Air Quality Standards:
The Decisionmaking Process III

97-722 ENR

CONTENTS FOR THIS SECTION

The Administrator's Decision

The Evidence
The Criteria

Health

Sensitive populations
Adverse health effect
Exposure evaluation and risk assessment
Margin of safety

Costs

The Administrator's Decision

....[I]n the judgment of the Administrator.... [CAA, § I 09(b)( 1)]

The CAA specifies that the Administrator shall use her "judgment...,based on [the] criteria [document] and allowing an adequate margin of safety" to determine the NAAQS "requisite to protect the public health" [CAA, §109(b)(1)]. Thus the decision involves weighing of the scientific evidence, collected and analyzed in the criteria document, of the policy options laid out in the staff paper, and of the comments of CASAC following the criteria dictated in the CAA.

Several challenges to the Administrator's judgment have been made under various regulatory provisions of the 1970 Amendments to the Clean Air Act with respect to the criteria EPA should use. A landmark case concerning the appropriate criteria for air quality regulatory judgments is Ethyl Corp. v. EPA. A 3-judge panel, voting 2-1, invalidated the Administrator's regulation of lead in fuels based on § 211 (regulation of fuels) of the CAA ( No. 73-2205 (D.C. Cir. Jan.28, 1975)). The decision hinged on the burden of proof the Administrator had to meet in order to justify the proposed standard, with the majority holding that the Administrator had to show actual harm rather than the threat or risk of harm. Subsequently, the initial decision was vacated and the U.S. Court of Appeals granted a rehearing en banc; the full court upheld the Administrator's regulations on a 5-4 vote, holding that §211 states a merely precautionary standard - i.e., does not require actual harm.

Even though vacated, the initial Ethyl decision raised issues affecting all clean air standards setting that were directly addressed in the 1977 Amendments to the CAA.10 In its report on the bill amending the CAA, the House Committee on Interstate and Foreign Commerce identified six issues raised by the case that "required further congressional clarification":

(1) whether the Administrator could "act to prevent harm before it occurs or should he be authorized to regulate an air pollutant only if he finds actual harm has already occurred";
(2) whether the Administrator could assess risks or only "make findings of past fact";
(3) whether the Administrator could consider the cumulative risk of a pollutant from multiple sources, or only the risk from the single class of sources being regulated;
(4) whether different standards of proof apply to different sources;
(5) whether "protection of public health" referred only to healthy normal adults or included "susceptible individuals within the exposed population"; and
(6) whether a "Court's standard of review of informal rulemaking by the Administrator to protect public health be whether he has relied on conclusive or indisputable facts or whether he has reached reasonable conclusions which are rationally justified."

To resolve these issues, the Committee added language amending the act, using "a standardized basis for future rulemaking to protect the public health: the Administrator may regulate a pollutant, emissions of which in his judgment cause or contribute to air pollution which may reasonably be anticipated to endanger public health or welfare.' This same basic formula" was used in the several standards-setting provisions of the Act, including sections 108 (criteria for NAAQS), 111 (new source performance standards), 112 (hazardous air pollutants), 202 (motor vehicle emission standards), 21 1 (regulation of fuels and fuel additives), and 231 (aircraft emissions), as well as subtitle B of Title I (ozone and stratospheric protection).

In using this language in amending the act, as discussed in the report on the bill, the Committee intended -

(1) To emphasize the preventative or precautionary nature of the act, i.e., to assure that regulatory action can effectively prevent harm before it occurs.......;
(2) To authorize the Administrator to weigh risks and make reasonable projections of future trends.......;
(3) To assure consideration of the cumulative impact of all sources of a pollutant in seeing ambient and emission standards, not just the extent of the risk from the emissions from a single source or class of sources of the pollutant;....
(4) To provide the same standard of proof for regulation of any air pollutant.......;
(5) To assure that the health of susceptible individuals, as well as healthy adults, will be encompassed in the term 'public health,' regardless of the section of the act under which the Administrator proceeds; and
(6) To reflect awareness of the uncertainties and limitations in the data which will be available to the Administrator in the foreseeable future to enable him to execute his rulemaking duties under this act, because of the limitations on research resources and the fact that decisionmaking about the risks to public health from air pollution falls on 'the frontiers of scientific and medical knowledge.'

