So far the US Environmental Protection Agency (EPA) hasn't put much emphasis on ammonia as one of the growing air pollutants. This is because there isn't a direct health risk from ammonia itself but EPA still needs to closely monitor the levels of ammonia in the air because ammonia is often a precursor to particulate matter, a major source of air pollution and health issues such as asthma and heart problems.
Ammonia has the ability to quickly react with other airborne elements; for instance it reacts with sulfuric acid to make ammonium sulfate salts and with nitric acid to make ammonium nitrate. According to researchers these particles can not only impact air quality but also atmospheric visibility, formation of clouds, influence climate patterns and nutrient cycling.
The major sources of ammonia air pollution are vehicles and industry. Ammonia air pollution is usually the highest in winter because cars and tracks are much more used during the cold winter months.
Ammonia is also the main air pollutant emitted from agricultural sources, mostly emitted from manure produced in animal houses which later gets stored or applied to the land as fertilizer. The big increases in atmospheric ammonia emissions have been common sight in recent years in areas of intensive animal agriculture.
Reducing ammonia emissions at global levels has so far proved quite uncertain and very demanding, with only modest regional reductions achieved to date.
According to EPA people can detect ammonia at five to 50 parts per million (ppm) while concentrations above 100 ppm are uncomfortable for most people.
Many studies have so far given hard proofs that EPA should regulate ammonia emissions in order to reduce particulate matter pollution. There is certainly a very strong case for EPA to directly regulate ammonia emissions.