The use of critical loads in developing regulatory policy

摘要

Information on the spatial distribution of sensitive receptors may be incorporated into assessments of the potential benefits arising from reductions in sulphur dioxide emissions. Drawing on energy forecasts, illustrative future scenarios for power generation were developed and corresponding national sulphur dioxide emissions inventories constructed. These were used as input to a transport and deposition model. Total sulphur deposition was estimated taking account of other United Kingdom sources and European emissions. Model outputs were overlain on maps of critical loads for soil acidification. Environmental disbenefit was esimated from the number of squares exceeding the critical load and plotted against power station sulphur dioxide emission. These plots suggested that reductions in emissions below a sector total of about 200 to 300 ktonnes may result in proportionally smaller environmental benefit than reductions down to this value. Analyses of the impact of a unit source in different areas of the country showed that emissions in the North-West have over two times the impact on acid sensitive ecosystems than those in the Thames Valley.