This paper reported that the modeled decline in surface ozone levels appears closely linked to a regional wetting trend in northwestern China, in line with observations. Increased precipitation enhances the removal of ozone precursors and ozone itself through wet deposition and promotes cloud cover, which reduces photochemical ozone production by limiting sunlight. Additionally, higher humidity and wetter conditions can alter atmospheric chemistry, leading to lower ozone formation rates. Together, these factors contribute significantly to the reduction in surface ozone concentrations in northwestern China. Authors conducted extensive model sensitivity simulations to highlight falling ozone concentrations induced by rising humidity in this part of China. The results are convincing and the paper is publishable in the ACP after addressing following comments.

1. Figure 1 captions indicate the figure illustrates O₃ attribution (fraction) between the two scenarios (S1 and S3), but the figure does not show such attribution. I would understand here you mean “difference” in Fig. 1c. You can add such the attribution figure as the fraction between Fig. 1a and 1b in revised Fig. 1, which could help readers understand further the effect of meteorology on O₃ trend.

2. Figure 2c and line 261-262, does SAT trend in scenario 2 (S2) differ from baseline scenario S1? Unless you turned on feedback simulations in WRF-Chem, SAT trends between S1 and S2 should not differ each other.

3. There are several objectively analyzed ozone databases providing global and China’s gridded daily O₃ concentrations, such as MERRA-2. Authors may compare their modeled O₃ trend under baseline scenario (S1) with these datasets, thereby further verifying their model results.  

Please see the supplement