辽宁农村代表区域降水离子组成及与气态污染物相关性

Ion composition in precipitation and its correlation with gaseous pollutants in representative rural area in Liaoning province

对辽宁农村代表区域站点——辽中县马龙村观测站2007年2月至2008年1月酸雨、气态污染物浓度观测资料进行了研究。结果表明:辽中站降水的化学组成阴离子主要为SO42-和NO3-,阳离子主要为NH4+和Ca2+,SO24-/NO3-比值为2.9,Na+/Cl-比值较大,大于1。各种离子浓度冬春季高,夏秋季较低,表明研究区域降水酸化与污染关系不显著。实测的9种主要阴离子、阳离子总浓度比(∑阴离子/∑阳离子)与降水pH值相关性不高,表明目前酸雨研究观测的主要9种阴阳离子不能完全包括降水中的离子组成。降水酸性与近地面污染气体浓度相关各异,pH与NOX、CO、NO2和O3浓度有较明显的负相关,与SO2浓度负相关不明显;降水pH值与颗粒物等碱性污染物浓度正相关明显。降水中主要致酸离子SO24-和NO3-的浓度与相应酸性气体污染物SO2和NOX近地面浓度的相关不明显。

The chemical characteristics of precipitation were analyzed based on the observational data of acid rain and gaseous pollutants from February 2007 to January 2008 in Malong observation station of Liaozhong county, Liaoning province. The results indicate that the primary anions of precipitation are SO4^2- and NO3 , and the primary cations are NH4 and Ca2＋. The SO4^2-/NO3 ratio is 2.9, and the Na ＋/Cl- ratio is greater than 1.0. The concentrations of the total ions are higher in winter and spring and lower in summer and autumn, and it shows that the relationship between regional rainfall acidification and pollution is not significant. The total concentration ratios （ ∑ anions ∑ cations） of the observed 9 kinds＇ ions are not obviously related with pH value of precipitation,and it suggests that the observed 9 kinds＇ ions are not able to include entirely the ions compositions in precipitation under current acid rain observation conditions. The relationships between rainfall acidity and concentrations of the different gaseous pollutants near the ground are different, pH value of precipitation is a significantly negative correlation with concentrations of NOx, CO, NO2 and 03 , while it is not significant with the concentration of SO2. pH value of precipitation is a significant positive correlation with concentrations of alkaline pollutants such as particulate and so on. The relationships between concentrations of main acidic ions such as SO24 - and NO3 and that of the acidic gaseous pollutants such as SO2 and NOx near the ground are not significant.