standards justify costs is disputed: EPA estimates that costs may exceed quantifiable benefits for the new ozone standard, but that benefits exceed costs by 10 to 20 times for the new particulate standard. Industry disputes these figures. At the same time, some health and environmental groups contend that even more stringent standards are warranted. In any event, under the statute, EPA is required to set standards solely on the basis of public health considerations. Costs may, however, be considered in state plans for implementing the standards.

Stakeholders have been entreating Congress to intervene pro or con, and Congress has responded, in part by conducting more than 20 days of hearings as the administrative rulemaking process proceeded. Once EPA issues a final decision, Congress has new authority establishing a 60-day congressional review period for regulations. Congress could also amend the Clean Air Act to address issues raised by the proposal or attach instructions to EPA's appropriation.

The explicit purpose of the Clean Air Act (CAA) is to protect and enhance the quality of the nation's air resources so as to promote the public health and welfare and the productive capacity of its population (Section 101(b)(1)). Key to this purpose, the Act directs the Environmental Protection Agency (EPA) to set National Ambient Air Quality Standards (NAAQS), which limit ambient air levels of designated air pollutants. Particulate matter (PM), ozone (smog), nitrogen dioxide (NO2, or, inclusively, nitrogen oxides, NOx), sulfur oxides (SOx, or, specifically, sulfur dioxide, SO2), carbon monoxide, and lead are the six categories of air pollutants for which NAAQSs have been set.

Since 1970, when the CAA was rewritten to establish the modern federal role in protecting air quality, the difficulty of achieving the NAAQSs -- most especially achieving the ozone NAAQS in urban areas -- has fostered continued debate on the effectiveness, technical feasibility, and costs and benefits of air pollution control requirements. Major amendments in 1990 revised procedures for attaining the NAAQSs, with particular attention to areas failing to attain the ozone standard. To achieve the NAAQSs, the 1990 Amendments both extended deadlines and prescribed a series of requirements; the strategy was to impose on the most polluted areas the most stringent requirements but to give them more time to achieve compliance (up to 20 years for the worst case of ozone pollution, Los Angeles).

The NAAQSs are designed to prevent ambient concentrations of the designated air pollutants from rising to levels causing adverse effects on the public health or welfare. For each of the six designated pollutants, EPA prepares a ``Criteria Document,'' which lays out the best scientific information on the relationship between levels of the pollutant and adverse effects. The review is comprehensive and thorough; the most recent ones for ozone and particulate matter run a combined 4,000 pages. Criteria documents are reviewed by the Clean Air Scientific Advisory Committee (CASAC), an independent panel of scientists (mostly from academic or research institutions) appointed by the Administrator of EPA.

Based on the Criteria Document, EPA prepares a ``Staff Paper'' that develops from the scientific evidence a set of policy options for agency decision. This Staff Paper is also reviewed by CASAC. On the basis of the scientific evidence in the Criteria Document and the analysis in the Staff Paper, the EPA Administrator sets the NAAQSs necessary to prevent adverse effects.

The CAA provides for two levels of NAAQSs: primary standards, set at a level to protect the public health, with an ``adequate margin of safety''; and secondary standards, set at a level to protect the public welfare. The CAA defines public welfare as including ``effects on soils, water, crops, vegetation, man-made materials, animals, wildlife, weather, visibility, and climate, damage to and deterioration of property, and hazards to transportation, as well as effects on economic values and on personal comfort and well-being'' (Section 302(h)). The Act sets specific deadlines for the attainment of the primary NAAQSs, but not for the secondary ones.

In principle, the relationship between pollutant levels and adverse health effects solely drives the decision for setting the level of a primary NAAQS. The presumption, indicated by the ``margin of safety'' provision, is that for an ambient air pollutant, there will be a threshold concentration below which adverse health effects do not occur. On this presumption, setting a NAAQS is an objective, scientific determination of that threshold. The Act prohibits consideration of costs, technical feasibility, and other non-health criteria in determining a NAAQS. (See Endnote 1.) The recent ozone and PM Criteria Documents do not find a threshold, however; this implies that in practice the decision of the level for a NAAQS represents a risk management decision.

Each state is responsible for developing a plan (a State Implementation Plan, or SIP) for achieving and maintaining each NAAQS. The NAAQS itself does not directly concern regulatory controls on specific sources; it is the SIP that provides for such controls. These must reduce emissions sufficiently to achieve and maintain the NAAQS. (See Endnote 2.) Costs become of concern in state decisions on regulatory controls to include in SIPs. (See Endnote 3.)

Because knowledge about relationships between pollutant levels and health evolves with more research and increasing scientific understanding, the CAA provides that NAAQSs should be reviewed every 5 years. This review entails the writing of a new Criteria Document that incorporates new research findings since the last one, followed by a decision as to whether the existing NAAQS remains appropriate or should be adjusted (up or down).

Such a Criteria Document for ozone was completed in 1989, but EPA delayed making a decision based on that review. Following a suit by the American Lung Association, EPA in 1993 decided to retain the existing ozone standard but, because of important new studies, committed to accelerate the next review. This led to a settlement agreement in which EPA agreed to prepare a new Criteria Document and, if necessary, propose new standards for ozone. Also, following a separate suit initiated in 1993, EPA became subject to a court-ordered schedule for reviewing the particulate standard, with a proposed rule to be issued by November 29, 1996, and a final rule by June 28, 1997 (See Endnote 4.) (the deadline for the final rule has since been extended to July 19, 1997).

EPA announced the proposed new ozone and PM NAAQSs November 27, 1996, initiating a contentious debate on health implications, costs, benefits, scientific justification, feasibility, and alternatives. This report discusses the issues raised by EPA's proposals and reviews potential congressional and judicial responses to the proposals. As of this writing, a crucial step portending finalization of the proposals has been the President's June 25, 1997 endorsement of the standards, with some modifications.

The proposed decisions for the new ozone and particulate standards appeared in the Federal Register December 13, 1996, (See Endnote 5.) and are also available on EPA's world wide web site. (See Endnote 6.) EPA's deadline for issuing final decisions for the ozone and PM NAAQSs, as well as for two complementary rules, is July 19, 1997.

The proposed new NAAQS for ozone tightens the standard from 0.12 parts per million (ppm) to 0.08 ppm, increases the averaging time from 1 hour to 8 hours, and calculates exceedances by averaging concentrations rather than by counting individual 1-hour peak concentrations. The net result is a more stringent standard, but not by as much as a straight comparison of concentration levels might suggest. The longer averaging time and the use of average concentrations give weight to the magnitude of the exceedance and reduce the influence of unusual meteorological conditions on compliance with the NAAQS. These changes increase what is called the ``robustness'' of the standard, meaning that it more accurately represents the risks posed by the pollution level.

Ozone is the primary ingredient of smog. (See Endnote 8.) Ozone itself is not emitted as a pollutant; rather, it forms in the atmosphere as a reaction between nitrogen oxides (NOx) and volatile organic compounds (VOCs) in the presence of sun-light. (See Endnote 9.) Ozone concentrations usually peak in the late morning or afternoon and decline in the evening. As long as NOx and VOCs remain in the atmosphere, ozone continues to form downwind; ozone concentrations are often higher in the suburbs and rural downwind areas than in cities, and can remain high in areas -- such as Maine -- hundreds of miles beyond major emissions sources. (See Endnote 10.)

The health effects of ozone include aggravated asthma, respiratory problems, inflamed lung tissue, and temporary reductions in lung capacity. Studies of hospital admissions show a correlation between ozone concentrations and daily admissions for respiratory causes. Those mainly at risk from ozone pollution are persons who spend time outdoors during hot weather, particularly children, exercisers, and outdoor workers.

