Introduction: Cycling is currently promoted at the municipal, provincial and national level as a form of active transportation that increases physical activity while at the same time reducing traffic congestion, traffic-related air pollution and greenhouse gas emissions. While at a population level the health benefits of exercise via cycling are estimated to substantially exceed any health impacts related to air pollution exposure and injuries from traffic accidents , cyclists are known to experience elevated exposures to traffic-related air pollutants. Combined with exposure to elevated concentrations of air pollutants, cyclists also are subject to substantially increased inhaled doses due to their level of exertion and consequently increased inhalation rate. Therefore, given that cyclists experience exposures to relatively high concentrations of traffic-related air pollutants and that their inhalation of these pollutants is increased, it is important to evaluate the potential health impacts of this scenario. Research on the potential health impacts related to exercise (cycling) and urban air pollution exposure can help inform public communication strategies related to air quality and its health impacts. In addition, as our previous work suggests substantial variability in air pollution exposures to cyclists that is related to the route type and the levels of traffic along cycling routes, there is potential for transportation planners to promote increased cycling by enhancing infrastructure while at the same time developing routes that also minimize exposure to air pollution. The cyclist population is also interested in information regarding the air pollution exposures and potential health impacts related to cycling.