Integrated Framework for Evaluating Population Health Exposure to Emissions from Transportation Sources

Calls to address the problems of climate change, expanding carbon footprint, overdependence on vehicles and urban sprawl show the need for sustainable solutions to be born from interdisciplinary research. The objective of this research is to develop an integrated framework that can shed light on the interactions between transportation, emissions, air quality and human health. Integrating knowledge from these domains helps in addressing issues of climate change, environmental justice and policy decision making. The framework integrates models of travel demand, emissions and energy consumption, air dispersion and health assessment. Thus, it provides a holistic approach to capture the dynamic interplay between daily activities of people, their resulting travel patterns, roadway conditions, vehicular emissions, pollutant concentrations and health exposure levels. The modeling starts with location allocation and time activity pattern information from an activity based travel demand model. The travel demand is assigned dynamically onto the roadway network using a dynamic traffic assignment model that generates time-varying operational level performance measure. These performance measures along with other factors related to vehicle, roadway conditions, meteorology and fuel supply are incorporated into an emission model. The dispersion of these emissions into the atmosphere is calculated by an air dispersion model based on pollutant properties, site specific conditions related to atmospheric and land use characteristics. Health exposure levels are computed based on the resulting pollutant concentration levels, location allocation and inhalation rates of people. The overall framework is showcased on a three city-subregion case study in Maricopa County, Arizona. The significant contribution from this research is to utilize the framework to evaluate urban planning policies. The framework can be used to measure the effect of policies on travel behavior, which in turn affects emissions, air quality and finally is reflected on human health. The policy analysis capability of the framework is demonstrated through an infrastructure capacity expansion case study in downtown Sacramento, California and estimation of health impacts for vulnerable population subgroups in densely populated Gold Coast region in Chicago, Illinois.