title: Near roadway air pollution across a spatially extensive road and cycling network.
abstract: This study investigates the variability in near-road concentrations of ultra-fine particles (UFP). Our results are based on a mobile data collection campaign conducted in 2012 in Montreal, Canada using instrumented bicycles and covering approximately 475 km of unique roadways. The spatial extent of the data collected included a diverse array of roads and land use patterns. Average concentrations of UFP per roadway segment varied greatly across the study area (1411-192,340 particles/cm(3)) as well as across the different visits to the same segment. Mixed effects linear regression models were estimated for UFP (R(2) = 43.80%), incorporating a wide range of predictors including land-use, built environment, road characteristics, and meteorology. Temperature and wind speed had a large negative effect on near-road concentrations of UFP. Both the day of the week and time of day had a significant effect with Tuesdays and afternoon periods positively associated with UFP. Since UFP are largely associated with traffic emissions and considering the wide spatial extent of our data collection campaign, it was impossible to collect traffic volume data. For this purpose, we used simulated data for traffic volumes and speeds across the region and observed a positive effect for volumes and negative effect for speed. Finally, proximity to truck routes was also associated with higher UFP concentrations.
authors.affiliation: Civil Engineering, McGill University, 817Sherbrooke St. W., Room 492, Montreal, QC, H3A 2K6, Canada. Electronic address: william.farrell@mail.mcgill.ca.
authors.forename: William
authors.initials: W
authors.lastname: Farrell
authors.affiliation: Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, 1020 Pine Ave. West, Montreal, QC, H3A 1A2, Canada. Electronic address: scott.weichenthal@mail.mcgill.ca.
authors.forename: Scott
authors.initials: S
authors.lastname: Weichenthal
authors.affiliation: Division of Clinical Epidemiology, McGill University Health Center, 687 Pine Ave. W., Royal Victoria Hospital, Room 4.29, Montreal, QC, H3A 1A1, Canada. Electronic address: mark.goldberg@mcgill.ca.
authors.forename: Mark
authors.initials: M
authors.lastname: Goldberg
authors.affiliation: Division of Clinical Epidemiology, McGill University Health Center, 687 Pine Ave. W., Royal Victoria Hospital, Room 4.29, Montreal, QC, H3A 1A1, Canada. Electronic address: marie-france.valois@mcgill.ca.
authors.forename: Marie-France
authors.initials: MF
authors.lastname: Valois
authors.affiliation: Civil Engineering, McGill University, 817Sherbrooke St. W., Room 492, Montreal, QC, H3A 2K6, Canada. Electronic address: maryam.shekarrizfard@mail.mcgill.ca.
authors.forename: Maryam
authors.initials: M
authors.lastname: Shekarrizfard
authors.affiliation: Civil Engineering, University of Toronto, 35St George Street, Room: GB305F, Toronto, ON, M5S 1A4, Canada. Electronic address: marianne.hatzopoulou@utoronto.ca.
authors.forename: Marianne
authors.initials: M
authors.lastname: Hatzopoulou
mesh_terms: D000393:Air Pollutants / Q000009:adverse effects* / Q000032:analysis; D002170:Canada; D004784:Environmental Monitoring / Q000379:methods; D016014:Linear Models; D008962:Models, Theoretical; D018986:Motor Vehicles; D052638:Particulate Matter / Q000032:analysis; D014186:Transportation; D001335:Vehicle Emissions / Q000032:analysis*; D014919:Wind
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D001335:Vehicle Emissions
keywords: Air pollution; Environmental monitoring; Land use regression; Ultrafine particles