Assessing population exposures to motor vehicle exhaust.

Background Conceptual Framework Surrogate Techniques Modeling Techniques Regression Modeling Approaches Dispersion Modeling Measurement Techniques Within-city spatial variability in pollutant concentrations Components of the motor vehicle emissions mixture: Diesel exhaust Recommendations ABSTRACT The need is growing for a better assessment of population exposures to motor vehicle exhaust in proximity to major roads and high- ways. This need is driven in part by emerging scientific evidence of adverse health effects from such exposures and policy requirements for a more targeted assessment of localized public health impacts related to road expansions and increasing commercial transportation. The momentum for improved methods in measuring local exposures is also growing in the scientific community, as well as for discerning which constituents of the vehicle exhaust mixture may exert greater public health risks for those who are exposed to a disproportionate share of road- way pollution. To help elucidate the current state-of-the-science in exposure assessments along major roadways and to help inform decision makers of research needs and trends, we provide an overview of the emerging policy requirements, along with a conceptual frame- work for assessing exposure to motor-vehicle exhaust that can help inform policy decisions.