Who lives on the wrong side of the environmental tracks? Evidence from the EPA's risk-screening environmental indicators model

Abstract

We analyze the social and economic correlates of air pollution exposure in U.S. cities. Methods. We combine 1990 Census block group data for urbanized areas with 1998 data on toxicity-adjusted exposure to air pollution. Using a unique data set created as a byproduct of the EPA's Risk-Screening Environmental Indicators Model, we improve on previous studies of environmental inequality in three ways. First, where previous studies focus on the proximity to point sources and the total mass of pollutants released, our measure of toxic exposure reflects atmospheric dispersion and chemical toxicity. Second, we analyze the data at a fine level of geographic resolution. Third, we control for substantial regional variations in pollution, allowing us to identify exposure differences both within cities and between cities. Results. We find that African Americans tend to live both in more polluted cities in the United States and in more polluted neighborhoods within cities. Hispanics live in less polluted cities on average, but they live in more polluted areas within cities. We find an extremely consistent income-pollution gradient, with lower-income people significantly more exposed to pollution. Conclusions. Communities with higher concentrations of lower-income people and people of color experience disproportionate exposure to environmental hazards. Our findings highlight the importance of controlling for interregional variation in pollution levels in studies of the demographic correlates of pollution.