title: Investigating the role of transportation models in epidemiologic studies of traffic related air pollution and health effects.
abstract: In two earlier case-control studies conducted in Montreal, nitrogen dioxide (NO2), a marker for traffic-related air pollution was found to be associated with the incidence of postmenopausal breast cancer and prostate cancer. These studies relied on a land use regression model (LUR) for NO2 that is commonly used in epidemiologic studies for deriving estimates of traffic-related air pollution. Here, we investigate the use of a transportation model developed during the summer season to generate a measure of traffic emissions as an alternative to the LUR model. Our traffic model provides estimates of emissions of nitrogen oxides (NOx) at the level of individual roads, as does the LUR model. Our main objective was to compare the distribution of the spatial estimates of NOx computed from our transportation model to the distribution obtained from the LUR model. A secondary objective was to compare estimates of risk using these two exposure estimates. We observed that the correlation (spearman) between our two measures of exposure (NO2 and NOx) ranged from less than 0.3 to more than 0.9 across Montreal neighborhoods. The most important factor affecting the "agreement" between the two measures in a specific area was found to be the length of roads. Areas affected by a high level of traffic-related air pollution had a far better agreement between the two exposure measures. A comparison of odds ratios (ORs) obtained from NO2 and NOx used in two case-control studies of breast and prostate cancer, showed that the differences between the ORs associated with NO2 exposure vs NOx exposure differed by 5.2-8.8%.
authors.affiliation: Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke St. W., Room 492, Montréal, Québec, Canada H3A 2K6. Electronic address: maryam.shekarrizfard@mail.mcgill.ca.
authors.forename: Maryam
authors.initials: M
authors.lastname: Shekarrizfard
authors.affiliation: Department of Medicine, McGill University, Division of Clinical Epidemiology, McGill University Health Centre, QC, Canada H3A 1A1. Electronic address: marie-france.valois@mcgill.ca.
authors.forename: Marie-France
authors.initials: MF
authors.lastname: Valois
authors.affiliation: Department of Medicine, McGill University, Division of Clinical Epidemiology, McGill University Health Centre, QC, Canada H3A 1A1. Electronic address: mark.goldberg@mcgill.ca.
authors.forename: Mark S
authors.initials: MS
authors.lastname: Goldberg
authors.affiliation: Department of Sociology, University of New Brunswick, Fredericton, New Brunswick, Canada. Electronic address: dlcrouse@gmail.com.
authors.forename: Dan
authors.initials: D
authors.lastname: Crouse
authors.affiliation: Department of Geography, McGill University, 805 Sherbrooke St. W., Montreal, Quebec, Canada H3A 2K6. Electronic address: nancy.ross@mcgill.ca.
authors.forename: Nancy
authors.initials: N
authors.lastname: Ross
authors.affiliation: INRS-Institut Armand-Frappier, Institut national de la recherche scientifique, Unité d'épidémiologie et biostatistique, 531, Boul. des Prairies, Laval, Québec, Canada H7V 1B7. Electronic address: marie-elise.parent@iaf.inrs.ca.
authors.forename: Marie-Elise
authors.initials: ME
authors.lastname: Parent
authors.affiliation: Department of Civil Engineering & Applied Mechanics, McGill University, Suite 483, 817 Sherbrooke St. W., Montréal, Québec, Canada H3A 2K6. Electronic address: shamsunnahar.yasmin@mail.mcgill.ca.
authors.forename: Shamsunnahar
authors.initials: S
authors.lastname: Yasmin
authors.affiliation: Department of Civil Engineering and Applied Mechanics, McGill University, Macdonald Engineering Building, Room 278b, 817 Sherbrooke St. W., Montréal, Québec, Canada H3A 2K6. Electronic address: marianne.hatzopoulou@mcgill.ca.
authors.forename: Marianne
authors.initials: M
authors.lastname: Hatzopoulou
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D001943:Breast Neoplasms / Q000139:chemically induced / Q000453:epidemiology*; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D008297:Male; D008962:Models, Theoretical; D009589:Nitrogen Oxides / Q000633:toxicity; D017698:Postmenopause; D011471:Prostatic Neoplasms / Q000150:complications / Q000453:epidemiology*; D011792:Quebec / Q000453:epidemiology; D014186:Transportation; D001335:Vehicle Emissions / Q000633:toxicity*
chemical_list: D000393:Air Pollutants; D009589:Nitrogen Oxides; D001335:Vehicle Emissions
keywords: Air pollution; Land-use regression; MOVES; Traffic-related emissions; Trip-level NO(x) emissions