1992—2012年浙江省酸雨变化特征及成因分析

Analysis on Spatial and Temporal Evolution of Acid Rain and Its Causes from 1992 to 2012 in Zhejiang

为了解20世纪90年代以来,浙江地区酸雨污染的演变特征及成因,以杭州地区为代表,结合全省酸雨监测数据,揭示1992—2012年浙江省酸雨变化特征及成因。结果表明:1992—2012年,浙江地区酸雨的污染大致经历了3个阶段:1992—1999年为酸雨改善期;2000—2004年酸雨污染再次出现了恶化;2005—2012年为酸雨再次改善期。SO_2排放减少是近年来浙江地区酸雨污染出现好转的重要原因,但NO_x对酸雨的贡献有增加的趋势,酸雨污染类型逐渐由"硫酸型"为主转变为"硫酸硝酸混合型",机动车排放对浙江地区酸雨污染的贡献已不容忽视。全省强酸雨区主要分布在浙北、浙中和东部沿海等经济发达地区,经济相对落后的浙西南地区酸雨污染较轻,酸雨污染与地区经济发展密切相关,控制本地污染排放对于防治和减轻当地酸雨污染具有重要意义。

In order to understand the rainwater acidity variation and its causes since the 1990 s in Zhejiang province,the data of rainwater pH value from 13 monitoring sites in Hangzhou and Zhejiang Province was analyzed. The results showed that the pollution of acid rain in Zhejiang went through three periods. The first period was from 1992 to 1999 when the acidity of rainwater gradually weakened; the second period was from 2000 to 2004 when the acidity of rainwater enhanced; the third period was from 2005 to 2012 when the acidity of rainwater weakened again. Reduction of sulfur dioxide emissions played a significant role in the improvement of acid rain pollution in recent years in Zhejiang,while the contribution of nitrogen oxides to acid rain pollution was increasing. Acid rain pollution pattern was converting from ＂ Sulfuric acid＂ to ＂ Mixed pollution of sulfuric acid and nitric acid＂,implying that the contribution of vehicle emissions to acid rain pollution is increasing in Zhejiang. The region affected by serious acid rain lies in the north,the middle and eastern coastal areas where there is developed economy while acid rain pollution was slighter in southwest Zhejiang where there is a relatively poor economy,which indicates rainwater acidity is closely related to the regional economic development,hence controlling local emissions is very useful for preventing acid rain pollution in developed economy areas.