1 Department of Biomedical & Molecular Sciences, Queen's University, Kingston, Ontario, Canada; Allergy Research Unit, Kingston General Hospital, Kingston, Ontario, Canada.
2 Center for Environmental Medicine, Asthma, and Lung Biology, School of Medicine, University of North Carolina, Chapel Hill, North Carolina; Department of Pediatrics, University of North Carolina, School of Medicine University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
3 Department of Biomedical & Molecular Sciences, Queen's University, Kingston, Ontario, Canada; Allergy Research Unit, Kingston General Hospital, Kingston, Ontario, Canada; Division of Allergy and Immunology, Department of Medicine, Queen's University, Kingston, Ontario, Canada.
4 Air Pollution Exposure Laboratory, Vancouver Coastal Health Research Institute, Vancouver General Hospital, Vancouver, British Columbia, Canada; Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada. Electronic address: carlsten@mail.ubc.ca.