THE CHEMICAL CHARACTERISTICS OF SPRINGTIME PRECIPITATION IN LUSHAN-MOUNTAINS, EAST CHINA

A comprehensive field measurement was set up in the springtime of 1993 to study the chemical characteristics of precipitation in the Lushan Mountains. The results showed that the concentrations of gaseous SO2, NOx, NH3, and HNO3 were low and precipitation was seriously acidified. The pH of all samples was less than 5.6 with an average of 4.6 and a minimum of 3.71. Sulfuric acid was the primary acidic substance to cau se the acidification and nitric acid was the secondary. Both acidity a nd concentrations of compositions in cloud water were much higher than those in rainwater. Comparisons of different phases of precipitation showed that concentrations of ionic components in the solid phase were two to five times higher than those in rainwater, and its pH was 0.6 higher than that of rainwater. According to the measurement results, i t was postulated that the acidification of precipitation was caused by joint effects of washout of local atmospheric pollutants and long-dis tance transportation of acidic substances.