Does Community Vulnerability Amplify the Relationship Between Traffic Exposure and Adverse Birth Outcomes? A University-State-USEPA Research Collaborative on Environmental Health Inequalities

This research project assesses the relationship between traffic exposure and risk of low birth weight and preterm birth, both strong predictors of health status throughout the life course, among 1.5 million births in California during 2001-2006. The analysis also examines whether measures of community and individual vulnerability confound or amplify the adverse effects of these exposures. While previous studies have examined relationships between ambient air pollution and adverse birth outcomes, most of these studies have not assessed whether and how individual- and area-level measures of community vulnerability affect observed pollutant-perinatal outcome relationships. Preliminary results indicate an increased risk of low birth weight and preterm birth with higher estimated traffic exposures. Effect estimates remain robust after conducting sensitivity analysis using different exposure assessment techniques. This unique collaborative between academic, US EPA, and California Department of Public Health scientists produced a novel application of GIS spatial analysis to estimate traffic exposure metrics for every census block in the state. Results of this collaborative study will enhance understanding about how source-specific measures, such as traffic burden, can elucidate policy-relevant opportunities for environmental agencies to reduce community exposure to multiple pollutants by taking actions such as targeting enforcement actions, encouraging voluntary reductions, and requiring mitigations.