Institution: | University of Helsinki, Department of Physics, P.O. Box 9 (Siltavuorenpenger 20D), FIN-00014 University of Helsinki, Finland;Finnish Meteorological Institute, Air Quality Department, Sahaajankatu 22 E, SF-00810 Helsinki, Finland;Stockholm University, Department of Meteorology, S-10691 Stockholm, Sweden;;University of Lund, Department of Nuclear Physics, Sölvegatan 14, S-22362 Lund, Sweden |