Risk of eutrophication measured as exceedance of critical loads of nitrogen deposition in Europe, in 2022

Air pollution threatens biodiversity. Excess amounts of nitrogen can cause eutrophication, disrupting terrestrial and aquatic ecosystems and leading to changes in species diversity, for example in nutrient-poor grasslands. The main sources of atmospheric nitrogen deposition are combustion processes, which result in nitrogen oxides (NOx) being emitted to the air, and ammonia (NH₃) emissions from agriculture. Nitrogen deposited in terrestrial ecosystems causes harmful eutrophication when so-called critical loads are exceeded.