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Atmos. Chem. Phys. Discuss., 7, 3901-3939, 2007
www.atmos-chem-phys-discuss.net/7/3901/2007/
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Understanding the formation of biogenic secondary organic aerosol from α-pinene in smog chamber studies: role of organic peroxy radicals

B. Bonn1,*, H. Korhonen2, T. Petäjä1, M. Boy1, and M. Kulmala1
1Department of Physical Sciences, University of Helsinki, Helsinki, Finland
2School of Earth and Environment, University of Leeds, Leeds, UK
*now at: Department of Plant Physiology, Estonian University of Life Sciences, Tartu, Estonia

Abstract. This study focusses on the description of the nucleation process observed during the ozone reaction of the biogenic monoterpene α-pinene in smog chambers. Therefore, a detailed aerosol dynamics model (UHMA) was extended by a tropospheric chemistry module and a detailed description of the first steps of organic nucleation. We assume secondary ozonides to act as nucleation initiating molecules, which are subsequently activated by reactions with organic peroxy radicals (RO2). With this set-up the observed particle size distributions of an exemplary experiment in Valencia was reproduced, when only the long-lived organic compounds like carboxylic acids and carbonyl compounds are detected by the available aerosol size distribution instruments. Our results indicate that fragile or reactive species might get destroyed because of weak bond breakage during the size classification. This assumption would imply a serious detection problem in nucleation studies to be solved.

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Citation: Bonn, B., Korhonen, H., Petäjä, T., Boy, M., and Kulmala, M.: Understanding the formation of biogenic secondary organic aerosol from α-pinene in smog chamber studies: role of organic peroxy radicals, Atmos. Chem. Phys. Discuss., 7, 3901-3939, 2007.   Bibtex   EndNote   Reference Manager