Characterizing Determinants of Near-Road Ambient Air Quality for an Urban Intersection and a Freeway Site

Traffic emissions are an important source of urban air pollution, and exposure to traffic-related air pollution has been associated with various adverse health effects. However, exposure assessment is challenging because traffic-related air pollution is a complex mixture of many particulate and gaseous pollutants and is highly variable across locations and time. Developing accurate models of traffic-related air pollution for use in exposure assessment for epidemiological studies relies on understanding traffic activity and air flow at small spatial scales within cities. Dr. H. Christopher Frey from North Carolina State University and his team proposed a study to explore how traffic activity metrics, land use parameters, and transport of pollutants influence near-road air pollutant concentrations. One question they posed was whether more detailed measurements of factors affecting near-road air pollutant levels can help with the development of models of concentrations of primary and secondary air pollutants within hundreds of meters of roads, and which of those measurements most improved the air quality model performance at different locations and times. They incorporated key concepts from various fields related to roads and air pollution, including transportation, mobile source emissions, traffic operations, and meteorology.