Photodegradation of methyl thioglycolate particles as a proxy for organosulphur containing droplets

Abstract

Understanding the formation and transformation of sulphur-rich particles is of prime importance since they contribute to the global atmospheric sulphur budget. In this work, we performed a series of experiments on a photoactive organosulphur compound namely, methyl thioglycolate, as a model of an organosulphur species of marine origin. By investigating the photoproducts within levitated droplets, we showed that elemental sulphur (α-S₈) and sulphate (SO₄²⁻) can be photochemically generated at the gas–liquid interface by heterogeneous interaction with gaseous O₂ and H₂O. These results demonstrate that the surface of levitated droplets facilitate the oxidation of methyl thioglycolate in the dark, while illumination is necessary to produce the oxidation in bulk experiments.