Air Data airdata.dev

airdata.dev

Air Data

Air quality for every US county, from 1980 to yesterday.

The daily Air Quality Index for every US county with an EPA monitor, joining EPA's validated history to the preliminary days since its last release, plus yearly county summaries. Each row says whether it is validated or preliminary.

Browse the datasets Read the docs

What you get

  • Plain files over HTTPS

    Each series for each place as a small JSON or CSV file, plus every dataset as one CSV or Parquet file. No key or signup.

  • Versions you can cite

    Every update gets a version id, and a pinned URL always returns the same data. The first version of each month is kept for good, so results stay reproducible.

  • Checked before publishing

    Each update is validated against its contract. If a check fails, the last good version stays live.

  • Licenses up front

    Every dataset names its source, its license, the exact credit line and whether commercial use is allowed.

Datasets

All 2 datasets

  • Yearly air quality summary by county

    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

  • Daily air quality index by county

    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

Quickstart

Three requests: the catalog, one dataset's metadata and one data file.

curl -s "https://api.airdata.dev/v1/catalog"
curl -s "https://api.airdata.dev/v1/county-aqi-annual"
curl -s "https://api.airdata.dev/v1/county-aqi-annual/summary/us-county-09001.csv"

Base URL: https://api.airdata.dev. Next: the docs and the API reference.