1,1,2,3,1- 1Max Planck Institute for Chemistry, Multiphase Chemistry Department, Mainz, Germany (t.berkemeier@mpic.de)
- 2Georgia Institute of Technology, School of Civil and Environmental Engineering, Atlanta, GA, USA
- 3University of Colorado, Department of Mechanical Engineering, Boulder, CO, USA
- 4Georgia Institute of Technology, School of Chemical and Biomolecular Engineering, Atlanta, GA, USA
- 5Georgia Institute of Technology, School of Earth and Atmospheric Sciences, Atlanta, GA, USA
Recent studies have shown that evaporation rates of secondary organic aerosol (SOA) particles may be slower than expected (Vaden et al. 2011; Berkemeier et al. 2020) and that growth rates of ambient SOA nanoparticles show surprisingly little dependency on condensable vapors in the gas phase (Kulmala et al., 2022). A large fraction of SOA may exist in oligomerized form, which might alter their condensation and evaporation. Additionally, SOA can be highly viscous, which leads to kinetic limitations in evaporation, slowing of particle-phase chemistry, and non-equilibrium partitioning. The effects of composition, oligomerization, and slow diffusion are inherently coupled, as high concentrations of low-volatility compounds or products of accretion reactions can cause high viscosity.
We use a kinetic multi-layer model to estimate the kinetic limitations affecting SOA formation and fate in laboratory experiments and the ambient atmosphere. The model explicitly considers gas- and particle-phase chemistry, kinetic gas-particle partitioning, and composition-dependent bulk diffusivity. We re-analyze data from laboratory chamber experiments with mixtures of terpenes as SOA precursors (Berkemeier et al. 2020) as well as published field and laboratory chamber data of nanoparticle growth (Stolzenburg et al., 2025) to find pronounced effects of multiphase chemistry and particle phase state under these conditions. Especially the partitioning of semi and low-volatile organic compounds (SVOC/LVOC) is strongly affected by these processes in the model, while the partitioning of extremely- and ultra-low volatility organic compounds (ELVOC/ULVOC) is less affected. We discuss the possible effect of growth limitation through bulk accommodation in models that follow monolayer adsorption schemes versus models that allow the “burying” of surface-adsorbed molecules through multi-layer adsorption.
The model predicts that, during particle evaporation, particles may be radially heterogeneous with respect to composition and diffusivity: higher volatility chemical species evaporate more quickly than oligomers or lower volatility species, leaving behind a near-surface layer crust of more viscous material that presents a barrier for further evaporation. The results highlight gaps in our knowledge about the physical and chemical properties of SOA and their interactions.
References
Berkemeier, T., Takeuchi, M., Eris, G., Ng, N. L. Atmos. Chem. Phys. 20, 15513-15535 (2020).
Kulmala, M., Cai, R., Stolzenburg, D., et al. Environ. Sci.: Atmos. 2, 352-361 (2022).
Stolzenburg, D., Sarnela, N., Bianchi, F. et al. npj Clim Atmos Sci 8, 75 (2025).
Vaden, T. D., Imre, D., Beranek, J., et al. P. Natl. Sci. Acad. USA 108, 2190–2195 (2011).
How to cite: Berkemeier, T., Kang, H. G., Zhang, Z., Radecka, M., Takeuchi, M., Ng, N. L., and Pöschl, U.: Interplay of phase state and multiphase chemistry in nanoparticle growth and evaporation of secondary organic aerosol, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19660, https://doi.org/10.5194/egusphere-egu26-19660, 2026.
