Mackenzie-Rae, Felix A., Wallis, Helen J., Rickard, Andrew R. orcid.org/0000-0003-2203-3471 et al. (4 more authors) (2018) Ozonolysis of a-phellandrene - Part 2:Compositional analysis of secondary organic aerosol highlights the role of stabilized Criegee intermediates. Atmospheric Chemistry and Physics. pp. 4673-4693. ISSN 1680-7324
Abstract
The molecular composition of secondary organic aerosol (SOA) generated from the ozonolysis of α-phellandrene is investigated for the first time using high pressure liquid chromatography coupled to high-resolution Quadrupole-Orbitrap tandem mass spectrometry. In total, 21 prominent products or isomeric product groups were identified using both positive and negative ionisation modes, with potential formation mechanisms discussed. The aerosol was found to be composed primarily of polyfunctional first- and second-generation species containing one or more carbonyl, acid, alcohol and hydroperoxide functionalities, with the products significantly more complex than those proposed from basic gas-phase chemistry in the companion paper (Mackenzie-Rae et al., 2017a). Mass spectra show a large number of dimeric products are also formed. Both direct scavenging evidence using formic acid, and indirect evidence from double bond equivalency factors, suggests the dominant oligomerisation mechanism is the bimolecular reaction of stabilised Criegee intermediates (SCIs) with non-radical ozonolysis products. Saturation vapour concentration estimates suggest monomeric species cannot explain the rapid nucleation burst of fresh aerosol observed in chamber experiments, hence dimeric species are believed to be responsible for new particle formation, with detected first- and second-generation products driving further particle growth in the system. Ultimately, identification of the major constituents and formation pathways of α-phellandrene SOA leads to a greater understanding of the atmospheric processes and implications of monoterpene emissions and SCIs, especially around Eucalypt forests regions where α-phellandrene is primarily emitted.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © Author(s) 2018. |
Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Chemistry (York) |
Funding Information: | Funder Grant number NATURAL ENVIRONMENT RESEARCH COUNCIL NE/K003941/1 |
Depositing User: | Pure (York) |
Date Deposited: | 15 Aug 2017 09:45 |
Last Modified: | 26 Nov 2024 00:35 |
Published Version: | https://doi.org/10.5194/acp-18-4673-2018 |
Status: | Published |
Refereed: | Yes |
Identification Number: | 10.5194/acp-18-4673-2018 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:120181 |