Southwestern Pennsylvania Growth Alliance v. Browner

Under the Clean Air Act (CAA), the Environmental Protection Agency (EPA), through its administrator (the administrator) (defendants) designated areas of the country as attainment, nonattainment, or unclassifiable for the pollutant ozone, depending on whether the area complied with the national ambient-air-quality standard (NAAQS) for ozone. The EPA’s designation applied for a three-year period based on measurements collected from monitoring sites located within an area; if a monitoring site registered more than one “exceedance” per year over the period, then that area was in nonattainment. In 1990, the EPA classified an area around Pittsburgh (the Pittsburgh area) as moderate nonattainment for ozone based on exceedances between 1987 and 1989. In November 1993, Pennsylvania submitted a request for redesignation based on data for 1991 to 1993, during which time there had been only three exceedances. In July 1995, the EPA determined that the Pittsburgh area was in attainment. However, not long thereafter, ozone monitors in the area registered 16 exceedances over a seven-day period, with two sites recording more than three exceedances each. The EPA revoked its earlier determination and disapproved the redesignation of the Pittsburgh area. Southwestern Pennsylvania Growth Alliance (SWPGA) (plaintiff) petitioned for review of the EPA’s denial of redesignation. SWPGA argued that it was improper for the EPA to consider ozone data from the summer of 1995, which was more than 18 months after the state’s redesignation request, and not to consider the role of ozone transported from another area to the area in question.