Characterization of secondary organic aerosol from photo-oxidation of gasoline exhaust and specific sources of major components
Characterization of secondary organic aerosol from photo-oxidation of gasoline exhaust and specific sources of major components
复制标题
汽油尾气光氧化二次有机气溶胶的表征及主要成分的具体来源
DOI：
10.1016/j.envpol.2017.09.018
复制
发表时间：
2018-01-01
影响因子：
8.9
通讯作者：
Zhang, Haixu
中科院分区：
文献类型：
--
作者：
Ma, Pengkun;Zhang, Peng;Zhang, Haixu
利用真空紫外光电离质谱仪（VUV-PIMS）研究了轻芳烃前体物（甲苯、间二甲苯和1，3，5-三甲基苯（1，3，5-TMB））和怠速汽油尾气光氧化产生的二次有机气溶胶（SOA）组分的组成和分布。通过在VUV-PIMS中应用软电离方法，从SOA的质谱中清楚地观察到具有最小分子碎片的SOA组分的分子离子峰。对比实验结果表明，在尾气-SOA和轻芳烃混合物-SOA中观察到的主要团簇离子的分布几乎都与混合物-SOA相似。通过对单个轻芳烃前体形成的SOA的表征实验，发现在尾气SOA中观察到的分子量为98和110 amu的SOA组分主要来自甲苯和间二甲苯的光氧化，分子量为124 amu的组分主要来自间二甲苯;分子量为100、112、128、138和156 amu的组分主要来源于1，3，5-TMB。这些结果表明，C-7-C-9轻芳烃是重要的SOA前体和SOA的主要成分来自汽油废气。此外，利用VUV-PIMS首次观察到了一些新的轻芳烃-SOA组分。本研究还提出了相应的反应机理，丰富了轻质芳烃-SOA化合物生成机理的知识库。(C)2017爱思唯尔有限公司版权所有
To further explore the composition and distribution of secondary organic aerosol (SOA) components from the photo-oxidation of light aromatic precursors (toluene, m-xylene, and 1,3,5-trimethylbenzene (1,3,5-TMB)) and idling gasoline exhaust, a vacuum ultraviolet photoionization mass spectrometer (VUV-PIMS) was employed. Peaks of the molecular ions of the SOA components with minimum molecular fragmentation were clearly observed from the mass spectra of SOA, through the application of soft ionization methods in VUV-PIMS. The experiments comparing the exhaust-SOA and light aromatic mixture-SOA showed that the observed distributions of almost all the predominant cluster ions in the exhaust-SOA were similar to that of the mixture-SOA. Based on the characterization experiments of SOA formed from individual light aromatic precursors, the SOA components with molecular weights of 98 and 110 amu observed in the exhaust-SOA resulted from the photo-oxidation of toluene and m-xylene; the components with a molecular weight of 124 amu were derived mainly from m-xylene; and the components with molecular weights of 100, 112, 128, 138, and 156 amu were mainly derived from 1,3,5-TMB. These results suggest that C-7-C-9 light aromatic hydrocarbons are significant SOA precursors and that major SOA components originate from gasoline exhaust. Additionally, some new light aromatic hydrocarbon-SOA components were observed for the first time using VUV-PIMS. The corresponding reaction mechanisms were also proposed in this study to enrich the knowledge base of the formation mechanisms of light aromatic hydrocarbon-SOA compounds. (C) 2017 Elsevier Ltd. All rights reserved.