郑州市秋季VOCs污染特征及来源解析研究

Characteristics and Source Apportionment of Ambient Volatile Organic Compounds in Zhengzhou in Autumn

为探究郑州市秋季挥发性有机化合物(VOCs)污染特征及来源,采用GC5000在线气相色谱仪对郑州市秋季大气环境中VOCs进行实时监测,分析了气象因素对臭氧(O)及其前体物的影响和VOCs污染特征,并重点利用B/T/E(苯/甲苯/乙苯)比值和正交矩阵因子模型(PMF)方法分别对VOCs来源进行了研究。结果表明:郑州市秋季温度对O生成影响明显,尤其是高温、扩散较差气象条件下,有利于O前体物的反应消耗,促使O生成及累积。郑州市秋季VOCs平均质量浓度为93.4μg/m,浓度占比贡献较大组分为烷烃(52.6%)、芳香烃(28.7%)及烯烃(17.7%),贡献较大前10物种为乙烷、乙烯、丙烷、间/对-二甲苯及甲苯等,占总VOCs的64.9%。秋季臭氧生成潜势(OFP值)为350.7μg/m,其中烯烃和芳香烃贡献最大,分别为45.8%和41.7%,其次为烷烃12.2%,OFP贡献前10物种主要为乙烯、间/对-二甲苯、异戊二烯、甲苯及邻-二甲苯等,占总OFP的74.9%。B/T/E比值显示机动车尾气排放、溶剂涂料使用及燃烧源是郑州市秋季VOCs的主要来源,尤其机动车尾气排放源贡献最为突出。PMF源解析显示,机动车尾气(汽油车和柴油车)排放源、溶剂涂料使用源、燃烧源是郑州市秋季VOCs排放主要来源,贡献率为35.1%、20.4%、19.7%,尤其9月柴油车尾气较为突出,汽油车尾气排放逐月增加。其中机动车尾气(汽油车和柴油车排放)和溶剂涂料使用源是对郑州市秋季O生成贡献较大的来源,贡献率分别为33.8%和20.6%,需重点关注。

In order to explore the VOCs pollution characteristics and sources,the GC5000 online gas chromatograph was used to monitor the volatile organic compounds(VOCs)in the atmospheric environment of Zhengzhou City in autumn,the influence of meteorological factors on ozone(O)and its precursors,and VOCs pollution characteristics were analyzed.The sources of VOCs were emphatically studied by using B/T/E ratio and the positive matrix factorization(PMF)model assessment method.The results showed that autumn temperature in Zhengzhou had a significant impact on Ogeneration,especially under the meteorological conditions of high temperature and poor diffusion,which was conducive to reaction consumption of Oprecursors and promoted Ogeneration and accumulation.The average concentration of VOCs in autumn was 93.4μg/m~3,and the concentration of alkanes(52.6%),aromatic hydrocarbons(28.7%)and olefin(17.7%)were the major contributors.The top ten species that contributed more were ethane,ethylene,propane,m-xylene and toluene,accounting for 64.9%of the total VOCs.The OFP value in autumn was 350.7μg/m~3,and the contribution of olefin and aromatic hydrocarbons were 45.8%and41.7%,respectively,followed by alkanes 12.2%.The top ten species contributing to OFP were ethylene,m/p-xylene,isoprene,toluene and o-xylene,accounting for 74.9%of the total OFP.The B/T/E ratios showed that motor vehicle exhaust,industrial process,solvent coating usage and combustion sources were the main sources of VOCs in Zhengzhou in autumn,especially motor vehicle exhaust emission source.PMF source analysis showed that motor vehicle exhaust source(gasoline and diesel vehicle emissions),solvent paint usage source,combustion source were the main sources of VOCs emissions,with the concentration of 35.1%,20.4%and 19.7%respectively,especially in september diesel vehicle exhaust was more prominent,gasoline vehicle exhaust emissions increased month by month.Among them,motor vehicle exhaust(gasoline vehicle and diesel vehicle emissions)and solvent coating usage were mainly the sources contributing to Ogeneration,accounting for 33.8%and 20.6%respectively.Therefore,it is necessary to pay attention to the emission of motor vehicle exhaust and solvent coating usage sources.