1 National Centre for Epidemiology and Population Health, Australian National University, Canberra, ACT 0200, Australia. Electronic address: colin.butler@anu.edu.au.
2 Center for Environmental and Respiratory Health Research, University of Oulu, Oulu, Finland; Finnish Meteorological Institute, Helsinki, Finland.
3 Charles Perkins Centre and School of Life and Environmental Sciences, Faculty of Science, University of Sydney, Sydney, NSW, Australia.
4 Faculty of Health, University of Canberra, Canberra, ACT, Australia.
5 Research Centre for Hauora and Health, Massey University Wellington Campus, Wellington, New Zealand; Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA; Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA, USA.