Chemical Characteristics and Cause Analysis of Precipitation in the South of Liaodong Peninsula

Based on the acid rain observation data of 12 observation points from 2007 to 2009 in Dalian Environmental Monitoring Center and Dalian Meteorological Bureau, the paper analyzes the spatial and temporal distribution status of acid rain and the chemical characteristics of precipitation in the south of Liaodong Peninsula, makes an initial cause analysis, and does the Spearman rank correlation coefficient test of materials since 2004. The results show that, the frequency of acid rain shows a trend of significant increase while the pH value shows a clear downward trend, it has already been at medium level of acid rain. The equivalent concentration ratio of sulfate to nitrate ion in precipitation is 2.7. The acid rain is not entirely caused by the local pollutant emission but affected by a wide range of regional pollution. The enhancement of the acid rain is because that the control of pollutant emissions results in the decrease of neutralization of alkaline substances.