The existing ozone primary NAAQS is 1 hour at 0.12 ppm with 3 exceedances per 3 consecutive years allowed. To be in attainment with the ozone NAAQS, therefore, an ozone monitor must not show more than 0.12 ppm ozone average concentration over 1 hour more than 3 times in 3 consecutive years. (The present standard replaced a more stringent standard of 1-hour at 0.08 ppm, which was in effect from 1971 to 1979.) The validity of the averaging time and the stringency of the standard have always been problematic, however. The assumption that the 1-hour averaging time was justified by sharp peaks in ozone concentrations has been challenged by studies showing that ambient ozone concentrations often have broad daytime peaks, with maximum 8-hour averages close to 90% of peak 1-hour levels; thus, the 1-hour measurement may not fully represent the risk posed by longer exposures. Moreover, controlled studies relating ozone exposure to lung function indicate that symptoms may appear in moderately exercising adults at or below the current standard, especially overlonger periods of exposure. Finally, the scientific evidence suggests that there may not be a threshold concentration below which biological responses will not occur. (See Endnote 11.)

As a result of the review of such studies in the new Criteria Document, the EPA proposed a new 8-hour, 0.08 ppm ozone NAAQS. An area would be in attainment with the standard when the annual third highest daily maximum 8-hour concentration, averaged over 3 years, is below 0.08 ppm (abbreviated as 8-hrs, avg 3rd max, .08 ppm). (As approved by the President on June 25, 1997, the annual fourth highest concentrations would be averaged over 3 years. This reduces somewhat the stringency of the standard from that originally proposed by EPA, but it would still be more stringent than the existing standard.) Averaging concentrations rather than counting individual exceedances increases the robustness of the measurement of compliance; this change has been strongly supported by CASAC, among others. The net effect of the new proposed NAAQS would be to increase the stringency of the ozone standard.

According to EPA, compared to the existing ozone standard, the proposed one would result in annual benefits of 1.5 million fewer cases of significant breathing problems; significantly reduce hospital admissions, missed school and work days, restricted activity, and emergency room visits for respiratory problems; cut illness in children overall; reduce episodes when asthmatic children require medication or medical treatment; and reduce agricultural crop losses caused by ozone. (See Endnote 12.)

The costs of achieving the new standard are necessarily speculative; indeed, it is uncertain how to attain the existing standard in the most polluted areas. EPA estimates that the number of metropolitan areas not attaining the ozone NAAQS -- which have declined from over 100 a few years ago to about 50 (See Endnote 13.) --would more than double,perhaps triple. EPA has prepared lists and a set of maps showing counties projected not to meet the new standard. (See Endnote 14.) Sources of VOCs and NOx would necessarily have to ratchet down emissions further; and constraints on sources, including vehicles, might compel lifestyle changes.

EPA's proposed new particulate matter NAAQS would focus on finer particles, those smaller than 2.5 micrometers (µm) in diameter, than the present standard, which regulates particles smaller than 10 µm. The new PM2.5 standard would be in addition to the present PM10 standard. It would be based on temporal (3-year) and spatial averaging of concentrations. The net effect would be to increase the stringency of the PM NAAQS and to shift the focus of control from capturing particles to regulating gaseous emissions, especially NOx and SO2.

Particulate matter is a mix of coarse and fine particles in the air; it is the only criteria air pollutant that is not a specific chemical. Particles vary in biological effect depending on their composition and size. Particles larger than þ 10 þm are of little health concern since only a small proportion penetrate to the lungs. Particles smaller than 10 µm (PM10) fall into two categories, dividing at about 2.5 µm.

Particles between 10 and 2.5 µm (PM10-2.5) are composed largely of mechanically dispersed, soil-like particles, tend to be alkaline, and persist in the atmosphere for relatively short periods because they tend to settle out. (See Endnote 16.) Particles smaller than 2.5 µm (PM2.5) form largely from gaseous precursors, tend to be acidic, and are relatively stable. Fine particles smaller than 2.5 µm result from combustion and secondary chemical reactions in the atmosphere involving especially NOx, SO2, and VOCs. (See Endnote 17.)

Particulate matter is associated with a number of health problems. The foremost concern is evidence that acute and chronic exposure to particulate matter causes premature mortality from respiratory diseases and heart attacks, particularly among the elderly and those with heart and lung diseases. The studies do not indicate any threshold. EPA interprets the studies as indicating that as many as 40,000 premature deaths linked to particulate matter occur annually. EPA suggests that the majority of these premature deaths is due to PM2.5. However, the CASAC review of the PM Criteria Document pointed out a number of uncertainties affecting the conclusions about the number of premature deaths and whether PM2.5 (as opposed to PM10-2.5) was the primary causative agent. CASAC specified a number of research areas that EPA should address to add robustness to future reviews of the PM standard. (See Endnote 18.) Additional health problems attributed to PM include aggravated asthma, increased illness and respiratory problems among children, and increased hospital admissions and emergency room visits. Haze and diminished visibility are the principal welfare impacts of PM2.5.

The existing NAAQS for particulate matter limits particles smaller than 10 µm (PM10) to a maximum annual concentration of 50 µg/m3 [micrograms per cubic meter] and to a 24-hour concentration of 150 µg/m3. It was issued in 1987 and replaced a standard for total suspended particulates. SIP controls to attain and maintain the PM10 NAAQS have primarily focused on the coarser particles between 10 and 2.5 µm (although pollution controls resulting from the needs to achieve the NO2, SOx, and ozone NAAQSs contribute to reductions in PM2.5). Controls have included capturing particulate emissions with baghouses (a kind of filtering process) and electrostatic precipitators, and reducing the generation of particles both by paving roads, and by wetting demolition sites and dusty roads during operations. Most of the nation (86% of counties with PM monitors) is in compliance with the present standard.

Based on the new PM Criteria Document, EPA concluded that the PM2.5 fraction of particulate matter is the primary cause of remaining adverse health effects from PM, and that controls based on PM10 do not adequately address that finer fraction. EPA is therefore proposing adding a new PM2.5 NAAQS: annual 15 µg/m3 and 24-hour 50 µg/m3. (As approved by the President on June 25, 1997, the annual standard would be 65 µg/m3, rather than 50. This change reduces slightly the stringency of the standard from that originally proposed by EPA and gives more flexibility for individual, episodic sources of fine particulates.) The annual PM2.5 standard would be met when the 3-year average of the annual arithmetic mean of PM2.5 concentrations, spatially averaged across designated air quality monitors, does not exceed 15 µg/m3.

The existing PM10 standard would continue, with the 24-hour standard revised from a 1-exceedance form to a 98th percentile form averaged over 3 years. (See Endnote 19.) This change would in effect reduce the stringency of the PM10 standard; of the approximately 40 counties currently out of attainment, about three-fourths would meet the PM10 standard as measured by the new method.

EPA estimates that every year the new PM2.5 standard would reduce premature deaths linked with particulate air pollution by about 15,000 annually (See Endnote 20.); reduce aggravated asthma episodes and incidence of acute childhood respiratory problems, each by a quarter million occurrences; reduce chronic bronchitis by 60,000 cases; reduce hospital admissions due to respiratory problems by 9,000; and cut haze and visibility problems. (See Endnote 21.)

Under this new PM2.5 standard, EPA estimates that about 170 counties in the nation would not be in compliance (compared to about 40 out of compliance with the existing PM10 standard). However, the projection is crude, because of a lack of current monitoring data for PM2.5. (See Endnote 22.) The new standard would involve a new control regimen: where existing PM controls focus on filters and preventing dust dispersion, the new controls would necessarily focus on controlling precursor gases, especially NOx, SO2, and VOCs. (See Endnote 23.) To some extent, these would coincide with requirements to reduce NOx, SO2, and ozone, to meet NAAQSs, acid rain control requirements, and any future regional haze program. Continuing compliance efforts on these programs will reduce any reductions necessitated by a PM2.5 standard, which could not become implemented for several years.

