Riskscape and the Colorline: Methodological and Science-Policy Considerations for Addressing Environmental Health Disparities

Advocates concerned about environmental justice argue that communities of color and the poor face a higher frequency and magnitude of exposures to environmental as well as psychosocial stressors. Concern has centered on the limited science related to the cumulative impact of multiple exposures to environmental hazards and the vulnerability of poor communities to their toxic effects. This combination of elevated environmental hazard exposures, on one hand, and socioeconomic stressors, on the other, has been described as a form of “double jeopardy”. This talk describes theoretical approaches for understanding the cumulative impact of multiple hazard exposures and how indicators of social vulnerability, such as poverty, social inequality, and racial residential segregation can lead to and shape environmental health disparities among diverse communities. We then empirically test our theoretical framework using California birth outcome data and ambient criteria pollutant monitoring information, to assess relationships between ambient air pollution exposures and risk of adverse perinatal outcomes. We assess whether measures of social inequality confound or amplify any observed relationships between criteria air pollutant exposures and adverse birth outcomes. We find that a negative association between ambient ozone and PM exposure and birth weight. This relationship is slightly modified by metro area-level income inequality and maternal race/ethnicity. Results indicate that individual and neighborhood levels stressors can enhance vulnerability to the toxic effects of pollutants. .We conclude by discussing measures of cumulative impact and social vulnerability that can be translated into transparent, scientifically valid indicators that facilitate regulatory decision-making to address environmental health inequalities.