河南省冬季PM_(2.5)水溶性离子及污染特征研究

Analysis on Characteristics of Water-soluble Ion Pollution in PM_(2.5)in Winter of Henan Province

为了解河南省多个城市间PM_(2.5)中水溶性离子组成及污染特征,研究选取2020年12月至2021年1月四个城市空气自动监测点位的PM_(2.5)水溶性离子进行监测和分析,并结合了水溶性离子浓度占比、NO_(3)^(-)与SO_(4)^(2-)比值、SOR和NOR转化率、主成分分析及后向轨迹分析等方法进行探究。结果表明,离子浓度整体上呈现NO_(3)^(-)>NH_(4)^(+)>SO_(4)^(2-)>Cl^(-)>F^(-)>K^(+)>Ca^(2+)>Na^(+)>Mg^(2+)的特征,二次离子(NO_(3)^(-)、NH_(4)^(+)和SO_(4)^(2-))是主要离子成分,累计占比为81.36%~88.10%;NO_(3)^(-)与SO_(4)^(2-)比值大于1,以移动源(机动车尾气)污染为主;SOR平均值为0.28~0.36,NOR平均值为0.22~0.63,硫氧率和氮氧率二次转化程度高,相对湿度与SOR和NOR值相关性较好;冬季河南省各点位主要受西北季风的控制。

In order to know the composition and pollution characteristics of water-soluble ions in PM_(2.5)between cities in Henan Province,this study selected four sites to analysethe water-soluble ions in PM_(2.5)from December 2020 to January 2021,using methods such as the proportion of water-soluble ion concentration,NO_(3)^(-)to SO_(4)^(2-) ratio,SOR and NOR conversion rates,principal component analysis and backward trajectory analysis.The results showed that the overall ion concentration is NO_(3)^(-)>NH_(4)^(+)>SO_(4)^(2-)>Cl^(-)>F^(-)>K^(+)>Ca^(2+)>Na^(+)>Mg^(2+).Secondary ions(NO_(3)^(-),NH_(4)^(+),and SO_(4)^(2-))are the main ion components,with a cumulative proportion of 81.36%to 88.10%.The ratio of NO_(3)^(-)to SO_(4)^(2-) is greater than 1,pollution is mainly caused by mobile sources(motor vehicle exhaust).The average SOR value is 0.28~0.36,and the average NOR value is 0.22~0.63.The secondary conversion degree of sulfur oxygen rate and nitrogen oxygen rate is high.The correlation between relative humidity and SOR and NOR values is good.The concentration of particulate matter in urban sites of Henan Province during winter is mainly controlled by the northwest monsoon.