1. Department of Environmental Health, and
2. Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA
3. Department of Physics, University of Nevada-Reno, Reno, Nevada, USA
4. School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
5. Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA