title: Intercity transferability of land use regression models for estimating ambient concentrations of nitrogen dioxide.
abstract: Land use regression (LUR) is a method for predicting the spatial distribution of traffic-related air pollution. To facilitate risk and exposure assessment, and the design of future monitoring networks and sampling campaigns, we sought to determine the extent to which LUR can be used to predict spatial patterns in air pollution in the absence of dedicated measurements. We evaluate the transferability of one LUR model to two other geographically comparable areas with similar climates and pollution types. The source model, developed in 2003 to estimate ambient nitrogen dioxide (NO(2)) concentrations in Vancouver (BC, Canada) was applied to Victoria (BC, Canada) and Seattle (WA, USA). Model estimates were compared with measurements made with Ogawa passive samplers in both cities. As part of this study, 42 locations were sampled in Victoria for a 2-week period in June 2006. Data obtained for Seattle were collected for a different project at 26 locations in March 2005. We used simple linear regression to evaluate the fit of the source model under three scenarios: (1) using the same variables and coefficients as the source model; (2) using the same variables as the source model, but calculating new coefficients for local calibration; and (3) developing site-specific equations with new variables and coefficients. In Scenario 1, we found that the source model had a better fit in Victoria (R(2)=0.51) than in Seattle (R(2)=0.33). Scenario 2 produced improved R(2)-values in both cities (Victoria=0.58, Seattle=0.65), with further improvement achieved under Scenario 3 (Victoria=0.61, Seattle=0.72). Although it is possible to transfer LUR models between geographically similar cities, success may depend on the between-city consistency of the input data. Modest field sampling campaigns for location-specific model calibration can help to produce transfer models that are equally as predictive as their sources.
authors.affiliation: Spatial Sciences Research Laboratory, Department of Geography, University of Victoria, Victoria, British Columbia, Canada. poplawski@alumni.uvic.ca
authors.forename: Karla
authors.initials: K
authors.lastname: Poplawski
authors.forename: Timothy
authors.initials: T
authors.lastname: Gould
authors.forename: Eleanor
authors.initials: E
authors.lastname: Setton
authors.forename: Ryan
authors.initials: R
authors.lastname: Allen
authors.forename: Jason
authors.initials: J
authors.lastname: Su
authors.forename: Timothy
authors.initials: T
authors.lastname: Larson
authors.forename: Sarah
authors.initials: S
authors.lastname: Henderson
authors.forename: Michael
authors.initials: M
authors.lastname: Brauer
authors.forename: Perry
authors.initials: P
authors.lastname: Hystad
authors.forename: Christy
authors.initials: C
authors.lastname: Lightowlers
authors.forename: Peter
authors.initials: P
authors.lastname: Keller
authors.forename: Marty
authors.initials: M
authors.lastname: Cohen
authors.forename: Carlos
authors.initials: C
authors.lastname: Silva
authors.forename: Mike
authors.initials: M
authors.lastname: Buzzelli
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002170:Canada / Q000453:epidemiology; D002947:Cities / Q000453:epidemiology; D004784:Environmental Monitoring / Q000379:methods / Q000706:statistics & numerical data; D062665:Epidemiological Monitoring; D005843:Geography; D006801:Humans; D008954:Models, Biological; D015233:Models, Statistical; D009585:Nitrogen Dioxide / Q000032:analysis*; D012044:Regression Analysis; D014481:United States / Q000453:epidemiology; D014504:Urban Health
chemical_list: D000393:Air Pollutants; D009585:Nitrogen Dioxide