Observation of viscosity transition in α-pinene secondary organic aerosol

Autor(en)

Emma Jaervinen, Karoliina Ignatius, Leonid Nichman, Thomas B. Kristensen, Claudia Fuchs, Christopher R. Hoyle, Niko Hoeppel, Joel C. Corbin, Jill Craven, Jonathan Duplissy, Sebastian Ehrhart, Imad El Haddad, Carla Frege, Hamish Gordon, Tuija Jokinen, Peter Kallinger, Jasper Kirkby, Alexei Kiselev, Karl-Heinz Naumann, Tuukka Petaja, Tamara Pinterich, Andre S. H. Prevot, Harald Saathoff, Thea Schiebel, Kamalika Sengupta, Mario Simon, Jay G. Slowik, Jasmin Troestl, Annele Virtanen, Paul Vochezer, Steffen Vogt, Andrea C. Wagner, Robert Wagner, Christina Williamson, Paul M. Winkler, Chao Yan, Urs Baltensperger, Neil M. Donahue, Rick C. Flagan, Martin Gallagher, Armin Hansel, Markku Kulmala, Frank Stratmann, Douglas R. Worsnop, Ottmar Moehler, Thomas Leisner, Martin Schnaiter

Abstrakt

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 α-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, α-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.

Organisation(en)

Aerosolphysik und Umweltphysik

Externe Organisation(en)

Karlsruher Institut für Technologie, Leibniz-Institut für Troposphärenforschung, University of Manchester, Paul Scherrer Institute, Eidgenössische Forschungsanstalt für Wald, Schnee und Landschaft, California Institute of Technology (Caltech), University of Helsinki, European Organization for Nuclear Research (CERN), Johann Wolfgang Goethe-Universität Frankfurt am Main, University of Leeds, University of Eastern Finland, National Oceanic and Atmospheric Administration, University of Colorado, Boulder, Carnegie Mellon University, Leopold-Franzens-Universität Innsbruck, IONICON Analytik GmbH, Aerodyne Res Inc

Journal

Atmospheric Chemistry and Physics

Band

16

Seiten

4423-4438

Anzahl der Seiten

16

ISSN

1680-7316

DOI

https://doi.org/10.5194/acp-16-4423-2016

Publikationsdatum

2016

Peer-reviewed

Ja

ÖFOS 2012

103039 Aerosolphysik

Schlagwörter

ASJC Scopus Sachgebiete

Atmospheric Science

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/8708552f-8a63-4471-ad73-38d5b1ca56cd