The impact of ammonia and hydrogen sulfide emissions from animal agriculture
Ammonia emissions impact human and ecosystem health while hydrogen sulfide is primarily a human health concern.
Air emissions from animal feeding operations, large and small, commercial and hobby farms can’t be completely avoided. Efforts to reduce those emissions can improve the ecosystem health, human health, and neighbor relations. It is important to understand what effect air emissions have. Two of the most well known emissions, ammonia and hydrogen sulfide, are addressed here.
Ammonia (NH3) is a gas that results from the incomplete conversion of feed nitrogen into animal product (meat and/or milk). While livestock raised on commercial farms are more efficient in using feed nutrients than most humans, not all of the nutrients in feed are converted into product (growth, meat, milk, eggs, offspring). Al Rotz3 gas. Atmospheric NH3 is an important pollutant due to its impact on ecosystems. Too much NH3 in the air can lead to deposition into surface waters via rainfall and cause over-enrichment, or eutrophication, of surface waters (algal blooms). Deposition often occurs far away from where the NH3 gas was produced. Red tide outbreaks in the Chesapeake Bay are attributed, in part, to over-enrichment with nitrogen. reported in 2004 that the conversion efficiency of nitrogen in animal production might range from 20 percent to 40 percent. Thus, a considerable amount of nitrogen in animal feed is excreted in urine and feces with the potential to be to be converted to NH
Ammonia gas can react in the atmosphere with other gaseous compounds (acids such as those arising from natural processes in land, or from coal production) to form fine particulates (ammonium (NH4+) aerosols), which are of a health concern. These fine particulates (called PM2.53 and NH4+) linger in the atmosphere for days and can be transported hundreds of miles, a regional-scale perspective is necessary when considering the environmental effects of NH3. particulates) are respiratory irritants. Because both ammonia and ammonium (NH
While the focus here is on-farm sources of emissions, NH3 concentrations inside our own homes may be as high as that in farm areas, particularly when concentrated cleaning agents, litter boxes and even smokers are present.
Hydrogen sulfide (H2S) is best known for its characteristic odor: rotten eggs. At high concentrations hydrogen sulfide can be deadly (silo gas). Even at low concentrations H2S is a respiratory irritant. Although hydrogen sulfide is not transported great distances, at the farm it can mix with other compounds to contribute to odor. Compared to NH3, H2S emissions are quite low; oftentimes they are 10-fold or more lower than NH3 emissions. H2S forms under anaerobic conditions (absence of oxygen), so sources of H2S are largely from manure storage whereas NH32S is emitted from both animal housing and manure storage areas. Some states have property line H2S standards (Iowa and Minnesota). Challenges meeting the state standard have been the result of locating uncovered manure storages near the property line and/or poor farm management practices.