Emissions Factors & AP 42

An emissions factor is a representative value that attempts to relate the quantity of a pollutant released to the atmosphere with an activity associated with the release of that pollutant. These factors are usually expressed as the weight of pollutant divided by a unit weight, volume, distance, or duration of the activity emitting the pollutant (e.g., kilograms of particulate emitted per megagram of coal burned). Such factors facilitate estimation of emissions from various sources of air pollution. In most cases, these factors are simply averages of all available data of acceptable quality, and are generally assumed to be representative of long-term averages for all facilities in the source category (i.e., a population average).

The general equation for emissions estimation is:

E = A x EF x (1-ER/100)

where:

E = emissions;
A = activity rate;
EF = emission factor, and
ER =overall emission reduction efficiency, %

For information about emissions factors from highway vehicles and nonroad mobile sources, visit the Office of Transportation and Air Quality web site.

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

For current information on AP 42 updates and the activities of the Measurement Policy Group, you can subscribe to the CHIEF Listserv.
AP 42 FAQs	Answers to frequently asked questions about AP 42
Drafts	Draft Sections Under Review
AP 42 listing of supplements and updates.	Supplements A through F (1996 - 2000) Updates 2001 to present
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 below.
Procedures	Procedures for Preparing Emission Factor Documents -- Describes procedures for developing and reporting emission factors in EPA publications -- November 1997 (PDF 477K) Addendum to Procedures for Preparing Emission Factor Documents. August 2008 (PDF 21K) The draft version of the document, Detailed Procedures For Preparing Emissions Factors, has been removed and is being redeveloped. August 2008.
Contents	Cover page, detailed Table of Contents, Publications in Series, Insertion Instructions, and Key Word Index (PDF 128K). This is current through Fifth Edition, Supplement C of AP 42. For sections and chapters added after November 1997, see the chapter web pages below.

AP 42, Volume I, Fifth Edition
Introduction	Introduction to AP 42, Volume I, Fifth Edition - January 1995 (PDF 40K)
Chapter 1	External Combustion Sources
Chapter 2	Solid Waste Disposal
Chapter 3	Stationary Internal Combustion Sources
Chapter 4	Evaporation Loss Sources
Chapter 5	Petroleum Industry
Chapter 6	Organic Chemical Process Industry
Chapter 7	Liquid Storage Tanks
Chapter 8	Inorganic Chemical Industry
Chapter 9	Food and Agricultural Industries
Chapter 10	Wood Products Industry
Chapter 11	Mineral Products Industry
Chapter 12	Metallurgical Industry
Chapter 13	Miscellaneous Sources
Chapter 14	Greenhouse Gas Biogenic Sources
Chapter 15	Ordnance Detonation
Appendix A	Miscellaneous Data & Conversion Factors -- September 1985 (PDF 103K)
Appendix B.1	Particle Size Distribution Data and Sized Emission Factors for Selected Sources -- October 1986 (PDF 2M)
Appendix B.2	Generalized Particle Size Distributions -- September 1996 (PDF 137K)
Appendix C.1	Procedures for Sampling Surface/Bulk Dust Loading -- July 1993 (PDF 65K)
Appendix C.2	Procedures for Laboratory Analysis of Surface/Bulk Dust Loading Samples -- July 1993 (PDF 42K)

Chapter & Section	Description	Comments Requested by:
Draft Sections Under Review
After the comment period, can I use a draft section? (TXT 1K)
Chapter 15	Ordnance Detonation	February 20, 2009
Section 4.12	Manufacture of Rubber Products	February 2, 2009
Section 2.4	Municipal Solid Waste Landfills	February 5, 2009

AP 42 Emissions Factors by Chapter

Emissions Factors & AP 42

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