Free APIGeo & WeatherAPI keyOfficial
OpenAQ
Open global air-quality measurements (PM2.5, NO2, O3) from thousands of stations
OpenAQ aggregates open air-quality data worldwide, exposing monitoring locations, sensors and historical/latest measurements for pollutants like PM2.5, PM10, NO2, O3, SO2 and CO. The v3 API is free but requires a free API key sent in the X-API-Key header.
Free tier
Free with a free API key. Nonprofit/open-data project.Rate limits
Per-key limit of 60 requests/minute; returns standard x-ratelimit-* headers that reset every 60 seconds.Auth
API keyBase URL
https://api.openaq.org/v3What you'd build with it
- Show nearest air-quality readings for a user's coordinates
- Enrich automation runs with PM2.5/NO2 for a city
- Build health or environmental alerts on pollutant thresholds
- Pull historical air-quality series for analysis
Key endpoints
- GET
/locationsFind monitoring locations by country/coordinates/radius - GET
/locations/{id}/latestLatest measurements for a location - GET
/sensors/{id}/measurementsHistorical measurements for a sensor - GET
/parametersList measurable pollutant parameters
Members
Members get the runnable recipe
Sign in free to copy the example request, see a sample response, and read the gotchas.
Tags
air-qualityenvironmentgeoopen-data