Mechanism development for tropospheric multiphase chemistry with CAPRAM

In this study mechanism development for the treatment of detailed tropospheric multiphase chemistry is described. Whereas the gas phase chemistry is described by RACM [1] the aqueous phase part of the mechanism is represented by CAPRAM2.4 (MODAC-mechanism) (= Chemical aqueous phase radical mechanism) [2], one of the most detailed mechanism treating cloud chemistry. In common aqueous phase mechanisms the organic chemistry is restricted only to C-2 organic compounds (e.g., [3-5]), but in CAPRAM also C-2 organic compounds are considered. Furthermore, an extension to this mechanism was developed including the oxidation processes initiated by the OH radical of higher organics such as dicarboxylic acids (C-3 and C-4) in the aqueous phase in detail. Not only the influence of the tropospheric aqueous phase on the oxidation efficiency of the tropospheric gas phase but also possible effects of the modification of the organic content of solid particles by cloud processing is discussed.