1. Department of Community Medicine, UiT–The Arctic University of Norway, Tromsø, Norway
2. NILU–Norwegian Institute for Air Research, Fram Centre, Tromsø, Norway
3. University Hospital of North Norway, Tromsø, Norway
4. NILU–Norwegian Institute for Air Research, Kjeller, Norway
5. Department of Chemistry, University of Oslo, Oslo, Norway
6. Department of Physical and Environmental Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada