FACT SHEET

Draft Volatile Organic Compound Emission Models for Animal Feeding

Operations

ACTION

•	On November 18, 2022, the U.S. Environmental Protection Agency (EPA) published a
progress report on the development of volatile organic compound (VOC) draft air emission
models, developed using data gathered during the National Air Emissions Monitoring Study
(NAEMS).

•	The progress report lays out a summary of the data and next steps in completing
preliminary draft models to estimate daily and annual air emissions of volatile organic
compounds from barns, manure lagoons, and basins from animal feeding operations
(AFOs).

•	Now that the preliminary draft emission models for all animal sectors (swine, broiler
chickens, egg-laying operations, dairies, and VOCs) are released, EPA will take time to revise
and improve the preliminary draft models for all animal types. Once all the models have
been reviewed and revised, EPA will release the entire set of revised draft models for a
formal public comment period. We are targeting summer 2023 for the formal public
comment period.

•	Once finalized, the emission models will be used by animal feeding operations participating
in a voluntary consent agreement known as the Air Compliance Agreement to determine
whether their emissions trigger certain Clean Air Act (CAA) permitting requirements.

•	EPA also expects the final models may be useful for general estimates of air emissions from
dairy operations across the United States or comparisons between operations in different
regions.

BACKGROUND

•	Under the 2005 Air Compliance Agreement (the Agreement) with the animal production
industry, EPA is responsible for using NAEMS data to develop emission models for emissions
of ammonia, hydrogen sulfide, particulate matter, and VOCs at animal feeding operations
raising swine, broiler chickens, egg-laying operations, and dairies.

•	In 2013, EPA's Science Advisory Board (SAB) reviewed the original draft emission models
and made recommendations for improving their development. SAB's recommendations
have been incorporated into the draft VOC emission models.

FOR MORE INFORMATION

•	Today's action and other background information are also available electronically at:
https://www.epa.gov/afos-air/national-air-emissions-monitoring-study.

•	Questions, suggestions, and voluntary submissions of supplemental data or information can
be sent to NAEMS@epa.gov.

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