Methods for the calculation of critical loads and their exceedances in the UK

Report to Defra, prepared under Contract AQ0826. This report describes the calculation and mapping of critical loads and their exceedances in the UK. It consolidates information from earlier “UK Status Reports” into a single report. Part I describes the methods and data used to (a) map the distribution of 14 UK habitats sensitive to acidification and/or eutrophication; (b) calculate critical loads of acidity and of nutrient nitrogen. Part II describes the calculation of critical load exceedances (ie, the amount of excess deposition above the critical load) and presents results and maps based on UK deposition data for 2009-2011. Part III describes the application of site-relevant critical loads to UK SACs, SPAs, SSSIs.