AP-42: Compilation of Air Emissions Factors from Stationary Sources

AP-42, Compilation of Air Pollutant Emissions Factors from Stationary Sources, has been published since 1972 as the primary compilation of EPA's emissions factor information. It contains emissions factors and process information for more than 200 air pollution source categories. A source category is a specific industry sector or group of similar emitting sources. The emissions factors have been developed and compiled from source test data, material balance studies, and engineering estimates. The latest emissions factors are available below on this website. Use the AP-42 Chapter webpage links below to access the document by chapter. Emission factors are being updated as data are received and evaluated.