| Title: | Increasing role of phenolic oxidative branch in daytime oxidation process of aromatics in Chinese haze period |
| Author(s): | Wang F; Liu X; Lv S; Zhang S; Wu C; Liu S; Lei Y; Chen Y; Li R; Wang G; |
| Address: | "Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China. Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China; Institute of Eco-Chongming, Chenjia Zhen, Chongming, Shanghai 202150, China. Electronic address: ghwang@geo.ecnu.edu.cn" |
| DOI: | 10.1016/j.scitotenv.2022.159578 |
| ISSN/ISBN: | 1879-1026 (Electronic) 0048-9697 (Linking) |
| Abstract: | "To understand the photooxidation mechanisms of aromatic compounds in the NOx-rich atmosphere, gaseous aromatics and their oxidization products (i.e., methyl glyoxal (MGLY), and nitrated phenols (NPs) including nitrophenols (NPhs) and methylnitrophenols (MNPs)) were measured with a 1-h time resolution on Chongming Island, a downwind region of the Yangtze River Delta (YRD) metropolitans of China in winter 2019 by using a proton-transfer-reaction mass spectrometer (PTR-MS). During the entire observation period, concentrations of the measured VOCs were 9.6 +/- 7.1 ppbv for aromatics, 118 +/- 59 pptv for MGLY, 36 +/- 10 pptv for NPhs, and 9.3 +/- 2.8 pptv for MNPs, respectively. Secondary NPs (SNPs) accounted for only 19-24 % of the total nitrated phenols during the clean and transition periods but increased to 44 % of the total on the hazy days. Moreover, the daytime mixing ratios of SNPs increased along with an increasing NO(2) concentration during the clean and transition periods, but in the haze period the daytime SNPs first increased along with the increasing NO(2) levels and then increased much more sharply when NO(2) was >25 ppbv. Such highly proportional and sharply increased daytime SNPs in the haze period indicated an enhanced phenolic oxidation under the high NOx conditions. In addition, the lack of correlations between aromatics and MGLY, increased MGLY(aro) (MGLY produced by aromatics), and sharply increased DeltaSNPs / Delta(benzene + toluene) further suggested that such an increasing role of the phenolic oxidative branch in the daytime oxidation process of aromatics during the YRD haze period was caused by the strong atmospheric oxidation capacity and the high level of NOx" |
| Keywords: | *Air Pollutants/analysis Particulate Matter/analysis Environmental Monitoring Nitrogen Dioxide Nitrogen Oxides Nitrates China Phenols Oxidative Stress *Volatile Organic Compounds/analysis Aromatics oxidation pathway Bicyclic RO(2) oxidation branch High-NO; |
| Notes: | "MedlineWang, Fanglin Liu, Xiaodi Lv, Shaojun Zhang, Si Wu, Can Liu, Shijie Lei, Yali Chen, Yubao Li, Rui Wang, Gehui eng Netherlands 2022/10/22 Sci Total Environ. 2023 Jan 20; 857(Pt 2):159578. doi: 10.1016/j.scitotenv.2022.159578. Epub 2022 Oct 18" |
