Emission factors

Emission factors indicate what proportion of nitrogen excreted on pastures, in stalls, or on farm yards, stored in manure storage facilities, or applied as fertilizer to grassland or arable land is emitted as ammonia into the air.

Emission factors are expressed as percentages of TAN (Total Ammoniacal Nitrogen), the soluble nitrogen fraction responsible for most ammonia emissions from livestock operations, manure storage, and application.

Additional emission sources include mineral and recycled fertilizer application (measured as % of total or soluble nitrogen) and soil and plant processes (measured in kg ammonia-nitrogen per hectare of agricultural land).

The emission factors used in the model are listed under Technical Model Description.