1. Boston University School of Public Health, 715 Albany Street, T4W, Boston,
Massachusetts 02118, United States
2. Nicholas School of the Environment, Duke University, 450 Research Drive, Durham, North
Carolina 27708, United States
3. Division of Laboratory Sciences,
National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Highway
NE, Mailstop F53, Atlanta, Georgia 30341, United States
4. Science and Technology Branch, Environment Canada, 4905 Dufferin Street, Toronto,
Ontario, M3H 5T4 Canada