1. Institute for Atmospheric and Earth System Research, University of Helsinki, PO Box 64, 00014, Finland
2. Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
3. Aerosol Physics Laboratory, Tampere University, PO Box 692, 33014 Tampere University, Finland
4. Finnish Meteorological Institute, PO Box 503, 00101 Helsinki, Finland
5. Qvidja Research Farm, Qvidja 15, 21630 Parainen, Finland
6. Helsinki Institute of Physics (HIP)/Physics, Faculty of Science, University of Helsinki, 00014 Helsinki, Finland