The One-Two-Three Punch: Exposure, Susceptibility, and Disease Burden among U.S. Populations of Color.

Multiple studies have demonstrated that people of color in the United States are typically exposed to higher levels of air pollution than White Americans, regardless of income.[1,2,3] This persistent inequity appears to increase vulnerability to pollution-related disease among these groups.[4] The authors of a new paper in Environmental Health Perspectives explored whether health disparities might be reduced if federal regulators considered differences in the association between air pollution exposure and mortality across different racial/ethnic groups.[5]

Many of the same policies and practices that have led to poorer air quality in communities of color, such as redlining and inequitable siting of freeways and industrial facilities, have also increased residents’ vulnerability to pollution, according to the authors of the new paper. “In the end, what we have is a manifestation of different facets of systemic racism that have left Black American communities in particular with less access to health care, less access to educational opportunity, worse socioeconomic factors, and less access to credit,” says first author Elisheba Spiller, a lead senior economist with Environmental Defense Fund (EDF). “All of the systemic racism that’s part of our society has built up to these communities having worse health outcomes when exposed to environmental pollution.”

Charles Claville stands in his front yard, which is across the highway from the Valero refinery in Port Arthur, Texas, 29 August 2014. A history of practices such as redlining and siting industrial facilities near communities of color has left a legacy of disparate exposures to environmental pollution among Black Americans. Image: © AP Photo/David J. Phillip.

A 2017 report in the New England Journal of Medicine helped quantify this disparity in susceptibility by calculating race-specific concentration–response functions (CRFs), or estimated relationships, between air pollution and mortality, based on a representative nationwide sample of Medicare recipients.[4] This influential study suggested that Black, Asian, and Hispanic Americans, as well as less-affluent people overall, had a higher estimated risk of death from any cause in association with exposure to fine particulate matter (), compared with the general population.

Spiller et al. built on this work by demonstrating how the use of race/ethnicity-stratified CRFs can provide a more accurate picture of pollution-related adverse health outcomes nationwide. In contrast, federal regulators currently rely on CRFs derived from studies of largely White populations.[6,7]

The authors applied race/ethnicity-specific CRFs to estimate -related premature death for Black, White, Hispanic, Asian, and Native Americans over 65 years of age. Compared with estimates using nonspecific CRFs, the estimates using alternative CRFs were higher by approximately 150% for Black Americans, 52% for Hispanic Americans, 34% for Native Americans, and 28% for Asian Americans, but lower by approximately 13% for White Americans. Overall, applying race/ethnicity-specific CRFs increased the estimated number of -related premature deaths in older populations by a net 9%.

Devon Payne-Sturges, an associate professor at the University of Maryland, says the study is an important and timely contribution to the environmental justice literature. “There has been a longstanding need to do the kind of analysis that they did in this paper, but it really hasn’t been done, and certainly hasn’t been done in the policy context, to inform a policy decision,” says Payne-Sturges, who was not affiliated with the study. “This paper comes at a really important time, given the enhanced interest in environmental health disparities, environmental justice, and health inequities.”

Harvard University professor of biostatistics Francesca Dominici, who coauthored the 2017 paper that provided the foundation for this study, says that although the precise CRFs used in the study can be further refined, the overall findings and messages stand. “I think that the results are extremely interesting and potentially very powerful,” she says. “I also think that this general idea of estimated ethnicity- or race-specific concentration–response functions is really central to the issue of environmental justice and environmental health disparity.”

In recent months the U.S. Environmental Protection Agency has for the first time used race/ethnicity-specific CRFs in its policy assessment for reconsidering the National Ambient Air Quality Standard for , a precursor to reviewing the standard itself.[8] Although the agency chose not to incorporate the stratified CRFs into the main review of the standard, it documented racial disparities in its consideration of impacts on at-risk populations. “This is an important acknowledgment of the issue,” says Ananya Roy, an EDF senior health scientist and coauthor of the new paper.

“There is increasing awareness that people of color and minority populations are seeing not only higher exposures but also much larger adverse effects and that they already bear higher burdens of disease in their communities, creating a one-two-three punch,” says Roy. “What we are doing here in this paper is explicitly incorporating that [reality] structurally into our assessments of policies and decision making. That’s what we are calling for here.”