Production of N2O5 and ClNO2 in summer in urban Beijing, China


The heterogeneous hydrolysis of dinitrogen pentoxide (N2O5) has a significant impact on both nocturnal particulate nitrate formation and photochemistry on the following day through the photolysis of nitryl chloride (ClNO2), yet these processes in highly polluted urban areas remain poorly understood. Here we present measurements of gas-phase N2O5 and ClNO2 by high-resolution time-of-flight chemical ionization mass spectrometer (ToF-CIMS) during summer in urban Beijing, China as part of the Air Pollution and Human Health (APHH) campaign. N2O5 and ClNO2 show large day-to-day variations with average (±1σ ) mixing ratios of 79.2±157.1 and 174.3±262.0 pptv, respectively. High reactivity of N2O5, with ., (N2O5)'1 ranging from 0.20 × 10'2 to 1.46 × 10'2 s'1, suggests active nocturnal chemistry and a large nocturnal nitrate formation potential via N2O5 heterogeneous uptake. The lifetime of N2O5, ., (N2O5), decreases rapidly with the increase in aerosol surface area, yet it varies differently as a function of relative humidity with the highest value peaking at 1/4 40 %. The N2O5 uptake coefficients estimated from the product formation rates of ClNO2 and particulate nitrate are in the range of 0.017-0.19, corresponding to direct N2O5 loss rates of 0.00044-0.0034 s'1. Further analysis indicates that the fast N2O5 loss in the nocturnal boundary layer in urban Beijing is mainly attributed to its indirect loss via NO3, for example through the reactions with volatile organic compounds and NO, while the contribution of the heterogeneous uptake of N2O5 is comparably small (7-33 %). High ClNO2 yields ranging from 0.10 to 0.35 were also observed, which might have important implications for air quality by affecting nitrate and ozone formation.

Publication DOI:
Divisions: College of Engineering & Physical Sciences > School of Infrastructure and Sustainable Engineering > Chemical Engineering & Applied Chemistry
College of Engineering & Physical Sciences
Additional Information: © Author(s) 2018. This work is distributed under the Creative Commons Attribution 4.0 License.
Uncontrolled Keywords: Atmospheric Science
Publication ISSN: 1680-7324
Full Text Link:
Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
https://www.atm ... /18/11581/2018/ (Publisher URL)
PURE Output Type: Article
Published Date: 2018-08-16
Accepted Date: 2018-07-26
Authors: Zhou, Wei
Zhao, Jian
Ouyang, Bin
Mehra, Archit
Xu, Weiqi
Wang, Yuying
Bannan, Thomas J.
Worrall, Stephen D. (ORCID Profile 0000-0003-1969-3671)
Priestley, Michael
Bacak, Asan
Chen, Qi
Xie, Conghui
Wang, Qingqing
Wang, Junfeng
Du, Wei
Zhang, Yingjie
Ge, Xinlei
Ye, Penglin
Lee, James D.
Fu, Pingqing
Wang, Zifa
Worsnop, Douglas
Jones, Roderic
Percival, Carl J.
Coe, Hugh
Sun, Yele



Version: Published Version

License: Creative Commons Attribution

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