Datasets

EPA's yearly Air Quality Index (AQI) summary for every US county with a monitor, from 1980: how many days fell in each AQI category, the maximum, 90th-percentile and median daily AQI, and how many days each pollutant set the AQI. Validated EPA AirData; the latest year is partial until EPA's next release completes it.

Time series Every 6 months

The daily Air Quality Index (AQI) for every US county with an EPA monitor, from 1980 to yesterday. Rows up to EPA's latest AirData release are validated (validated: true). Later days are preliminary (validated: false): EPA AirNow data from federal, state, local and tribal agencies, not yet verified and subject to change. For those days the county AQI is a derived value calculated by airdata.dev as the highest site AQI reported to AirNow in the county that day, the way EPA summarizes a county; the site AQI values themselves are as received. Preliminary days cover ozone, PM2.5, PM10 and CO only. A preliminary row never replaces a validated one.

Time series Daily