The OpenAQ REST API allows up to 300 requests per 5 minute window or about one request per second. Exceeding this limit will result in a temporary block and return an HTTP 429 error code.
Data on OpenAQ are free and open to use. We only use data that, to the best of our knowledge, is available for free redistribution and use throughout the world. In some cases, attribution of data source may be required.
See our Data Policy for more information.
Updated over 1 year ago