气候变化领域集成服务门户(CCPortal): Evaluating the sensitivity of radical chemistry and ozone formation to ambient VOCs and NOxin Beijing

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DOI	10.5194/acp-21-2125-2021
	Evaluating the sensitivity of radical chemistry and ozone formation to ambient VOCs and NOxin Beijing
	Whalley L.K.; Slater E.J.; Woodward-Massey R.; Ye C.; Lee J.D.; Squires F.; Hopkins J.R.; Dunmore R.E.; Shaw M.; Hamilton J.F.; Lewis A.C.; Mehra A.; Worrall S.D.; Bacak A.; Bannan T.J.; Coe H.; Percival C.J.; Ouyang B.; Jones R.L.; Crilley L.R.; Kramer L.J.; Bloss W.J.; Vu T.; Kotthaus S.; Grimmond S.; Sun Y.; Xu W.; Yue S.; Ren L.; Joe F. Acton W.; Nicholas Hewitt C.; Wang X.; Fu P.; Heard D.E.
发表日期	2021
ISSN	1680-7316
起始页码	2125
结束页码	2147
卷号	21 期号:3
英文摘要	Measurements of OH, HO2, complex RO2 (alkene-and aromatic-related RO2) and total RO2 radicals taken during the integrated Study of AIR Pollution PROcesses in Beijing (AIRPRO) campaign in central Beijing in the summer of 2017, alongside observations of OH reactivity, are presented. The concentrations of radicals were elevated, with OH reaching up to 2:8 × 107 molecule cm-3, HO2 peaking at 1 × 109 molecule cm-3 and the total RO2 concentration reaching 5:5×109 molecule cm-3. OH reactivity (k.OH/) peaked at 89 s-1 during the night, with a minimum during the afternoon of 22s-1 on average. An experimental budget analysis, in which the rates of production and destruction of the radicals are compared, highlighted that although the sources and sinks of OH were balanced under high NO concentrations, the OH sinks exceeded the known sources (by 15 ppbvh-1) under the very low NO conditions (< 0:5ppbv) experienced in the afternoons, demonstrating a missing OH source consistent with previous studies under high volatile organic compound (VOC) emissions and low NO loadings. Under the highest NO mixing ratios (104 ppbv), the HO2 production rate exceeded the rate of destruction by 50ppbvh-1, whilst the rate of destruction of total RO2 exceeded the production by the same rate, indicating that the net propagation rate of RO2 to HO2 may be substantially slower than assumed. If just 10 % of the RO2 radicals propagate to HO2 upon reaction with NO, the HO2 and RO2 budgets could be closed at high NO, but at low NO this lower RO2 to HO2 propagation rate revealed a missing RO2 sink that was similar in magnitude to the missing OH source. A detailed box model that incorporated the latest Master Chemical Mechanism (MCM3.3.1) reproduced the observed OH concentrations well but over-predicted the observed HO2 under low concentrations of NO (< 1ppbv) and under-predicted RO2 (both the complex RO2 fraction and other RO2 types which we classify as simple RO2) most significantly at the highest NO concentrations. The model also under-predicted the observed k.OH/consistently by 10s-1 across all NOx levels, highlighting that the good agreement for OH was fortuitous due to a cancellation of missing OH source and sink terms in its budget. Including heterogeneous loss of HO2 to aerosol surfaces did reduce the modelled HO2 concentrations in line with the observations but only at NO mixing ratios < 0:3ppbv. The inclusion of Cl atoms, formed from the photolysis of nitryl chloride, enhanced the modelled RO2 concentration on several mornings when the Cl atom concentration was calculated to exceed 1 × 104 atoms cm-3 and could reconcile the modelled and measured RO2 concentrations at these times. However, on other mornings, when the Cl atom concentration was lower, large under-predictions in total RO2 remained. Furthermore, the inclusion of Cl atom chemistry did not enhance the modelled RO2 beyond the first few hours after sunrise and so was unable to resolve the modelled under-prediction in RO2 observed at other times of the day. Model scenarios, in which missing VOC reactivity was included as an additional reaction that converted OH to RO2, highlighted that the modelled OH, HO2 and RO2 concentrations were sensitive to the choice of RO2 product. The level of modelled to measured agreement for HO2 and RO2 (both complex and simple) could be improved if the missing OH reactivity formed a larger RO2 species that was able to undergo reaction with NO, followed by isomerisation reactions reforming other RO2 species, before eventually generating HO2. In this work an a-pinene-derived RO2 species was used as an example. In this simulation, consistent with the experimental budget analysis, the model underestimated the observed OH, indicating a missing OH source. The model uncertainty, with regards to the types of RO2 species present and the radicals they form upon reaction with NO (HO2 directly or another RO2 species), leads to over an order of magnitude less O3 production calculated from the predicted peroxy radicals than calculated from the observed peroxy radicals at the highest NO concentrations. This demonstrates the rate at which the larger RO2 species propagate to HO2, to another RO2 or indeed to OH needs to be understood to accurately simulate the rate of ozone production in environments such as Beijing, where large multifunctional VOCs are likely present. © 2021 Author(s).
语种	英语
scopus关键词	atmospheric chemistry; concentration (composition); nitrogen oxides; ozone; peroxy radical; sensitivity analysis; volatile organic compound; Beijing [China]; China
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/247150
作者单位	School of Chemistry, University of Leeds, Leeds, LS2 9JT, United Kingdom; National Centre for Atmospheric Science, University of Leeds, Leeds, LS2 9JT, United Kingdom; National Centre for Atmospheric Science, University of York, Heslington, York, YO10 5DD, United Kingdom; Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, Heslington, York, YO10 5DD, United Kingdom; Centre for Atmospheric Science, School of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, United Kingdom; National Centre for Atmospheric Science, University of Manchester, Manchester, M13 9PL, United Kingdom; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States; Department of Chemistry, University of Cambridge, Cambridge, United Kingdom; School of Geography Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, United Kingdom; Department of Meteorology, University of Reading, Reading, United Kingdom; Instit...
推荐引用方式 GB/T 7714	Whalley L.K.,Slater E.J.,Woodward-Massey R.,et al. Evaluating the sensitivity of radical chemistry and ozone formation to ambient VOCs and NOxin Beijing[J],2021,21(3).
APA	Whalley L.K..,Slater E.J..,Woodward-Massey R..,Ye C..,Lee J.D..,...&Heard D.E..(2021).Evaluating the sensitivity of radical chemistry and ozone formation to ambient VOCs and NOxin Beijing.ATMOSPHERIC CHEMISTRY AND PHYSICS,21(3).
MLA	Whalley L.K.,et al."Evaluating the sensitivity of radical chemistry and ozone formation to ambient VOCs and NOxin Beijing".ATMOSPHERIC CHEMISTRY AND PHYSICS 21.3(2021).