INTRA-ANNUAL VARIATION FEATURES OF MASS DISTRIBUTION AND WATER SOLUBLE COMPOSITION DISTRIBUTION OF ATMOSPHERIC AEROSOLS OVER GUANGZHOU

An Andersen particle sampler(Model 20-709) was used for the collection and measurement of atmospheric total aerosol samples in Guangzhou during May 1988 to April 1989. The mass distribution of total aerosol and the distribution of fluorine, chlorine. nitric. sulphuric. sodium. ammonia. potassium. calcium. magnesium ions of water soluble were analyzed. The results show that the concentration of aerosol are lower in rainy seasons than those in dry seasons in Guangzhou. The concentration of sulphuric and calcium ions that are soluble in water are the largest in each month of the year. The mass distribution of total aerosol exhibits a triseak distribution. On the other hand. The distribution of water soluble composition is diversified. the magnesium. nitric. potassium and fluorine ions mostly exhibit triseak distribution. and the calcium ions are mainly bimodally distributed. and the chlorine and sodium ions are of quasi-unimodal distribution. the sulphuric ions are enriched greatly in Guangzhou, especially in rainy seasons. The m. m. d are larger in rainy seasons than in dryseasons, the same being true total aerosol and water soluble composition. The sulphuric is the most important canon in aerosols in Guangzhou. but concentration of nitric ions is very low. different from those observed in rain water. There are free acid in aerosols in Guangzhou in most of the year. especially in rainy season. causing aerosol to show neutral or weak acidity. It accounts for easy formation of acidrain in Guangzhou.