Since 1970, transportation, power generation, and manufacturing have dramatically transformed as air pollutant emissions have fallen significantly. To evaluate the causal impacts of the Clean Air Act on these changes, we synthesize and review retrospective analyses of air quality regulations....

Economists have for decades recommended that carbon dioxide and other greenhouse gases be taxed—or otherwise priced—to provide incentives for their reduction. The United States does not have a federal carbon tax; however, many state and federal programs to reduce carbon emissions effectively...