Primarily Study On Pollution Characters Of Acid Rain And Their Impact Factors In Pearl River Delta

Recent decades, the intense emission of air pollutants has been caused by the rapid development of economy in the Pearl River Delta where the car ownership has increased, long-term rainfall acidity and acid rain, high frequency,acid rain pollution problems to be solved.In this study, the temporal and spatial distribution of acidity and chemical composition was analyzed by historic data collected from routine monitoring network and the Hong Kong-Guangdong Pearl River Delta Regional Air Quality Monitoring Network. The temporal and spatial distribution of some principal pollutants, such as SO2,NOx,PM10 and O3, and their contribution to the formation of acid rain were then investigated. The primary causes and main impact factors were explored according to the emission of pollutants as well as the local social and economical backgrounds. The result of this study was showing that:(1) Acid rain pollution in PRD was still severe without any restraint yet. In last decades, acidity of precipitation was stable, otherwise the frequency of acid rain is increasing. The average pH of precipitation is 4.75 in 2010 and the frequency of acid rain is 63.1%.(2) Concentration of SO42- of precipitation was decreasing, relating strongly with the decrease of SO2 emission from 2001 to 2010. However, the concentration of NO3-apparently increased, which implied that the type of acid rain in this area was changing from the single type of sulphuric to a complex type of sulphuric and nitric mixture and increasingly suffering from an influence of atmospheric NOx, NH4+ and Ca2+.(3) Acid rain and related air pollutants showed strong spatial distribution with the northwest and northeast part of PRD, the most severely affected region, much as the same distribution character of SO2,NO2 and PM10. The distribution of acidity and frequency of precipitation was generally overlapping:the lower the acidity of the rainfall, the higher the frequency of the precipitation.(4) The formation impact factors of acid rain in PRD was complicated, with multiple effects of emissions of acid-causing substances in the type and quantity, weather conditions, the process of long distance transportation of atmosphericphotochemical reactions and soil pH. The emissions of acid-causing substances was of great significance that cannot be ignored.Moreover, this study proposed practical control strategies from the perspectives of management policies, control technology, scientific support, providing scientific basis for integrated prevent and control policies toward local acid rain and air pollution.