The cornerstone of the Clean Air Act Amendments of 1970 is the requirement that the Environmental Protection Agency (EPA) set geographically uniform national ambient air quality standards (NAAQS). Congress' goal of assuring healthy air quality across the nation is embodied in its commitment to achieve attainment of the NAAQS by prescribed dates. While the Clean Air Act Amendments of 1977 postponed the deadlines for achievement of the NAAQS, they retained the basic strategy and made several revisions which augment EPA's responsibility and authority concerning review and revision of the ambient standards. Pursuant to the 1977 amendments, EPA has promulgated new standards for lead, revised standards for ozone, and has proposed to adjust the short-term primary standard for carbon monoxide.¹ In addition, new standards are under development for carbon monoxide, short-term nitrogen oxides, sulfur oxides, and particulates.²

The new and revised standards for lead and ozone were promptly challenged in the District of Columbia Circuit Court of Appeals. Industry petitioners argued in both Lead Industries Association, Inc. v. Environmental Protection Agency (Lead)³ and American Petroleum Institute v. Costle (Ozone)⁴ that the Administrator of EPA, due to his failure to consider economic costs of compliance, had set overly stringent standards, and that the evidence in the record did not support the Administrator's conclusions concerning the health effects of the regulated substances. Environmental groups countered that the standard provided less than the required degree of health protection. Both environmental and industry petitioners raised numerous procedural objections to the lead and ozone rulemakings. Yet, the court overwhelmingly rejected all substantive and procedural challenges to both the lead and ozone standards in two decisions which appear to firmly settle the broad scope of EPA's authority in setting NAAQS.