Jump to main content
Jump to site search

Volume 200, 2017
Previous Article Next Article

Condensed-phase biogenic–anthropogenic interactions with implications for cold cloud formation

Author affiliations


Anthropogenic and biogenic gas emissions contribute to the formation of secondary organic aerosol (SOA). When present, soot particles from fossil fuel combustion can acquire a coating of SOA. We investigate SOA–soot biogenic–anthropogenic interactions and their impact on ice nucleation in relation to the particles’ organic phase state. SOA particles were generated from the OH oxidation of naphthalene, α-pinene, longifolene, or isoprene, with or without the presence of sulfate or soot particles. Corresponding particle glass transition (Tg) and full deliquescence relative humidity (FDRH) were estimated using a numerical diffusion model. Longifolene SOA particles are solid-like and all biogenic SOA sulfate mixtures exhibit a core–shell configuration (i.e. a sulfate-rich core coated with SOA). Biogenic SOA with or without sulfate formed ice at conditions expected for homogeneous ice nucleation, in agreement with respective Tg and FDRH. α-pinene SOA coated soot particles nucleated ice above the homogeneous freezing temperature with soot acting as ice nuclei (IN). At lower temperatures the α-pinene SOA coating can be semisolid, inducing ice nucleation. Naphthalene SOA coated soot particles acted as ice nuclei above and below the homogeneous freezing limit, which can be explained by the presence of a highly viscous SOA phase. Our results suggest that biogenic SOA does not play a significant role in mixed-phase cloud formation and the presence of sulfate renders this even less likely. However, anthropogenic SOA may have an enhancing effect on cloud glaciation under mixed-phase and cirrus cloud conditions compared to biogenic SOA that dominate during pre-industrial times or in pristine areas.

Back to tab navigation

Associated articles

Additions and corrections

Article information

11 jan. 2017
24 jan. 2017
First published
24 jan. 2017

Faraday Discuss., 2017,200, 165-194
Article type

Condensed-phase biogenic–anthropogenic interactions with implications for cold cloud formation

J. C. Charnawskas, P. A. Alpert, A. T. Lambe, T. Berkemeier, R. E. O’Brien, P. Massoli, T. B. Onasch, M. Shiraiwa, R. C. Moffet, M. K. Gilles, P. Davidovits, D. R. Worsnop and D. A. Knopf, Faraday Discuss., 2017, 200, 165
DOI: 10.1039/C7FD00010C

Social activity

Search articles by author