Trade between Canada, the United States and Mexico has grown rapidly since the implementation of the North American Free Trade Agreement (NAFTA). This study examines the environmental impacts of that trade on five bi-national segments of three primary NAFTA trade corridors, with a particular focus on air pollution emissions. The corridor segments selected for the analysis are Vancouver-Seattle, Winnipeg-Fargo, Toronto-Detroit, San Antonio-Monterrey and Tucson-Hermosillo. The study determines current and future commodity flows, freight vehicle traffic volumes and emissions in each of these corridor segments. The impacts of several mitigation strategies are also explored.