1. Respiratory Health Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia, USA
2. Department of Geology and Geography, West Virginia University, Morgantown, West Virginia, USA
3. Department of Geography, Kyung Hee University, Seoul, South Korea
4. Section of Environmental Epidemiology and Toxicology, Office of Public Health, Louisiana Department of Health, Baton Rouge, Louisiana, USA
5. Gangarosa Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA
6. Division of Environmental Health Science and Practice, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
7. College of Public Health, Department of Environmental, Agricultural, and Occupational Health, University of Nebraska Medical Center, Omaha, Nebraska, USA