Lastly, this paper examines the impact of speed on active traveler pollution dose, but many other factors also influence pollution dose and related health impacts. For example, pollutant concentrations, C in Equation 1, vary substantially throughout an urban road network, and are impacted by meteorology, road infrastructure, near-road land use, and many other factors. A broad range of strategies can be employed to reduce air pollution risks for active travelers, including development of urban transport networks with more separated bicycle and pedestrian infrastructure, pollution-specific routing recommendations for active travelers, and a general reduction in emissions through vehicle, fuel, and travel controls