| Title: | Concurrent dominant pathways of multifunctional products formed from nocturnal isoprene oxidation |
| Author(s): | Li H; Cui L; Huang Y; Zhang Y; Wang J; Chen M; Ge X; |
| Address: | "Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Sciences and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China. State Key Laboratory of Loess and Quaternary Geology (SKLLQG) and Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China. Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Sciences and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China. Electronic address: 002565@nuist.edu.cn" |
| DOI: | 10.1016/j.chemosphere.2023.138185 |
| ISSN/ISBN: | 1879-1298 (Electronic) 0045-6535 (Linking) |
| Abstract: | "Determination of dominant chemical pathways toward the formation of nocturnal secondary organic aerosols (SOA) remains ambiguous by which nitrogen oxides (NO(x)) always affect oxidation of volatile alkenes. Here, comprehensive chamber simulations on dark isoprene ozonolysis were conducted under different nitrogen dioxides (NO(2)) mixing ratios to exam multiple functionalized isoprene oxidation products. Aside from that the oxidation processes were concurrently driven by nitrogen radical (NO(3)) and small hydroxyl radicals (OH), ozone (O(3)) cycloaddition at isoprene was launched initially regardless of NO(2) to rapidly form first-generation oxidation products, i.e., carbonyls and Criegee intermediates (CI) referred to carbonyl oxides. They could further undergo complicated self- and cross-reactions to produce alkylperoxy radicals (RO(2)). Corresponding to yields of the C(5)H(10)O(3) tracer, weak OH pathway at night was credited to ozonolysis of isoprene but suppressed by unique NO(3) chemistry. Following the ozonolysis of isoprene, NO(3) played a crucial supplementary role in nighttime SOA formation. The ensuing production of gas-phase nitrooxy carbonyls (the first-generation nitrates) became dominant in the production of a sizeable pool of organic nitrates (RO(2)NO(2)). By contrast, isoprene dihydroxy dinitrates (C(5)H(10)N(2)O(8)) were outstanding with the elevated NO(2), related to typical second-generation nitrates. As such, the yielding number concentrations of dark SOA were promoted to approximately 1.8 x 10(4) cm(-3) but presented a nonlinear relation with excess high-NO(2) condition. This study provides valuable insights into importance of multifunctional organic compounds from alkene oxidation to constitute nighttime SOA" |
| Keywords: | Nitrates/chemistry *Air Pollutants/analysis Nitrogen Dioxide *Ozone/chemistry Aerosols/chemistry Chamber simulations Isoprene oxidation NO(3) oxidation Nocturnal atmospheric chemistry Ozonolysis Soa; |
| Notes: | "MedlineLi, Haiwei Cui, Long Huang, Yu Zhang, Yunjiang Wang, Junfeng Chen, Mindong Ge, Xinlei eng England 2023/02/23 Chemosphere. 2023 May; 322:138185. doi: 10.1016/j.chemosphere.2023.138185. Epub 2023 Feb 20" |
