Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 18, 1909-1921, 2018
https://doi.org/10.5194/acp-18-1909-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
09 Feb 2018
Formation of highly oxygenated organic molecules from aromatic compounds
Ugo Molteni1, Federico Bianchi2, Felix Klein1, Imad El Haddad1, Carla Frege1, Michel J. Rossi1, Josef Dommen1, and Urs Baltensperger1 1Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
2Institute for Atmospheric and Earth System Research, University of Helsinki, 00014 Helsinki, Finland
Abstract. Anthropogenic volatile organic compounds (AVOCs) often dominate the urban atmosphere and consist to a large degree of aromatic hydrocarbons (ArHCs), such as benzene, toluene, xylenes, and trimethylbenzenes, e.g., from the handling and combustion of fuels. These compounds are important precursors for the formation of secondary organic aerosol. Here we show that the oxidation of aromatics with OH leads to a subsequent autoxidation chain reaction forming highly oxygenated molecules (HOMs) with an O : C ratio of up to 1.09. This is exemplified for five single-ring ArHCs (benzene, toluene, o-/m-/p-xylene, mesitylene (1,3,5-trimethylbenzene) and ethylbenzene), as well as two conjugated polycyclic ArHCs (naphthalene and biphenyl). We report the elemental composition of the HOMs and show the differences in the oxidation patterns of these ArHCs. A potential pathway for the formation of these HOMs from aromatics is presented and discussed. We hypothesize that AVOCs may contribute substantially to new particle formation events that have been detected in urban areas.
Citation: Molteni, U., Bianchi, F., Klein, F., El Haddad, I., Frege, C., Rossi, M. J., Dommen, J., and Baltensperger, U.: Formation of highly oxygenated organic molecules from aromatic compounds, Atmos. Chem. Phys., 18, 1909-1921, https://doi.org/10.5194/acp-18-1909-2018, 2018.
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Short summary
Anthropogenic volatile organic compounds often dominate the urban atmosphere and consist to a large degree of aromatics. These compounds are already known as important precursors for the formation of secondary organic aerosol. This study shows how the oxidation of aromatics with an OH radical leads to subsequent autoxidation chain reactions forming highly oxygenated molecules. We hypothesize that these may contribute substantially to new particle formation events detected in urban areas.
Anthropogenic volatile organic compounds often dominate the urban atmosphere and consist to a...
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