Concurrently with the ozone and PM NAAQS proposals, EPA is also proposing two complementary rules: one on Monitoring Requirements for Particulate Matter, and the other on an Interim Implementation Policy for the Ozone and PM NAAQSs. They contain many details that would ultimately determine the implications of the new NAAQSs. In addition, the proposals were accompanied by an advance notice of proposed rulemaking concerning the relationship between the ozone and PM NAAQSs and regional haze controls.

EPA proposed an Interim Implementation Policy (IIP) that represents its preliminary statement on how it would handle the transition from existing policies that are designed to meet the current ozone and PM10 NAAQSs to the policies that would be required to meet the new standards. (See Endnote 25.) The IIP does not bind states to certain actions; that process is left to future rulemaking. Rather, it represents the first step for EPA to issue rules for implementing the new NAAQSs after the final decisions on the standards are promulgated.

(During congressional briefings after the President announced support for new ozone and PM NAAQS [see page 24 below], EPA indicated that the IIP would be modified, in particular by following the letter of the law in enforcing the existing standard. EPA is expected to issue a revised IIP by July 19, along with the final NAAQS standards.)

Based on the CAA's general SIP requirements to implement reasonably available control technology'' and to demonstrate reasonable progress toward attainment (Section 172(c)(1-2)), and current detailed ozone requirements (Section 182(c)(2)(C)), the IIP, as proposed, focused state planning efforts for the transition on maintaining reasonable further progress (RFP). The IIP indicated EPA is more interested in states moving toward compliance with the new NAAQS than meeting the deadlines contained in the 1990 CAA Amendments for the existing NAAQS. EPA would encourage this shift by de- emphasizing provisions focused on compliance with the existing NAAQS (such as attainment demonstration or reclassification penalties) and by emphasizing provisions that contribute to a state's further progress toward meeting the new NAAQS (such as existing New Source Review requirements). EPA seeks to prevent states from losing ground (``backsliding'') during the transition to the new NAAQS.

The IIP would remain in effect for a state until it has a new, EPA-approved SIP that, when implemented, would achieve the new or revised NAAQS. This process could involve 5-8 years. (See Endnote 26.) During this time, several non- compliance areas could be subject to reclassification and compliance demonstration requirements under the 1990 CAA Amendments. Under the IIP, however, EPA would not enforce these requirements if states were making acceptable progress in reducing ozone or PM concentrations. To define an acceptable ``rate of progress'' for ozone reductions, EPA would generally require states to submit interim SIPs that would reduce actual emissions by at least 3% annually averaged over a 3-year period beginning November 15, 1996.

In addition, EPA proposed that within 90 days of promulgating a final ozone NAAQS, states lay out elements of an ozone attainment demonstration program that includes adoption and implementation of regional control measures, urban analysis of the reductions necessary to meet the existing NAAQS by its statutory deadline, and an early assessment of the emission reductions necessary to achieve the revised NAAQS. In particular, EPA reaffirmed its belief that regional measures are critical to attainment of the existing or new ozone NAAQS. Reflecting this more regional approach, EPA specifically proposes to permit VOC reductions made outside of a non-attainment area but within 100 km of that area (200 km for NOx reductions) to count toward an area's 3% annual rate of progress requirement (with some exclusions).

In terms of PM, the IIP focuses on PM10 compliance, leaving issues concerning PM2.5 implementation to the future when data on emissions and ambient concentrations are available. In general, the IIP for PM follows the same ``no backsliding''principle that the ozone guidance does.

Implementation of the new PM NAAQS will depend significantly on EPA's proposed PM monitoring rule, which has three purposes: First, the proposed rule would support EPA's proposed PM2.5 NAAQS by requiring development of a PM2.5 monitoring system from the ground up. Second, it would revise the existing ambient air quality monitoring requirements for PM10 to meet proposed measurement revisions to the PM10 NAAQS. Third, it would coordinate existing visibility monitoring requirements with the proposed PM monitoring requirements to accommodate any future regional haze program and to reduce administrative burdens.

An ambient air quality monitoring network to support a PM2.5 NAAQS does not currently exist. The proposed rule calls for a two-track monitoring system for fine particles, reflecting the differing monitoring requirements for the 24-hour and the annual PM2.5 NAAQS. Compliance with the annual PM2.5 NAAQS would be based on an annual arithmetic mean derived from multiple, population-oriented monitoring sites. Such spatial averaging would make monitor siting more complex, but EPA believes that it is more in keeping with the science than other approaches. Sampling would be conducted daily, at least for the first few years of the program, to improve the data base and emissions characterization. Compliance with the 24-hour PM2.5 NAAQS would be based on the single population oriented monitor within a monitoring planning area with the highest measured PM2.5 levels. The network requirements are to be phased in over 3 years. EPA estimates that the PM2.5 network will require 1,200 monitoring sites at a 3-year implementation cost of $61 million, including initial capital costs.

Because EPA anticipates that the PM2.5 NAAQS will be the controlling standard with respect to PM, revisions to the PM10 network focus on reducing the frequency and number of locations for PM10 data collection. Sampling at PM10 monitoring sites would be reduced to a minimum of once in 6 days. PM10 monitoring sites in areas of relatively low PM10 concentrations or in areas not required for trends analysis would eventually be discontinued. EPA estimates that the current network of 1650 PM10 monitoring sites will be reduced to 600 sites. The implementation cost of relocating or discontinuing sites, along with changing to one in 6-day schedule is estimated at $30 million over 3 years.

Finally, to improve the PM2.5 data base in support of the proposed secondary NAAQS and to augment the existing visibility monitoring network in anticipation of a regional haze program, EPA adds two additional monitoring objectives to the criteria for core PM2.5 stations. The first objective is to determine the extent of regional pollutant transport among populated areas, which may involve remote sources. The second objective is to determine the welfare-related impacts of PM2.5 in more rural and remote areas. EPA anticipates that the additional monitors necessary to achieve these objectives, along with the existing visibility monitoring system, will be an integrated part of the network necessary to monitor compliance with any regional haze program. The capital and operating costs of these monitors for a 3-year period are included in the PM2.5 monitoring estimates provided above.

One implication of decisions on the ozone and PM2.5 NAAQSs concerns EPA's upcoming program to address regional haze and visibility (CAA, Section 169A, 169B). EPA released an advanced notice of proposed rulemaking on the regional haze program along with the NAAQS proposals issued November 27.

It outlines ``policy and technical implementation issues and principles, and questions for issues associated with the potential revision of the ozone and PM NAAQSs and the development of a regional haze program.'' (See Endnote 29.) A haze program would substantially overlap with programs to control ozone and PM2.5, since it would focus on SO2 and NOx. The IIP and the Particulate Monitoring proposals both make a point of the relationship. In the end, many of the controversies embedded in the stringency of the ozone and, especially, the PM2.5 NAAQS will replay in EPA's decisions on a regional haze regulatory program. EPA says it intends to propose the regional haze program in mid-1997.

In discussing the proposed standards, at least four sets of issues have been raised:

The first set, raised by EPA itself in requesting public comments, concerns whether the Agency should choose specific alternatives to the proposals. Seventeen specific questions were listed for comment by EPA in an effort to solicit public input to the final decision. These questions are listed individually below.

The second set of issues concerns the scientific conclusiveness of the evidence underlying EPA's analysis and decisions. Given the Clean Air Act's mandate to protect public health and the judicial interpretation that this language bars consideration of cost and technical considerations, the sufficiency of the science underlying EPA's decision is the central issue.

A third set of issues that have been raised concerns the potential regulatory impacts of the proposals, including costs and benefits, small business impacts, and state and local government impacts (unfunded mandates), among others.

