1. Department of Earth System Science Department of Chemistry University of California, Irvine Irvine CA USA
2. Now at Cooperative Institute for Research in Environmental Science CU Boulder NOAA Earth System Research Laboratories Boulder CO USA
3. Department of Environmental Science Stockholm University Stockholm Sweden
4. Laboratory of Atmospheric Chemistry Paul Scherrer Institute Villigen Switzerland
5. Extreme Environments Research Laboratory École Polytechnique Fédérale de Lausanne Lausanne Switzerland
6. Department of Meteorology Stockholm University Stockholm Sweden