New On-line Mass Spectrometer for Identification of Reaction Products in the Aqueous Phase: Application to the OH-oxidation of N-methylpyrrolidone under Atmospheric Conditions

Abstract

The atmosphere is a complex medium where chemicals are released, dispersed by physical processes and oxidized by photochemical reactions initiated by solar radiation. One of the most efficient oxidants is the OH radical produced by complex photochemical processes (Atkinson, 2000). In the past, the studies of Volatile Organic Compounds (VOCs) were focused on the gas phase reactivity. In the 1980s, inter-relations between gas and aqueous phases in the troposphere started to be considered (Graedel and Weschler, 1981). It was recognized that the aqueous phase photochemistry of Water Soluble Organic Compounds (WSOCs) has an impact on the gas phase concentrations of key species such as OH, HO₂ and O₃ (Lelieveld and Crutzen, 1990; Monod and Carlier, 1999; Herrmann, 2003). More recently, the contribution of WSOC to aerosol hygroscopicity and their ability to act as cloud condensation nuclei was found (Gelencser et al., 2003; Claeys et al., 2004; Ervens et al., 2004).