Development of a Model to Predict and Mitigate Environmental and Public Health Impacts of Traffic Flows and Traffic Management Policies in Urban Transportation Microenvironments

Urban residents spend a considerable amount of time in transportation microenvironments as pedestrians, bicyclists, public transit users, residents and workers situated along roadways, and automobile commuters. Within these microenvironments, vehicles powered by carbon-based fuels (e.g., gasoline, diesel) have a negative impact on air quality. Vehicular exhaust is the source of a multitude of air contaminants, including particulate matter (PM). Particulate matter of concern ranges in size from the largest PM10 (diameter<10 micrometers) and PM2.5 (diameter<2.5 micrometers), to microscopic ultrafine particles (UFP). Ultrafine particles have diameters smaller than 0.1 micrometers. The majority of UFP present in an urban environment are the…

Urban residents spend a considerable amount of time in transportation microenvironments as pedestrians, bicyclists, public transit users, residents and workers situated along roadways, and automobile commuters. Within these microenvironments, vehicles powered by carbon-based fuels (e.g., gasoline, diesel) have a negative impact on air quality. Vehicular exhaust is the source of a multitude of air contaminants, including particulate matter (PM). Particulate matter of concern ranges in size from the largest PM10 (diameter<10 micrometers) and PM2.5 (diameter<2.5 micrometers), to microscopic ultrafine particles (UFP). Ultrafine particles have diameters smaller than 0.1 micrometers. The majority of UFP present in an urban environment are the result of traffic emissions (Zhang and Morwaska, 2002; Kittelson, 1998; Ristovsk et al., 1998). Significant adverse human health impacts have been connected to UFP number concentrations.
UFP levels that would be experienced by cyclists in roadway environments were used in this study to characterize urban residents’ exposure to traffic-related pollution. Additionally, the study focused on the evaluation of mitigation strategies to lower an urban road user’s exposure. The first strategy evaluated decreasing proximity of cyclists to motor vehicles in a downtown urban corridor environment, and the second evaluated the use of sound wall barriers as a shielding technique to lower exposure in a freeway/bike facility microenvironment.