Abstract View
Global Distribution of the Phase State and Mixing Times within Secondary Organic Aerosol Particles in the Troposphere Based on Room-Temperature Viscosity Measurements
ADRIAN MACLEAN, Ying Li, Natalie R. Smith, Giuseppe Crescenzo, Anusha P.S. Hettiyadura, Kyla Siemens, Celia Faiola, Alexander Laskin, Sergey Nizkorodov, Manabu Shiraiwa, Allan Bertram, University of British Columbia
Abstract Number: 292
Working Group: Aerosol Chemistry
Abstract
Information on the phase state of secondary organic aerosol (SOA) and the mixing time of water in SOA are critical for predicting when SOA can act as ice nuclei in the atmosphere. As well, information on the mixing times of organics in SOA are important for predicting SOA growth, evaporation, and reactivity. Using meteorological fields and laboratory viscosity data, we estimated the phase state and mixing times of organics and water in biogenic and anthropogenic SOA in the troposphere. Based on the laboratory viscosity data, biogenic and anthropogenic SOA are in a glassy state in the upper free troposphere. Mixing times of water are often > 1 h at altitudes > 10 km. Mixing times of organics are often > 1 h at altitudes > 7 km, suggesting the particles are not in equilibrium with the surrounding environment in the upper free troposphere. The results obtained using our methodology are consistent with the results from Shiraiwa et al. (Nature Communications, 2017) using a different approach and further illustrate the importance of the glass state and slow mixing times of water and organic molecules in the upper part of the free troposphere.