1. Population Studies Division, Health Canada, Vancouver, British Columbia, Canada
2. Population Studies Division, Health Canada, Ottawa, Ontario, Canada
3. Geographic Information Health and Exposure Science Laboratory (GIS HEAL), School of Public Health, University of California, Berkeley, Berkeley, California, USA
4. Department of Environmental Health Sciences, Fielding School of Public Health, University of California, Los Angeles, Los Angeles, California, USA
5. Department of Sociology, University of New Brunswick, Fredericton, New Brunswick, Canada
6. Special Surveys Division, Statistics Canada, Ottawa, Ontario, Canada
7. Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada
8. Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, USA
9. Vaccine and Immunization Program Surveillance Division, Public Health Agency of Canada, Ottawa, Canada
10. Health Analysis Division, Statistics Canada, Ottawa, Ontario, Canada
11. Maternal, Child and Youth Health, Surveillance and Epidemiology Division, Public Health Agency of Canada, Ottawa, Ontario, Canada
12. Air Health Science Division, Health Canada, Ottawa, Ontario, Canada