Opinion ID: 184866
Heading Depth: 2
Heading Rank: 2

Heading: Ozone's Health Benefits

Text: Petitioners presented evidence that according to themshows the health benefits of tropospheric ozone as a shieldfrom the harmful effects of the sun's ultraviolet rays--including cataracts and both melanoma and nonmelanoma skincancers. In estimating the effects of ozone concentrations,EPA explicitly disregarded these alleged benefits. EPA explained its decision first as a matter of statutoryinterpretation. Under the Clean Air Act, EPA's ambientstandards for any pollutant are to be based on [the] criteriathat EPA has published for that pollutant. 42 U.S.C.s 7409(b)(1) & (2). The criteria, in turn, are to reflect thelatest scientific knowledge useful in indicating the kind andextent of all identifiable effects on public health or welfarewhich may be expected from the presence of such pollutant inthe ambient air, in varying quantities. Id. s 7408(a)(2). The reference to all identifiable effects would seem on itsface to include beneficent effects. EPA attempts to avoid this straightforward reading inseveral ways. First, it points to the term such pollutant,arguing that the statute requires it to focus exclusively on thecharacteristics that make the substance a pollutant. Butthe phrase pollutant is simply a label used to identify asubstance to be listed and controlled by the statute. While itis perfectly true that a substance known to be utterly withoutadverse effects could not make it onto the list, this fact ofnomenclature does not visibly manifest a congressional intentto banish consideration of whole classes of identifiable effects. EPA also relies on the fact that two of the three specifiedconsiderations under s 108(a)(2)'s general mandate refer toadverse effect[s]: 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. Id. s 7408(a)(2) (emphasis added). EPA's argument wouldbe of uncertain force even if all three types of effects specifically required to be considered were spoken of as adverseeffects; there is no reason to read adverse back into theall identifiable effects of s 108(a)(2). But as one of thethree specified classes refers to effects unmodified, id.s 7408(a)(2)(A), we can reject EPA's argument without evenreaching that issue. That Congress qualified effects inclauses (B) and (C) with adverse seems only to strengthenthe supposition that in (A)--and in the general mandate--itintended to cover all health or welfare effects. Therefore ifpetitioners' contentions are right, clause (A) applies to ozone: the presence of ultraviolet radiation at various levels alter[s]the effects [of ozone] on public health or welfare by makingthem on the whole less malign--perhaps even beneficial. EPA next argues that Title VI of the Clean Air Act, id.ss 7671-7671q, which mandates certain measures to preservestratospheric ozone, represents a complete consideration ofozone's beneficial role as a UV shield. Petitioners' claim,however, is that ground-level (tropospheric) ozone--the subject of this rule--has a UV-screening function independent ofthe ozone higher in the atmosphere. EPA points to nothingin the statute that purports to address tropospheric ozone. Finally, EPA directs us towards legislative history from the1970 and 1990 Clean Air Act Amendments. The all identifiable effects language, however, dates to the 1967 Amendments. Legislative history from the 1970 and 1990 Congresses cannot be an authoritative interpretation of what the[1967] statute meant, because it is the function of the courtsand not the Legislature, much less a Committee of one Houseof the Legislature, to say what an enacted statute means. Pierce v. Underwood, 487 U.S. 552, 566 (1988). Under Chevron, we defer to an agency's interpretation of astatute if the statute is silent or ambiguous with respect tothe specific issue and the agency's answer is based on apermissible construction of the statute. 467 U.S. at 843. We find no such ambiguity in this case. Further, EPA'sinterpretation fails even the reasonableness standard of Chevron's second part: it seems bizarre that a statute intended toimprove human health would, as EPA claimed at argument,lock the agency into looking at only one half of a substance'shealth effects in determining the maximum level for thatsubstance. At oral argument even EPA counsel seemedreluctant to claim that the statute justified disregard of thebeneficent effects of a pollutant bearing directly on the healthsymptoms that accounted for its being thought a pollutant atall (suppose, for example, a chemical that both impedes andenhances breathing, depending on the person or circumstances); he also seemed unable to distinguish that case from the one here--where the chemical evidently impedes breathing but provides defense against various cancers. Legally, then, EPA must consider positive identifiable effects of a pollutant's presence in the ambient air in formulating air quality criteria under s 108 and NAAQS under s 109. EPA's other arguments are technical, and are of two sorts: those that allegedly show petitioners' studies to be fatallyflawed and those that allegedly show specific inflation ofresults in these studies. We need only consider the first sort,for EPA chose to give the studies no weight at all. Petitioners rely primarily on studies by