1. Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
2. Institute for Atmospheric and Environmental Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
3. Ionicon GesmbH, 6020 Innsbruck, Austria
4. Institute for Atmospheric and Earth System Research (INAR)/Physics, Faculty of Science, University of Helsinki, Post Office Box 64, FI-00014 Helsinki, Finland
5. Institute for Ion and Applied Physics, University of Innsbruck, 6020 Innsbruck, Austria
6. Faculty of Sciences, University of Lisbon, Campo Grande 016, 1749-016 Lisboa, Portugal
7. Helsinki Institute of Physics, FI-00014 Helsinki, Finland
8. University of Leeds, Leeds LS2 9JT, United Kingdom
9. Finnish Meteorological Institute, Erik Palménin Aukio 1, 00560 Helsinki, Finland
10. Lebedev Physical Institute of the Russian Academy of Sciences, Leninsky Prospekt 53, 119991 Moscow, Russia
11. Department of Environmental Systems Science, ETH Zurich, 8092 Zürich, Switzerland
12. Department of Applied Physics, University of Eastern Finland, Post Office Box 1627, 70211 Kuopio, Finland
13. Instituto Dom Luiz (IDL), Universidade da Beira Interior, 6201-001 Covilhã, Portugal
14. Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
15. CERN, CH-1211 Geneva, Switzerland
16. Aerosol and Haze Laboratory, Beijing University of Chemical Technology, Beijing 100029, China
17. Aerodyne Research, Incorporated, 45 Manning Road, Billerica, Massachusetts 01821, United States