Council (STFC) (UK) RATIONALE Ammonia (NH 3) is the most abundant alkaline gas in the atmosphere and has major impacts on air, soil, and water quality. It is responsible for the formation ammonium (NH 4 +) particles in the atmosphere which have a significant impact on human health (e.g. cardiovascular and respiratory diseases). In the UK, agriculture represents 88% of atmospheric NH 3 emissions. The UK government aims to reduce emissions by 16% in 2030 compared to 2005 levels. The Code of Agricultural Practice (COGAP) for Reducing Ammonia Emissions was published in 2018 and is a guidance document that explains practical steps to minimize NH 3 emissions.