Response relationship between atmospheric O₃ and its precursors in Beijing based on smog chamber simulation and a revised MCM model

Abstract. Ozone (O₃) pollution has been receiving increasing attention, but its simulation performance in models remains unsatisfactory. This study characterized the response relationship between O₃ and its precursors in the atmospheric relavant condition through a combination of smog chamber experiments and Master Chemical Mechanism (MCM) box model. By adding chamber wall related reaction mechanisms, the model achieved significant improvement in simulating O₃ with an Normalized Mean Bias (NMB) value changing from -76.1 % to -12.7 %. The enhanced model was subsequently extended to the ambient atmospheric conditions in the Daxing District of Beijing, incorporating the parameterization of ground related reactions, heterogeneous reactions of Nitrogen Dioxide (NO₂), and unidentified NO₂ sinks. Compared to basic model, the resulting revised model demonstrated substantially enhanced accuracy in simulating ambient O₃ concentrations with an Normalized Mean Bias (NMB) value changing from 113.8 % to -5.2 % and enhanced O₃ formation sensitivity to Volatile Organic Compounds (VOCs) in Daxing District. These findings underscore that incorporating interface mediated chemical processes and accounting for unidentified NO₂ sinks into model is critical for determining the sensitivity of O₃ formation and optimizing regional O₃ pollution control strategies.