Enhanced Rates of Transition-Metal-Ion-Catalyzed Oxidation of S(IV) in Aqueous Aerosols: Insights into Sulfate Aerosol Formation in the Atmosphere.

The oxidation of S(IV) is a critical step in the fate of sulfur dioxide emissions that determines the amount of sulfate aerosol in the atmosphere. Herein, we measured accelerated S(IV) oxidation rates in micron-sized aqueous aerosols compared to bulk solutions. We have investigated both buffered and unbuffered systems across a range of pH values in the presence of atmospherically relevant transition-metal ions and salts and consistently found the oxidation rate to be accelerated by ca.