Lutter and Cupitt. EPA found that these could be ignored because the marginalbenefits are difficult, if not impossible, to quantify reliablyand because there is no convincing basis for concluding thatany such effects ... would be significant. But these are notthe criteria by which EPA assesses adverse health effects. Itdoes not rigorously or uniformly demand either quantifiability, see, e.g., Ozone Final Rule, 62 Fed. Reg. at 38,860/3(admitting that quantitative risk estimates could not bedeveloped for certain adverse effects of ozone on which EPAregulated); EPA Ozone Brief at 48 (defending considerationof various effects that played an important role in theAdministrator's final decision despite absence of quantification: EPA did not estimate the risk for such effects because'information [was] too limited to develop quantitative estimates,'--not because there is doubt the effects occur.) (alteration and emphasis in original) (citation omitted), or anyspecific level of significance. As we can see no reason forimposing a higher information threshold for beneficent effectsthan for maleficent ones, we have no basis for affirmingEPA's decision to disregard the studies. As we said above, we are remanding to EPA to formulateadequate decision criteria for its ordinary object of analysis-- ill effects. We leave it to the agency on remand to determinewhether, using the same approach as it does for those,tropospheric ozone has a beneficent effect, and if so, then toassess ozone's net adverse health effect by whatever criteriait adopts. IV. Particulate Matter A.PM10 as Coarse Particle Indicator We now turn to petitioners' challenges to the Agency'sregulation of coarse particulate pollution. Both the 1987NAAQS and the proposed standards regulate all particleswith diameters under 10 micrometers, signified by the indicator PM10. The PM10 spectrum includes both coarse and fineparticles. While the main distinction between coarse and fineparticles is the process by which they are produced, EPA andepidemiologists who study the health effects of particulatepollution identify coarse and fine particles through roughapproximations of those particles' diameters. Coarse particles, which become airborne usually from the crushing andgrinding of solids, generally have diameters between 2.5 and10 micrometers and can thus be identified by the indicatorPM10-2.5. Fine particles, indicated in these new NAAQS byPM2.5, come mainly from combustion or gases and generallyhave diameters of 2.5 micrometers or less. Despite EPA's conclusion that coarse and fine particlespose independent and distinct threats to public health, theAgency chose not to adopt an indicator, such as PM10-2.5, thatwould measure only the coarse fraction of PM10. Petitionersmake two arguments: that there is no scientific basis forregulating coarse particles at all, and that even if there were,retention of the PM10 indicator simultaneously with the establishment of the new fine particle indicator is unsupported byevidence in the record and arbitrary and capricious. Weagree with this latter argument. Beginning with petitioners' first challenge, we think therecord contains sufficient evidence to justify the Agency'sdecision to regulate coarse particulate pollution. While therelationship between PM10 pollution and adverse health effects justifying the 1987 NAAQS was well-established, seeNRDC v. EPA, 902 F.2d 962, 967-68 (D.C. Cir. 1990), twostudies contained in the record of these proceedings concentrated specifically on the health effects caused by the coarsefraction of PM10 pollution. See Mary Ellen Gordian et al.,Particulate Air Pollution and Respiratory Disease in Anchor- age, Alaska, 104 Envtl. Health Persp. 290 (1996) (studyingvolcanic ash); Brockton J. Hefflin et al., Surveillance forDust Storms and Respiratory Diseases in Washington State,1991, 49 Archives of Envtl. Health 170 (1994) (studyingfugitive dust). In addition, the record contains at least ninemultivariate analyses finding statistically significant relationships with health effects for both PM2.5 and PM10, suggestingthat the portion of PM10 pollution unaccounted for by PM2.5(i.e., coarse particles) explains some of the observed adversehealth effects. In other words, because regression analysisholds the PM2.5 component constant, the PM10 effect recognized in these equations actually evidences results fromcoarse particulate pollution. To be sure, petitioners havepointed to some evidence to the contrary. But given that ourreview is limited to ascertaining that the choices made bythe Administrator were reasonable and supported by therecord, and does not include judg[ing] the merits of competing expert views, Lead Industries, 647 F.2d at 1160, we findample support for EPA's decision to regulate coarse particulate pollution above the 1987 levels. Having found independent health consequences fromcoarse particulate pollution, EPA nevertheless decided toregulate the coarse fraction of PM10 indirectly, using PM10(which includes both coarse and fine PM) as a surrogate forcoarse fraction particles. PM Final Rule, 62 Fed. Reg. at38,668/2. While recognizing that PM10-2.5 would have servedas a satisfactory coarse particle indicator, EPA offers threejustifications for its decision to use PM10 instead: (1) Both theGordian and Hefflin studies