1. Department of Civil, Architectural and Environmental Engineering, The University of Texas, 301 East Dean Keeton Street, Stop C1700, Austin, Texas 78712, United States
2. School of Population and Public Health, The University of British Columbia, 2206 East Mall, Vancouver, British Columbia V6T1Z3, Canada
3. Health Effects Institute, 75 Federal Street, Suite 1400, Boston, Massachusetts 02110, United States
4. MRC-PHE Centre for Environment and Health, Imperial College London, London W2 1PG, United Kingdom
5. Department of Economics, Brigham Young University, Provo, Utah 84602, United States