- 1University of Alabama in Huntsville, Huntsville, USA
- 2University of York, Heslington, York, YO10 5DD, UK
Oxygenated organic molecules (OOMs) formed from oxidation of anthropogenic and volatile organic compounds VOCs are essential ingredients for atmospheric new particle formation (NPF) and secondary organic aerosol formation. There is a large variety of OOM compounds, but currently, for the vast majority of OOMs, their molecular structures and formation pathways are largely unknown. Here, we made detailed chemical analysis of gas- and aerosol-phase OOMs produced from a-pinene ozonolysis, using a high-resolution time-of-flight chemical ionization mass spectrometer (HrTOF-CIMS) attached to the filter inlet for gas and aerosol (FIGAERO), as well as an ultrahigh-performance liquid chromatography-electrospray ionization Orbitrap mass spectrometer (UPLC/(-)ESI-Orbitrap MS). Based on LC and MS/MS fragmentation ions, we identified isomer molecular structures and chemical formation pathways. For C19H30O5, one isomer forms in the particle phase via aldol condensation, whereas another isomer forms via esterification. Two isomers of C16H26O6 form via decarboxylation from different C17H26O8 isomers. Thus, our experimental results with detailed chemical speciation show that OOM NPF precursors also form in the particle phase. Currently, parameterizations for the growth of newly formed particles are based on the gas-to-particle conversion of low-volatility OOMs formed in the gas phase. Our study demonstrates that particle-phase formation pathways of OOMs should also be considered for the growth of new particles in the atmosphere.
How to cite: Vasudevan-Geetha, V., Tiszenkel, L., Russo, R., Bryant, D., and Lee, S.-H.: Oxygenated Organic Molecules in Newly Formed Biogenic Particles: Molecular Structures and Formation Pathways, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13005, https://doi.org/10.5194/egusphere-egu25-13005, 2025.