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Formation and temperature dependence of highly oxygenated organic molecules (HOMs) from Δ3-carene ozonolysis
- Source :
- Atmospheric Chemistry and Physics, Vol 24, Pp 9459-9473 (2024)
- Publication Year :
- 2024
- Publisher :
- Copernicus Publications, 2024.
-
Abstract
- Δ3-carene is a prominent monoterpene in the atmosphere, contributing significantly to secondary organic aerosol (SOA) formation. However, knowledge about Δ3-carene oxidation pathways, particularly regarding their ability to form highly oxygenated organic molecules (HOMs), is still limited. In this study, we present HOM measurements during Δ3-carene ozonolysis under various conditions in two simulation chambers. We identified numerous HOMs (monomers: C7−10H10−18O6−14; dimers: C17−20H24−34O6−18) using a chemical ionization mass spectrometer (CIMS). Δ3-carene ozonolysis yielded higher HOM concentrations than α-pinene, with a distinct distribution, indicating differences in formation pathways. All HOM signals decreased considerably at lower temperatures, reducing the estimated molar HOM yield from ∼ 3 % at 20 °C to ∼ 0.5 % at 0 °C. Interestingly, the temperature change altered the HOM distribution, increasing the observed dimer-to-monomer ratios from roughly 0.8 at 20 °C to 1.5 at 0 °C. HOM monomers with six or seven O atoms condensed more efficiently onto particles at colder temperatures, while monomers with nine or more O atoms and all dimers condensed irreversibly even at 20 °C. Using the gas- and particle-phase chemistry kinetic multilayer model ADCHAM, we were also able to reproduce the experimentally observed HOM composition, yields, and temperature dependence.
Details
- Language :
- English
- ISSN :
- 16807316 and 16807324
- Volume :
- 24
- Database :
- Directory of Open Access Journals
- Journal :
- Atmospheric Chemistry and Physics
- Publication Type :
- Academic Journal
- Accession number :
- edsdoj.7578f4b0324344ea8f06eae7bcc5df6e
- Document Type :
- article
- Full Text :
- https://doi.org/10.5194/acp-24-9459-2024