昆明市PM_(2.5)中水溶性无机离子的化学特征及来源解析  

Chemical characteristics and source analysis of water-soluble inorganic in PM_(2.5) in Kunming

作　　者：朱若珲 曹芳 范美益[1,2] ZHU Ruohui;CAO Fang;FAN Meiyi(School of Applied Meteorology,Nanjing University of Information Science and Technology,Nanjing,210044,China;Atmospheric Environment Center,Joint Laboratory for International Cooperation on Climate and Environmental Change,Ministry of Education,Nanjing University of Information Science and Technology,Nanjing,210044,China)

机构地区：[1]南京信息工程大学应用气象学院,南京210044 [2]南京信息工程大学,教育部气候与环境变化国际合作联合实验室,大气环境中心,南京210044

出　　处：《环境化学》2024年第6期2005-2016,共12页Environmental Chemistry

基　　金：国家自然科学基金(41977185)资助.

摘　　要：为探究昆明市大气中水溶性无机离子的化学组分、季节差异及主要来源,本研究于2019年12月至2020年11月在云南大学进行PM_(2.5)样品采集,利用离子色谱仪分析样品中水溶性无机离子的质量浓度,并结合离子相关性分析、后向轨迹分析和主成分分析等方法,阐明了昆明市大气中PM_(2.5)及其水溶性无机离子的季节污染特征及来源.结果表明,采样期间各季节总水溶性无机离子浓度均值排序为春季((5.6±2.2)μg·m^(−3))>冬季((5.5±2.6)μg·m^(−3))>秋季((4.3±2.8)μg·m^(−3))>夏季((3.6±2.2)μg·m^(−3)),水溶性无机离子年质量浓度的均值从大到小为SO_(4)^(2−)>Ca^(2+)>NO_(3)^(−)>NH_(4)^(+)>K^(+)>Cl^(−)>Na^(+)>Mg^(2+)>F^(−),其中SO_(4)^(2−)、Ca^(2+)、NO_(3)^(−)和NH_(4)^(+)是主要的水溶性无机离子.Ca^(2+)主要源于土壤粉尘,其他三者由前体物(SO_(2)、NO_(x)和NH_(3))二次转化生成,主要受化石燃料燃烧排放影响.SOR和NOR全年均值分别为0.20和0.02,表明在相同的环境里,SO_(2)二次转化为SO_(4)^(2−)的过程更易发生,且在秋季转化速率最大(SOR=0.23).SO_(4)^(2−)、NO_(3)^(−)和NH_(4)^(+)在秋季主要以NH_(4)NO_(3)和(NH_(4))_(2)SO_(4)的形式存在,其他三季则以NH_(4)HSO_(4)和NH_(4)NO_(3)的形式存在.昆明市大气PM_(2.5)中水溶性无机离子在冬、秋和春季一致,主要来自二次源和生物质燃烧源,其次是工业源和土壤尘,而夏季则主要来自机动车尾气、生物质燃烧源和土壤尘.除本地排放的影响外,冬季和夏季受到来自缅甸、老挝和贵州污染气团的影响,春季污染气团来自缅甸、云南本地和贵州,而秋季则受到云南东部和南部地区的气团输送影响.In this study,PM_(2.5) samples were collected at Yunnan University,Kunming from December 2019 to November 2020 to explore the chemical composition,seasonal variation,and sources of water-soluble inorganic ions in Kunming.The analyzed mass concentration of water-soluble inorganic ions(WSIIs)were combined with correlation,backward trajectory,and principal component analysis to clarify the seasonal characteristics and potential sources of PM_(2.5) and WSIIs in Kunming.The results indicated that the mean concentrations of WSIIs peaked in spring((5.6±2.2)μg·m^(−3)),followed by winter((5.5±2.6)μg·m^(−3)),autumn((4.3±2.8)μg·m^(−3)),and summer((3.6±2.2)μg·m^(−3)).The average annual mass concentration of WSIIs was SO_(4)^(2−)>Ca^(2+)>NO_(3)^(−)>NH_(4)^(+)>K^(+)>Cl^(−)>Na^(+)>Mg^(2+)>F^(−),among which SO_(4)^(2−),Ca^(2+),NO_(3)^(−),and NH+4 dominant the fractions in WSIIs.Ca^(2+)mainly came from soil dust,while the other three were generated by the secondary formation of its precursors(i.e.,SO_(2),NO_(x),and NH_(3)),which are mainly emitted by anthropogenic emissions(i.e.,fossil fuel combustion).Here,the annual average values of SOR and NOR are 0.20 and 0.02,respectively,indicating that the secondary conversion from SO_(2) to SO_(4)^(2−) is more likely to occur with the same weather conditions.The conversion rate was highest in autumn(SOR=0.23).SO_(4)^(2−),NO_(3)^(−),and NH_(4)^(+) mainly exist in the form of NH_(4)NO_(3) and(NH_(4))2SO_(4) in autumn,and the other seasons exist in the form of NH_(4)HSO_(4) and NH_(4)NO_(3).The WSIIs and PM_(2.5) in Kunming showed the similar sources,which were mainly from the secondary reaction and biomass combustion sources,followed by industrial and soil dust sources,in winter,autumn,and spring.In contrast,WSIIs and PM_(2.5) were mainly from motor vehicle exhaust,biomass burning sources,and soil dust in summer.Apart from the local emissions,the polluted air masses showed a seasonal variation:Myanmar,Laos,and Guizhou in winter and summer;Myanmar,Yunna

关 键 词：水溶性无机离子 PM_(2.5) 来源解析 昆明 后向轨迹分析 

分 类 号：X-1[环境科学与工程] O6[理学—化学]