Fig. 4: Impacts of cross-source interactions on O3 photochemistry.

Comparison of the source attribution results for a-b O3 concentrations (top panel), c-d OH turnover rates (middle panel), and e-f OH concentrations (bottom panel) between the BASE simulation and the sensitivity experiments, removing a, c, e domestic AVOC emissions (SENS_NO_DAVOC, left panel) and b, d, f transboundary transport (SENS_NO_TRANSB, right panel), respectively. Results are area-averaged for different regions of China in the boundary layer during the study period.