Abstract: Based on the data of five short-term boundary layer vertical observations in Nanjing from 2018 to 2022,combined with a series of observation-based models,the effect of different types of aerosols on the photochemical processes of ozone (O₃) in the boundary layer was discussed in this study.The observed results show that absorbing aerosols in the boundary layer are negatively correlated with the ozone concentrations,inhibiting ozone photochemical formation.Scattering aerosols are positively correlated with ozone concentrations above the boundary layer,promoting ozone formation.The ozone volume fraction and downward shortwave radiation at the top of the boundary layer increased abruptly on polluted days,and the changes were 4.8×10^-9 and 20.6 W/m² per 100 meters,respectively,while the changes were only 0.8×10^-9 and 6.6 W/m² on clean days.The simulation results show that the absorbing aerosols reduce upward shortwave radiation throughout the whole layer,with a maximum reduction of 4.4 W/m² near the surface,and then reduce the photolysis rate of nitrogen dioxide (JNO₂) across the column,thereby inhibiting ozone formation.Scattering aerosols enhance upward shortwave radiation up to 4.5 W/m² in the upper layer,and increase JNO₂,thereby stimulating ozone photochemical generation in the upper boundary layer.The concentration ratio of absorbing to scattering aerosols does not change the mechanism of aerosol type on ozone photochemical formation.