Interstate Air Pollution Governance in the United States: Exploring Clean Air Act Section 126

Abstract Toxic air pollution is arguably the most pressing human health concern today, accounting for approximately 7–9 million premature deaths worldwide. In the United States, more than 200,000 early deaths are attributable to air pollution and almost half of these are estimated to result from emissions originating in neighboring states–i.e., transboundary air pollution. Yet more than 40% of these deaths are assessed to be cause by air pollution produced by neighboring states. This article examines the governance mechanisms used by the US to address this transboundary issue, with a focus on section 126 of the Clean Air Act. All section 126 petitions submitted from 2000–2022 (N = 13), critical factors including case length, evidence used, and case outcome are compiled and assessed using comparative case analysis. From this analysis, four main issues and corresponding recommendations to enhance US governance mechanisms related to section 126 are developed: the need for policy and procedural reforms to adjust the burden of proof on petitioning states the need for clarity on the criteria for sufficient evidence for petitioners; potential practical measures to address challenges with response timelines in petitioning process; and the means by which section 126 petitioning capacity can be made accessible to all states. The article concludes with a discussion on the significance of modeling techniques employed in the petitioning process by the US EPA and states to facilitate informed–and fair–decision-making processes.