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Ice nucleation activity of diesel soot particles at cirrus relevant temperature conditions: Effects of hydration, secondary organics coating, soot morphology, and coagulation
Author(s) -
Kulkarni Gourihar,
China Swarup,
Liu Shang,
Nandasiri Manjula,
Sharma Noopur,
Wilson Jacqueline,
Aiken Allison C.,
Chand Duli,
Laskin Alexander,
Mazzoleni Claudio,
Pekour Mikhail,
Shilling John,
Shutthanandan Vaithiyalingam,
Zelenyuk Alla,
Zaveri Rahul A.
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl068707
Subject(s) - soot , ice nucleus , nucleation , materials science , aerosol , chemical engineering , cirrus , diesel exhaust , relative humidity , coagulation , mineralogy , combustion , chemistry , thermodynamics , atmospheric sciences , organic chemistry , psychology , physics , psychiatry , engineering , geology
Ice formation by diesel soot particles was investigated at temperatures ranging from −40 to −50°C. Size‐selected soot particles were physically and chemically aged in an environmental chamber, and their ice nucleating properties were determined using a continuous flow diffusion type ice nucleation chamber. Bare (freshly formed), hydrated, and compacted soot particles, as well as α ‐pinene secondary organic aerosol (SOA)‐coated soot particles at high relative humidity conditions, showed ice formation activity at subsaturation conditions with respect to water but below the homogeneous freezing threshold conditions. However, SOA‐coated soot particles at dry conditions were observed to freeze at homogeneous freezing threshold conditions. Overall, our results suggest that heterogeneous ice nucleation activity of freshly emitted diesel soot particles are sensitive to some of the aging processes that soot can undergo in the atmosphere.