Review of ammonia emission factors for United States animal agriculture

Ammonia emissions from agricultural industries are a significant source of atmospheric reactive nitrogen, which can lead to negative environmental consequences such as ecosystem change and formation of fine particulate. While a number of emission factors (EFs) have been proposed for developing ammonia emissions inventories for the US, most are based on European research with little discussion of their applicability to US production systems. Recently developed ammonia EFs from literature for animal feeding operations (AFOs), including production facilities for beef and dairy cattle, swine, and poultry, are presented. Tentative EFs for US animal agriculture are suggested until further research can be conducted. Currently, there is a dearth of EFs developed specifically for agricultural production practices in the US.