Three Measures of Environmental Inequality

Using data on industrial air pollution exposure in the United States, we compute three measures of environmental inequality at the national level and for the 50 states: the Gini coefficient of exposure, the ratio of median exposure of people of color to that of non-Hispanic whites, and the ratio of median exposure of poor households to that of nonpoor households. Comparing Gini coefficients of pollution exposure to those of income, we find that the distribution of pollution exposure is more unequal. Comparing the three measures of environmental inequality, we find that rankings across states vary considerably, and conclude that different measures are most appropriate depending on whether the policy concern is equal fulfillment of the intrinsic right to a clean and safe environment or interactions between environmental inequality and other socioeconomic disparities.