和田市城区PM2.5化学组成特征及来源分析

摘要

为了解中国极干旱区域和田市城区大气PM25的组成特征及污染水平,于2014年1-12月采集和田市城区大气PM25样品,并用气相色谱-质谱联用仪(GC-MS)、离子色谱仪(IC)、电感耦合等离子体质谱仪(ICP-MS)及元素分析仪分析其中PAHs(多环芳烃)、金属元素、水溶性无机离子、OC(有机碳)和EC(元素碳)等化学组分.结果表明,采样期间和田市城区大气PM25质量浓度年均值为(770.11±568.01) μg/m3,呈夏季最高、冬季最低趋势;金属元素、水溶性无机离子、OC、EC、Σ16PAHs(总多环芳烃)分别占PM25质量浓度的15.292％、9.789％、4.246％、0.331％、0.015％.利用PMF(正交矩阵因子分解法)分别对PM25中PAHs和金属元素、水溶性无机离子、OC、EC进行来源解析表明,PAHs主要来源为煤和汽油燃烧排放(13.91％)、生物质燃烧(33.98％)、天然气燃烧(52.11％);金属元素、水溶性无机离子、OC、EC的主要来源为土壤尘(56.49％)、油类燃烧(25.49％)、机动车排放(10.09％)、燃煤及生物质燃烧(7.93％).研究显示,采样期间沙尘对和田市城区大气PM25组成影响较大,是该地区大气污染来源的主要因素.%In order to understand the component characteristics and contamination situation of atmospheric PM2.5 in the urban area of Hotan,which was the extreme arid area in China,PM2.5 samples were collected periodically from January to December in 2014.The seasonal distribution of the mass concentration of polycyclic aromatic hydrocarbons (PAHs),metal elements,water-soluble inorganic ions,organic carbon (OC) and elemental carbon (EC) were analyzed by chromatography-mass spectrometer,ion chromatographer (IC),inductively coupled plasma mass spectrometry,and elemental analyzer,respectively.The results showed that the annual average mass concentration of PM2.5 was (770.11±568.01) μg/m3 during the sampling period,with the highest in summer and the lowest in winter.The total mass of metal elements,water-soluble ions,OC,EC and PAHs accounted for 15.292％,9.789％,4.246％,0.331％ and 0.015％ of PM2.5,respectively.Subsequently,a positive matrix factorization (PMF) was exploited to analyze the sources of the components in P M2 5.The PAHs mainly stemmed from coal/gasoline emissions (13.91％),biomass combustion (33.98％) and natural gas combustion (52.11％).PMF also identified that dust (56.49％),oil burning (25.49％),motor vehicle emissions (10.09％),coal burning and biomass combustion (7.93％) were the main sources of the other components of PM2.5 The effect of sandstorm on the composition of PM2 5 was remarkable.The sandstorm was considered to be the major factor for the local air pollution.