Emissions from Livestock Production

What Emissions are of Interest and Why? 

Odors often appear at the top of farm air pollution complaints lists. Farm odors are comprised of over 200 different chemicals.

Ammonia is a gas emitted from farms because of the relatively inefficient conversion of feed nitrogen (20-40% conversion efficiency) into animal product (meat, egg, and/or milk). Deposition of NH3 can lead to over enrichment of nutrients and cause eutrophication of surface waters. Ammonia gas can react in the atmosphere with other gases to form fine particulates.

Hydrogen sulfide is produced by decomposition of animal manure whenever there are sulfur compounds, anaerobic conditions and sufficient moisture. It is an extremely toxic and irritating gas at high levels, and has a generally objectionable rotten egg odor.

Particulate matter (PM) or dust, is of interest because of its health and environmental concerns. The PM emitted from farms is highly complex in size, physical properties, and composition.

Greenhouse gases (GHG) in the atmosphere can delay heat on the Earth's surface from being lost to space like the glass walls of a greenhouse do (‘greenhouse’ effect), and contribute to global climate change. The GHGs that are emitted from activities related to animal agriculture include CO2, CH4, and N2O.

Potential Importance of Livestock Air Emissions at Different Spatial Scales (Adapted from NRC, 2003)

The effects of airborne pollutants from livestock air emissions differ in their potential severity and the spatial scales. For example, the effects of odor are of interest mainly at local level, while NH3 has relevant impacts mainly on a regional-scale perspective.

Emissions
Global & Regional
Local & Property Line
Primary Effects of Concern
Odor
Insignificant
Major
Nuisance, quality of life
VOC
Significant
Minor
Odorous, ozone formation
NH3
Major
Minor
Atmospheric deposition
H2S
Insignificant
Significant
Odorous, health
PM
Insignificant
Significant
Health, haze
GHGs
Significant
Insignificant
Global climate change
Rank order from high to low importance is major, significant, minor, and insignificant.