Characteristics of ambient volatile organic compounds during spring O_3 pollution episode in Chengdu, China
Characteristics of ambient volatile organic compounds during spring O_3 pollution episode in Chengdu, China
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成都春季O_3污染期间环境挥发性有机物特征
DOI：
10.1016/j.jes.2021.08.014
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发表时间：
2022
影响因子：
6.9
通讯作者：
Yang Fumo
中科院分区：
文献类型：
--
作者：
Chen Dongyang;Zhou Li;Wang Chen;Liu Hefan;Qiu Yang;Shi Guangming;Song Danlin;Tan Qinwen;Yang Fumo
地面臭氧（O_3）已成为影响我国大城市空气质量改善的重要污染物。成都市是我国西南地区四川盆地的特大城市，春夏两季O_3污染频繁发生。为了解成都市春季O_3浓度升高的情况，于4月份在成都市3个采样点进行了O_3污染监测。各站点挥发性有机物（VOCs）组成相似，含氧VOCs（OVOCs）含量占比最高（35%~ 45%），其次为烷烃、烯烃（包括乙炔）、卤代烃和芳烃。利用观测箱模型分析了O_3对前体物的敏感性。OVOCs的相对反应增量大于其他前体物，表明它们在O_3的形成中也起主导作用。在此基础上，利用正矩阵分解模型对北京市主要VOCs排放源进行了识别，并评价了其对北京市VOCs的贡献。春季VOCs的主要来源是燃烧（27.75%）、工业生产（24.17%）、机动车尾气（20.35%）和溶剂使用（18.35%）。通过对成都市VOCs和NOx减排方案的讨论，认为成都市是VOCs减排的典型地区，减少VOCs的排放将有助于O3的防治。基于VOCs源的减排情景分析表明，要实现O3的减排，VOCs与NO2的减排比必须达到3以上。从汽车尾气源和溶剂利用源减排可能更有效。
Surface ozone (O_3 ) has become a critical pollutant impeding air quality improvement in many Chinese megacities. Chengdu is a megacity located in Sichuan Basin in southwest China, where O_3 pollution occurs frequently in both spring and summer. In order to understand the elevated O_3 during spring in Chengdu, we conducted sampling campaign at three sites during O_3 pollution episodes in April. Volatile organic compounds (VOCs) compositions at each site were similar, and oxygenated VOCs (OVOCs) concentrations accounted for the highest proportion (35%-45%), followed by alkanes, alkens (including acetylene), halohydrocarbons, and aromatics. The sensitivity of O_3 to its precursors was analyzed using an observation based box model. The relative incremental reactivity of OVOCs was larger than other precursors, suggesting that they also played the dominant role in O_3 formation. Furthermore, the positive matrix factorization model was used to identify the dominant emission sources and to evaluate their contribution to VOCs in the city. The main sources of VOCs in spring were from combustion (27.75%), industrial manufacturing (24.17%), vehicle exhaust (20.35%), and solvent utilization (18.35%). Discussions on VOCs and NO_x reduction schemes suggested that Chengdu was typical in the VOC-limited regime, and VOC emission reduction would help to prevent and control O_3. The analysis of emission reduction scenarios based on VOCs sources showed that the emission reduction ratio of VOCs to NO_2 needs to reach more than 3 in order to achieve O_3 prevention. Emission reduction from vehicular exhaust source and solvent utilization source may be more effective.