宁波市“十二五”与“十一五”期间酸雨污染特征变化趋势分析

Analysis on the Trend of Acid Rain Characteristics during "Eleventh Five-Year" and "Twelfth Five-Year" Period in Ningbo

基于地面观测数据,分析了"十一五"和"十二五"期间宁波市酸雨污染特征变化趋势。结果表明,2015年降水pH从2010年的4.37上升到4.89;2010—2015年酸雨发生频率降低了17.4百分点;重酸雨区范围不断缩小,轻酸雨区范围不断扩大,酸雨污染程度有所改善。降水中化学组成变化显示,与"十一五"末相比,2015年除NO_3^-、Cl^-外其他离子浓度均有所下降;2015年SO_3^(2-)与NO_3^-的当量浓度之比从2010年的3.10下降到1.73,表明酸雨污染从硫酸型向硫酸与硝酸混合型转变。

Based on the acid rain observatory data,the trends of acid rain characteristics during ＂ 11 th Five-Year＂ and ＂ 12 th Five-Year＂ period in Ningbo were analyzed. The results showed that the pH value of acid rain increased from 4. 37 in 2010 to 4. 89 in 2015,and the acid rain frequency dropped 17. 4 percentage points from 2010 to 2015. The heavy acid rain areas had reduced continuously and the slight acid rain areas had expanded significantly. Acid rain pollution had been improved. The changes of the chemical composition showed that ion concentrations were decreased except the nitrate and chloride ions in 2015 compared with the ending of ＂ 11 th Five-Year ＂. The ratios of sulfuric ion and nitrate ion equivalent concentrations decreased from 3. 10 in 2010 to 1. 73 in 2015. It suggested that acid rain pollution type in urban of Ningbo was on the transition period from Sulfate type to Sulfate and Nitrate type.