Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 18, 3589-3601, 2018
https://doi.org/10.5194/acp-18-3589-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Research article
12 Mar 2018
Multi-generation chemical aging of α-pinene ozonolysis products by reactions with OH
Ningxin Wang1, Evangelia Kostenidou2,3, Neil M. Donahue1, and Spyros N. Pandis1,2,3 1Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, USA
2Department of Chemical Engineering, University of Patras, Patra, Greece
3Institute of Chemical Engineering Sciences (ICE-HT), FORTH, Patra, Greece
Abstract. Secondary organic aerosol (SOA) formation from volatile organic compounds (VOCs) in the atmosphere can be thought of as a succession of oxidation steps. The production of later-generation SOA via continued oxidation of the first-generation products is defined as chemical aging. This study investigates aging in the α-pinene ozonolysis system with hydroxyl radicals (OH) through smog chamber experiments. The first-generation α-pinene ozonolysis products were allowed to react further with OH formed via HONO photolysis. After an equivalent of 2–4 days of typical atmospheric oxidation conditions, homogeneous OH oxidation of the α-pinene ozonolysis products resulted in a 20–40 % net increase in the SOA for the experimental conditions used in this work. A more oxygenated product distribution was observed after aging based on the increase in aerosol atomic oxygen-to-carbon ratio (O : C) by up to 0.04. Experiments performed at intermediate relative humidity (RH) of 50 % showed no significant difference in additional SOA formation during aging compared to those performed at a low RH of less than 20 %.
Citation: Wang, N., Kostenidou, E., Donahue, N. M., and Pandis, S. N.: Multi-generation chemical aging of α-pinene ozonolysis products by reactions with OH, Atmos. Chem. Phys., 18, 3589-3601, https://doi.org/10.5194/acp-18-3589-2018, 2018.
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This study investigates aging in the α-pinene ozonolysis system with hydroxyl radicals (OH) through smog chamber experiments. After an equivalent of 2–4 days of typical atmospheric oxidation conditions, homogeneous OH oxidation of the α-pinene ozonolysis products resulted in a 20–40 % net increase in the organic aerosol concentration and an increase in aerosol O : C by up to 0.04. The relative humidity in the 5–50 % range had a minimum effect on aging.
This study investigates aging in the α-pinene ozonolysis system with hydroxyl radicals (OH)...
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