Acid rain pollution situation in Shijiazhuang,Hebei province

Based on the acid rain monitoring data of Shijiazhuang weather station from 1992 to 2005,annual average of rainfall pH and acid rain frequency were calculated.Acid rain characteristics and the relationships of average pH with meteorological conditions,conductivity and air pollution were analyzed.The results indicate that the frequency of annual acid rain is 8.7% in Shijiazhuang from 1992 to 2005.Acid rain often occurs in summer and autumn and accounts for 74.4% of the whole year.The changes of monthly rainfall pH and conductivity are similar,and the correlation coefficient reaches 0.661.Acid rain decreases because of the decrease of SO2 emission year by year.The correlation between monthly average wind speed and rainfall pH is not significant.The differences of acid rain occurrence frequency are large under the different rainfall grades.Acid rain occurrence frequency could reach 41.67% under the rainstorm weather conditions.According to Daniel trend test,acid rain pollution takes on decreasing trend in Shijiazhuang,Hebei province.