South Coast Air Quality Management District v. Environmental Protection Agency

Congress enacted the Clean Air Act (CAA) in 1970 to protect public health and required the Environmental Protection Agency (EPA) to prescribe a primary National Ambient Air Quality Standard (NAAQS) for airborne pollutants. However, this approach applied identically to all criteria pollutants and was difficult to achieve because it left broad EPA discretion as to how to accomplish the NAAQS. To narrow the focus and better achieve the goals of the CAA, Congress enacted the 1990 Amendment to the CAA, which included a comprehensive regulation of six key pollutants. The former, ends-driven approach was redesignated as Subpart 1. Congress specified that Subpart 1 would not apply to nonattainment areas that already had set attainment dates under other provisions of the CAA. Congress enacted Subpart 2 to address the pollutant ozone. Subpart 2 relied upon the existing NAAQS of 0.12 ppm, measured over one hour, and imposed several controls including penalty provisions and one-hour new-source reviews (NSRs). The CAA allowed for the EPA to adjust NAAQS based on reviews of the latest science. The EPA could relax a NAAQS, but it had to provide controls that were at least as strict as those currently in effect for nonattainment zones before such an adjustment to prevent backsliding. In 1997, the EPA adopted a new ozone standard and decided that the deadlines imposed by Subpart 1 would restart with the new date of classification under the new standard. The new standard was a stricter standard of 0.09 ppm, measured over eight hours. In 2004, the EPA adopted a rule that all controls from the one-hour era remained in place, but only certain programs of Subpart 2 were applicable, and others such as NSRs and penalty provisions would not be retained. In this rule, the EPA determined that if it did not need to impose Subpart 2 requirements, it would not because Subpart 2 was old, control requirements for marginal areas were similar to those for Subpart 1, and most marginal areas would achieve attainment within three years. The EPA subjected areas with eight-hour ozone levels of greater than 0.09 to Subpart 1.