| Title: | Enhancing effect of NO(2) on the formation of light-absorbing secondary organic aerosols from toluene photooxidation |
| Author(s): | Liu S; Wang Y; Wang G; Zhang S; Li D; Du L; Wu C; Du W; Ge S; |
| Address: | "Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 210062, China. Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 210062, China; Institute of Eco-Chongming, 3663 North Zhongshan Road, Shanghai 200062, China. Electronic address: ghwang@geo.ecnu.edu.cn. Environment Research Institute, Shandong University, Qingdao 266237, China. Institute of Urban Meteorology, China Meteorological Administration, Beijing 100089, China" |
| DOI: | 10.1016/j.scitotenv.2021.148714 |
| ISSN/ISBN: | 1879-1026 (Electronic) 0048-9697 (Linking) |
| Abstract: | "Aromatic hydrocarbons are one of the major precursors of atmospheric brown carbon (BrC) and both abundantly co-exist with NO(x) in the urban atmosphere especially in winter haze period. However, the impact of NOx on the formation of BrC derived from aromatic hydrocarbons is still not fully understood. In this study, the yield and light absorption of secondary organic aerosols (SOA) from toluene photooxidation under various nitrogen oxides (NO(2)) levels were investigated by using a 5 m(3) photooxidation smog chamber. A trend of increase at first and then decrease in the SOA yield with an increasing NO(2) concentration was observed. The acid-catalyzed heterogeneous reactions lead to the increase of SOA yield in the low-NO(2) regime. The formation of low-volatility species might be suppressed at high-NO(2) conditions is responsible for the decreased SOA yield. In contrast, light absorption and mass absorption coefficient (MAC) of the toluene-derived SOA continuously increased with the increasing NO(2) concentrations. HR-ToF-AMS results showed that nitrogen-containing organic compounds (NOCs) are the main species that lead to the increase of the SOA light absorption. The ratio of CHN family to the total NOCs, which are derived from the nitro compounds, also increased dominantly with the increasing NO(2) levels and accounted for more than half of the total NOCs when the NO(2) concentration increased to 495 ppbv, indicating that nitro compounds rather than organic nitrates are the major light-absorbing species and preferably formed in the toluene oxidation process" |
| Keywords: | Aerosols *Air Pollutants/analysis Atmosphere Nitrogen Dioxide Nitrogen Oxides Oxidation-Reduction *Toluene Brown carbon No(2) Nitrogen-containing organic compounds Photooxidation Toluene; |
| Notes: | "MedlineLiu, Shijie Wang, Yiqian Wang, Gehui Zhang, Si Li, Dapeng Du, Lin Wu, Can Du, Wei Ge, Shuangshuang eng Netherlands 2021/07/06 Sci Total Environ. 2021 Nov 10; 794:148714. doi: 10.1016/j.scitotenv.2021.148714. Epub 2021 Jun 27" |
