ELR Citation: ELR 20568
No(s). s. 97-1440 et al (D.C. Cir. Mar 26, 2002)

The court upholds the U.S. Environmental Protection Agency's (EPA's) promulgation of national ambient air quality standards (NAAQS) for ozone and for particulate matter having an aerodynamic diameter of 2.5 microns of less (PM2.5) against challenges from industry and environmental groups that the NAAQS were arbitrary and capricious. The court first holds that previous decisions in the case addressed only whether the Clean Air Act adequately limits EPA's discretion, and, thus, are not dispositive of whether EPA reasonably exercised that discretion, the question at issue here. The court then holds that industry's claims that the PM2.5 NAAQS must be vacated because EPA did not apply any legal standard, much less the correct standard, must fail. In a passage that industry cited as evidence that EPA failed to identify a safe level of PM2.5, the Agency merely disclaimed any obligation to set primary NAAQS by means of a two-step process. Nothing in the statement implied that EPA failed to determine safe levels for fine PM; indeed, the Agency's establishment of new primary NAAQS demonstrates that it did reach a conclusion regarding safe PM2.5 levels. The court also holds that another passage in the regulations documents EPA's rejection of lower standards, demonstrating that the Agency not only recognized, but acted upon, its statutory obligation to set the primary NAAQS at levels no lower than necessary to reduce public health risks. The court further holds that EPA's inability to guarantee the accuracy or increase the precision of the PM2.5 NAAQS in no way undermines the standard's validity. The court next holds that contrary to industry's contention, EPA did not err in failing to consider whether reducing atmospheric concentrations of fine particles would increase levels of ozone or a different fine particle component. Moreover, the court holds that EPA should not have set a stricter daily PM2.5 NAAQS rather than relying almost exclusively on the stringent annual standard as environmental groups claimed. Not only does the court owe deference to an agency's determination regarding the reliability of scientific evidence, but the environmental groups gave no reason to question EPA's judgment regarding the reliability of the risk assessment relied upon in setting the standard. Finally, the court holds that EPA acted properly in promulgating the ozone NAAQS. The record is replete with studies demonstrating the inadequacies of the old one-hour averaging standard, EPA discussed at length the advantages of a longer averaging time, and the selection of a 0.08 parts per million standard was not arbitrary or capricious.

[Prior decisions in this litigation are published at 29 ELR 21071, 30 ELR 20119, and 31 ELR 20512.]

The full text of this decision is available from ELR (27 pp., ELR Order No. L-477).

Counsel for Petitioners
F. William Brownell
Hunton & Williams
1900 K St. NW, Washington DC 20006
(202) 955-1500

Counsel for Respondents
Norman L. Rave Jr.
Environment and Natural Resources Division
U.S. Department of Justice, Washington DC 20530
(202) 514-2000