Revisiting the NAAQS Program for Regulating Greenhouse Gas Emissions under the Clean Air Act

Abstract

The future is uncertain for the regulation of greenhouse gases from power plants, including the U.S. Environmental Protection Agency’s (EPA) Clean Power Plan, which covers existing plants. The rule is under review in the D.C. Circuit Court of Appeals, and the Supreme Court has indicated its interest in hearing the case. Moreover, during his presidential campaign, president-elect Donald Trump promised to “scrap” the Clean Power Plan. If the rule is overturned or is severely weakened, whether through litigation or executive action, stakeholders are likely to litigate to seek to force the EPA to use other authorities under the Clean Air Act to regulate greenhouse gas emissions. This working paper examines the opportunities and challenges associated with regulation of greenhouse gases under the National Ambient Air Quality Standards (NAAQS) program, drawing a comparison with the Clean Power Plan’s approach under a different section of the Clean Air Act. The paper offers no opinion on the Clean Power Plan litigation, nor does it advocate for the Clean Power Plan or the NAAQS approach. Its focus is on understanding how the NAAQS program might incorporate greenhouse gases in in the event that the EPA pursues that approach.