Critical Loads of Nitrogen and their Exceedances

Year	2016
Pages	80
Number	UW-1642-E
Editor	Federal Office for the Environment FOEN
Series	Environmental studies

Swiss contribution to the effects-oriented work under the Convention on Long-range Transboundary Air Pollution (UNECE).

Critical loads are defined as those air pollutant depositions below which harmful effects on specified sensitive receptors of the environment do not occur according to present scientific knowledge. They are an established element for developing effects-based approaches under the UNECE Convention on Long-range Transboundary Air Pollution. Critical loads of nitrogen were determined and mapped for forests and for (semi-)natural ecosystems in Switzerland by applying two methods proposed by the UNECE: the simple mass balance (SMB) and the empirical method. Total nitrogen deposition was modelled with high spatial resolution for the time period 1990–2010. In 2010, the nitrogen deposition exceeded the critical loads on more than 90% of all forest sites and on approximately 70% of the (semi-)natural ecosystems. 

Critical Loads of Nitrogen and their Exceedances (PDF, 4 MB, 27.02.2017)