Automobiles, Air Toxics, and Adverse Health Risks: Environmental Inequities in Tampa Bay, Florida

Abstract

Few environmental justice studies of air pollution have examined the adverse health implications of exposure to transportation-related emissions or used statistical techniques that are appropriate for spatial data. This article addresses these gaps by examining the distribution of cancer and respiratory risks from inhalation exposure to vehicular emissions of hazardous air pollutants in the Tampa Bay Metropolitan Statistical Area, Florida. This study advances quantitative environmental justice research by (a) focusing on mobile source air pollution instead of major point sources; (b) examining the health risks of disproportionate exposure; (c) including transportation disadvantaged individuals, in addition to minority and low-income residents; and (d) using multiple regression models that account for spatial dependence. Data from the U.S. Environmental Protection Agency's 1999 National-Scale Air Toxics Assessment are utilized to estimate lifetime cancer and respiratory health risks from on-road vehicles for census tracts in the study area. Inequities associated with these risk estimates are investigated using relevant demographic and socioeconomic variables from Census 2000. Statistical analyses are based on simple comparisons, conventional multiple regression, and a set of spatial regression models that address spatial autocorrelation. Results indicate that race or ethnicity plays a persistent explanatory role in the distribution of health risks from vehicular emissions, after controlling for well-documented contextual factors. Additionally, tracts characterized by higher population density and lower rates of home ownership and vehicle ownership are facing significantly greater cancer and respiratory risks from traffic-related pollutants. These findings have several implications for transportation and land use policy in and beyond Tampa Bay.