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The Influence of Highway Traffic on Ambient NO2 Concentrations Beyond the Immediate Vicinity of Highways

Gilbert-L, N*; Goldberg-S, M; Brook-R, J; Jerrett, M§

doi: 10.1097/01.ede.0000276433.69563.9b

*Health Canada, Canada; †McGill University, Canada; ‡Environment Canada, Canada; and §University of Southern California, United States.


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The objective of these analyses was to determine whether highways significantly influence ambient concentrations of nitrogen dioxide (NO2) at distances greater than 200 m.

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Material and Methods:

NO2 was sampled for 14 consecutive days in May 2003 at 67 sites across Montréal, Canada. The association between logarithmic concentrations of NO2 and land-use variables was assessed using multiple regression. Locations less than 100 m from the nearest highways were excluded, leaving 61 data points. Then, locations less than 200 m were excluded, leaving 55 data points.

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Excluding sampling locations located less than 100 or 200 m from the nearest highway did not substantially change the regression parameters. NO2 remained significantly associated with both the distance from nearest highway and the traffic count on the nearest highway.

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The negative association found between distance from highways and NO2 concentration in previous land-use regression studies was not generated solely by the high concentrations found in the immediate vicinity of highways.

© 2007 Lippincott Williams & Wilkins, Inc.