| 北京市城区秋季O3污染过程VOCs污染特征及反应活性 |
| 摘要点击 2865 全文点击 2714 投稿时间：2022-03-01 修订日期：2022-05-19 |
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| 中文关键词 臭氧(O3) 挥发性有机物(VOCs) 污染特征 化学反应活性 臭氧生成潜势(OFP) |
| 英文关键词 ozone (O3) volatile organic compounds (VOCs) pollution characterization chemical activity ozone formation potential (OFP) |
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| 中文摘要 |
| 为深入了解挥发性有机物（VOCs）对臭氧（O3）污染的影响，基于北京市2019年秋季VOCs和O3高时间分辨率在线监测数据，开展O3污染情况下VOCs浓度水平、组成变化和臭氧生成潜势（OFP）研究.结果表明，大气φ（VOCs）平均值为（22.22±10.10）×10-9，其中，烷烃是体积分数最大的组分，占总VOCs的55.65%，其次是含氧有机物（OVOCs）和烯烃，分别占总VOCs的16.23%和8.13%.观测期间，北京市城区O3共出现3次污染过程，O3污染日和清洁日φ（VOCs）平均值分别为（26.22±12.52）×10-9和（16.37±7.19）×10-9，污染日VOCs体积分数比清洁日高60.17%.臭氧生成潜势（OFP）分析结果显示，污染日OFP为113.63μg ·m-3，比清洁日增加56.55%，OVOCs和芳香烃对OFP的贡献率分别增加6.51%和1.55%，而烯烃的贡献率下降8.72%.特征物种甲苯和苯的比值（T/B）的平均值为1.55，苯、甲苯和乙苯的比值（B ：T ：E）的平均值为0.36 ：0.55 ：0.09，表明机动车排放对北京市城区秋季大气VOCs贡献显著.后向轨迹研究发现，南部气团传输对北京市秋季城区VOCs影响较大. |
| 英文摘要 |
| In order to understand the effect of volatile organic compounds (VOCs) on ozone pollution, the concentrations, chemical composition variations, and ozone formation potential (OFP) were studied under different O3 concentrations, using high-resolution online monitoring data obtained in the urban site of Beijing in autumn of 2019. The results showed that the average concentration of VOCs was (22.22±10.10)×10-9, with the largest contribution of VOCs from alkanes (55.65%), followed by that of oxygenated volatile organic compounds (OVOCs) (16.23%) and alkenes (8.13%). Three ozone pollution episodes were captured during the observation period. The average concentration of VOCs on pollution days was (26.22±12.52)×10-9, which was 60.17%higher than that on clear days (16.37±7.19)×10-9. The value of ozone formation potential (OFP) on pollution days was 113.63 μg·m-3, which was 56.55%higher than that on clear days. The contributions of OVOCs and aromatics to OFP on pollution days increased by 6.51%and 1.55%, respectively, whereas that of alkenes declined (8.72%). The ratios of toluene to benzene (T/B) and benzene, toluene, and ethylbenzene (B:T:E) were 1.55 and 0.36:0.55:0.09, respectively, indicating that vehicle exhaust had significant effects on VOCs in autumn in urban Beijing. The back-trajectory results indicated a high contribution of southern air masses to atmospheric VOCs variations in autumn in urban Beijing. |
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