What is ammonia?
Ammonia (NH3) is a corrosive, colourless gas with a distinctive, pungent odour. It can also be stored as a liquid at high pressure and is easily soluble in water. Ammonia deposits itself in wet and dry forms, on land, plants, soils and water. It is of primary concern as an air pollutant as a secondary particulate precursor, meaning it combines with other compounds in the atmosphere such as nitric and sulphate acids to form ammonium salts, a harmful form of fine particulate matter.
Where does it come from?
Ammonia comes from both natural and man-made sources. Natural sources include decaying organic matter and human and animal waste, whilst man-made sources include fertilizer manufacture, industrial processes and waste disposal sites. Particular attention has recently been drawn to the large amounts of ammonia pollution generated by agriculture: both through fertilizer manufacture and use, and animal waste.
How does it affect human health?
Through contributing to the formation of harmful PM2.5, ammonia contributes to the serious health risks associated with this, including severe cardiovascular and respiratory effects, decreased lung function, asthma aggravation, even premature death.
Additionally, exposure to high concentrations of ammonia in the environment can cause irritation to eyes, nose and throat, as well as skin.
Ammonia can contribute to the environmentally damaging processes of soil acidification, eutrophication of water bodies, it can upset ecosystems, and contribute to smog and reduced visibility.