宿迁市PM2.5中水溶性无机离子的季节特征和来源分析

Seasonal Characteristics and Source Analysis of Water-soluble Inorganic Ions in PM in Suqian City

为了研究宿迁市PM2.5中水溶性无机离子的季节特征和来源,于2017年5月至2018年1月在宿迁市水汽通道上的3个监测点位采集了171份PM2.5样品,分析了PM2.5质量浓度以及9种水溶性无机离子含量.结果表明,宿迁市PM2.5中水溶性无机离子的年均浓度为(44.08±34.61)μg·m^-3,占PM2.5质量的41.8%,9种水溶性离子浓度大小排序为ρ(NO^-3)>ρ(SO4^2-)>ρ(NH^+4)>ρ(Cl-)>ρ(Na+)>ρ(Ca2+)>ρ(K+)>ρ(F-)>ρ(Mg^2+),其中NO^-3、SO4^2-和NH^+4是主要的离子组分,占总水溶性无机离子浓度的75.6%.ρ(NO^-3)/ρ(SO4^2-)年均值为1.53±0.88,表明移动污染源对PM2.5的贡献高于固定污染源.水溶性无机离子相关性分析表明,NH^+4与NO^-3、SO4^2-可能以(NH4)2SO4、NH4HSO4和NH4NO3的形式存在.结合主成分分析,水溶性无机离子主要来源于二次转化、工业源、生物质燃烧和扬尘.PM2.5浓度与相对湿度在冬季呈显著正相关,水汽传输在冬季更容易对PM2.5浓度增长有促进作用.

To study the seasonal pollution characteristics and sources of water-soluble inorganic ions in atmospheric PM2.5 in Suqian City,171 samples were collected at three monitoring points,which were in the water vapor channel,from May 2017 to January 2018.The mass concentrations of PM2.5 and nine water-soluble inorganic ions were analyzed.The results showed that the annual average concentration of water-soluble inorganic ions in PM2.5in Suqian City was(44.08±34.61)μg·m^-3,accounting for 41.8%of PM2.5.The concentrations of these species were in the order ofρ(NO^-3)>ρ(SO4^2-)>ρ(NH^+4)>ρ(ρl-)>ρ(Na+)>ρ(Ca2+)>ρ(K+)>ρ(F-)>ρ(Mg^2+);NO^-3,SO4^2-,and NH^+4 accounted for 75.6%of the total water-soluble ions.The annual average ratio ofρ(NO^-3)toρ(SO4^2-)was 1.53±0.88,indicating that mobile sources contributed more to PM2.5 pollution.Based on the correlation analysis of NH^+4 and SO4^2-,NO^-3 may exist in the form of(NH4)2SO4,NH4HSO4,or NH4NO3.According to the principal component analysis,secondary transformation,industrial pollution,biomass burning,and dust were the major sources of water-soluble inorganic ions.PM2.5concentrations were positively related to relative humidity in winter.Water vapor transmission is more likely to promote PM2.5 accumulation in winter.