1. Department of Environmental Science, Stockholm University, Stockholm SE-10691, Sweden
2. Department of Meteorology, Stockholm University, Stockholm SE-10691, Sweden
3. Bolin Centre for Climate Research, Stockholm University, Stockholm SE-10691, Sweden
4. Department of Physics and Atmospheric Science, Dalhousie University, Halifax CA-B3H 4R2, Canada
5. Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen CH-5232, Switzerland
6. Extreme Environments Research Laboratory, École Polytechnique Fédérale de Lausanne, Sion CH-1951, Switzerland
7. Division of Nuclear Physics, Lund University, Lund SE-22100, Sweden