AP-42: Compilation of Air Emissions Factors

On This Page:

• Compilation of Air Pollutant Emissions Factors (AP-42)
  • Draft/Revised/New Emissions Factors
  • AP-42 Draft Factors, But Not Finalized
  • AP-42, Fifth Edition Compilation of Air Pollutant Emissions Factors, Volume 1: Stationary Point and Area Sources
• Additional AP-42 Resources
  • Historical AP-42 Information
  • AP-42 Frequent Questions
  • Older editions of AP-42, Volume 1

Compilation of Air Pollutant Emissions Factors (AP-42)

AP-42, Compilation of Air Pollutant Emissions Factors, 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 Fifth Edition of AP-42 was published in January 1995. Since then EPA has published supplements and updates to the fifteen chapters available in Volume I, Stationary Point and Area Sources. The latest emissions factors are available below on this website. Use the AP-42 Chapter webpage links below to access the document by chapter.

Draft/Revised/New Emissions Factors

Documentation Supporting Draft and New Emissions Factors

AP-42 Draft Emissions Factors, But Not Finalized

After the comment period, can I use a draft section? (txt)  (1 p, 1 K)

AP-42, Fifth Edition Compilation of Air Pollutant Emissions Factors, Volume 1: Stationary Point and Area Sources

Historical AP-42 Information

Proposed and final rules related to emissions factors
October 14, 2009 - The Emissions Factors Program Improvements - Advanced notice of proposed rulemaking is available on the www.regulations.gov website. The comment period ended December 14, 2009.

AP-42 FAQs

Answers to frequent questions about AP-42.

There are currently no drafts sections under review.

AP-42 listing of supplements and updates.

AP-42 Chapter References

Supplements A through F (1996 - 2000)(PDF)(3 pp, 148 K, About PDF)

Updates 2001 to 2011 (PDF)(2 pp, 241 K, About PDF)

Older editions of AP-42, Volume 1

This information is available for historical purposes only. For the most recent emissions factors, supported by the EPA, please see the table of contents above.