重庆市主城区15年来酸雨变化趋势分析

本文运用重庆市主城区1993~2007年降水pH值监测资料,分析了重庆市最近15年来酸雨的变化趋势。结果表明,重庆市主城区降水pH值较低,15年来平均pH值介于3.8~4.5之间。重庆市年降水pH值基本呈递增趋势,倾向率达0.23/10 a;最近5年的月际变化中,降水酸度夏高冬低,酸雨频率夏低冬高;各季节中,秋季pH值年际变化呈明显的波动状升高的趋势,其余3个季节呈弱波动,升降趋势不明显。重庆市酸雨(pH<5.6)频率较高,各季节的酸雨频率基本在80%以上,且有增大的趋势;各季节中春季呈明显的升高趋势,其余季节略升高或趋势不明显。重庆市较强级别以上强度的酸雨(pH<4.5)频率年际变化幅度较大,介于30~80%之间,变化趋势不明显。重庆市酸雨强度的变化主要受污染源排放量及其它因素的影响。

Acid Rain Change in Chongqing City in Recent 15 Years

The change of acid rain in Chongqing city since recent 15 years was analyzed by using linear regression.The results showed that the pH value was relatively low, the annual average pH value in recent 15 years was between 3.8 and 4.5.In recent 5 years of monthly change, the pH value was higher in summer and lower in winner, while the acid rain frequency was lower in summer and higher in winner.The annual pH value increased at a tendency of 0.23/10a.The pH value in autumn increased with fluctuation, while the pH value in the other three seasons didn't have obvious increase or decrease tendency.Acid rain (pH<5.6) frequency in Chongqing was high.It was almost all higher than 80% in each season.The frequency of annual precipitation that pH value lover than 5.6 increased with fluctuate.Acid rain frequency in spring increased obviously and the other three seasons had no obvious trend.The frequency of acid rain exceed relatively strong intensity (pH<4.5) had greatly annual change, which was mainly between 30% and 80%.The annual precipitation that of the pH value was lower than 4.5 fluctuated greatly and had no obvious trend.The acid rain change of Chongqing was mainly influenced by pollutant emission.