In short, "The committee language is intended to emphasize the necessarily judgmental element in the task of predicting future health risks of present action and to confer upon the Administrator the requisite authority to exercise such judgment."

This is not, however, a blank check: "... the committee does not intend this language as a license for 'crystal ball' speculation. The Administrator's judgment must, of course, remain subject to restraints of reasoned decisionmaking."

The Evidence

[B]ased on such criteria [document] ... [CAA, § 1 09(b)( I)]

Air quality criteria for an air pollutant shall accurately reflect the latest scientific knowledge useful in indicating the kind and extent of all identifiable effects on public health or welfare which may be expected from the presence of such pollutant in the ambient air, in varying quantities. The criteria for an air pollutant, to the extent practicable, shall include information on
(A) those variable factors (including atmospheric conditions) which of themselves or in combination with other factors may alter the effects on public health or welfare of such air pollutant;
(B) the types of air pollutants which, when present in the atmosphere, may interact with such pollutant to produce an adverse effect on public health or welfare; and
(C) any known or anticipated adverse effects on welfare. [CAA, § l 08(a)(2)]

Each agency shall base its [regulatory] decisions on the best reasonably obtainable scientific, technical, economic, and other information concerning the need for, and consequences of, the intended regulation. [Executive Order 12866]

The evidence for a NAAQS decision ultimately resides in the criteria document, the staff paper, and the CASAC letters of closure, plus materials submitted during the public comment period. Ancillary information is included in the Regulatory Impact Analysis (discussed below). Summaries are included in the proposed and final rules as published in the Federal Register. In setting NAAQS, the generic direction of E.O. 12866 to regulatory agencies to base their "decisions on the best reasonably obtainable scientific, technical, economic, and other information...." is constrained by the CAA, which specifies that health protection is to be the criterion in determining the standard.

The Criteria

Health

Health is the sole criterion for setting the primary NAAQS. The question of whether costs or technical feasibility should be taken into account was litigated in the case of the lead NAAQS, and the decision was unambiguous:

... [T]he statute and its legislative history make clear that economic considerations play no part in the promulgation of ambient air quality standards under Section 109.
Section 109(b) speaks only of protecting the public health and welfare. Nothing in its language suggests that the Administrator is to consider economic or technological feasibility in setting ambient air quality standards.
The legislative history of the Act also shows the Administrator may not consider economic and technological feasibility in setting air quality standards; the absence of any provision requiring consideration of these factors was no accident; it was the result of a deliberate decision by Congress to subordinate such concerns to the achievement of health goals. [Lead Industries Association v. Environmental Protection Agency, 647 F.2d 1130 ([).C. Cir. 1980))

Beside the technical information underlying a health standard, the Administrator must consider several crucial policy issues: These include (1) defining whose health the standard is to protect, given that some people will be more susceptible to pollution than others; (2) defining which health effects of pollution are adverse health impacts to be protected against; (3) evaluating exposure and characterizing risk; and (4) considering what factors to take into account in providing "an adequate margin of safety." The statute and legislative history provide some guidance on these questions. As they are key elements of the judgment that the Administrator makes in deciding the standard, these questions are more or less explicitly posed in the staff paper.

Sensitive populations. For answering the first question, about whose health a primary standard should protect, the Senate Report on the Clean Air Act Amendments of 1970 provided explicit guidance:

In requiring that national ambient air quality standards be established at a level necessary to protect the health of persons, the Committee recognizes that such standards will not necessarily provide for the quality of air required to protect those individuals who are otherwise dependent on a controlled internal environment such as patients in intensive care units or newborn infants in nurseries. However, the Committee emphasizes that included among those persons whose health should be protected by the ambient standard are particularly sensitive citizens such as bronchial asthmatics and emphysematics who in the normal course of daily activity are exposed to the ambient environment In establishing an ambient standard necessary to protect the health of these persons, reference would be made to a representative sample of persons comprising the sensitive group rather than to a single person in such a group.
Ambient air quality is sufficient to protect the health of such persons whenever there is an absence of adverse effect on the health of a statistically related sample of persons in sensitive groups from exposure to ambient air. [Senate Committee on Public Works, Report No.91-1196(1970), p 10)

Also, as discussed earlier, the Committee on Interstate and Foreign Commerce, in its report language discussing amendments relating to the basis for administrative standards, expressly noted its intent to "assure that the health of susceptible individuals, as well as healthy adults, will be encompassed in the term 'public health,' regardless of the section of the act under which the Administrator proceeds."

