Regional variation in environmental inequality: Industrial air toxics exposure in U.S. cities

This paper analyzes how racial and ethnic disparities in exposure to industrial air toxics in U.S. cities vary with neighborhood income, and how these disparities vary regionally across the country. Exposure is estimated at the census block-group level using geographic microdata from the Risk-Screening Environmental Indicators of the U.S. Environmental Protection Agency (EPA). We find that racial and ethnic disparities in pollution exposure are strongest among neighborhoods with median incomes below $25,000, while income-based disparities are stronger among neighborhoods with median incomes above that level. We also find considerable differences in the patterns of disparity across the ten EPA regions. In the two regions with the highest median exposure (the Midwest and South Central regions), for example, African-Americans and Hispanics face significantly higher exposures than whites, whereas in the region with the next highest exposure (the Mid-Atlantic), the reverse is true. We show that the latter result is attributable to intercity variations — minorities tend to live in the less polluted cities in the region — rather than to within-city variations.