Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 13, 5587-5600, 2013
© Author(s) 2013. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research Article
06 Jun 2013
Evolution of particle composition in CLOUD nucleation experiments
H. Keskinen1, A. Virtanen1, J. Joutsensaari1, G. Tsagkogeorgas2, J. Duplissy3, S. Schobesberger3, M. Gysel4, F. Riccobono4, J. G. Slowik4, F. Bianchi4, T. Yli-Juuti3, K. Lehtipalo3, L. Rondo5, M. Breitenlechner6, A. Kupc7, J. Almeida5, A. Amorim8, E. M. Dunne9,10, A. J. Downard11, S. Ehrhart5, A. Franchin3, M.K. Kajos3, J. Kirkby12, A. Kürten6, T. Nieminen3, V. Makhmutov13, S. Mathot12, P. Miettinen1, A. Onnela12, T. Petäjä3, A. Praplan4, F. D. Santos8, S. Schallhart3, M. Sipilä3,14, Y. Stozhkov13, A. Tomé15, P. Vaattovaara1, D. Wimmer5, A. Prevot4, J. Dommen4, N. M. Donahue16, R.C. Flagan11, E. Weingartner4, Y. Viisanen17, I. Riipinen18, A. Hansel6,19, J. Curtius5, M. Kulmala3, D. R. Worsnop1,3,20, U. Baltensperger4, H. Wex2, F. Stratmann2, and A. Laaksonen1,17
1Dept. of Applied Physics, University of Eastern Finland, Kuopio, Finland
2Dept. of Physics, Leibniz Institute for Tropospheric Research, Leibniz, Germany
3Dept. of Physics, University of Helsinki, Helsinki, Finland
4Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
5Institute for Atmospheric and Environmental Sciences, Johann Wolfgang Goethe University Frankfurt, Frankfurt, Germany
6Institute for Ion and Applied Physics, University of Innsbruck, Innsbruck, Austria
7Faculty of Physics, University of Vienna, Vienna, Austria
8University of Lisbon, Lisbon, Portugal
9School of Earth and Environment, University of Leeds, Leeds, UK
10Finnish Meteorological Institute, Kuopio, Finland
11Division of Chemistry and Chemical Engineering, California Institute of Technology, California, USA
12Centre européen pour la recherche nucléaire (CERN), Geneva, Switzerland
13Solar and Cosmic Ray Research Laboratory, Lebedev Physical Institute, Moscow, Russia
14Institute of Physics, University of Helsinki, Helsinki, Finland
15University of Beira Interior, Beira, Portugal
16Carnegie Mellon University, Center of Atmospheric Particle Studies, Pittsburgh, USA
17Finnish Meteorological Institute, Helsinki, Finland
18University of Stockholm, Stockholm, Sweden
19Ionicon Analytik GmbH, Innbruck, Austria
20Aerodyne Research, Billerica, Massachusetts, USA

Abstract. Sulphuric acid, ammonia, amines, and oxidised organics play a crucial role in nanoparticle formation in the atmosphere. In this study, we investigate the composition of nucleated nanoparticles formed from these compounds in the CLOUD (Cosmics Leaving Outdoor Droplets) chamber experiments at CERN (Centre européen pour la recherche nucléaire). The investigation was carried out via analysis of the particle hygroscopicity, ethanol affinity, oxidation state, and ion composition. Hygroscopicity was studied by a hygroscopic tandem differential mobility analyser and a cloud condensation nuclei counter, ethanol affinity by an organic differential mobility analyser and particle oxidation level by a high-resolution time-of-flight aerosol mass spectrometer. The ion composition was studied by an atmospheric pressure interface time-of-flight mass spectrometer. The volume fraction of the organics in the particles during their growth from sizes of a few nanometers to tens of nanometers was derived from measured hygroscopicity assuming the Zdanovskii–Stokes–Robinson relationship, and compared to values gained from the spectrometers. The ZSR-relationship was also applied to obtain the measured ethanol affinities during the particle growth, which were used to derive the volume fractions of sulphuric acid and the other inorganics (e.g. ammonium salts). In the presence of sulphuric acid and ammonia, particles with a mobility diameter of 150 nm were chemically neutralised to ammonium sulphate. In the presence of oxidation products of pinanediol, the organic volume fraction of freshly nucleated particles increased from 0.4 to ~0.9, with an increase in diameter from 2 to 63 nm. Conversely, the sulphuric acid volume fraction decreased from 0.6 to 0.1 when the particle diameter increased from 2 to 50 nm. The results provide information on the composition of nucleated aerosol particles during their growth in the presence of various combinations of sulphuric acid, ammonia, dimethylamine and organic oxidation products.

Citation: Keskinen, H., Virtanen, A., Joutsensaari, J., Tsagkogeorgas, G., Duplissy, J., Schobesberger, S., Gysel, M., Riccobono, F., Slowik, J. G., Bianchi, F., Yli-Juuti, T., Lehtipalo, K., Rondo, L., Breitenlechner, M., Kupc, A., Almeida, J., Amorim, A., Dunne, E. M., Downard, A. J., Ehrhart, S., Franchin, A., Kajos, M.K., Kirkby, J., Kürten, A., Nieminen, T., Makhmutov, V., Mathot, S., Miettinen, P., Onnela, A., Petäjä, T., Praplan, A., Santos, F. D., Schallhart, S., Sipilä, M., Stozhkov, Y., Tomé, A., Vaattovaara, P., Wimmer, D., Prevot, A., Dommen, J., Donahue, N. M., Flagan, R.C., Weingartner, E., Viisanen, Y., Riipinen, I., Hansel, A., Curtius, J., Kulmala, M., Worsnop, D. R., Baltensperger, U., Wex, H., Stratmann, F., and Laaksonen, A.: Evolution of particle composition in CLOUD nucleation experiments, Atmos. Chem. Phys., 13, 5587-5600, doi:10.5194/acp-13-5587-2013, 2013.
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