Cattle waste tops cars as source of Southern California smog
Article first published online: 8 JUN 2012
©2012. American Geophysical Union. All Rights Reserved.
Eos, Transactions American Geophysical Union
Volume 93, Issue 24, page 232, 12 June 2012
How to Cite
2012), Cattle waste tops cars as source of Southern California smog, Eos Trans. AGU, 93(24), 232., (
- Issue published online: 8 JUN 2012
- Article first published online: 8 JUN 2012
- Cited By
- CalNex 2010;
- South Coast Air Basin;
- ammonium nitrate;
- automobile emissions;
- dairy farm emissions
A new study shows that cows, not cars, are the more substantial source of ammonia that leads to ammonium nitrate in California's South Coast Air Basin, the smoggiest place in the United States. Within the region, which consists of the area surrounding and downwind of Los Angeles, a large proportion of the fine-grained particulate matter that makes up smog is formed from ammonium nitrate. Nowak et al. found two main sources of ammonium nitrate: small gas-powered vehicles and dairy farms. Catalytic converters designed to stem the emissions of carbon monoxide, nitrogen oxides, and hydrocarbons from the region's 9.9 million vehicles can produce gaseous ammonia as an unwanted by-product. Bacteria decomposing organic wastes from the region's 298,000 dairy cattle, on the other hand, also account for a sizable source of ammonia emissions.