| 山东临沂大气夏季典型时段臭氧污染特征及其控制因素分析 |
| 摘要点击 2749 全文点击 941 投稿时间：2021-06-18 修订日期：2021-07-21 |
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| 中文关键词 臭氧(O3) 挥发性有机物(VOCs) 生成机制 主要化学机制(MCM) 经典动力学模拟法(EKMA) |
| 英文关键词 ozone (O3) volatile organic compound (VOCs) formation mechanism master chemical mechanism (MCM) empirical kinetics modeling approach (EKMA) |
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| 中文摘要 |
| 2020年6月，在山东省临沂城区开展臭氧（O3）及其前体物观测实验，基于观测数据结合MCM光化学模式模拟，对6月中旬O3污染特例生成机理及控制机制进行了分析.结果发现，尽管观测期间降水较多，一旦天气转晴，O3迅速积累并超标，1-h和8-h φ（O3）超标天数分别为10 d（频率32%）和14 d（45%）.O3日变化呈单峰模态，峰值出现在午后16：00.MCM模拟结果表明，光化学污染特例日O3日均净生成反应速率为20×10-9 h-1，HO2·+NO和RO2·（除CH3O2·外）+NO反应分别贡献O3生成的49.0%~51.1%和37.3%~40.2%；·OH+NO2反应对O3总消耗的贡献约为35.1%~57.4%.VOCs反应活性、增量反应活性RIR和基于EKMA曲线方法结果均表明O3的生成对烯烃（主要优势单体为反-2-戊烯和反-2-丁烯），芳香烃（主要优势单体为对/间-二甲苯和甲苯）更为敏感，而对NOx呈负敏感，即降低φ（VOCs）可使φ（O3）显著下降，而降低φ（NOx）反而会引起φ（O3）的上升.PMF源解析结果表明，溶剂使用挥发源和机动车尾气排放源对以上优势单体VOCs贡献显著.考虑机动车尾气排放NO对O3的滴定效应，控制溶剂使用挥发源可以实现O3污染精准有效控制. |
| 英文摘要 |
| In June 2020, an observation experiment of O3 and its precursors was carried out in Linyi City, Shandong Province. Based on the observation data and MCM photochemical model simulation, the formation mechanism and control mechanism of an ozone pollution case in mid-June were analyzed. The study found that, despite the high precipitation during the observation period, ozone concentrations rapidly accumulated and exceeded the limits once the weather cleared, with the 1-h average and 8-h φ (O3) exceeding the national ambient air quality standards on 10 days (32% in frequency)and 14 days (45%), respectively. The diurnal variation in O3 concentration was unimodal and accompanied by the afternoon peak at 16:00. MCM simulation results showed that the daily net reaction rate of O3 was 20×10-9 h-1, and HO2·+NO and RO2·(except CH3O2·)+NO contributed 49.0%-51.1% and 37.3%-40.2% of O3 generation, respectively. The contribution of the·OH+NO2 reaction to the total consumption of O3 was 35.1%-57.4%. The results of VOCs reactivity, relative incremental reactivity (RIR), and the EKMA curve method showed that the generation of O3 was more sensitive to alkenes (mainly trans-2-pentene and trans-2-butene)and aromatics (mainly m/p-xylene and toluene)but was negatively sensitive to NOx. In other words, the reduction in VOCs concentration would lead to the decrease in O3 concentration, whereas the reduction in NOx concentration would lead to the increase in O3 concentration. PMF source analysis results showed that volatile sources used by solvents and vehicle exhaust emissions contributed significantly to the above key precursor VOC species. Considering the titration effect of NO from vehicle exhaust emissions on ozone, controlling the use of volatile sources of solvents can realize the control of O3 pollution accurately and efficiently. |
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