Adverse health effect. The Clean Air Act does not define the adverse health effects against which NAAQS must protect, nor does the legislative history of the CAA contain much discussion of what constitutes an adverse health effect. The National Commission on Air Quality11 noted proposals that the Act contain greater specificity, but observed:

any attempt to identify specific types of health effects could inhibit identification of unanticipated effects that should be considered. In addition, most air pollutants affect public health in more than one way. To carry out its responsibilities under the Act, EPA, before making a final decision to set or revise an air quality standard, must have all relevant and reliable scientific information on the full range of possible health effects of a pollutant. 12

Indications of what constitutes an adverse health effect can be found in the distinction between primary and secondary standards and in the definition of hazardous air pollutants. While a primary NAAQS protects health, a secondary NAAQS protects welfare, which includes, by definition, "personal comfort and well-being." Thus, pollution effects that involve only "personal comfort and well-being" are not health effects that primary standards are directed toward. The definition of a hazardous air pollutant in the 1970 Act is "an air pollutant... ....... may cause, or contribute to, an increase in mortality or an increase in serious irreversible, or incapacitating reversible, illness." Unquestionably, "increase in mortality," irreversible" and "incapacitating" signal health effects. Are bouts of coughing or decreased lung functioning adverse health effects? If they are irreversible or incapacitating, the answer would seem clearly "yes." As a practical matter, if an effect necessitates medical intervention or leads to curtailed activity, such as missing school or work, the answer would seem "yes." The question of whether an effect is an adverse health effect can be difficult to answer, particularly if the effect appears minor but may cumulate over a lifetime.

Exposure evaluation and risk assessment.

In order to emphasize the precautionary or preventive purpose of the act (and, therefore, the Administrator's duty to assess risks rather than wait for proof of actual harm), the committee not only retained the concept of endangerment to health; the committee also added the words 'may reasonably be anticipated'....
By its use of the words 'cause or contribute to air pollution" the committee intends to require the Administrator to consider all sources of the contaminant which contribute to air pollution and to consider all sources of exposure to the contaminant -food, water, air, etc. - in determining health risk
Finally, the term 'in the judgment of the Administrator' is intended to modify both the 'cause and contribute to 'phrase and the 'reasonably may be anticipated' phrase [Committee on Interstate and Foreign Congress, Clean Air Act Amendments of 1977, Report 95-294 (1970), p. 51.]

As indicated in the previous discussions of the Ethyl and Lead Industries v. EPA cases, and as emphasized in House Report 95-294, the Administrator may promulgate a NAAQS in "reasonable" anticipation of public health endangerment. The practical effect of this criterion is to allow a "weight of evidence" approach to be used in setting a NAAQS; EPA need not prove that adverse health effects have already occurred, nor that the air-borne form of the pollutant solely caused the harm.

Margin of safety. On the question of what constitutes a "margin of safety," EPA's Staff Paper on Particulate Matter summarizes the situation as follows:

The U.S. Court of Appeals for the District of Columbia Circuit has held that the requirement for an adequate margin of safety for primary standards was intended to address uncertainties associated with inconclusive scientific and technical information available at the time of standard setting. It was also intended to provide a reasonable degree of protection against hazards that research has not yet identified (Lead Industries Association V. EPA, 647 F.2d 1130, 1154 (D.C. Cir. 1980), cert denied, 101 5. Ct. 621(1980); American Petroleum Institute v. Costle, 665 F.2d 1176, 1177 (D.C. Cir. 1981), cert denied, 102 S. Ct. 1737(1982)). Both kinds of uncertainties are components of the risk associated with pollution at levels below those at which human health effects can be said to occur with reasonable scientific certainty. Thus, by selecting primary standards that provide an adequate margin of safety, the Administrator is seeking not only to prevent pollution levels that have been demonstrated to be harmful but also to prevent lower pollutant levels that she finds may pose an unacceptable risk of harm, even if the risk is not precisely identified as to nature or degree.

