1. Goethe University Frankfurt Institute for Atmospheric and Environmental Sciences Frankfurt am Main Germany
2. CERN Geneva Switzerland
3. Now at Institute for Atmospheric and Climate Science ETH Zurich Zürich Switzerland
4. SIM University of Lisbon, University of Beira Interior Lisbon Portugal
5. Paul Scherrer Institute Villigen Switzerland
6. School of Earth and Environment University of Leeds Leeds UK
7. Finnish Meteorological Institute Atmospheric Research Centre of Eastern Finland Kuopio Finland
8. Department of Physics University of Helsinki Helsinki Finland
9. Helsinki Institute of Physics University of Helsinki Helsinki Finland
10. Faculty of Physics University of Vienna Vienna Austria
11. Now at Cooperative Institute for Research in Environmental Sciences University of Colorado Boulder, Boulder, Colorado, USA and Chemical Sciences Division, NOAA Earth System Research Laboratory Boulder Colorado USA
12. Now at Department of Applied Physics University of Eastern Finland Kuopio Finland
13. Now at Department of Atmospheric Sciences University of Washington Seattle Washington USA
14. Institute of Ion Physics and Applied Physics Leopold‐Franzens University Innsbruck Austria