Finally, the proposals raise implementation concerns, by creating conflicting requirements between specific provisions of the statute. Each of these sets of issues is discussed in turn in the following sections.

EPA's proposals for ozone and PM2.5 NAAQSs represent the Adminis-trator's choices from ranges of alternative standards presented in the Staff Papers. The public comment period provides the public and stakeholders formal opportunity to present their views on the scientific evidence underlying the proposals, on the specific standards proposed, and on alternatives. EPA's proposals single out a number of controversial issues and specifically solicit comments on them, including alternative levels of stringency for the NAAQSs themselves.

Interim Implementation Policy

The IIP proposal seeks the broadest possible scope of comments: ``The EPA solicits comment on each element contained in this proposal and seeks additional suggestions on approaches to increase flexibility during the interim period to improve both air quality and pollution reduction strategies with a change in the NAAQS.''<29>

Particulate Monitoring

Scientific Conclusiveness

A fundamental set of issues raised by the proposal concerns the conclusiveness of the underlying science and, in particular, the implications of the apparent lack of a threshold for adverse effects from ozone and PM.

Despite the wealth of scientific data examined in the Criteria Documents and the review of the Criteria Documents and Staff Papers by the CASAC, the conclusiveness of the scientific evidence in support of the proposed standards is open to debate.

On ozone, the key scientific issue concerns the magnitude and significance of adverse health effects. CASAC's ozone panel unanimously supported changing from a 1-hour to an 8-hour standard with multiple exceedances; individual members who expressed personal preferences for the level of the standard voted as follows: 0.09-0.10 (1 vote); 0.09 (3 votes); 0.08-0.09 (1 vote); 0.08 (3 votes)--two members said it was a policy call and expressed no preference.<30>

On PM2.5, a crucial scientific issue remains ``not unambiguous''<31>: the evidence that it is the PM2.5 fraction of particulate matter that accounts for many adverse health effects. Another health uncertainty arises from ambigu-ities in studies that attribute acute mortality to PM. Other important uncer-tainties concern the pollutant itself: which chemical species of PM2.5 may be causing adverse health effects, actual ambient concentrations of PM2.5, and sources. Important components of these uncertainties about PM2.5 result from the lack of monitoring information and cannot be resolved until new monitoring systems have been in place for several years. By a wide majority, 19 to 2, CASAC's PM panel endorsed establishing a new PM2.5 standard, but there was no consensus at what level to set it.<32> CASAC also specified needed research.

These and other scientific questions will be raised to challenge the standards. The uncertainties can cut both ways: some will argue that the uncertainties justify holding off increasing the stringency of the standards until better evidence is in hand; others will argue that the uncertainties mean risks of adverse effects may be greater than realized and as a precaution even more stringent regulations are warranted.

To research these uncertainties will take several years. At the same time, it will take several years to implement the proposed new ozone standard and, given the need to develop a monitoring system, even to begin implementing the PM2.5 standard. Because the CAA requires NAAQSs to be reviewed every 5 years, another round of Criteria Document preparation and agency decision on revising the rules will come due before the proposed standards can be substantively implemented--particularly for PM2.5. Some may therefore argue that holding off on new standards--especially for PM2.5--would be consistent with the CAA schedule for staying abreast of new scientific knowledge. Others will argue that the long implementation schedules mean that the process should begin as soon as possible.

On both pollutants, the scientific evidence calls into question the existence of thresholds for adverse health effects. If no threshold can be determined, EPA cannot identify a ``bright line'' separating pollutant concentrations having an adverse health effect and those having none. In the absence of a threshold, it appears to some that EPA's basis for choosing a particular standard is a policy determination that entails criteria beyond objective, scientific ones. Stakeholders may challenge the proposals as being based on improper criteria; and may contend that without a threshold, costs (and benefits) cannot be avoided in the NAAQS decisions.

Regulatory Impacts

A number of administrative and statutory mechanisms have been created to focus attention on various impacts of federal regulation. These include Executive Order 12866, which requires cost and benefit analyses of significant new rules; statutory requirements designed to identify significant impacts of new rules on small businesses, on state and local governments, and on the private sector; statutory provisions to minimize paperwork; and an executive requirement to consider environmental justice implications of new regulations.

As previously noted, the CAA has been judicially interpreted as disallowing EPA from considering economic costs when setting a NAAQS, leaving cost and technological feasibility issues to be considered in developing SIPs to implement the standards. Nevertheless, a NAAQS inevitably implies impacts on state and local governments in developing, implementing, and enforcing SIP requirements; on businesses and industries which must reduce emissions to meet those requirements; and on everyday lives through effects on products and transportation policies.

Because of these impacts, EPA concluded that the proposed rule for new NAAQSs for ozone and PM is a ``significant regulatory action'' under Executive Order 12866 and therefore submitted it to the Office of Management and Budget for review and comment and has prepared ``Regulatory Impact Analyses'' (RIA) on both the ozone<33> and PM<34> proposed new standards.

For ozone, based on a regional control strategy, the draft RIA indicates that measurable costs exceed measurable benefits. However, the RIA notes a large number of limitations and uncertainties inherent in estimating national costs and benefits over an extended period of time. These problems include the inability to monetize certain benefits, uncertainty about future control technolo-gies, and incomplete data on emissions. With these caveats in mind, the RIA projected benefits and costs for two scenarios that bracket the proposed one: an 8-hour, 0.08 ppm, 4-exceedances standard yielding projected annual benefits of partial attainment in 2007 of $0 to $600 million and costs of $600 million; and an 8-hour, 0.08 ppm, 1-exceedance standard yielding projected annual benefits of $100 million to $1.5 billion and costs of $2.5 billion (see table 1).

For PM2.5, with caveats similar to those cited for ozone, the RIA projected annual partial costs and benefits in 2007 of the proposed NAAQS are: benefits of $58 to $119 billion at a cost of $6 billion (see table 1). (Because some ozone and PM2.5 controls overlap, these cost estimates include some double counting; EPA says it will revise its regulatory impact analyses to reflect changes resulting from implementation strategies, and implies that flexibility and integrated approaches will likely reduce costs.)

That EPA's projected costs of the proposed new ozone standard exceed benefits is sure to intensify criticisms that the new standard is ill-advised and inappropriate. Since EPA began seriously considering alternative ozone NAAQS, stakeholders who would bear costs of a more stringent ozone NAAQS have been warning of excessive costs. On the proposed PM2.5 rule, where EPA estimates much higher benefits than costs, stakeholders who would bear costs argue that the scientific evidence used to justify the standard and to estimate

The Regulatory Flexibility Act (RFA) (5 U.S.C. 601 et seq.) provides that, whenever an agency is required to publish a general notice of rulemaking for a proposed rule, the agency must prepare regulatory flexibility analyses for the proposed and final rule unless the head of the agency certifies that it will not have a significant economic impact on a substantial number of small entities. After an extended discussion of whether the RFA requirements apply to the proposed rules for the ozone and PM NAAQSs, EPA concludes that a NAAQS does not itself directly affect small businesses; rather, it is the implementation of the NAAQS that does:

The proposed [ozone, or PM2.5] rule, if promulgated, will not establish requirements applicable to small entities. Instead, it will establish a standard of air quality that other Clean Air Act provisions will call on states (or in case of state default, the federal government) to achieve by adopting implementation plans containing specific control measures for that purpose. In other words, state (or federal) regulations implementing the NAAQS might establish requirements applicable to small entities, but the NAAQS itself would not.<41>

Consequently, the Administrator of EPA ``certifies'' that the proposed rules ``will not have a significant impact on a substantial number of small entities.''<42> EPA extends its finding that the ozone and PM NAAQS proposals do not have a significant economic impact on small business to mean that the agency is not obligated by a provision of the RFA that panels chosen by the Chief Counsel of Advocacy of the Small Business Administration (SBA) be convened to advise EPA on the proposed rule.<43>

EPA's certification that its proposed rule will not have a significant impact on a substantial number of small entities, and its consequent determination that the RFA does not apply, is subject to judicial review (5 U.S.C. 611).

