TR 062 : Ammonia Emissions to Air in Western Europe | July 1994
Anthropogenic ammonia (NH3) emissions to the atmosphere in western Europe (EEC + EFTA countries) are estimated to be between 2.8 and 5.2 Mt NH3–N/year in the year 1990, with 4.0 Mt NH3–N/year as best estimate. Waste from farm animals (cattle, sheep, goats, pigs, poultry and horses) is the principal source of atmospheric NH3, as shown in Table 1.
Table 1 Origin and Quantity of Ammonia Emissions to Air in Western Europe in 1990
(% of total)
|stables and manure||1.4||34|
|Leaf emission from crops||0.2||5|
The estimate of NH3 emissions from animal husbandry is based on calculated and measured N excretions and losses, adjusted for national conditions when data are available. Fertiliser derived emissions are estimated from consideration of reactions between fertiliser compounds and soil, taking typical national characteristics of soil into account. Crops can both take up and emit NH3 from the leaves; net emission is probably about 1.5 kg NH3–N/ha/year, but can be larger when the weather during ripening is adverse. A variety of other minor sources also contribute to atmospheric NH3: fur animals and other minor groups of farm animals, pets, exhalations from human beings, domestic use of ammonium products, refrigeration, combustion, treatment of waste water and disposal of sludge. Such emissions are included in “miscellaneous emissions”.
The emissions can only be crudely estimated, as they vary greatly with circumstances. Thus the estimates for the Netherlands have a range of uncertainty of approximately 30%. The range of uncertainty for other nations with fewer data useful for making emission estimates is probably even larger. The only source where the magnitude of NH3 emission is accurately known is that of the fertiliser industry, as most plants measure the emissions and report them to authorities.
The estimate of NH3 emissions in Western Europe from the animal sector is about 15% higher than the lowest of other recent estimates. This is well within the range of uncertainty of such estimates. The estimate of total emissions is about 20 to 25% higher than other recent estimates as items not covered by most other estimates are included (crops and miscellaneous).
Published estimates indicate that NH3 emissions in Western Europe increased by about 50% between 1950 and 1980. The emissions probably peaked around 1990. There are no EEC regulations for NH3 emissions, but national efforts and regulations are increasingly specifying rapid manure incorporation into soil after spreading; animal feed composition is better adjusted to avoid excessive N intake, and storage conditions for manures are being improved. Furthermore, fertiliser consumption is falling. Such measures should gradually reduce the emissions by about 20 to 30% of the 1990 level.