Air Quality by State

Select a state to view air quality data for all cities and regions. Each state page includes current AQI readings, historical trends, and city rankings.

Air quality varies significantly across the United States depending on geography, industry, traffic density, and weather patterns. Western states like California and Arizona frequently contend with wildfire smoke and ozone, while industrial regions in the Midwest can see elevated particulate matter. States in the Southeast often experience high ozone days during summer months. Use this directory to explore the data for your state, compare cities within it, and understand the local pollution sources that affect your daily air quality. Each state page is updated with the latest EPA monitoring data.