Share of days with good air quality (US EPA AQI)
Days with a daily Air Quality Index of 0 to 50 (good) as a percentage of the days of the year with an AQI in a US county. Calculated by Invokely from the day counts in the EPA AirData annual summaries; both counts are stored with each value.
United States counties with air quality monitors only, about 1,000 of some 3,100 in recent years; a county without monitors has no value. The number of days with an AQI differs between counties because some monitors run only in the ozone season.
Key facts
- Alamosa County had the highest share of days with good air quality (US EPA AQI) of 1000 counties in 2019, at 100%, and San Bernardino County the lowest, at 7.9%. Source: EPA.
- Published for 1,498 places, with figures from 1980 to 2025.
Rankings
- US counties
- Counties in Texas
- Counties in North Carolina
- Counties in Virginia
- Counties in California
- Counties in Ohio
- Counties in Kentucky
- Counties in Indiana
- Counties in Michigan
- Counties in Wisconsin
- Counties in Oklahoma
- Counties in Pennsylvania
US counties by share of days with good air quality (US EPA AQI), 2019
Places with data
Provinces and counties
- Los Angeles County
- Cook County
- Harris County
- Maricopa County
- San Diego County
- Orange County
- Miami-Dade County
- Dallas County
- Kings County
- Riverside County
- Lafayette Parish
- Linn County
- Chittenden County
- Cuyahoga County
- Jefferson Parish
- Houston County
Use this data in your AI agent
Invokely serves this figure to AI assistants through MCP and to code through a REST API, with the source and citation attached. Ask your assistant:
Which places have the highest share of days with good air quality (US EPA AQI)? Use official data and cite it.
rank_places {"indicator":"aqi_good_days_share","level":"province","within":"United States"}
GET https://invokely.ai/api/v1/rank?indicator=aqi_good_days_share&level=province&within=United%20States