Potential impacts of two SO2 oxidation pathways on regional sulfate concentrations: Aqueous-phase oxidation by NO2 and gas-phase oxidation by Stabilized Criegee Intermediates

► Examine the impact of aqueous-phase oxidation of S(IV) by NO2 on sulfate. ► The aqueous-phase oxidation of S(IV) by NO2 increases mean winter sulfate by 4-20%. ► The aqueous-phase oxidation of S(IV) by NO2 does not increase summer sulfate. ► Examine the impact of SO2 oxidation by Stabilized Criegee Intermediate on sulfate. ► The SO2 oxidation by Stabilized Criegee Intermediate does not enhance sulfate.