Heterogeneous ice nucleation of viscous secondary organic aerosol produced from ozonolysis of α-pinene
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Ignatius-2016-Heterogeneous ice nu.pdf
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Author(s)
Ignatius, Karoliina
Kristensen, Thomas B.
Järvinen, Emma
Nichman, Leonid
Fuchs, Claudia
Gordon, Hamish
Herenz, Paul
Hoyle, Christopher R.
Duplissy, Jonathan
Garimella, Sarvesh
Date Issued
May 2016
Journal
Atmospheric Chemistry and Physics
Publisher
Copernicus GmbH
Citation
Ignatius, Karoliina et al. “Heterogeneous Ice Nucleation of Viscous Secondary Organic Aerosol Produced from Ozonolysis of α-Pinene.” Atmospheric Chemistry and Physics 16.10 (2016): 6495–6509.
Version
Final published version
Abstract
There are strong indications that particles containing secondary organic aerosol (SOA) exhibit amorphous solid or semi-solid phase states in the atmosphere. This may facilitate heterogeneous ice nucleation and thus influence cloud properties. However, experimental ice nucleation studies of biogenic SOA are scarce. Here, we investigated the ice nucleation ability of viscous SOA particles. The SOA particles were produced from the ozone initiated oxidation of α-pinene in an aerosol chamber at temperatures in the range from −38 to −10 °C at 5–15 % relative humidity with respect to water to ensure their formation in a highly viscous phase state, i.e. semi-solid or glassy. The ice nucleation ability of SOA particles with different sizes was investigated with a new continuous flow diffusion chamber. For the first time, we observed heterogeneous ice nucleation of viscous α-pinene SOA for ice saturation ratios between 1.3 and 1.4 significantly below the homogeneous freezing limit. The maximum frozen fractions found at temperatures between −39.0 and −37.2 °C ranged from 6 to 20 % and did not depend on the particle surface area. Global modelling of monoterpene SOA particles suggests that viscous biogenic SOA particles are indeed present in regions where cirrus cloud formation takes place. Hence, they could make up an important contribution to the global ice nucleating particle budget.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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DOI of Published Version
https://doi.org/10.5194/acp-16-6495-2016
