title: Commuting behaviors and exposure to air pollution in Montreal, Canada.
abstract: BACKGROUND
  Vehicular traffic is a major source of outdoor air pollution in urban areas, and studies have shown that air pollution is worse during hours of commuting to and from work and school. However, it is unclear to what extent different commuting behaviors are a source of air pollution compared to non-commuters, and if air pollution exposure actually differs by the mode of commuting. This study aimed to examine the relationships between commuting behaviors and air pollution exposure levels measured by urinary 1-OHP (1-hydroxypyrene), a biomarker of exposure to polycyclic aromatic hydrocarbons (PAHs).
  
  
  METHODS
  A cross-sectional study of 174 volunteers living in Montreal, 92 females and 82 males, aged 20 to 53 years was conducted in 2011. Each participant completed a questionnaire regarding demographic factors, commuting behaviors, home and workplace addresses, and potential sources of PAH exposure, and provided a complete first morning void urine sample for 1-OHP analysis. Multivariable general linear regression models were used to examine the relationships between different types of commuting and urinary 1-OHP levels.
  
  
  RESULTS
  Compared to non-commuters, commuters traveling by foot or bicycle and by car or truck had a significantly higher urinary 1-OHP concentration in urine (p=0.01 for foot or bicycle vs. non-commuters; p=0.02 for car or truck vs. non-commuters); those traveling with public transportation and combinations of two or more types of modes tended to have an increased 1-OHP level in urine (p=0.06 for public transportation vs. non-commuters; p=0.05 for commuters with combinations of two or more types of modes vs. non-commuters). No significant difference in urinary 1-OHP variation was found by mode of commuting.
  
  
  CONCLUSIONS
  This preliminary study suggests that despite the mode of commuting, all types of commuting during rush hours increase exposure to air pollution as measured by a sensitive PAH metabolite biomarker, and mode of commuting did not explain exposure variation.
authors.affiliation: Department of Public Health Sciences, Queen's University, Kingston, ON, Canada; Cancer Research Institute at Queen's University, Kingston, ON, Canada.
authors.forename: Qun
authors.initials: Q
authors.lastname: Miao
authors.affiliation: Department of Environmental and Occupational Health, Chair in Toxicological Risk Assessment and Management, Université de Montréal, Montréal, QC, Canada.
authors.forename: Michèle
authors.initials: M
authors.lastname: Bouchard
authors.affiliation: Department of Geography, Queen's University, Kingston, ON, Canada.
authors.forename: Dongmei
authors.initials: D
authors.lastname: Chen
authors.affiliation: Department of Geography, Queen's University, Kingston, ON, Canada.
authors.forename: Mark W
authors.initials: MW
authors.lastname: Rosenberg
authors.affiliation: Department of Public Health Sciences, Queen's University, Kingston, ON, Canada; Cancer Research Institute at Queen's University, Kingston, ON, Canada. Electronic address: aronson@queensu.ca.
authors.forename: Kristan J
authors.initials: KJ
authors.lastname: Aronson
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000378:metabolism; D000397:Air Pollution / Q000706:statistics & numerical data*; D001336:Automobiles / Q000706:statistics & numerical data; D015415:Biomarkers / Q000378:metabolism; D003430:Cross-Sectional Studies; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D052638:Particulate Matter / Q000378:metabolism; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis / Q000378:metabolism*; D011721:Pyrenes / Q000378:metabolism; D011792:Quebec; D014186:Transportation / Q000706:statistics & numerical data*; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D015415:Biomarkers; D052638:Particulate Matter; D011084:Polycyclic Aromatic Hydrocarbons; D011721:Pyrenes; C033146:1-hydroxypyrene
keywords: 1-OHP; Air pollution; Commuters; Commuting behavior; PAH; Transportation