Review and revision of empirical critical loads of nitrogen for Europe

This report contains the scientific background to the review and revision of the empirical critical loads of nitrogen (CL_empN) that had been established for Europe in 2011 under the UNECE Convention on Long-range Transboundary Air Pollution. This review uses for the first time gradient studies to evaluate and determine the Cl_empN. The results, as presented in Table 1 of the Executive Summary, show that in many cases the outer ranges of the CL_empN have decreased compared to the 2011 values. The outcomes of this report are of major importance for the protection of N-sensitive natural and semi-natural ecosystems across Europe. This knowledge is used to support European policies to reduce air pollution.