“…In this study, a random forest (RF) model is used to predict O 3 concentrations, similar to our previous studies (H. Li et al, , 2022, with input data of assimilated O 3 concentrations in China that combine observations and results from GEOS-Chem model simulations, GEOS-Chem simulated O 3 concentrations outside of China, MERRA-2 meteorological variables, O 3 precursor emissions, land cover (LC), the normalized difference vegetation index (NDVI), topography (TOPO), population density (POP), the month of the year (MOY), and the geographic location of each model grid as spatiotemporal information. Details of the datasets are summarized in Table 1.…”