The pollution levels, variation characteristics, sources and implications of atmospheric carbonyls in a typical rural area of North China Plain during winter.
The pollution levels, variation characteristics, sources and implications of atmospheric carbonyls in a typical rural area of North China Plain during winter.
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DOI：
10.1016/j.jes.2020.05.003
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发表时间：
2020-09
影响因子：
6.9
通讯作者：
Jinhe Wang;Shuyu Sun;Chongxu Zhang;Chaoyang Xue;Pengfei Liu;Chenglong Zhang;Y. Mu;Hai Wu
中科院分区：
文献类型：
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作者：
Jinhe Wang;Shuyu Sun;Chongxu Zhang;Chaoyang Xue;Pengfei Liu;Chenglong Zhang;Y. Mu;Hai Wu
2017年11月13日至12月24日，对华北平原典型农村地区大气羰基化合物进行了监测，分析了该地区大气羰基化合物的污染特征、来源及环境意义。共检测到15种羰基化合物，其中甲醛、乙醛和丙酮最多占81%左右。重污染日总羰基化合物浓度比清洁日高出一倍。与其他羰基化合物相比，间甲苯甲醛在清洁日的浓度相对高于污染日。三种主要羰基化合物与CO的比值在不同的污染水平下表现出相似的日变化规律，白天有明显的峰值。多元线性回归分析表明，从清洁水平到重污染水平，背景源、一次源和二次源对3种主要羰基化合物的贡献呈现相似的变化趋势。甲醛的OH生成速率与其光降解速率的变化趋势相似，中午达到峰值，这对维持较高的OH水平，引发各种气相污染物氧化，形成二次污染物具有重要意义。OH自由基消耗速率和臭氧生成潜势（OFP）的计算表明，甲醛和乙醛是主要的氧化物种中测量羰基。对于OH自由基的消耗，正丁醛和间甲苯甲醛是重要的贡献者，而对于臭氧生成潜势，正丁醛和丙醛的贡献较大。此外，羰基化合物对二次有机气溶胶（SOA）形成的贡献也很重要，需要进一步研究。
Atmospheric carbonyls were measured at a typical rural area of the North China Plain (NCP) from November 13 to December 24, 2017 to investigate the pollution characteristics, sources and environmental implications. Fifteen carbonyls were detected, and formaldehyde, acetaldehyde and acetone accounted for about 81% at most. The concentration of the total carbonyls in heavily polluted days was twice more than that in clean days. In contrast to other carbonyls,m-tolualdehyde exhibited relatively high concentrations in the clean days in comparison with the polluted days. The ratios of three principal carbonyls to CO showed similar daily variations at different pollution levels with significant daytime peaks. Multiple linear regression analysis revealed that the contributions of background, primary and secondary sources to three principal carbonyls showed similar variation trends from the clean level to the heavily polluted level. The OH formation rate of formaldehyde showed a similar variation trend to its photodegradation rate, reaching the peak value at noon, which is important to maintain relatively high OH levels to initiate the oxidation of various gas-phase pollutants for secondary pollutant formation at the rural site. OH radical consumption rate and ozone formation potential (OFP) calculations showed that formaldehyde and acetaldehyde were the dominant oxidative species among measured carbonyls. As for OH radical consumption,n-butyraldehyde andm-tolualdehyde were important contributors, while for ozone formation potential,n-butyraldehyde and propionaldehyde made significant contributions. In addition, the contribution of carbonyl compounds to secondary organic aerosol (SOA) formation was also important and needs further investigation.