§ Mr. Skeetasked the Secretary of State for the Environment of the sulphur dioxide present in the atmosphere, what percentage he assesses is derived from (a) natural sources, (b) power stations burning fossil fuels, (c) cement works and other industrial plants and (d) domestic heating and vehicle exhausts.
§ Mr. WaldegraveIt is estimated that, globally, the amount of sulphur dioxide originating from natural sources is of the same order as that from man-made sources. However, over industrial regions the component from natural sources is thought to be relatively small. Information on sulphur dioxide emissions from fuel combustion by type of consumer is given in the "Digest of Environmental Pollution and Water Statistics" published by my Department. The latest figures (for 1981) are: 63 per cent. from power stations, 26 per cent. from other industry, 6 per cent. from domestic sources and vehicles, and 5 per cent. from other sources.
§ Mr. Skeetasked the Secretary of State for the Environment what tonnage of limestone would be required for processing to operate in scrubbers of flue gases should the removal of sulphur dioxide be required by legislation following the European Community proposals.
§ Mr. WaldegraveA conventional wet scrubbing process would require some two tonnes of limestone per tonne of sulphur dioxide removed. For a typical 2,000 megawatt coal-fired power station, with a 70 per cent. load factor, the requirement would be about 300,000 tonnes of limestone per year.