Observation of viscosity transition in α-pinene secondary organic aerosol
Item
Title (Dublin Core)
Observation of viscosity transition in α-pinene secondary organic aerosol
Description (Dublin Core)
Under certain conditions, secondary organic aerosol (SOA) particles can exist in the atmosphere in an amorphous solid or semi-solid state. To determine their relevance to processes such as ice nucleation or chemistry occurring within particles requires knowledge of the temperature and relative humidity (RH) range for SOA to exist in these states. In the Cosmics Leaving Outdoor Droplets (CLOUD) experiment at The European Organisation for Nuclear Research (CERN), we deployed a new in situ optical method to detect the viscous state of <i>α</i>-pinene SOA particles and measured their transition from the amorphous highly viscous state to states of lower viscosity. The method is based on the depolarising properties of laboratory-produced non-spherical SOA particles and their transformation to non-depolarising spherical particles at relative humidities near the deliquescence point. We found that particles formed and grown in the chamber developed an asymmetric shape through coagulation. A transition to a spherical shape was observed as the RH was increased to between 35 % at −10 °C and 80 % at −38 °C, confirming previous calculations of the viscosity-transition conditions. Consequently, <i>α</i>-pinene SOA particles exist in a viscous state over a wide range of ambient conditions, including the cirrus region of the free troposphere. This has implications for the physical, chemical, and ice-nucleation properties of SOA and SOA-coated particles in the atmosphere.
Creator (Dublin Core)
Järvinen, Emma
Ignatius, Karoliina
Nichman, Leonid
Kristensen, Thomas B.
Fuchs, Claudia
Hoyle, Christopher R.
Höppel, Niko
Corbin, Joel C.
Craven, Jill
Duplissy, Jonathan
Ehrhart, Sebastian
El Haddad, Imad
Frege, Carla
Gordon, Hamish
Jokinen, Tuija
Kallinger, Peter
Kirkby, Jasper
Kiselev, Alexei
Naumann, Karl-Heinz
Petäjä, Tuukka
Pinterich, Tamara
Prevot, Andre S. H.
Saathoff, Harald
Schiebel, Thea
Sengupta, Kamalika
Simon, Mario
Slowik, Jay G.
Tröstl, Jasmin
Virtanen, Annele
Vochezer, Paul
Vogt, Steffen
Wagner, Andrea C.
Wagner, Robert
Williamson, Christina
Winkler, Paul M.
Yan, Chao
Baltensperger, Urs
Donahue, Neil M.
Flagan, Rick C.
Gallagher, Martin
Hansel, Armin
Kulmala, Markku
Stratmann, Frank
Worsnop, Douglas R.
Möhler, Ottmar
Leisner, Thomas
Schnaiter, Martin
Date (Dublin Core)
2018-09-10
Type (Dublin Core)
Text
Format (Dublin Core)
application/pdf
Identifier (Dublin Core)
10.5194/acp-16-4423-2016
https://acp.copernicus.org/articles/16/4423/2016/
Source (Dublin Core)
eISSN: 1680-7324
Language (Dublin Core)
eng
