| 北京市城区夏季大气VOCs变化特征及臭氧生成潜势 |
| 摘要点击 1977 全文点击 1541 投稿时间：2022-04-15 修订日期：2022-07-01 |
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| 中文关键词 挥发性有机物(VOCs) 臭氧(O3) 日变化 臭氧生成潜势(OFP) 城区 |
| 英文关键词 volatile organic compounds(VOCs) ozone (O3) diurnal variation ozone formation potential(OFP) urban |
| 作者 | 单位 | E-mail | | 张蕊 | 北京市生态环境保护科学研究院, 国家城市环境污染工程技术研究中心, 城市大气挥发性有机物污染防治技术与应用北京市重点实验室, 北京 100037 | zhangrui@cee.cn | | 孙雪松 | 北京市生态环境保护科学研究院, 国家城市环境污染工程技术研究中心, 城市大气挥发性有机物污染防治技术与应用北京市重点实验室, 北京 100037 | sunxuesong@cee.cn | | 王裕 | 北京市生态环境保护科学研究院, 国家城市环境污染工程技术研究中心, 城市大气挥发性有机物污染防治技术与应用北京市重点实验室, 北京 100037 | | | 王飞 | 北京市人工影响天气中心, 中国气象局华北云降水野外科学试验基地, 云降水物理研究和云水资源开发北京市重点实验室, 北京 100089 | | | 罗志云 | 北京市生态环境保护科学研究院, 国家城市环境污染工程技术研究中心, 城市大气挥发性有机物污染防治技术与应用北京市重点实验室, 北京 100037 | |
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| 中文摘要 |
| 为深入了解臭氧（O3）污染高发季节大气挥发性有机物（VOCs）对O3生成的影响，基于北京市2019年夏季VOCs和O3高时间分辨率在线监测数据，开展VOCs变化规律、组成特征和臭氧生成潜势（OFP）研究.结果表明，大气φ（VOCs）平均值为（25.12±10.11）×10-9，其中，烷烃是体积分数最大的组分，占总VOCs的40.41%，其次是含氧有机物（OVOCs）和烯/炔烃，分别占总VOCs的25.28%和12.90%.VOCs体积分数日变化呈双峰型，早高峰出现在06：00~08：00，烯/炔烃占比明显增加，表明机动车排放对VOCs贡献显著，而午后VOCs体积分数降低，期间OVOCs占比呈现上升趋势，下午的光化学反应和气象要素对VOCs体积分数和组成影响较大.北京市城区夏季OFP为154.64 μg ·m-3，贡献率较高的组分是芳香烃、OVOCs和烯/炔烃，正己醛、乙烯和间/对-二甲苯等是关键活性物种，削减机动车、溶剂使用和餐饮源排放是北京市城区夏季控制O3污染的关键.乙烷/乙炔（E/E）和间-对二甲苯/乙苯（X/E）分析发现北京市城区气团老化明显，受光化学反应和区域传输的共同影响.反向轨迹研究表明，东南和西南部气团传输对烷烃和OVOCs浓度影响较大，烯烃和芳香烃则以本地源贡献为主. |
| 英文摘要 |
| To further understand the effect of volatile organic compounds (VOCs) on ozone (O3) formation in seasons when ozone (O3) pollution occurs frequently, the variation in VOCs, chemical composition characteristics, and ozone formation potential (OFP) were studied, using high-resolution online monitoring data obtained in an urban site of Beijing in the summer of 2019. The results showed that the averaged total mixing ratio of VOCs was (25.12±10.11)×10-9, with alkanes as the most abundant group (40.41%), followed by oxygenated volatile organic compounds (OVOCs) (25.28%) and alkenes/alkynes (12.90%). The diurnal variation in VOCs concentration showed a bimodal pattern with the morning peak appearing from 06:00 to 08:00, when the proportion of alkenes/alkynes increased significantly,indicating that the vehicle exhaust contributed more to VOCs. The VOCs concentration decreased in the afternoon when the proportion of OVOCs showed an upward trend, and the photochemical reaction and meteorological factors had great influences on VOCs concentration and composition.The OFP in urban Beijing in summer was 154.64 μg·m-3; aromatics, OVOCs, and alkenes/alkynes played dominant roles in OFP; and hexanal, ethylene, and m/p-xylene were the key species. The results suggested the need for the control of vehicle and solvent use and restaurants emissions to reduce the high level of O3in urban Beijing in summer. The diurnal variations in ethane/acetylene (E/E) and m/p-xylene/ethylbenzene (X/E) showed that the photochemical-aging of the air masses was obvious, which was jointly affected by photochemical reactions and regional transport. The back-trajectory results indicated a high contribution of southeastern and southwestern air masses to atmospheric alkanes and OVOCs concentration; moreover, aromatics and alkenes were mainly from local sources. |
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