标题：Racial/Ethnic Disparities in Cumulative Environmental Health Impacts in California: Evidence From a Statewide Environmental Justice Screening Tool (CalEnviroScreen 1.1)
摘要：Objectives. We used an environmental justice screening tool (CalEnviroScreen 1.1) to compare the distribution of environmental hazards and vulnerable populations across California communities. Methods. CalEnviroScreen 1.1 combines 17 indicators created from 2004 to 2013 publicly available data into a relative cumulative impact score. We compared cumulative impact scores across California zip codes on the basis of their location, urban or rural character, and racial/ethnic makeup. We used a concentration index to evaluate which indicators were most unequally distributed with respect to race/ethnicity and poverty. Results. The unadjusted odds of living in one of the 10% most affected zip codes were 6.2, 5.8, 1.9, 1.8, and 1.6 times greater for Hispanics, African Americans, Native Americans, Asian/Pacific Islanders, and other or multiracial individuals, respectively, than for non-Hispanic Whites. Environmental hazards were more regressively distributed with respect to race/ethnicity than poverty, with pesticide use and toxic chemical releases being the most unequal. Conclusions. Environmental health hazards disproportionately burden communities of color in California. Efforts to reduce disparities in pollution burden can use simple screening tools to prioritize areas for action. Communities of color in the United States often reside in neighborhoods with worse air quality, 1 more environmental hazards, 2 and fewer health-promoting environmental amenities such as parks. 3 This unequal distribution of exposures may contribute to racial/ethnic health disparities in environmentally sensitive diseases such as cancer and asthma. 4 Research has shown that communities of color in California experience higher cancer risk from toxic air contaminants 5 and higher average levels of nitrate contamination in their drinking water 6 and that they live closer to hazardous waste sites 7 and traffic. 8 However, less is known about the extent to which communities of color are simultaneously exposed to multiple potential sources of pollution and the implications of such coexposures for health. There is, thus, an increasing need for analytic frameworks and decision-making tools that account for exposures to multiple environmental hazards through a variety of routes. Such frameworks should also consider differential vulnerability to the health effects of those exposures, which can vary across the population because of both individual and community-level factors. 9–11 For example, age and health status, including suffering from preexisting cardiovascular disease or asthma, have been shown to increase susceptibility to the adverse health effects of air pollution. 12–14 Several studies suggest that an individual’s educational attainment modifies the health effects of air pollution: greater effects are observed among the less educated. 15,16 Poverty can hinder access to adequate nutrition and medical care to prevent and manage the health impacts of pollution. At the community level, the concentration of poverty in disadvantaged neighborhoods can lead to conditions that increase levels of chronic psychosocial stress that weaken the body’s ability to defend against external challenges. 17 A cumulative impact approach that considers differential vulnerability and environmental stressors is particularly important for assessing racial/ethnic environmental health disparities because communities of color in the United States experience lower average levels of education 18 and wealth 19 and, for some groups, higher rates of chronic health conditions 20 that increase susceptibility to environmental health hazards. Although the field is still in its infancy, several proposed methods are used to better reflect the cumulative impacts of environmental exposures and population vulnerabilities and provide assessments that can support the incorporation of equity and environmental justice goals into policymaking. 21–24 The California Environmental Protection Agency first released such a method—the California Communities Environmental Health Screening Tool, or CalEnviroScreen—in April 2013, and an updated version, CalEnviroScreen 1.1, was published in September 2013. 25 CalEnviroScreen is a screening tool that considers both pollution burden and population vulnerability in assessing the potential for cumulative impacts across California zip codes. It was developed following consultation with government, academic, business, and nongovernmental organizations and 12 public workshops in 7 regions of the state that resulted in more than 1000 oral and written comments on 2 preliminary drafts. 26 The tool employs a model that can be adapted to different applications and as new information becomes available. For example, subsequent iterations have been developed using a finer geographic resolution and the addition of new indicators. 27 It purposefully relies on publicly available data sets for transparency and relatively simple methods so that it can be understood by a general audience. We used CalEnviroScreen 1.1 to assess the extent of geographic and racial/ethnic disparities in the potential for cumulative environmental health impacts from multiple environmental hazards in California. We employed a concentration index to examine which environmental hazards are most inequitably distributed, and we considered variations to CalEnviroScreen to evaluate the sensitivity of our findings to the structure of the model.
