Application of VUV-PIMS coupled with GC-MS in chemical characterization, identification and comparative analysis of organic components in both vehicular-derived SOA and haze particles
Application of VUV-PIMS coupled with GC-MS in chemical characterization, identification and comparative analysis of organic components in both vehicular-derived SOA and haze particles
复制标题
VUV-PIMS 与 GC-MS 结合在车源 SOA 和雾霾颗粒中有机成分的化学表征、鉴定和比较分析中的应用
DOI：
10.1016/j.atmosenv.2017.06.013
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发表时间：
2017
影响因子：
5
通讯作者：
Li Zhen
中科院分区：
文献类型：
--
作者：
Zhang Peng;Ma Pengkun;Zhang Haixu;Shu Jinian;Yang Bo;Li Zhen
汽油车尾气是特大城市挥发性有机化合物(VOCs)的重要来源。本研究对车用汽油尾气经O_3、OH和NO_3自由基氧化产生的二次气溶胶颗粒和2015年12月23-25日北京一次雾霾期间采集到的气溶胶颗粒进行了详细的化学特征研究。利用新建的真空紫外光电离质谱仪(VUV-PIMS)对废气和空气中的二次有机气溶胶(SOA)进行热解吸后的表征，并用气相色谱-质谱仪(GC-MS)对其进行了鉴定。结果表明，汽油车尾气和气溶胶的氧化产物具有一系列共同的特征质量峰ATM/z98、112、126和140。经PFBHA衍生化和GC-MS分析，进一步确定ATM/z98、112、126、140为羰基化合物。结果表明，在ATM/Z98、112、126和140雾霾颗粒物中，尾气中的羰基化合物分别占51.7%、57.5%、36.3%和27.9%，表明汽油车尾气氧化生成的SOA是影响北京空气质量的主要因素。在废气中，同时检测到的两种(P(O_3/OH))或三种(P(O_3/NO_3/OH))氧化反应中的羰基物种对雾霾颗粒物中的这些羰基物种的贡献率分别为10.6%/z98、18.3%/z112、23.4%/z126和20.5%/z140。这些结果表明，尾气中的不饱和VOCs(即烯烃)可能是一种重要的SOA前体，它们在大气中的化学降解可能对北京等重污染城市的空气质量产生重要影响，特别是在严重的冬季雾霾天气期间。
Gasoline vehicle exhaust is a significant source of volatile organic compounds (VOCs) in megacities. In this study, chemical characterization of secondary aerosol particles from the oxidation of gasoline vehicular exhaust by O3, OH, and NO3radicals and the airborne aerosol particles collected during a heavy haze episode (23–25 December 2015) in Beijing were elaborately investigated. The secondary organic aerosols (SOAs) collected from the exhaust and airborne aerosol particles were characterized with a newly built vacuum ultraviolet photoionization mass spectrometer (VUV-PIMS) after thermal desorption, and identified by gas chromatography mass spectrometry (GC-MS). The obtained photoionization mass spectra revealed that the SOAs from the oxidation of gasoline vehicular exhaust and airborne aerosol particles possess a series of common characteristic mass peaks atm/z98, 112, 126, and 140. The components atm/z98, 112, 126, 140 were further identified to be carbonyl species after PFBHA derivatization followed by GC-MS analyses. The carbonyl species from exhaust SOAs were found to be responsible for 51.7%, 57.5%, 36.3%, and 27.9% of the chemical components in haze particles atm/z98, 112, 126, and 140, respectively, which indicates that these SOA components from the oxidation of gasoline vehicular exhaust are a major factor that affects the air quality in Beijing. Among the exhaust SOAs, the carbonyl species detected simultaneously in two (P(O3/OH)) or three kinds of exhaust oxidation reactions (P(O3/NO3/OH)) make a significant contributions to these carbonyl species in haze particles (10.6% form/z98, 18.3% form/z112, 23.4% form/z126, and 20.5% form/z140). These results implies that the unsaturated VOCs (i.e. alkenes) from exhaust may be one kind of important SOA precursor and that their chemical degradation in the atmosphere may have an important impact on urban air quality in heavy polluted cities such as Beijing, especially during severe winter haze weather.