1. Environmental Inorganic Chemistry, Department of Chemical and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden.
2. Respiratory Medicine and Allergology, Sahlgrenska University Hospital, Gothenburg, Sweden.
3. Occupational and Environmental Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
4. Atmospheric Science, Department of Chemistry, University of Gothenburg, Gothenburg, Sweden.