Although EPA concludes that the RFA does not apply to the proposed ozone and PM NAAQS, EPA notes that the agency has conducted a more general analysis of the potential costs impacts on small businesses, and included that analysis in the RIA. Furthermore, EPA says that it will voluntarily work with the SBA to hold panel exercises to solicit comment, advice, and recommendations on the proposed rules from representatives of small business.

The Unfunded Mandates Reform Act (UMRA) (2 U.S.C. 1501-1571) imposes a series of requirements on federal agencies proposing regulations that would result in expenditures by state, local, and tribal governments, in the aggregate, or by the private sector, of $100 million or more in a year. UMRA requires the regulatory agency to prepare a cost-benefit analysis, to notify small governments so they can comment during development of the regulation, and to identify and consider alternative regulations. As in its conclusion about the RFA, EPA has determined that because ``EPA cannot consider in setting a NAAQS the economic or technological feasibility of attaining ambient air quality standards,'' the specified requirements of the UMRA do not apply.<44>

EPA does observe in the proposed rule, however, that economic ``factors may be considered to a degree in the development of State plans to implement the standards,'' so EPA ``will address unfunded mandates as appropriate,'' for example when it requires revisions to State Implementation Plans to achieve the new NAAQSs.<45>

Finally, in the proposed rule, EPA notes that any implications for reporting requirements (which might be subject to the Paperwork Reduction Act) would arise in implementing the NAAQS, and would be addressed in the final RIA. Also, EPA notes that environmental justice concerns (which are to be assessed under Executive Order 12848) are addressed in the draft RIA.

Implications for the CAA

For ozone especially, and to a lesser extent for PM, new NAAQSs could raise issues of consistency with provisions in the CAA. When the CAA was last reauthorized in 1990, one focus of the debate was the failure of numerous regions to attain the current ozone and PM10 standards. For ozone, Congress created an elaborate structure classifying ozone nonattainment areas into five categories (Marginal, Moderate, Serious, Severe, or Extreme), granting areas with more severe air pollution problems longer periods of time to meet the standard. In return, the more severely polluted areas were required to implement increasingly stringent emission controls specified in the Act. A parallel but simpler 2-category classification scheme was established for PM10: All areas classified as PM10 nonattainment are initially classified as ``Moderate''; if EPA determines an area cannot practicably attain the PM10 NAAQS by the attainment date, it is reclassified as ``Serious.''

The CAA, as written, specifically references the existing 1-hour, 0.12 ppm ozone standard<46> (Section 181) and the PM10 standard (Section 188) in categorizing the nonattainment areas. Section 182 then spells out SIP requirements for each ozone noncompliance category, and Section 185 contains specific enforcement requirements for severe and extreme nonattainment areas that fail to attain. Similarly, Section 189 spells out SIP requirements for the PM10 noncompliance areas.

If the ozone standard changes from 0.12 ppm to 0.08 ppm, the statutory definition of the 5 categories becomes an anomaly, requiring measured progress toward a standard that would no longer exist--although virtually all parties concede that the ozone control measures required under existing law are the same types of controls one would use to meet the new standard. Since EPA is proposing to retain the existing PM10 standard, the question of references in the CAA specifically to PM10 as the PM standard poses less a problem. Nonetheless, that the Act specifically refers to PM10 but not to PM2.5 might create inconsistencies. As noted previously, EPA has proposed an interim implementa-tion plan for dealing with the transition to new ozone and PM standards.

The issue is not whether EPA could implement new ozone and PM standards: the CAA provides EPA general authorities to implement NAAQSs. The issue is whether EPA can disregard the specific statutory requirements relating to the existing standards, as implied by the IIP. For example, EPA suggests in the IIP that the agency would not use statutory criteria based on the existing ozone standard for reclassifying areas or imposing sanctions, even though those actions are specifically required.

Responding to the Proposed NAAQS

Stakeholders--including affected business and industry interests, state and local governments, and health and environmental public interest groups--will have several opportunities to affect the final decisions on the NAAQS besides the public comment process. Already, they have been making entreaties to the Congress and the White House. Congress could delay, suspend, or change the proposal, for example through amending the CAA or adding a rider to an appropriations bill. Also, issuance of a final rule will trigger a 60-day congressional review under Subtitle E, Congressional Review of Agency Rulemaking, a provision of the Small Business Regulatory Enforcement Fairness Act (Title II of P.L. 104-121). Court challenges are also possible, many think inevitable. Thus, the final outcome of the proposed ozone and PM decisions may not be resolved until after legislative and judicial processes are completed.

Public Comment and Lobbying

The rules being proposed--the ozone and PM NAAQSs, the Interim Implementation Plan, and the PM Monitoring Requirements (plus the advance notice of proposed rulemaking for the regional haze program)--provide for a 60-day formal comment period. There will also be an EPA-sponsored public hearing. This process of federal rulemaking is governed by the Administrative Procedure Act (5 U.S.C. 553).

During the comment period, which ends February 18, 1997, concerned parties can submit in writing to EPA any criticisms, suggestions, and options concerning the proposals and the scientific evidence underlying them, as well as on the alternatives EPA has identified. EPA is then obligated to review the comments, and can be expected to respond to significant comments in a discussion accompanying the final decisions.<47> Public hearings took place January 14 and 15, 1997. EPA has pledged to issue the final rules by June 28, 1997 (the date required by court order for the particulate decision).

At the same time that concerned stakeholders are submitting written comments to EPA, they can also be expected to direct comments to the public generally and to the Congress and the White House specifically. The Congress has several avenues by which it can weigh in both on EPA's deliberations and on its issuance of the rule. Industry and business have already urged the White House, EPA, and the Congress not to tighten the ozone and PM standards, claiming excessive costs, lack of significant demonstrable benefits, loss of competitiveness, and technical infeasibility.<48> An industry-business Air Quality Standards Coalition has been formed to contest the stronger rules. At the same time, health and environmental stakeholders have either supported the proposals or proposed tightening them further.<49>

Legislative Options

Congress had expressed its interest in the new standards even before EPA formally proposed them. The conference report to accompany H.R. 3666, making fiscal 1997 appropriations for EPA, noted:

The conferees are aware that EPA is under court order to make a decision on whether to change the current National Ambient Air Quality Standard for Particulates. ... The conferees note that at present, there appears to be insufficient data available for the Agency to decide what changes, if any, should be made to the current standard. ... Given that monitoring and research into causality have only just begun, the conferees believe it may be premature for the Agency to promulgate new particulate standards at this time.<50>

On July 26, the PM standard was one of several issues raised by the Congressional Oil and Gas Forum in a letter sent to the White House.<51> The letter, signed by 21 Senators and 75 Members of the House, sought eased EPA regulations on the oil and gas production industry. Eight Senators--including Small Business Committee Chairman Bond--wrote to the EPA Administrator October 9 criticizing the decision not to perform a regulatory flexibility analysis of the impacts of the proposed standards on small businesses, as required by the Small Business Regulatory Enforcement Fairness Act.<52> Chairman Bond, joined by then Ranking Member Bumpers, followed with a second letter on January 7, urging the agency to prepare the regulatory flexibility analysis.<53>

Following EPA's proposal, in early December, staff of the Senate Environment and Public Works Committee circulated for signatures a draft letter, approved by the Committee Chairman, to the Administrator; the letter raises a number of issues concerning the NAAQS proposals.<54> Also, the Chairman of the House Commerce Oversight and Investigations Subcommittee wrote the Administrator December 3, 1996, with a list of questions concerning EPA's authorities to implement the new standards.<55> These actions, as well as the substantial press coverage of EPA's proposal,<56> suggest that Congress will conduct oversight hearings on the proposal early in the new session. The forum for such a review would most likely be the committees of jurisdiction: the Environment and Public Works Committee in the Senate, and the Commerce Committee in the House; others, for example, the House Committees on Government Reform and Oversight and on Science, may also weigh in.

