1. a Exposure Modeling Research Branch, Human Exposure and Atmospheric Sciences Division, National Exposure Research Laboratory, Office of Research and Development , U.S. Environmental Protection Agency , Research Triangle Park , North Carolina , USA
2. b ManTech Environmental Technology, Inc. , Durham , North Carolina , USA
3. c Environmental Characterization and Apportionment Branch, Human Exposure and Atmospheric Sciences Division, National Exposure Research Laboratory, Office of Research and Development , U.S. Environmental Protection Agency , Research Triangle Park , North Carolina , USA
4. d Houston Health Science Center, School of Public Health, University of Texas , Houston , Texas , USA
5. e Department of Internal Medicine , University of New Mexico School of Medicine , Albuquerque , New Mexico , USA
6. f Center for Aerosol Technology, RTI International , Research Triangle Park , North Carolina , USA
7. g Epidemiology and Biomarkers Branch, Human Studies Division, National Health and Environmental Effects Research Laboratory , U.S. Environmental Protection Agency , Research Triangle Park , North Carolina , USA
8. h National Exposure Research Laboratory, Office of Research and Development , U.S. Environmental Protection Agency , Research Triangle Park , North Carolina , USA