The court of appeals granted a petition for review and remanded. The court held that the Environmental Protection Agency’s 2010 approval of the 2004 state implementation plan for the San Joaquin Valley’s nonattainment area for the ozone ambient air quality standard was arbitrary and capricious for failure to consider new data or to explain choice not to consider the new data.
The Clean Air Act (CAA) authorizes the Environmental Protection Agency (EPA) to establish National Ambient Air Quality Standards (NAAQS) that apply to air pollutants that are dangerous to health. The EPA designates areas that fail to attain NAAQS as nonattainment areas. California’s San Joaquin Valley (the Valley) was been designated as an extreme nonattainment area for the pollutant ozone.
