Separate and Unequal: Residential Segregation and Estimated Cancer Risks Associated with Ambient Air Toxics in U.S. Metropolitan Areas

Abstract

This study examines links between racial residential segregation and estimated ambient air toxics exposures and their associated cancer risks using modeled concentration estimates from the U.S. Environmental Protection Agency’s National Air Toxics Assessment. We combined pollutant concentration estimates with potencies to calculate cancer risks by census tract for 309 metropolitan areas in the United States. This information was combined with socioeconomic status (SES) measures from the 1990 Census. Estimated cancer risks associated with ambient air toxics were highest in tracts located in metropolitan areas that were highly segregated. Disparities between racial/ethnic groups were also wider in more segregated metropolitan areas. Multivariate modeling showed that, after controlling for tract-level SES measures, increasing segregation amplified the cancer risks associated with ambient air toxics for all racial groups combined [highly segregated areas: relative cancer risk (RCR) = 1.04; 95% confidence interval (CI), 1.01–107; extremely segregated areas: RCR = 1.32; 95% CI, 1.28–1.36]. This segregation effect was strongest for Hispanics (highly segregated areas: RCR = 1.09; 95% CI, 1.01–1.17; extremely segregated areas: RCR = 1.74; 95% CI, 1.61–1.88) and weaker among whites (highly segregated areas: RCR = 1.04; 95% CI, 1.01–1.08; extremely segregated areas: RCR = 1.28; 95% CI, 1.24–1.33), African Americans (highly segregated areas: RCR = 1.09; 95% CI, 0.98–1.21; extremely segregated areas: RCR = 1.38; 95% CI, 1.24–1.53), and Asians (highly segregated areas: RCR = 1.10; 95% CI, 0.97–1.24; extremely segregated areas: RCR = 1.32; 95% CI, 1.16–1.51). Results suggest that disparities associated with ambient air toxics are affected by segregation and that these exposures may have health significance for populations across racial lines.

Socioeconomic Status and Its Relationship to Chronic Respiratory Disease

“…Access to goods and services, the built environment, and social norms and other factors relevant to health are often determined by the community [17]. Researchers and public health officials have acknowledged that the context in which one lives also contributes to health [18,19]. Examples of contextual measures of SES may be at the neighborhood level and include ZIP codes, census tracts, census block groups or census blocks.…”

Identifying Vulnerable Populations through an Examination of the Association Between Multipollutant Profiles and Poverty

“…8 These disparities in environmental exposures are increasingly recognized as potential determinants of health inequities. 9,10 These health inequities have led researchers to recognize the need for knowledge about the cumulative health effects of multiple environmental hazards such as exposure to multiple air pollutants 11 and the potential vulnerability of people in poor communities who suffer from their toxic effects. 11,12 As a result, environmental justice advocates have urged regulators to develop scientifically valid indicators from a multipollutant approach to examine environmental health inequities and guide decision making.…”

Integrating Public Health And Community Development To Tackle Neighborhood Distress And Promote Well-Being

“…16 These factors can be as critical to health outcomes as are access to medical insurance or health care, if not more so. 17,18 In the community development field, there is also a growing understanding of the importance of place making in promoting both economic vitality and health.…”

“…16,21,22 Equally important, the aspirations and well-being of low-income communities are often limited by the regions in which they are located, which makes it imperative for community development corporations to promote regional prosperity to avoid simply becoming "managers of decline." 23 The second insight involves a new understanding of the fact that high-income neighborhoods are not actually rich in jobs; instead, they are rich in amenities.…”