Among the questions likely to be considered during oversight are whether there is sufficient scientific justification for the proposed changes, the potential impacts on regions and sectors of the economy, the EPA decision that the NAAQSs decisions are not subject to the Regulatory Flexibility Act, and the broader question of how to set health-based standards in cases where science indicates a continuum of health effects at all levels of exposure.

Congress now has new tools to review EPA regulatory decisions as the result of legislation enacted in March 1996. Under the Small Business Regulatory Enforcement Fairness Act (Title II of P.L. 104-121, 5 U.S.C. 801-808), federal agencies promulgating major rules must submit to each House of Congress and the Comptroller General a copy of the rule and a cost-benefit analysis of it. Before the rule can take effect, the Congress is given 60 legislative days to pass a joint resolution of disapproval, under procedures specified in the Act.<57> The revised NAAQSs may be among the early tests of this new congressional power.

A resolution of disapproval would prevent EPA from implementing the new standards or from reissuing them in substantially the same form. Such resolutions are subject to the presidential veto power, however. Thus, it could take a two-thirds majority in each chamber (overriding a veto) to prevent implementation of new standards, a formidable challenge.<58>

As EPA moves toward final promulgation of the new standards--and if they are finalized in something like their current form--other legislative options may pose more significant hurdles to the Agency as it acts to issue the standards and then moves toward implementation.

Appropriations. EPA will need a continuing flow of resources to review monitoring data submitted by the states, categorize areas as nonattainment, oversee the Interim Implementation Plan, review new State Implementation Plans, and promulgate regulations affecting specific sources of pollution. As noted earlier, the conferees on the 1997 EPA appropriation expressed their misgivings concerning the new PM standard, even before its proposal. It would not be surprising, therefore, if the appropriations committees continued their interest, perhaps entertaining measures to influence EPA's actions directly through appropriation language.

CAA Amendments. Another legislative option would be for Congress to enact amendments to the CAA that target the ozone and/or PM NAAQSs. However, as the proposals for new standards raise fundamental questions about the structure of the Clean Air Act, the two authorizing committees (Senate Environment and Public Works, and House Commerce) might wish to address the proposals in a broader context, as part of a CAA reauthorization.

The Act is among a group of environmental statutes that require the setting of standards based on protection of public health, without consideration of cost or any formal weighing of costs and benefits. Such language, variants of which appear in the Resource Conservation and Recovery Act (regulating hazardous waste management), the Food Quality Protection Act (regulating pesticide residues in foods), and the state standard-setting process for water quality under the Clean Water Act, implies that there is some threshold below which exposure to pollutants will have no adverse impact on public health.

However, most pollutants are now seen to impose a continuum of health impacts, with more sensitive populations (including children, the elderly, and the infirm) affected at lower levels of exposure than the general population. In the case of air pollutants, there may be effects to some sensitive individuals even at background levels. Requiring an explicit weighing of costs and benefits, however, as some propose, poses a different set of practical difficulties. Both benefits and costs are notoriously difficult to quantify. Costs are frequently overstated as a result of assuming static technologies, or understated by narrowly defining the impacts of the action under consideration. Benefits are extremely difficult to measure, given the scientific uncertainties involved in epidemiology, and difficult to value even where impacts can be correctly identified: lives saved, illnesses avoided, etc. are benefits in more than a monetary sense; monetizing them raises ethical questions, as well. Whether to rewrite the Act to more clearly address cost-benefit considerations, and how to do so if a majority views such an action as desirable, are fundamental questions that Congress may be asked to face.

On a more prosaic level, the Act requires review and possibly restructuring in its practical details. As noted earlier, Sections 181, 182, and 185 of the Act establish a structure for compliance with the ozone standard that specifically references the current 1-hour standard and categorizes nonattainment areas based on the degree to which monitored pollution levels exceed it. Unless the Act is amended, this categorization will remain in place after EPA changes the standard to reflect longer averaging times, new measurement of what constitutes exceedance of the standards, and a greater emphasis on regional measures to counteract ozone formation. References to the particulate standard in Sections 188-190 of the Act, on the other hand, are less affected, since the PM10 standard is maintained.

These incentives to amend the Act add to pressures already mounting. Authorization of appropriations for the Act expire in 1998, and, although this does not necessarily mean that Congress must review the Act, several members of Congress had already proposed broad packages of amendments during the 104th Congress.<59> Thus, revision of the NAAQSs may increase pressure on the Congress to open the Act for amendment and reauthorization.

Judicial Review

During the processes of setting and implementing new ozone and PM NAAQSs, EPA may make a number of decisions that stakeholders litigate, either to stop the process or change its direction.

One or both of the new proposed NAAQSs may be subjected to legal challenge. Few would be surprised if EPA were challenged both that the proposed new NAAQSs for ozone and PM have gone too far and are excessively stringent, and that the decisions have not gone far enough and fall short of statutorily required protection of health; or if EPA were challenged that it has failed to comply with mandated procedural requirements. Challenges to EPA's final NAAQS decisions must be filed within 60 days of promulgation in the U.S. Court of Appeals for the District of Columbia (CAA, Section 307(b)).

EPA's certification that it need not prepare a regulatory flexibility analysis under the Regulatory Flexibility Act has already been identified as a possible point of litigation.<60> Such certifications are now subject to judicial review as a result of the 1996 amendments to the Regulatory Flexibility Act (5 U.S.C. 611). A finding that a certification was improper could result in the remand of the rule to the agency for completion of a regulatory flexibility analysis prescribed by Section 604 of the RFA and deferral of enforcement of the rule against small entities until compliance is achieved (5 U.S.C. 611(a)(4)). A challenge to the propriety of the certification would also implicate the failure of EPA to meet the requirements of Section 244 of the Small Business Enforcement Fairness Act for convening Small Business Advocacy Review Panels. Similarly, EPA's determination that requirements of the Unfunded Mandates Reform Act did not apply to the NAAQSs decisions might also be challenged.

Moreover, the Regulatory Impact Analyses prepared by EPA pursuant to E.O. 12866, as well as any information generated in compliance with the Unfunded Mandates Reform Act of 1995 (see 2 U.S.C. 1532, 1533(a)(1), 1571(a)(4)), will be part of the record for court review and may be used to assess the reasonableness and rationality of the agency's overall rulemaking decisions on setting the NAAQSs.<61>

Once the standards are finalized, subsequent litigation that might arise could concern whether EPA approvals of a revised SIP meet statutory requirements; any state failures to revise SIPs; actions EPA might take to sanction or not sanction states that are late in revising SIPs; and possible EPA failures or delays in promulgating Federal Implementation Plans when states have failed to revise SIPs.

Table 1: Proposed Ozone and PM NAAQS Annual Benefit/Cost Estimates in 2007 (Billions 1990$)

Pollutant/Standard	Monetized Annual Benefits of Partial (a) Attainment	Annual Costs of Partial (a) Attainment (b)
Ozone
8-hours, 0.08 ppm, 1 exceedance	$0.1-$1.5	$2.5
8-hours, avg 3rd max, 0.08 ppm [as proposed]	bracketed by estimates above and below	bracketed by estimates above and below
8-hours, 0.08 ppm, 4 exceedances	$0-$0.6	$0.6
PM2.5 [as proposed]
annual 15 µg/m3, 24-hour 50 µg/m3.	$58-$119	$6

Source: RIAs for Ozone and PM. The RIAs contain extended discussions of the assumptions, uncertainties, and methods involved in making these estimates, and include benefit/cost estimates for other levels of standards.

