The Influencing Factors Analysis Of Acid Rain And Forecast Of Precipitation Acidity In Qingdao

Qingdao is one of the northern cities whose acid rain pollution is serious. From the monitored data of rain in 1997 to 2006, it can be seen that Qingdao is the only city in Shandong province whose precipitation's pH value is lower than threshold 5.60. Therefore, it has great significance to analyze the acid rain pollution characteristics and causes, to forecast the precipitation acidity in the future, and then to takes corresponding controlling measures.Based on the detailed precipitation and atmospheric environmental monitoring data of Qingdao during the period from 1997 to 2006, the following two aspects are studied in this article: First, this study investigates systemically on the time and space distribution of the precipitation's pH and chemical composition in Qingdao urban area. What's more, the study analyzes carefully some factors which have effect on the precipitation's pH and chemical composition, combining lots of statistics and correlative data. Second, acid rain statistical prediction models suited to the characteristics of Qingdao is built in this study using the multivariate linear regression theory and the grey system theory, and then the precipitation acidity in the future is forecasted. It can provide scientific base for taking environmental management measures, controlling the harms of acid rain, and improving the ecological environment of cities. The research indicates that,1. The space distribution of acid rain shows that the acid rain pollution levels are different in every area of Qingdao, the city zone is more serious than suburb, and the eastern of Qingdao is lighter. The annual distribution of acid rain exhibits that the acid rain pollution is serious from 1997 to 1999, and from 2000, the acid rain status improved significantly. The acid rain pollution in Qingdao has typical seasonal characteristic, the seasonal variation of precipitation acidity is: winter > spring > autumn > summer.2. The key ions in precipitation of Qingdao are SO₄^2-, NO₃^-, Cl^-, Ca²⁺ and NH₄⁺, the precipitation pollution belongs to sulphuric acid type. The research using correlation analysis method indicates: SO₄^2- and NO₃^-, Mg²⁺ and Na⁺ in precipitation both have prominent correlation which may have the same resources. The precipitation acidity has relativity to Cl^-, K⁺ and Mg²⁺, but it has small relativity to SO₄^2- in precipitation, all of the above proves that the precipitation acidity is the comprehensive influencing result of SO₄^2-, NO₃^- and alkaline buffering ions in precipitation.3. The formation of acid rain in Qingdao is based on the presence of certain precursors, and it has close relationships with the buffering capacity of atmospheric aerosol, the atmospheric humidity, and the layer of meteorological condition. The large amount of sulfur dioxide and nitrogen oxide emission by fossil fuel combustion are found to be the fundamental causes, at the same time, the increasing vehicle exhaust emissions and the aerosol followed by southeaster from sea in summer are other reasons of acid rain. Because of the particularity of the layer of meteorological condition, the acid rain in Qingdao mostly comes from local pollutants, supplemented by external pollutants, and the scope of impacting is also limited because of many reasons.4. Based on the multivariate linear regression theory and GM (1,1) theory, the multivariate linear regression model and GM (1,1) model are established. Then the mathematical expectation of the pH value is estimated, and the precipitation acidity in the future is also forecasted.Finally, this study put some suggestions for the controlling of acid rain pollution according to the acid rain pollution characteristics, influencing factors and the conclusions of forecast, hoping to provide a scientific basis for improving the environmental quality and controlling the acid rain pollution effectively.