Report Cards

The American Lung Association "State of the Air 2024" report ranks cities and grades counties based on ozone and particle pollution during 2020, 2021 and 2022. For particle pollution, we rank separately the areas with high year-round (annual average) levels and high short-term levels (24-hour) found in monitoring sites across the United States. We take official data from the U.S. Environmental Protection Agency (EPA) to compile the results. For more information about how we rank and grade cities and counties, go to Methodology.