TEMPORAL AND SPATIAL DISTRIBUTION OF ACID RAIN IN HUBEI PROVINCE WITH A DISCUSSION ON THE CAUSE

The temporal and spatial distribution,cause and tendency of acid rain in Hubei province are studied according to recent ten years statistical monitoring results,the geographic conditions and acid gas emissions.The acid rain is distributed mainly in the areas along(mainly in south to)the Yangtze River and in Enshi prefecture.The pH in the rain decreases from north to south,from east to west.The acid rain is much more frequent in summer and autumn than in other seasons.It is certificated by the ionic monitoring that the acid rain in Hubei is sulphur-type acid rain.The acid rain formation is related mainly to local emission,remote transmission geographic condition and meteorological factors.For example acid rain in Enshi city is famous in whole province because of its local high-sulphur coal and mountain-valley topography.The rate of acid rain mass to total rain mass and acid rain frequency rate in recent five years is analysed by way of Danniel statistatics,indicating a polluting tendency.