Research led by U-M could help regulators better protect marginalized communities from outsized accumulation of pollution, other environmental stressors
Study: Cumulative Environmental Burdens and Vulnerable Populations: Taking into Account the Intensity and Count of Burdens in Environmental Justice Analyses (DOI: 10.1088/1748-9326/ae2c0d)
Vulnerable communities in the United States often face the highest risks from individual environmental burdens, such as exposure to toxic air pollutants. But new research shows that these communities are also exposed to a disproportionate number of multiple high-intensity burdens at once.
"We found very strong relationships between where multiple burdens are concentrated and where vulnerable populations are also concentrated," said Paul Mohai, lead author of the new report and a professor at the University of Michigan School for Environment and Sustainability, or SEAS.
In particular, the study found that communities of color and communities with limited English fluency face an outsized likelihood of experiencing multiple burdens at once. Put another way, if you find an area in the U.S. where burdens concentrate, that's a strong predictor that it's also home to one of those two communities-more so than any other sociodemographic group.
"These relationships were stronger for racial and ethnic categories than for other socioeconomic categories, reflecting outcomes of a long history of public policies that have segregated and disadvantaged certain populations in the U.S.," Mohai said.
The report was published in the journal Environmental Research Letters and co-authored by Charles Lee, a visiting scholar at the Howard University School of Law and former director of the Office of Environmental Justice at the U.S. Environmental Protection Agency.
Both Lee and Mohai have worked for decades in the field of environmental justice, which examines how the environmental impacts of modernization and industrialization are distributed across different communities and demographics. Research from this field has helped inform policies that attempt to make the distribution of environmental benefits more equitable and reverse historical trends that have placed outsized environmental burdens on already vulnerable communities (in fact, both Lee and Mohai have supported federal environmental justice efforts under previous administrations).
Because of data limitations, however, the vast majority of existing research in this realm focuses on environmental burdens separately, one or two at a time. The new study looked at the combination of up to 13 environmental burdens in more than 84,000 census tracts across all 50 states and Puerto Rico, while also considering the intensity or magnitude of those burdens.
"People don't live with one type of pollution at a time," Lee said. "They live in communities that can have a lot of pollutants and social stressors that can lead to great impacts."
Recently, New Jersey became the first state to require mandatory denial of permits in areas overburdened by cumulative impacts, which are assessed with help from its Environmental Justice Mapping, Assessment and Protection Tool. Lee said the new study could help make such tools and approaches more robust and accessible for more states and communities across the country.
"What Paul has done is validate the existence and viability of a new generation of cumulative impact tools," Lee said. "I don't think that's an overstatement."
Experts who peer-reviewed the study, who are granted anonymity to share candid feedback, agreed.
"Overall, this is an excellent paper that is likely to be highly influential in the analysis of environmental justice in the U.S.," one wrote.
An inflection point
The availability of sufficient data had been the primary reason that researchers were limited to exploring individual burdens one at a time, Mohai said. But that has been changing as states and the federal government began collecting and sharing available information.
That culminated with the creation of the national assessment tool, EJScreen, about a decade ago. Working with EJScreen's data, Mohai could simultaneously analyze up to 13 different burdens that included wastewater discharge, toxic air pollutants and proximity to superfund sites contaminated with hazardous waste. Census data also allowed the duo to see where these burdens accumulated geographically and understand the demographic makeup of communities in those areas.
"That reflects the shape and contours of these issues as they are manifested within the United States," Lee said. "This has a lot of relevance to help better understand the processes that led to this-say, for example, redlining-and their impact in terms of the creation and structuring of American neighborhoods."
While the data now exists to enable such a study, Mohai stressed that researchers can always use more. One of the limitations Mohai and Lee encountered, for example, is that the health and economic consequences aren't yet documented for every environmental burden.
"We don't actually have data that reflect the impacts on the population," Mohai said. "But it is a very reasonable and strong hypothesis to say, as the intensity and counts of these burdens are increasing, the likely harm is also increasing."
Although the current presidential administration is working to eliminate federal support for such efforts-it has effectively shut down the EJScreen tool-researchers, policymakers and community leaders are continuing the work at the state and local levels, Mohai said.
"I think this type of work will only stop when the problems are solved," Mohai said. "As long as the disparities and inequities exist, we're going to see continued attention to these issues."