(a) The projections are for "partial attainment" because existing control measures are not yet available for attainment of all areas by 2007, the date used in the analysis.

(b) Ozone costs and PM2.5 costs cannot be added together since some controls overlap, which would result in double counting.

costs and benefits is inconclusive and incomplete, and that no new standard is warranted until further research is completed. Meanwhile, stakeholders who represent health and environmental concerns have been warning that the proposed ozone and PM standard fails to protect millions of people from adverse effects that an even tighter standard would prevent.

To support these positions, stakeholders are likely to sponsor and cite alternative analyses of costs and benefits.<35> For example, to highlight costs, the American Petroleum Institute has pointed to a study<36> it sponsored that estimated the costs of an 8-hour, 0.08 ppm, 1-exceedance ozone standard for the Chicago area alone at $5.5 to $14.1 billion per year. It also has prepared a study estimating that PM nonattainment areas could increase sixfold under a stringent new PM rule.<37> Conversely, the American Lung Association, which supports even more stringent standards, has released a study<38> estimating that an 8-hour, 0.07 ppm, 1-exceedance standard would protect up to 57 million more people than an 8-hour, 0.085 ppm, 5-exceedances standard.<39> On PM benefits, both the Natural Resources Defense Council and the American Lung Association have called for tightening EPA's proposed annual PM2.5 standard of 15 µg/m3 to 10 µg/m3; the NRDC says the tighter standard would prevent nearly 35,000 more premature cardiopulmonary deaths than EPA's proposal.<40>

<1> Lead Industries Association v. EPA, 647 F.2d 1130 (D.C. Cir. 1980). Some CAA requirements do direct EPA to take into account costs and other impacts, however--for example, in setting New Source Performance Standards (section 111(a)(1)).

<2> This SIP process for mandating emissions reductions is complemented by other CAA provisions, including statutory emissions limits imposed on automobiles and trucks; EPA-established national new source performance standards limiting emissions of designated pollutants from major new sources; controls imposed on specified toxic air pollutants; a program preventing significant deterioration of clean air areas; and the acid rain control program to reduce sulfur dioxide emissions from utilities.

<3> However, when EPA reviews a SIP for approval, it may only consider whether the SIP satisfies the Act's requirements, not whether it is economically feasible (Union Electric Co. v. EPA, 427 U.S. 246 (1976)).

<4> American Lung Association v. Browner, CIV-93-643-TUC-ACM (D. Ariz., October 6, 1994).

<7> U.S. Environmental Protection Agency, National Ambient Air Quality Standards for Ozone: Proposed Decision http://ttnwww.rtpnc.epa.gov/o3fact.htm [November 27, 1996]); 61 Federal Register 65716-65750 (December 13, 1996).

<8> Ground-level ozone is an air pollutant that causes smog, adversely affects health, and injures plants; it should not be confused with stratospheric ozone that is a natural layer some 6 to 20 miles above the earth and provides a degree of protection from harmful radiation.

<9> NOx results primarily from combustion, and is emitted by utilities, industrial boilers, and automobiles. Nitrogen dioxide (NO2) is itself a criteria air pollutant, and is directly regulated by a statutory automobile emission standard. VOCs result from combustion; evaporation of hydrocarbons, such as gasoline; and emissions from processes employing hydrocarbons, from major sources such as chemical plants to small sources such as dry cleaners and charcoal lighter fluids. Various species of VOCs are directly regulated by an automobile emission standard and by hazardous air pollutant regulations. SIPs to attain the ozone NAAQS actually focus on controlling NOx and hydrocarbons.

<10> To deal with this problem, the 1990 CAA established an ozone transport region in the Northeast. Special planning and control requirements apply in the region.

<11> For a useful summary of the science underlying the proposed new ozone standard, see George T. Wolff, ``The Scientific Basis for a New Ozone Standard,'' Environmental Management (Sept. 1996), 27-32. (Dr. Wolff, of the General Motors Environmental and Energy Staff, is Chair of EPA's Clean Air Scientific Advisory Committee.)

<12> ``EPA Proposes Air Standards for Particulate Matter and Ozone,'' Environmental News (Nov. 27, 1996), attachment, ``Public Health Effects of Ozone and Fine Particle Pollution,'' p. 2; see also, http://ttnwww.rtpnc.epa.gov/naaqspro/o3hlth.htm .

<13> Based on 1991-93 data, 104 areas were in nonattainment; based on 1993-95 data, about 50 are in nonattainment, although EPA has not formally reclassified all of the areas that have achieved attainment with the existing ozone NAAQS.

<14> As part of its information package related to the proposed new standard, EPA has listed counties not complying with the current standard, based on 1993-1995 data: see http://www.rtpnc.epa.gov/naaqspro/o3list.htm ; and prepared maps depicting counties projected not to comply with the proposed standard, also based on 1993-1995 data: see http://www.rtpnc.epa.gov/naaqspro/ozone2.gif .

<15> Environmental Protection Agency, National Ambient Air Quality Standards for Particulate Matter: Proposed Decision http://ttnwww.rtpnc.epa.gov/naaqspro/pmfact.htm [November 27, 1996]); 61 Federal Register 65638-65713 (December 13, 1996).

<16> Particles larger than 2.5 µm are formed primarily by mechanical processes, such as industrial crushing and grinding operations, materials handling, vehicle travel on unpaved roads, and windblown dust.

<17> NOx and SO2 are themselves criteria pollutants, acid rain precursors, and impair visibility; they along with VOCs are subject to a range of statutory and SIP controls, which thus affect concentrations of fine particles.

<18> George T. Wolff, ``The Scientific Basis for a Particulate Matter Standard,'' Environmental Management (October 1996), 26-31.

<19> This change, like the averaging of 3rd highest annual ozone readings over 3 years and the PM2.5 use of an arithmetic mean, takes into account the degree of exceedance and reduces the influence of unusual weather conditions on the likelihood of compliance.

<20> ``EPA Proposes Air Standards for Particulate Matter and Ozone,'' Environmental News (Nov. 27, 1996), attachment, ``Public Health Effects of Ozone and Fine Particle Pollution,'' p. 1; see also http://www.rtpnc.epa.gov/naaqspro/pmhlth.htm .

<21> For EPA-prepared lists of counties not meeting the current PM10 standard, the proposed revised PM10 standard, and the new PM2.5 standards, see http://www.rtpnc.epa.gov/naaqspro/pmlist.htm . The American Petroleum Institute has also estimated the impact of a new PM2.5 standard: see ``PM Nonattainment Areas Could Increase Sixfold Under New Rule, Industry Estimates,'' Environment Reporter (November 1, 1996), 1404-1405.

<22> Cate Jones, ``New PM 2.5 Standard Ensnares More than Just Particulates,'' Power November/December 1996), 57-60. For a discussion of options, see State and Territorial Air Pollution Program Administrators-Association of Local Air Pollution Officials, Controlling Particulate Matter under the Clean Air Act: A Menu of Options ([Washington, D.C.]: July 1996).

<23> Environmental Protection Agency, Interim Implementation Policy on New or Revised Ozone and Particulate Matter (PM) National Ambient Air Quality Standards (NAAQS) http://www.rtpnc.epa.gov/naaqspro/iipfact.htm [November 27, 1996]); 61 Federal Register 65752-65762 (December 13, 1996).

