Erin E. McDuffie^1,2, Randall Martin^2,3, Michael Brauer^4,5, Steven Smith⁶, Melanie Sarah Hammer^2,7 and Aaron van Donkelaar^2,8, (1)Dalhousie University, Department of Physics and Atmospheric Science, Halifax, Canada, (2)Washington University in St. Louis, Energy, Environmental & Chemical Engineering, St. Louis, United States, (3)Dalhousie University, Department of Physics and Atmospheric Science, Halifax, NS, Canada, (4)University of British Columbia, School of Population and Public Health, Vancouver, BC, Canada, (5)University of Washington, Institute for Health Metrics and Evaluation, Seattle, United States, (6)Joint Global Change Research Institute, College Park, MD, United States, (7)Dalhousie University, Physics and Atmospheric Science, Halifax, Canada, (8)Dalhousie University, Dept Physics & Atmospheric Science, Halifax, NS, Canada