- 1The University of Alabama in Huntsville
- 2Aarhus University
- 3University of York
New particle formation (NPF) from the interactions between biogenic and anthropogenic precursors is responsible for a large portion of the sub-micron particle loadings observed in the atmosphere. Previous observations of aerosol chemical composition in these environments have found that organosulfates form in the particle phase. However, it is not clear how organosulfates form and how they contribute to the formation and growth of new particles. We present the results of laboratory studies of NPF in a mixed organic/inorganic system including α-pinene, isoprene, sulfur dioxide and ozone in a fast flow reactor. Highly-oxidized organic compounds, organosulfates and sulfuric acid clusters were measured online with nitrate high-resolution time-of-flight (HRToF) CIMS at the end of the flow tube. Additionally, newly formed particles were collected on filters for offline analysis of their chemical composition with an ultra- performance liquid chromatography-electrospray ionization Orbitrap mass spectrometer (UPLC/(-)ESI-Orbitrap MS). There was a significant amount of oxygenated organosulfates in the particle phase, which is consistent with our previous studies. We also detected significant amounts of gas-phase organosulfates in the experimental system and found that their contribution to nucleation rates depends on the molecular size, precursor compound, and O:C ratio within the oxygenated organosulfate compound. We present detailed formation mechanisms of oxygenated organosulfates determined through MS/MS fragmentation analysis and quantum chemical modelling. Currently, parameterizations of atmospheric NPF sum the contributions of each individual chemical precursor as a separate process. Our observations demonstrate that chemical interactions of precursors in the gas and particle phase must be considered in NPF parameterizations to predict particle formation and growth in biogenic environments with transported sulfur plumes, or urban environments with abundant monoterpenes and isoprene.
How to cite: Tiszenkel, L., Vasudevan Geetha, V., Elm, J., Bryan, D., and Lee, S.: The Role of Oxygenated Organosulfates in Mixed Biogenic and Anthropogenic New ParticleFormation, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12883, https://doi.org/10.5194/egusphere-egu25-12883, 2025.