<24> The proposed IIP does not include specific implementation guidance for PM2.5. EPA explains that it ``cannot reasonably amend its own regulations until it is technically able to predict and measure emissions of fine particles generated by individual sources and better understand and estimate the formation and dispersion of ambient fine particle concentrations in the atmosphere'' (61 FR 65762 [Dec. 13, 1996]). In effect, PM2.5 implementation awaits appropriate data on emissions and ambient concentrations.

<25> As indicated in its ANPR for regional haze regulations, EPA intends to issue its integrated implementation strategy for the ozone and PM NAAQSs in two phases. Phase 1, providing guidance to states concerning actions prior to and including designation of non-attainment areas, is anticipated to be proposed in mid-1997 and finalized in mid-1998. Phase 2, which would actually include EPA's guidance with respect to control strategies, is not expected to be proposed before mid-1998; it is not expected to be finalized until mid-1999. (Advance Notice, Regional Haze Regulations, 61 FR 65771 [Dec. 13, 1996].

<26> U.S. Environmental Protection Agency, Proposed Requirements for Designation of Reference and Equivalent Methods for PM2.5 and Ambient Air Quality Surveillance for Particulate Matter http://www.rtpnc.epa.gov/naaqspro/pmonfact.htm [November 27, 1996]); 61 Federal Register 65780-65782 (December 13, 1996).

<27> Environmental Protection Agency, Implementation of New or Revised Ozone and Particulate Matter (PM) National Ambient Air Quality Standards (NAAQS) and Regional Haze Regulations http://www.rtpnc.epa.gov/naaqspro/anprfact.htm [November 27, 1996]); 61 Federal Register 65764-65778 (December 13, 1996).

<30> George T. Wolff, ``The Scientific Basis for a New Ozone Standard,'' Environmental Management (September 1996), pp. 30-31.

<31> George T. Wolff, ``The Scientific Basis for a Particulate Matter Standard,'' Environmental Management (October 1996), p. 28.

<33> U.S. EPA, Regulatory Impact Analysis for Proposed Ozone National Ambient Air Quality Standard [draft] (December 1996).

<34> U.S. EPA, Regulatory Impact Analysis for Proposed Particulate Matter National Ambient Air Quality Standard [draft] (December 1996)

<35> Contending analyses of costs and benefits were a feature of debates during consideration of the Clean Air Act Amendments of 1990s, with estimates often varying widely. For a review of various costs estimates and a discussion of the differing assumptions and methodologies giving rise to the range of estimates, see E.H. Pechan & Associates, Clean Air Act Amendment Costs and Economic Effects: A Review of Published Studies (Prepared for National Clean Air Coalition, National Clean Air Fund, Washington, D.C., October 1990), published in the Congressional Record, October 27, 1990, pp. S16963-S16969 [daily edition].

<36> Sierra Research, Inc., Socio-Economic Study of Possible Eight-Hour Ozone Standard, prepared for American Petroleum Institute (June 4, 1996) [Report No. SR96-06-01], p. ES-16.

<37> ``PM Nonattainment Areas Could Increase Sixfold Under New Rule, Industry Estimates,'' Environment Reporter (November 1, 1996), 1404-1405.

<38> American Lung Association, Gambling with Public Health (Washington, D.C.: September, 1996), p. 2.

<39> Note that both the API and ALA use baseline standards for comparison that differ somewhat from EPA's actual proposal of an 8-hours, avg 3rd max, 0.08 ppm, standard.

<40> Deborah Shprentz, Breath-Taking: Premature Mortality Due to Particulate Air Pollution in 239 American Cities ([New York]: Natural Resources Defense Council, May 1996), p. 89; see also ``ALA Calls for Tighter Fine PM Standard, Says EPA Proposal Leaves Millions at Risk,'' Daily Environment Report (January 14, 1997), A-6 - A-7.

<43> This provision (5 U.S.C. 609) was added to the RFA by the Small Business Regulatory Enforcement Fairness Act (Title II of P.L. 104-121).

<46> Areas with ozone readings of 0.121 to 0.138 were defined as Marginal and given a 3-year deadline to reach attainment; 0.138 to 0.160 as Moderate, with a 6-year deadline; 0.160 to 0.180 as Serious, with a 9-year deadline; etc.

<47> EPA's Assistant Administrator for Air and Radiation Mary Nichols has emphasized that the proposals are not yet final decisions: ``The proposals are just that--proposals--and we have asked for a broad range of comment on a number of issues, including alternative levels for each of the standards.'' ``Air Chief Says Congress May Seek to Derail Proposed Ozone, Fine Particulate Standards,'' Daily Environment Report (December 10, 1996), p. AA-1.

<48> E.g., ``Industry Group Meets with White House Officials over PM/Ozone Revisions,'' Clean Air Report (22 August 1996), 8-9; ``Industry Predicts NAAQS Revisions Will Spark Legislative Attack on Act,'' Clean Air Report (28 November 1996), 19.

<49> On October 2, 1996, 102 environmental and public health interest groups wrote President Clinton to urge his support for strong ozone and PM standards; another letter, signed by 12 of the groups, went to EPA Administrator Browner and called on EPA to set the new standards strictly on the basis of health protection. ``Delays in Release of Ozone, PM Proposals Threaten Valid OMB Review, Industry Says,'' Daily Environment Report (October 10, 1996), AA-2.

<50> U.S. Congress, House of Representatives, ``Making Appropriations for the Departments of Veterans Affairs and Housing and Urban Development, and for Sundry Independent Agencies ...,'' H. Rept. 104-812, September 20, 1996, p. 70.

<51> ``Congressional Coalition Seeks to Ease EPA Regulations on Oil, Gas Production,'' Environment Reporter (September 27, 1966), 1187.

<52> Described in ``Senators Blow Whistle on EPA Bid to `Skirt' Reg Review Law,'' Clean Air Report (October 31, 1996), 7.

<53> ``Two Senators Press for SBREFA Review of Proposals to Revise Ozone, PM Rules,'' Daily Environment Report (January 10, 1997), A-6 - A-7.

<54> ``Chafee Drafts Letter to Browner Calling for Cost Consideration,'' Clean Air Report (December 12, 1996), 3-4 [includes text of draft letter dated December 2]. (As of January 14, the letter had not been sent, although EPA had received the draft.)

<55> Letter, to Carol M. Browner, Administrator, EPA, from Joe Barton, Chairman, Subcommittee on Oversight and Investigations, House Commerce Committee (December 3, 1996).

<56> For example, Lorraine Woellert and Viki Reath, ``New Air Standards Could Cost Billions,'' Washington Times (November 28, 1996), A1, A10; Joby Warrick and John E. Yang, ``Stricter Air Quality Rules May Test Hill's New Veto,'' Washington Post (November 28, 1996), A1, A15; John J. Falka, ``Group Gears Up to Block EPA Proposals on National Air-Quality Standards,'' Wall Street Journal (November 29, 1996), B3; Gregg Easterbrook, ``Ignore All Doomsayers on EPA Laws,'' Los Angeles Times [Washington Edition] (December 6, 1996), A2-A3.

<57> Among the procedures are means to expedite consideration of such resolutions in the Senate, whose rules might otherwise keep such resolutions from coming to the floor.

<58> For additional information on congressional review procedures, see CRS Report 96-777A, Congressional Review of Agency Rulemaking: A Brief Overview and Assessment, by Morton Rosenberg.

<59> For a list and discussion of some of these bills, see CRS Issue Brief 95034, Clean Air Issues.

<60> ``Congress Believes EPA Violates Reg Flex Act in PM/Ozone Proposal,'' Clean Air Report (December 12, 1996), p. 8.

<61> See, for example, Corrosion Proof Fittings v. EPA, 947 F. 2d 1201 (5th Cir. 1991); AFL-CIO v. OSHA, 965 F. 2d 962 (11th Cir. 1992).

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