1. Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
2. Université de Lyon, Université Claude Bernard Lyon 1, CNRS, IRCELYON, 69626 Villeurbanne, France
3. Institute for Atmospheric and Environmental Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
4. Institute for Ion and Applied Physics, University of Innsbruck, 6020 Innsbruck, Austria
5. Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, 91125 California, United States
6. Center for Atmospheric Particle Studies, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, 15213 Pennsylvania, United States
7. Finnish Meteorological Institute, 00560 Helsinki, Finland
8. Department of Experimental Aerosol and Cloud Microphysics, Leibniz Institute for Tropospheric Research, 04318 Leipzig, Germany
9. Institute for Atmospheric and Earth System Research (INAR)/Physics, Faculty of Science, University of Helsinki, 00014 Helsinki, Finland
10. Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
11. Helsinki Institute of Physics, University of Helsinki, 00014 Helsinki, Finland
12. Department of Chemistry & CIRES, University of Colorado Boulder, UCB 215, Boulder, 80309-0215 Colorado, United States
13. Department of Applied Physics, University of Eastern Finland, P.O. Box 1627, 70211 Kuopio, Finland
14. Aerodyne Research, Inc., Billerica, 01821 Massachusetts, United States
15. Atmospheric and Oceanic Sciences, Princeton University, Princeton, 08540 New Jersey, United States
16. CERN, the European Organization for Nuclear Research, CH-1211 Geneva 23, Switzerland
17. Department of Physics, University of Genoa & INFN, 16146 Genoa, Italy
18. Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, 15213 Pennsylvania, United States
19. Department of Atmospheric and Oceanic Sciences, University of Colorado, Boulder, UCB 311, Boulder, 80309 Colorado, United States
20. P. N. Lebedev Physical Institute of the Russian Academy of Sciences, 119991 Moscow, Russia
21. Tofwerk AG, CH-3600 Thun, Switzerland