A comprehensive modeling framework for transportation-induced population exposure assessment

This research is motivated by the need to improve transportation policy analysis through the development of a holistic framework to evaluate transportation externalities. Traditionally, transportation planning has been focused primarily on the improvement of transportation infrastructure and network performance and little attention has been paid to the resulting externalities that negatively impact public health. The paper presents a holistic analysis framework that enables policy makers analyze the chain effect of transportation demand on air quality and population health exposure. Holism is achieved by incorporating the interactions between transportation demand, network performance measurement, vehicular emissions, air quality modeling and population exposure assessment. The eventual impact of vehicular emissions on population is measured through the use of an intake fraction metric, which measures the fraction of pollutant inhaled by an exposed population over a defined period of time. The proposed framework takes advantage of the existing state-of-the-art domain specific models so there is no need to re-invent the wheels. Instead, the focus of the this research is to provide a prescriptive process of addressing data gaps and resolution matching between these models as well as other models alike. The proposed population exposure assessment incorporates key parameters including different microenvironments and inhalation rates not accounted for in the existing literature of exposure assessment. The entire framework is evaluated with the three city sub-region of Maricopa County in Arizona. Further investigations demonstrate the importance of differentiating microenvironments and inhalation rates to properly capturing population exposure.