ARB Research Seminar

This page updated June 19, 2013

Separate and Unequal: Residential Segregation and Estimated Cancer Risks Associated with Ambient Air Toxics In California

Rachel Morello-Frosch, Ph.D., M.P.H., Brown University

July 20, 2005
Cal EPA Headquarters, 1001 "I" Street, Sacramento, CA



Previous research has documented racial and income disparities in exposures to various categories of air pollutants. Underlying this research is the belief that pollution may play an important, yet poorly understood, role in the complex pattern of disparate health status among the poor and people of color in the United States. However, few environmental justice studies have elucidated pathways that explain how social context shapes demographic disparities in environmental hazard exposures. This study examines links between social inequality-particularly residential segregation-- with estimated community ambient air toxics exposures and their associated cancer risks.

For this study, we assessed whether racial and economic disparities in estimated cancer risk associated with air toxics are mediated by levels of residential segregation in California. To analyze the relationship between pollution and health risk burdens with race-based residential segregation, we obtained modeled ambient air toxics concentration estimates from U.S. EPA's National Air Toxics Assessment (NATA) and combined these data with cancer potency information. We find that overall, estimated cancer risks associated with ambient air toxics are highest in counties that are highly segregated. Moreover, disparities between racial/ethnic groups are also higher in more segregated counties.

Multivariate modeling suggests that race plays an explanatory role in cancer risk distributions even after controlling for other economic and demographic factors, but that patterns of racial disparity are significantly mediated by patterns of segregation. This suggests that spatial socioeconomic forces, such as segregation, play a key role in shaping the environmental "riskscape" and ultimately contribute to persistent and complex patterns of racial disparities in community susceptibility to pollution exposures.

Speaker Biography

Rachel Morello-Frosch is an assistant professor at the Department of Community Health, School of Medicine and the Center for Environmental Studies at Brown University. She completed her bachelor's degree in development economics, a master of public health degree in epidemiology and biostatistics, and her Ph.D. in environmental health sciences at the University of California, Berkeley. She teaches methods courses on environmental health, risk assessment, and policy, epidemiology, and a seminar on the science and political economy of environmental health and justice.

Rachel's research examines race and class determinants of the distribution of health risks associated with air pollution among diverse communities in the United States. Her current work focuses on: comparative risk assessment and environmental justice, developing models for community-based environmental health research, science and environmental health policy-making, children's environmental health, and the intersection between economic restructuring and community environmental health.

Rachel is currently working on a research collaborative with academic colleagues in Southern California, and Communities for a Better Environment on "Air Pollution, Toxics and Environmental Justice." She is also collaborating with Silent Spring Institute in Massachusetts on a community-based household exposure study in Richmond, California on endocrine-disrupting chemicals funded by the National Institute of Environmental Health Sciences.

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