Mechanism of UV-light induced SO₂ oxidation to H₂SO₄

Abstract

Abstract. The electron-excited chemistry of sulfur dioxide oxidation induced by UV irradiation of air with trace O3 and SO2 is considered. The importance of this mechanism is evaluated based on recent laboratory experiments on SO2 oxidation in a laminar tube with air induced by UV irradiation. Results show that under respective conditions the route of SO2 oxidation involving electron excited oxygen molecules may be as efficient as a known OH-radical mechanism. Hence, an influence of UV irradiation on SO2 oxidation chemistry, if confirmed, may provide an additional external source affecting the oxidation and aerosol formation processes in atmosphere.