北京市某城区采暖期大气细颗粒物污染特征及来源分析

Characteristics and sources analysis of ambient PM_(2.5) in heating period in an urban area of Beijing

目的分析采暖期北京市某城区交通干道附近大气细颗粒物(PM_(2.5))中的无机元素、水溶性离子和含碳组分的水平和特征,初步探讨该研究地区PM_(2.5)的来源。方法在北京市某城区交通干道附近设立采样点,于2014年11月—2015年3月进行连续采样,采用电感耦合等离子体-质谱(ICP-MS)法分析了PM_(2.5)中18种主要元素(Cl、Al、Ca、Cr、Cu、Fe、K、Mg、Mn、Na、Ni、Pb、Si、Sr、Ti、V、Zn、Br)含量,以离子色谱法分析3种离子(NO_3^-、SO_4^(2-)、NH_4^+)含量,以热光透射法分析元素碳(EC)和有机碳(OC)的含量,运用因子分析法对PM_(2.5)的主要来源进行解析。结果研究期间该采样点PM_(2.5)的平均浓度为(129.27±142.46)μg/m^3,其中含碳成分、水溶性离子和无机元素分别占PM_(2.5)质量浓度的33.00%、13.13%和13.32%。因子分析法确定该地区PM_(2.5)的主要污染源是燃煤及工业过程和机动车尾气混合源、土壤风沙尘和建筑尘、二次转化及道路扬尘等,贡献率分别为41.46%、22.75%、17.30%和10.12%。结论该地区采暖期大气PM_(2.5)污染较为严重,来源多样,需要采取相应措施降低PM_(2.5)污染。

Objective To understand the characteristics of ambient fine particulate matter（PM2.5） and the related chemical components including inorganic elements, water-soluble ions, organic and elemental carbon, and sources of PM2.5 near traffic road in an urban area of Beijing. Methods PM2.5 samples were collected from a site near traffic road in an urban area of Beijing from November 2014 to March 2015 and the chemical compositions were analyzed, including eighteen elements（Cl, Al,Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Si, Sr, Ti, V, Zn, Br） by using ICP-MS, three water-soluble ions（NO3^-, SO4^2-, NH4^＋） by using ion chromatography and organic and elemental carbon by using NIOSH TOT. Factor analysis was used to conduct sources apportionment of the PM2.5. Results The average PM2.5 concentration during the study was（129.27 ±142.46） μg/m^3,carbonaceous species（organic and elemental carbon）, water-soluble ions and inorganic elements were the major components accounting for 33.00%, 13.13% and 13.32% of PM2.5 mass respectively in this urban area of Beijing. Principle component analysis suggested that a mixed source of coal burning, industrial processing and vehicle emission, soil dust and construction dust, secondary transformation, and road dust were the four main sources of PM2.5, accounting for 41.46%, 22.75%, 17.30%,10.12% of the total variance in the data set respectively. Conclusions PM2.5 pollution is severe during the heating period in the investigated urban area of Beijing with various sources. Appropriate effective control measures should be proposed to reduce the PM2.5 level in Beijing.