1. Center for Environmental Medicine, Asthma, and Lung Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
2. Department of Environmental Sciences and Engineering (ESE), Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
3. Marsico Lung Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
4. Curriculum in Toxicology and Environmental Medicine, University of North Carolina at Chapel Hill, 116 Manning Drive, Chapel Hill, North Carolina 27599-7310, United States
5. Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
6. Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States