Evaluating health outcomes from vehicle emissions exposure in the long range regional transportation planning process

- Evaluate air quality related health outcomes of regional transportation plans.
- Emissions exposure and health risks decline initially and then grow over time.
- Low income and minority populations have much higher health risks.

The air quality impacts of a metropolitan region's long range transportation plans are generally evaluated by estimating the change in a region's vehicle emission inventory. A change in the overall quantity of vehicle emissions in a region is generally associated with lower concentrations of vehicle related air pollutants and therefore a reduction in public health risks from exposure to vehicle emissions. A major limitation of this common approach is that aggregate emission inventories provide no information about localized impacts. While some areas experience air quality improvements, air quality can become worse in others. Such aggregate analyses are ill suited for addressing contemporary transportation planning questions such as identifying vehicle emission exposure hotspots, quantifying health risks, and evaluating environmental justice concerns. In this paper we describe a computationally efficient analysis framework for evaluating a regional transportation plan with spatially detailed estimates of vehicle emission exposures and related health outcomes. We then apply our framework in a case study of fine particulate matter exposure in the Atlanta, Georgia metropolitan area and the changes expected to occur through the year 2040 under the region's long range transportation plan. We find that exposure and health risks decline from current levels by 2020 but then begin to slowly increase in some areas by 2040. We also find that low income and minority populations have the greatest health risks, confirming environmental justice concerns that have been noted in other regions.