Assessing the impact of segregation on environmental equity using GIS

A considerable amount of empirical research, conducted during the last decade, has attempted to determine whether racial minorities and the economically disadvantaged are disproportionately located in neighborhoods that contain environmental hazards. Demographic studies on this subject, however, have failed to examine the effect of the intra-uiban spatial distribution of various social groups and how this factor constrains the equitable distribution of hazards. The objective of this paper is to conduct a GIS-based analysis of the effect of residential segregation on environmental equity assessment. The relationship between a commonly used index of segregation and an aggregate distance-based measure of environmental equity is examined, using a stratified random sample of 15 urban counties. We specifically focus on income segregation and income inequities in the distribution of industrial toxic emission locations in these counties. The indices of segregation and equity are computed by using the analytical capabilities of GIS software and 1990 Census data at the block group level of aggregation. Our findings indicate a moderately strong negative linear association between the measures of segregation and equity.