Help & FAQ

OpenAQ provides a REST API for programmatic access of the entire data set. Bulk data downloads are also available via Amazon Web Services S3 object storage downloads. OpenAQ also provides an interactive web application for browsing and searching the database from a graphical user interface.

OpenAQ ingests ambient air quality data measurements from ground-level stations. Data must be ‘raw’ and reported in physical concentrations on their originating site. Data cannot be shared in an ‘Air Quality Index’ or equivalent format. Data must be at the ‘station-level,’ associable with geographic coordinates, not aggregated into a higher (e.g., city) level. Data should be from measurements averaged between 10 minutes and 24 hours.

The OpenAQ database currently ingests the following pollutant data, with a focus on those in bold.

  • PM1 - particulate matter 1 microns (μm)
  • PM2.5 - particulate matter 2.5 microns (μm)
  • PM4 - particulate matter 4 microns (μm)
  • PM10 - particulate matter 10 microns (μm)
  • BC - black carbon particulates, part of PM2.5
  • O₃ - Ozone gas
  • CO - Carbon monoxide gas
  • NO₂ - Nitrogen dioxide gas
  • NO - Nitrogen monoxide gas
  • NOx - Nitrogen oxides
  • SO₂ - Sulfur dioxide gas
  • CH₄ - Methane gas
  • CO₂ - Carbon dioxide gas

For information on these pollutants, their sources, their health risks, and recommended guideline values, visit World Health Organization’s “Types of pollutants” web page . Britannica’s air pollution page is another good source of information on air and climate pollutants.

Units of measurement

Measurements of pollutants are reported in a variety of units depending on how the data is reported from the original data provider. Units are not normalized in the OpenAQ system, with the exception of converting ppm (parts per million) to ppb (parts per billion). Volume units are not converted to mass units, nor vice versa; they are served as originally reported.

Air quality data is factual in nature, and in some jurisdictions may not be subject to copyright or other protections limiting its use or distribution. However, in some jurisdictions, copyright and/or laws and regulations may apply to some of the data on the OpenAQ platform.

A number of our sources provide their air quality data under specific licensing, such as Creative Commons licensing or open government licenses, which require source attribution. Regardless of such requirements, we believe in the importance of attributing data sources and strongly encourage everyone to do so. Read our Data Policy for more information.

When you use OpenAQ and its tools to access air quality data, we request attributions both to the original data provider and OpenAQ whenever the original data provider is known. Suggested citations:

If data provider is known (via metadata):

Data Provider. (202X). Dataset Title (if known). OpenAQ API Available from:

General OpenAQ citation:

OpenAQ, Inc. (202X). OpenAQ API Available from: 	

If using bibtex . For author include OpenAQ and any data providers from metadata in accordance with source license.

   author = {{ OpenAQ }},
   title = {{Retrieved from }},
   howpublished = "\url{ }",
   year = {2023},

Links to our training resources can be found in: . Contact us if you would like to host an OpenAQ training (due to limited capacity, we prioritize larger, mission-aligned projects).