宁波市春节期间水溶性离子污染来源和特征分析

Source Analysis and Composition Characteristics of Water-soluble Ions During Spring Festival in Ningbo

利用在线气体及气溶胶检测系统对宁波市春节期间痕量气体和水溶性离子组分进行观测,结合气象要素,分析研究细颗粒物中水溶性离子污染来源和组分特征.观测期间ρ(PM_(2.5))平均值为33.1μg·m^(-3),存在轻度污染.水溶性离子浓度大小排序为:NO_(3)^(-)>SO_(4)^(2-)>NH^(4+)>K^(+)>Cl_(-)>Na^(+)>Ca^(2+)>Mg^(2+),二次无机离子ρ(NO_(3)^(-))、ρ(SO_(4)^(2-))和ρ(NH^(4+))分别为12.5、10.5和7.2μg·m^(-3),是主要的水溶性离子.使用PMF进行源解析得到,爆竹燃烧源、二次生成(背景、工业源)和扬尘源是观测期间PM_(2.5)主要的污染来源,贡献率分别是21.9%、64.5%和13.6%.二次污染较重时,NH^(4+)占阳离子浓度的92.2%.爆竹燃烧在除夕到初二为主要污染时,K^(+)占比增加.扬尘源为主要来源时,K^(+)+Ca^(2+)和Na^(+)+Mg^(2+)占比增加,主要源于西北大气输送.

Water-soluble ions and some trace gases during the Spring Festival in Ningbo were observed using an ion online gas composition and aerosol monitoring system.Combined with meteorological elements data,the source analysis and composition characteristics of water-soluble ions and trace gases were analyzed.The average concentration ofρ(PM_(2.5))during the observation period was 33.1μg·m^(-3),and there was light pollution.The order of concentration of water-soluble ions was NO_(3)^(-)>SO_(4)^(2-)>NH^(4+)>K^(+)>Cl_(-)>Na^(+)>Ca^(2+)>Mg^(2+).The secondary inorganic ionsρ(NO_(3)^(-)),ρ(SO_(4)^(2-)),andρ(NH^(4+))were the most water-soluble ions,which were 12.5,10.5,and 7.2μg·m^(-3),respectively.According to the PMF source analysis,firecracker combustion,secondary generation(background,industrial source),and dust sources were the major sources of fine particles during the observation period,and their contribution rates of PM_(2.5) were 21.9%,64.5%,and 13.6%,respectively.When the secondary generation was the main pollution,NH^(4+)accounted for 92.2%of the cations.When firecracker combustion was the main pollution from New Year's Eve to the second day,the proportion of K^(+)ions significantly increased.Dust sources were affected by regional transport from the northwest direction.When the dust source was the main pollution,the proportion of K^(+)+Ca^(2+)and Na^(+)+Mg^(2+)increased.