Aerosol inhibition on photochemical surface ozone formation under future climate and air quality scenarios

Abstract

Aerosols significantly influence tropospheric oxidation and ozone formation by modulating photolysis rates and radical sinks. This study employs the GEOS-Chem model to analyze different aerosol heterogeneous uptake coefficients (0, 0.1, 0.2 and 0.4) and their effects on photochemical ozone levels across global regions under future Shared Socioeconomic Pathways (SSP) scenarios. Lower uptake coefficients lead to an increase in the concentration of radical species like HO₂ and reduce the extent of aerosol-inhibited regime (AIR) in regions such as India and East Asia which are currently within AIR, leading to a notable increase in surface ozone (40–50%), particularly during colder months. Projections for 2046 indicate a global reduction in AIR, resulting from stricter emission controls. By 2096, the extent of AIR further diminishes, with regions like Southeast Asia transitioning to NOx-limited conditions, though aerosol uptake of HO₂ continues to elevate surface ozone levels by 10–15% in heavily aerosol-loaded areas.