泉州市冬季PM2.5中水溶性离子污染特征及来源解析

Pollution characteristics of water - soluble ion and source analysis of PM2.5 in winter in Quanzhou

2017年1月,选取市区涂山街国控环境空气自动监测点位,采用美国Thermo 2300四通道大气颗粒物采样器对大气中的细颗粒物(PM2.5)进行为期1个月的滤膜采样,PM2.5质量浓度及其水溶性离子组分分析结果显示:PM2.5中主要水溶性无机离子为SO42-、NO3-和NH4+,三者在大气中PM2.5质量占比为(48.8±14.6)%,且主要来自气态物质的二次转化,以(NH4)2SO4和NH4NO3的形式存在,PM2.5整体偏弱酸性。结合在线单颗粒气溶胶质谱仪(SPAMS 0515)源解析结果,初步分析我市冬季中大气中PM2.5主要污染来源以二次无机盐、燃煤固定源和机动车尾气为主,其次为生物质燃烧、土壤和建筑尘和海盐粒子等。其中,从后向轨迹图分析,我市冬季PM2.5污染易受到外来源区域性传输的影响。

In January 2017,the nationally-controlled automatic ambient air monitoring point of Tushan Street in the urban area was selected,and the United States Thermo 2300 four-channel atmospheric particulate sampler was used to filter fine particulate matter(PM2.5)in the atmosphere for one month.The membrane sampling,PM2.5 mass concentration and water-soluble ion composition analysis results show that the main water-soluble inorganic ions in PM2.5 are SO42-,NO3-and NH4+,and the proportion of PM2.5 in the atmosphere is(48.8±14.6)%,and it mainly comes from the secondary conversion of gaseous substances.It exists in the form of(NH4)2SO4 and NH4NO3.PM2.5 as a whole is slightly acidic.Based on the analysis results of the online single particle aerosol mass spectrometer(SPAMS 0515),a preliminary analysis of the main sources of PM2.5 pollution in the winter in our city is dominated by secondary inorganic salts,coal-fired fixed sources and motor vehicle exhaust,followed by biogenic Material combustion,soil and building dust and sea salt particles.Among them,from the backward trajectory map analysis,the winter PM2.5 pollution in our city is susceptible to regional transmission from external sources.