From the Introduction: "The 117th Congress is likely to face wide-ranging air pollution issues as it conducts oversight and deliberates on legislation related to air quality standards, smoke from wildfires, air quality monitoring, air toxics, and permitting requirements. Congress may factor multiple issues into these deliberations, including environmental and public health objectives, economic impacts, and how the U.S. Environmental Protection Agency (EPA) accounts for 'distributional effects' in benefit-cost analysis for Clean Air Act (CAA) rulemakings. Diverse sources of air emissions--including power plants, industrial facilities, small commercial facilities, motor vehicles, and wildfires--contribute to the various gaseous and particle pollutants in ambient, or outdoor, air, which is the purview of the Clean Air Act. Air quality has improved substantially since Congress enacted the CAA in 1970. [...] At the same time, EPA has tightened air quality standards as the scientific understanding of the health effects of air pollution has evolved. The goal of clean air continues to elude many areas. [...] This report begins with background about the CAA framework, including federal and state roles, and summarizes congressional actions related to the CAA in the 116th and earlier Congresses. The report also discusses some prominent air topics of potential interest in the 117th Congress: EPA's review of particulate matter and ozone standards; management of wildfire smoke; EPA's review of hazardous air pollutant standards; classification of hazardous air pollutant sources; and revisions to applicability determinations under the preconstruction permitting program, known as New Source Review (NSR)."
CRS Report for Congress, R46684
Congressional Research Service: https://crsreports.congress.gov/