Source Attribution of Eutrophying and Acidifying Pollutants on the UK Natura 2000 Network

Abstract

Atmospheric nitrogen (N) and sulphur (S) deposition from industrial, transport and agricultural sources may exert a range of different types of impacts on Natura 2000 sites in Europe. The FRAME (Fine Resolution Atmospheric Multi-pollutant Exchange) model, incorporating emission point sources and sectors, was used to provide footprints of N and S deposition across the UK from 160 sources or groups of sources. The resulting matrix of source attribution by sector, and exceedance statistics for each site, provide a means of impact assessment for the whole UK’s Natura 2000 network. For 2005 80 % of Special Areas of Conservation (SACs) in the UK have at least one feature exceeding their minimum N critical load, while the figure for acidity exceedance is 75 %. By 2020, the values are estimated at 74 and 62 %, respectively, indicating that current policies are insufficient to avoid exceedance of the critical loads. Although NO_x emissions are projected to decrease substantially, the modest reduction in exceedance is a consequence of the contribution of NH₃ from agricultural sources, which is projected to decrease only slightly between 2005 and 2020. Future analysis should address the spatial importance of source location and site proximity to a source, and examine the relationship between dry and wet deposition by source sector.