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

Department of Community Health, School of Medicine, Brown University, Providence, Rhode Island 02912-1943, USA.
Environmental Health Perspectives (Impact Factor: 7.98). 04/2006; 114(3):386-93. DOI: 10.1289/ehp.8500
Source: PubMed


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.

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    • "derives from the most recent estimate of LCR associated with annual average ambient air-toxic concentrations as determined by U.S. EPA (2011) in its 2005 National Air Toxics Assessment (NATA). The NATA data has been used with increasing frequency in recent academic case studies of environmental inequality (e.g., Chakraborty, 2009; Gilbert and Chakraborty, 2011; Morello-Frosch and Jesdale, 2006; Pastor et al., 2005). "
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    ABSTRACT: This article contributes to environmental inequality outcomes research on the spatial and demographic factors associated with cumulative air-toxic health risks at multiple geographic scales across the United States. It employs a rigorous spatial cluster analysis of census tract-level 2005 estimated lifetime cancer risk (LCR) of ambient air-toxic emissions from stationary (e.g., facility) and mobile (e.g., vehicular) sources to locate spatial clusters of air-toxic LCR risk in the continental United States. It then tests intersectional environmental inequality hypotheses on the predictors of tract presence in air-toxic LCR clusters with tract-level principal component factor measures of economic deprivation by race and immigrant status. Logistic regression analyses show that net of controls, isolated Latino immigrant-economic deprivation is the strongest positive demographic predictor of tract presence in air-toxic LCR clusters, followed by black-economic deprivation and isolated Asian/Pacific Islander immigrant-economic deprivation. Findings suggest scholarly and practical implications for future research, advocacy, and policy.
    Full-text · Article · Nov 2015 · Social Science Research
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    • "Many studies of racial/ethnic residential segregation have compared residents in a segregated area with those in other areas [10,11]. However, some discrimination studies focused only on the bottom level of the hierarchy of place, such as our previous study [16]. "
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    ABSTRACT: Background Several studies have reported that individualized residential place-based discrimination (PBD) affects residents’ health. However, studies exploring the association between institutionalized PBD and health are scarce, especially in Asian countries including Japan. Methods A cross-sectional study was conducted with random two-stage sampling of 6191 adults aged 25–64 years in 100 census tracts across Osaka city in 2011. Of 3244 respondents (response rate 52.4%), 2963 were analyzed using multilevel logistic regression to examine the association of both individualized and institutionalized PBD with self-rated health (SRH) after adjustment for individual-level factors such as socioeconomic status (SES). An area-level PBD indicator was created by aggregating individual-level PBD responses in each tract, representing a proxy for institutionalized PBD, i.e., the concept that living in a stigmatized neighborhood affects neighborhood health. 100 tracts were divided into quartiles in order. The health impact of area-level PBD was compared with that of area-level SES indicators (quartile) such as deprivation. Results After adjustment for individual-level PBD, the highest and third area-level PBD quartiles showed odds ratio (OR) 1.57 (95% credible interval: 1.13-2.18) and 1.38 (0.99-1.92), respectively, for poor SRH compared with the lowest area-level PBD quartile. In a further SES-adjusted model, ORs of area-level PBD (highest and third quartile) were attenuated to 1.32 and 1.31, respectively, but remained marginally significant, although those of the highest area-level not-home-owner (census-based indicator) and deprivation index quartiles were attenuated to 1.26 and 1.21, respectively, and not significant. Individual-level PBD showed significant OR 1.89 (1.33-2.81) for poor SRH in an age, sex, PBD and SES-adjusted model. Conclusion Institutionalized PBD may be a more important environmental determinant of SRH than other area-level SES indicators such as deprivation. Although it may have a smaller health impact than individualized PBD, attention should be paid to invisible and unconscious aspects of institutionalized PBD to improve residents’ health.
    Full-text · Article · May 2014 · BMC Public Health
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    • "Previous research has also shown that populations of color and low-income groups living in poor environmental conditions have health risks due in part to various social determinants of health including segregation, racism, socioeconomic status (SES), income inequality, and inequities in planning and zoning [1-4,6,14,19,20,28-31]. Studies have shown that underlying social and economic vulnerabilities contribute to increased health disparities [29,31,32], which further enhance the long-term effects of environmental injustice. "
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    ABSTRACT: Environmental justice research has shown that many communities of color and low-income persons are differentially burdened by noxious land uses including Toxic Release Inventory (TRI) facilities. However, limited work has been performed to assess how these populations tend to be both overburdened and medically underserved. We explored this "double disparity" for the first time in Maryland. We assessed spatial disparities in the distribution of TRI facilities in Maryland across varying levels of sociodemographic composition using 2010 US Census Health Professional Shortage Area (HPSA) data. Univariate and multivariate regression in addition to geographic information systems (GIS) were used to examine relationships between sociodemographic measures and location of TRI facilities. Buffer analysis was also used to assess spatial disparities. Four buffer categories included: 1) census tracts hosting one or more TRI facilities; 2) tracts located more than 0 and up to 0.5 km from the closest TRI facility; 3) tracts located more than 0.5 km and up to 1 km from a TRI facility; and 4) tracts located more than 1 km and up to 5 km from a TRI facility. We found that tracts with higher proportions of non-white residents and people living in poverty were more likely to be closer to TRI facilities. A significant increase in income was observed with an increase in distance between a census tract and the closest TRI facility. In general, percent non-white was higher in HPSA tracts that host at least one TRI facility than in non-HPSA tracts that host at least one TRI facility. Additionally, percent poverty, unemployment, less than high school education, and homes built pre-1950 were higher in HPSA tracts hosting TRI facilities than in non-HPSA tracts hosting TRI facilities. We found that people of color and low-income groups are differentially burdened by TRI facilities in Maryland. We also found that both low-income groups and persons without a high school education are both overburdened and medically underserved. The results of this study provide insight into how state agencies can better address the double disparity of disproportionate environmental hazards and limited access to health care resources facing vulnerable communities in Maryland.
    Full-text · Article · Apr 2014 · Environmental Health
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