Department of Chemistry, Göteborg University, Kemivägen 4, 41296 Göteborg, Sweden

IVL Swedish Environmental Research Institute, P.O. Box 47086, 40258 Göteborg, Sweden

Norwegian Institute for Air Research (NILU), P.O. Box 100, 2027 Kjeller, Norway

Department of Chemistry, Göteborg University, Kemivägen 4, 41296 Göteborg, Sweden

IVL Swedish Environmental Research Institute, P.O. Box 47086, 40258 Göteborg, Sweden

Institute of Environmental Physics, University of Bremen, NW1, Otto-Hahn-Allee 1, 28359 Bremen, Germany

Ecological Spectroscopy Laboratory, Institute of Physics, Gostauto 12, 2600 Vilnius, Lithuania

Institute of Environmental Physics, University of Bremen, NW1, Otto-Hahn-Allee 1, 28359 Bremen, Germany

Environmental Canada: Meteorological Service of Canada, 4905 Dufferin Street, Toronto, Canada