used PM10, not PM10-2.5, as thevariable in their models, (2) the PM10 standards will work inconjunction with the PM2.5 standards by regulating the portion of particulate pollution not regulated by the PM2.5 standards, and (3) a nationwide monitoring program for PM10already exists. We find none of these explanations persuasive. As to the first argument, while acknowledging that theindicator used in the studies captures both coarse and fineparticles, EPA nevertheless maintains that PM10 is an effective indicator for the regulation of coarse particulate pollu- tion. Adopting the indicator used in the studies, the Agency says, increases the likelihood that the level selected willresult in the health protections predicted. But as EPA'sown staff paper suggests, PM10 is inherently confounded bythe presence of PM2.5 particles, meaning that any regulationof PM10 pollution will include both coarse and fine particles. See PM Staff Paper at V-59. Using PM10 as the coarseparticle indicator, instead of PM10-2.5, will thus regulate morethan just the coarse fraction of PM10, and the amount ofcoarse particulate pollution permitted will depend (quite arbitrarily) on the amount of PM2.5 pollution in the air. Forexample, assuming the 50 microgram annual PM10 leveladopted by the Agency and a region with an annual PM2.5pollution level of 15 micrograms, the PM10 indicator wouldprohibit coarse particulate (PM10-2.5) pollution from exceeding35 micrograms. But in an area with only 5 micrograms ofPM2.5 pollution, the NAAQS would permit coarse particulatepollution to reach as high as 45 micrograms. EPA's second argument--that the PM10 standard will workin conjunction with the PM2.5 standard--suffers from thesame deficiency. Accepting EPA's finding of profound physicochemical differences between coarse and fine PM, PMStaff Paper at V-59, such that each requires independentregulation, we cannot discern exactly how a PM10 standard,instead of a PM10-2.5 standard, will work alongside a PM2.5standard to regulate only the coarse fraction of PM10. EPAprovides no explanation to aid us in understanding its decision. In fact, as the example above indicates, it is the verypresence of a separate PM2.5 standard that makes retention ofthe PM10 indicator arbitrary and capricious. Far from working in conjunction to regulate coarse particles, PM10 and PM2.5indicators, when used together, lead to double regulation ofthe PM2.5 component of PM10 and potential underregulation ofthe PM10-2.5 component since the amount of PM10-2.5 permittedwill always depend on the amount of PM2.5 in the air. EPA's final argument is pragmatic. It maintains that PM10is a better indicator than PM10-2.5 for coarse particulatepollution because a nationwide monitoring program for PM10 already exists. But as EPA acknowledges elsewhere in itsbrief, NRDC bars EPA from considering factors unrelated topublic health in setting air quality standards. Echoing ourdecision in Vinyl Chloride, NRDC held that the Administrator may not consider cost and technological feasibility indetermining what is 'safe'; such a determination 'must bebased solely upon the risk to health.'  NRDC, 902 F.2d at973 (quoting Vinyl Chloride, 824 F.2d 1146, 1166 (D.C. Cir.1990) (in banc)); see also American Petroleum Inst. v. Costle,665 F.2d 1176, 1185 (D.C. Cir. 1981); Lead Industries, 647F.2d at 1148-55. The administrative convenience of usingPM10 cannot justify choosing an indicator poorly matched tothe relevant pollution agent. In view of our conclusion that PM10 amounts to an arbitraryindicator for coarse particle pollution, we need not addresspetitioners' separate challenge to the PM10 levels or secondary standards. We note, however, that whatever levels theAgency ultimately selects for coarse particle pollution willneed to comply with the requirements set forth in Part I ofthis opinion. B.Fine Particles as New Pollutant The Attorneys General of Ohio, Michigan, and West Virginia (state petitioners) argue that EPA is regulating PM2.5for the first time. Because they consider PM2.5 to be a newpollutant, they argue that s 108 of the Clean Air Act requires EPA to conduct further research on PM2.5's healtheffects before listing it as a pollutant, to issue an air qualitycriteria document reflecting the latest science on the healtheffects of the pollutant, and to assist states by developingdata relating to the cost of installation and operation, energyrequirements, emission reduction benefits, and environmentalimpact of the emission control technology. 