Pollution Characteristics of Atmospheric Carbonyl Compounds in a Large City of Northern China
Pollution Characteristics of Atmospheric Carbonyl Compounds in a Large City of Northern China
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DOI：
10.1155/2022/3292598
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发表时间：
2022-01
影响因子：
3
通讯作者：
Jinhe Wang;Sha Chen;Xiaoguo Qiu;Wenya Niu;Ouyang Li;Chaocheng Zhu;Xi Zhang;X. Yang;
中科院分区：
文献类型：
--
作者：
Jinhe Wang;Sha Chen;Xiaoguo Qiu;Wenya Niu;Ouyang Li;Chaocheng Zhu;Xi Zhang;X. Yang;
为深入了解济南市大气羰基化合物的污染特征和形成机理，以2 h采样频率对济南市大气羰基化合物进行了为期1个月的连续监测。比较了2018年和2020年夏季羰基化合物的来源、污染特征和浓度变化。2018年和2020年羰基化合物的总浓度分别为10.51 ± 0.13 ppbV和6.30 ± 1.08 ppbV。在这两年中，甲醛、丙酮和乙醛是主要的羰基化合物。日变化和相关性分析表明，济南市机动车尾气排放对羰基化合物浓度有显著贡献，其中甲醛为净生成。2018年甲醛/乙醛（C1/C2）比值为2.64，2020年为2.03，表明羰基化合物受到人为源和光化学反应的共同影响。主化学机理模型分析表明，济南市甲醛的生成受RO + O2反应控制，甲醛主要通过光解和与羟基自由基反应消耗。原位光化学可以进一步促进甲醛的产生。不同的羰基化合物的反应性的比较表明，甲醛，乙醛，丁醛，丙醛在羟基自由基反应和臭氧的产生中起着重要的作用。在所有测量的羰基化合物中，苯甲醛对二次有机气溶胶（SOAs）的贡献最大。总体而言，这项研究提供了新的见解羰基化合物的形成机制，以及它们的污染特征。
To better understand the pollution characteristics and formation mechanisms of atmospheric carbonyl compounds, continuous measurements of carbonyl compounds in Jinan were taken for one month at a sampling frequency of 2 h. The sources, pollution characteristics, and concentration changes of carbonyl compounds during the summers of 2018 and 2020 were compared. The total concentrations of carbonyl compounds were 10.51 ± 0.13 ppbV and 6.30 ± 1.08 ppbV in 2018 and 2020, respectively. In both years, formaldehyde, acetone, and acetaldehyde were the major carbonyls. Diurnal variations and correlation analyses showed that exhaust emissions from motor vehicles during peak traffic periods significantly contributed to the concentrations of carbonyl compounds in Jinan, with formaldehyde exhibiting net production. The ratio of formaldehyde/acetaldehyde (C1/C2) was 2.64 in 2018 and 2.03 in 2020, indicating that carbonyl compounds are jointly affected by anthropogenic sources and photochemical reactions. Master Chemical Mechanism model analyses showed that the formation of formaldehyde in Jinan was controlled by RO + O2 reactions, and formaldehyde was mainly consumed via photolysis and its reaction with the hydroxyl radical. In situ photochemistry can further promote formaldehyde production. The comparison of the reactivities of different carbonyl compounds revealed that formaldehyde, acetaldehyde, butyraldehyde, and propionaldehyde play an important role in hydroxyl radical reactions and ozone generation. Among all the measured carbonyl compounds, benzaldehyde contributed the most to secondary organic aerosols (SOAs). Overall, this study provides new insights into the formation mechanisms of carbonyl compounds as well as their pollution characteristics.