In low concentrations, ammonia is not harmful to human health. However, when ammonia emissions combine with pollution from industry and transport (like diesel fumes) they form very fine particulate matter (PM), which can be transported significant distances, adding to the overall background levels to which people are exposed. When inhaled, particulate matter can penetrate deeply into body organs and contribute to causing cardiovascular and respiratory disease. It is estimated that particulate matter emissions result in 29,000 early deaths in the UK.
When deposited on land, ammonia can acidify soils and freshwaters, ‘over-fertilising’ natural plant communities. The extra nitrogen can increase the growth of some species (such as rough grasses and nettles), which out-compete other species (such as sensitive lichens, mosses, and herb species) that have lower nitrogen requirements. In 2014, 96% of the area of nitrogen-sensitive habitat in England received more nitrogen than it could cope with effectively. Once the soil quality has changed, together with the balance of species on the land, it takes a long time, and can be costly, to restore it.
88% of the UK’s ammonia gas emissions are from farming