Ammonia gas packs quite the smelly punch. In small doses, it's what makes smelling salts so effective. But high levels of ammonia can be a health hazard and a pollutant.
Dairy farms are one of the major sources of ammonia emissions. The U.S. Environmental Protection Agency estimated that dairy farms contributed more than 20% of the ammonia emitted from animal husbandry operations in 2015.
Now, a recent study has compiled and analyzed data from 25 previous studies. Researchers honed in on factors that influence how much ammonia dairy barns emit.