Volatile organic compounds(VOCs)oxidation processes play a very important role in atmo-spheric chemistry,and the chemical reactions are expressed in various manners in chemical mechanisms.To gain an improved understanding of VOCs evolution during oxidation pro-cesses and evaluate the discrepancies of VOCs oxidation schemes among different mech-anisms,we used the total VOC reactivity as a diagnostic and evaluated tool to explore the differences for six widely used chemical mechanisms.We compared the total VOC reactiv-ity evolution under high-NOx conditions for several sets of precursors,including n-pentane,toluene,ethene,isoprene and a mixture of 57 Photochemical Assessment Monitoring Sta-tions(PAMS)species in a 0-D photochemical box model.Inter-comparison of total VOC re-activity of individual precursor simulations showed discrepancies to different extent of the oxidation schemes among the studied mechanisms,which are mainly attributed to the different lumping approaches for organic species.The PAMS simulation showed smaller discrepancy than individual precursor cases in terms of total VOC reactivity.SAPRC07 and RACM2 performances are found to better match the MCM for simulation of total VOC re-activity.Evidences suggest that the performance in simulating secondary organic products,OH concentrations and NOx concentrations are related to the OH reactivity discrepancies among various chemical mechanisms.Information in this study can be used in selection of chemical mechanisms to better model OH reactivity in different environments.The results in this study also provide directions to further improve the ability in modelling total VOC reactivity with the chemical mechanisms.

Xiaoyun Yang;Bin Yuan;Zhe Peng;Yuwen Peng;Caihong Wu;Suxia Yang;Jin Li;Min Shao

Institute for Environmental and Climate Research,Jinan University,Guangzhou 511443,China;Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality,Guangzhou 511443,China;Department of Chemistry and Cooperative Institute for Research in Environmental Sciences,University of Colorado,Boulder,CO 80309,USA

环境科学学报（英文版）

[1]Xiaoyun Yang;Bin Yuan;Zhe Peng;Yuwen Peng;Caihong Wu;Suxia Yang;Jin Li;Min Shao-.Inter-comparisons of VOC oxidation mechanisms based on box model:A focus on OH reactivity)[J].环境科学学报（英文版）,2022(04):286-296

lumping,SAPRC07,RACM2

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