Source attribution of eutrophying and acidifying pollutants on the UK Natura 2000 network

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 NOx 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.