1. Department of Environmental Systems Science, Institute of Agricultural Sciences, ETH Zurich, 8092 Zurich, Switzerland
2. Department of Environmental Sciences, Environmental Geosciences, University of Basel, 4056 Basel, Switzerland
3. Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
4. Air Quality Research Division, Environment and Climate Change Canada, Toronto, ON, M3H 5T4, Canada
5. Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, 75007 Uppsala, Sweden