42 U.S.C.s 7408(b)(1). Although EPA never responds to this argument, five northeastern states (as respondent intervenors and amici) do. Pointing out that previous NAAQS have always includedPM2.5, these attorneys general support the EPA's decision notto list PM2.5 separately as a new pollutant. We agree. The state petitioners cannot escape the fact that the original standards for particulate pollution using Total SuspendedParticulates (TSP) as indicator, as well as the 1987 NAAQSthat used PM10, included by definition every particle 2.5micrometers and smaller. Moreover, in some areas fineparticles often dominate PM10 pollution. See PM Staff Paperat V-63. By refining the NAAQS to focus on smaller particles that EPA found posed distinct threats to public health,EPA has done with these regulations exactly what we held itcould do in 1987 when it made the change from Total Suspended Particulates to PM10. See NRDC, 902 F.2d at 965-66. EPA's decision to update the NAAQS to focus on PM2.5merely continues a trend based on evolving science. It doesnot violate the provisions of s 108 of the Clean Air Act. C.Failure to Identify a Biological Mechanism for Particu- late Pollution's Relationship to Adverse Health Effects Also challenging the establishment of a fine particle standard, non-state petitioners argue that EPA failed to explainthe biological mechanism through which particulate pollutioncauses adverse health effects. Even if epidemiological studies show robust statistical relationships between pollution andhealth effects, they say, the absence of proof of causation-- i.e., how particles actually interact with cells and organs tocause sickness and death--is fatal to the standard. Wedisagree. To begin with, the statute itself requires no such proof. The Administrator may regulate air pollutants emissions ofwhich, in his judgment, cause or contribute to air pollutionwhich may reasonably be anticipated to endanger publichealth or welfare. 42 U.S.C. s 7408(a)(1)(A) (1994) (emphasis added). Moreover, this court has never required the typeof explanation petitioners seek from EPA. In fact, we haveexpressly held that EPA's decision to adopt and set airquality standards need only be based on reasonable extrapolations from some reliable evidence. NRDC v. Thomas, 805F.2d 410, 432 (D.C. Cir. 1986). Indeed, were we to acceptpetitioners' view, EPA (or any agency for that matter) wouldbe powerless to act whenever it first recognizes clear trends of mortality or morbidity in areas dominated by a particularpathogen. The numerous epidemiological studies appearing in thisrecord, some of which EPA also used to support the 1987NAAQS, easily satisfy the standard articulated in the statuteand emphasized repeatedly in decisions of this court. Covering diverse geographic locations with widely varying mixes ofair pollution, the studies found statistically significant relationships between air-borne particulates signified by a varietyof indicators and adverse health effects. Given EPA's statutory mandate to establish standards based on the latestscientific knowledge, 42 U.S.C. ss 7408(a)(2), 7409(d), thegrowing empirical evidence demonstrating a relationship between fine particle pollution and adverse health effects amplyjustifies establishment of new fine particle standards. D.Visibility Effects The Environmental Petitioners challenge the EPA's decision to set the secondary PM2.5 NAAQS at levels equivalent tothe primary NAAQS. According to the petitioners, theEPA's failure to set the secondary NAAQS at more stringentlevels will result in adverse visibility impacts in parts of thecountry. In view of our conclusion in Part I, above, that theEPA has not adequately explained the principles upon whichit relied in setting the levels in the NAAQS for PM, we neednot reach the main thrust of the petitioners' challenge to thesecondary NAAQS. On the other hand, the EnvironmentalPetitioners have also raised a question of statutory interpretation, the resolution of which should assist the EPA if itrevisits its decision to set the secondary PM2.5 NAAQS. In the PM Final Rule, the EPA decided to address thewelfare effects of PM on visibility by setting secondarystandards identical to the suite of PM2.5 primary standards, inconjunction with the establishment of a regional haze program under s 169A of the Act. PM Final Rule, 62 Fed.Reg. at 38,679/3. Section 169A declares as a national goalthe prevention ... and the remedying of any ... impairmentof visibility in mandatory class I Federal areas ... result[ing]from manmade air pollution. 42 U.S.C. s 7491. Mandatory class I areas include all international parks, and nationalparks and wilderness areas of a certain size. See 42 U.S.C.s 7472(a). The EPA concluded that reduction of PM2.5 levelsin class I areas would benefit the surrounding areas as wellbecause the same haze that degrades visibility within orlooking out from a national park also degrades visibilityoutside it. PM Final Rule, 62 Fed. Reg. at 38,682/1. The Environmental Petitioners argue that s 109(b)(2), 42U.S.C. s 7409(b)(2), requires the EPA to set secondaryNAAQS at a level sufficient to eliminate all adverse visibilityeffects and that it leaves the EPA no discretion to decide thatsome visibility impairment is better remedied through another program. This argument must be wrong. For, as theEPA argues, the Congress required the EPA to implement aregional haze program specifically in order to address adverse visibility effects that persist in class I areas afterattainment of the secondary NAAQS. See 42 U.S.C.s 7470(1) (purpose of this part of Clean Air Act is to protectpublic ... welfare from any actual or potential adverse effectwhich ... may reasonably be anticipate[d] to occur ...notwithstanding attainment and maintenance of all[NAAQS]). Accordingly, we conclude that the Congress didnot intend the secondary NAAQS to eliminate all adversevisibility effects and, therefore, that the EPA acted within thescope of its authority in deciding to rely upon the regionalhaze program to mitigate some of the adverse visibilityeffects caused by PM2.5.