Mechanistic studies on the OH-initiated oxidation of acetone in the aqueous phase

Acetone is a ubiquitous compound due to its source strength of about 95 Tg/yr and poor reactivity in the gas phase [1]. The latter allows acetone to reach the upper troposphere where it is mainly removed by photolysis reactions. Acetone degradation has an impact on the oxidizing capacity of the (upper) troposphere producing HOx and ozone. Another potential sink for acetone in the tropospheric multiphase system is the oxidation in aqueous solution. According to the low Henrys law constant of acetone it was thought that this pathway is only of minor importance. However, a recent study detected much higher concentrations in cloud water than expected [2]. An increased uptake into the aqueous phase could be of importance for the formation of SOA (secondary organic aerosol) since acetone serves as precursor for semi volatile organic compounds. Furthermore, an additional effective sink for acetone in turn influences also the HOx budget of the troposphere. Phase transfer processes as well as degradation reactions of acetone in the aqueous phase are still not completely understood and need further investigation.