| Title: | Nighttime NO(x) loss and ClNO(2) formation in the residual layer of a polluted region: Insights from field measurements and an iterative box model |
| Author(s): | Yun H; Wang T; Wang W; Tham YJ; Li Q; Wang Z; Poon SCN; |
| Address: | "Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China. Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China; Research Institute for Sustainable Urban Development, The Hong Kong Polytechnic University, Hong Kong, China. Electronic address: cetwang@polyu.edu.hk. Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China; Department of Physics, University of Helsinki, Helsinki, Finland. Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China; Research Institute for Sustainable Urban Development, The Hong Kong Polytechnic University, Hong Kong, China" |
| DOI: | 10.1016/j.scitotenv.2017.11.352 |
| ISSN/ISBN: | 1879-1026 (Electronic) 0048-9697 (Linking) |
| Abstract: | "The heterogeneous reaction of dinitrogen pentoxide (N(2)O(5)) on aerosols is an important sink of nitrogen oxides (NO(x)) in the polluted boundary layer, and the production of nitryl chloride (ClNO(2)) can have significant effects on the atmospheric oxidative capacity. However, the heterogeneous loss of N(2)O(5) and the formation of ClNO(2) are still not well quantified, especially in China. In a previous study, we measured ClNO(2) and N(2)O(5) concentrations in several air masses at a high-elevation site in Hong Kong, and found the highest levels ever reported at one night. The present study employed an iterative box model to investigate five N(2)O(5)/ClNO(2)-laden nights. We first estimated the N(2)O(5) uptake coefficient and ClNO(2) yield and then calculated the relative importance of N(2)O(5) heterogeneous reactions to NO(x) loss and the accumulated ClNO(2) production over the entire night. The average uptake coefficient was 0.004+/-0.003, and the average yield was 0.42+/-0.26. As the air masses aged, the accumulated ClNO(2) reached up to 6.0ppbv, indicating significant production of ClNO(2) in the polluted air from the Pearl River Delta. ClNO(2) formation (N(2)O(5)+Cl(-)), N(2)O(5) hydrolysis (N(2)O(5)+H(2)O), and NO(3) reactions with volatile organic compounds (NO(3)+VOCs) consumed 23%, 27%, and 47% of the produced NO(3), respectively, as the average for five nights. A significant portion of the NO(x) in the air masses (70%+/-10%) was removed during the night via NO(3) reactions with VOCs (~40%) and N(2)O(5) heterogeneous loss (~60%)" |
| Keywords: | ClNO(2) N(2)o(5) NO(x) loss Uptake coefficient Yield; |
| Notes: | "PubMed-not-MEDLINEYun, Hui Wang, Tao Wang, Weihao Tham, Yee Jun Li, Qinyi Wang, Zhe Poon, Steven C N eng Netherlands 2017/12/11 Sci Total Environ. 2018 May 1; 622-623:727-734. doi: 10.1016/j.scitotenv.2017.11.352. Epub 2017 Dec 13" |
