Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 15, 21-35, 2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
07 Jan 2015
Aqueous-phase oligomerization of methyl vinyl ketone through photooxidation – Part 1: Aging processes of oligomers
P. Renard1, F. Siekmann1, G. Salque2, C. Demelas1, B. Coulomb1, L. Vassalo1, S. Ravier1, B. Temime-Roussel1, D. Voisin2, and A. Monod1 1Aix-Marseille Université, CNRS, LCE FRE 3416, 13331, Marseille, France
2Université Joseph Fourier, Grenoble 1/CNRS-INSU, Laboratoire de Glaciologie et Géophysique de l'Environnement, 54 rue Molière, 38402 Saint-Martin-d'Hères, France
Abstract. It has recently been established that unsaturated water-soluble organic compounds (UWSOCs) might efficiently form oligomers in polluted fogs and wet aerosol particles, even for weakly soluble ones like methyl vinyl ketone (MVK). The atmospheric relevance of these processes is explored by means of multiphase process model studies in a companion paper. In the present study, we investigate the aging of these aqueous-phase MVK oligomers formed via OH oxidation, as well as their ability to form secondary organic aerosol (SOA) upon water evaporation. The comparison between aqueous-phase composition and aerosol composition after nebulization of the corresponding solutions shows similar trends for oligomer formation and aging. The measurements reveal that oligomer aging leads to the formation of organic diacids. Quantification of the SOA mass formed after nebulization is performed, and the obtained SOA mass yields seem to depend on the spectral irradiance of the light used to initiate the photochemistry. Investigating a large range of initial MVK concentrations (0.2–20 mM), the results show that their OH oxidation undergoes competition between functionalization and oligomerization that is dependent on the precursor concentration. At high initial MVK concentrations (≥ 2 mM), oligomerization prevails over functionalization, while at lower initial concentrations, oligomerization is not the major process, and functionalization dominates, resulting in small carbonyls, dicarbonyls and monoacids. The atmospheric implications of these processes are discussed.

Citation: Renard, P., Siekmann, F., Salque, G., Demelas, C., Coulomb, B., Vassalo, L., Ravier, S., Temime-Roussel, B., Voisin, D., and Monod, A.: Aqueous-phase oligomerization of methyl vinyl ketone through photooxidation – Part 1: Aging processes of oligomers, Atmos. Chem. Phys., 15, 21-35,, 2015.
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