In selecting a margin of safety, the EPA considers such factors as the nature and severity of the health effects involved, the size of the sensitive population(s) at risk, and the kind and degree of the uncertainties that must be addressed. Given that the "margin of safety" requirement by definition only comes into play where no conclusive showing of adverse effects exists, such factors which involve unknown or only partially quantified risks have their inherent limits as guides to action. The selection of any particular approach to providing an adequate margin of safety is a policy choice left specifically to the Administrator's judgment (Lead Industries Association v. EPA,supra, 647 F.2d at 1161-62). [EPA, Particulate Matter Staff Paper (1996), pp. II-l - II-2]

In effect, the "margin of safety" allows the Administrator to take into account the dimensions of the decision that scientific data cannot resolve.

Costs

As noted above, health being the criterion, costs are not taken into account in setting primary NAAQS. The National Commission on Air Quality explained the principle as follows:

The statutory basis for setting national ambient air quality standards does not take economic factors into account. In the Act, Congress recognized that while the levels of air pollution at which public health is affected generally do not vary among different locations, the costs of meeting a specific standard can vary substantially from area to area, depending upon the severity of the pollution. Thus, if a national air quality standard were based in part on the costs of complying with it, the high costs of meeting the standard in a few heavily polluted areas could result in the standard's being set at a less protective level than is achievable in a reasonable, economic fashion in other areas. The health benefits of good air quality and the economic, social, energy, and other costs of meeting health-based standards can be balanced more effectively and appropriately when control programs are established for particular areas than when national primary standards are set. 13

The concept of deferring cost considerations until the implementation of standards, rather than incorporating them in standards-setting, arose early in the evolution of the CAA. The Senate Report on the Air Quality Act of 1967 affirmed the primacy of health protection in setting NAAQS:

Considerations of technology and economic feasibility, while important in helping to develop alternative plans and schedules for achieving goals of air quality, should not be used to mitigate against protection of the public health and welfare. [Senate Committee on Public Works, Report No.403 (1967), pp.28-29]

Subsequently, in bringing to the floor the Senate bill that became the Clean Air Act Amendments of 1970, Senator Muskie repeated that language and called it a "warning" that had been ignored by those who sought to compromise health standards because of costs:

That warning... has been on the books of this committee for 3 years, for all to read
Contrary 10 this intent, these [cost and feasibility] considerations have been used as arguments to compromise the public health. Therefore the committee has made explicit in this bill what is implicit to standards designed to protect our health. That concept and that philosophy are behind every page of the proposed legislation.

The first responsibility of Congress is not the making of technological or economic judgments - or even to be limited by what is or appears to be technologically feasible. Our responsibility is to establish what the public interest requires to protect the health of persons.

[Senator Muskie, debate on the National Air Quality Standards Act of 1970 (Congressional Record, September 21, 1970, pp.32901-02)]

It was this explicitness of the statute and of the legislative history behind it that led to the unequivocal judgment in Lead Industries Association v. Environmental Protection Agency [647 F.2d 1130 (').C. Cir. 1980)], as previously noted. Nevertheless, some still urge that costs can and should be considered in setting NAAQS; such arguments were proffered among the public comments submitted for EPA's 1997 proposed ozone and PM2.5 standards. EPA responded to these comments at some length. 14

ENDNOTES

10 This discussion, including the quotations, are from U.S. Congress, House, Committee on Interstate and Foreign Commerce, Clean Air Act Amendments of 1977, House Rept. No.95-294, to accompany H.R. 6161 (95th Congress, 1" session) (Washington, D.C.: U.S. Govt. Print. Off., 1977), pp.43-51.

11 The National Commission on Air Quality was created by the Clean Air Act Amendments of 1977, §323, to review the Act and to report to the Congress the effects of the Act, alternative ways of controlling air pollution, and any recommended midcourse corrections.

12 National Commission on Air Quality, To Breathe Clean Air (Washington, D.C.: 1981), p.3.1-2.

13 National Commission on Air Quality, To Breathe Clean Air (Washington, D.C.: 1981), p.3.1-2.

14 See, for example, EPA, "Cost Considerations," National Ambient Air Quality Standards for Ozone; Final Rule, 62 Federal Register 38878-38883 (July 18, 1997).

15 The Clean Air Act Amendments of 1977 substantially revised these procedures. The reasons for the changes and their intent are discussed at length in U.S. Congress, House, Committee on Interstate and Foreign Commerce, Clean Air Act Amendments of 1977, House Rept No 95-294, to accompany H.R. 6161 (95th Congress, lst session) (Washington, D.C.: U S Govt Print Off, 1977), pp.318-325.

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