Ecosystem area at risk of eutrophication and the magnitude of exceedance

Air pollution threatens biodiversity. Excess amounts of nitrogen deposited in terrestrial ecosystems causes harmful eutrophication when so-called critical loads are exceeded. This can lead to changes in species diversity, for example in nutrient-poor grasslands. The main sources of atmospheric nitrogen deposition are nitrogen oxide (NO_x) emissions from combustion processes and ammonia (NH₃) emissions from agriculture.