How new tools are helping officials, communities work toward environmental justice

In a new report published in the journal Environmental Justice, Paul Mohai of the University of Michigan examined how new tools are leading to innovative policies to protect vulnerable communities from disproportionate environmental burdens.

“These tools that are coming online have been proving themselves to be very useful in both identifying disadvantaged communities, but they’ve also been groundbreaking in that they’re being used to make proactive decisions in the community,” said Mohai, professor of environmental justice at the U-M School for Environment and Sustainability.

“We’re now developing tools not just to make assessments about where environmental burdens are concentrated, but to also make decisions rather than waiting for some crisis to occur.”

Matrix approaches

In the new study, Mohai examines what are called matrix approaches. These approaches are especially powerful when vulnerable communities—for example, communities of color and low-income communities—are facing multiple concentrated environmental burdens, he said. These burdens include cancer risk, wastewater discharge, high air pollution concentrations, traffic proximity and volume, proximity to hazardous waste sites and other environmental stressors.

“The question I raise in the article is, ‘What if you have a community where there are five burdens, or even 10 or 20, that meet threshold criteria?'” Mohai said. “I think, on some intuitive level, you have to say that the probability of harm is also getting greater as the number of concentrated environmental burdens is getting greater.”

Researchers currently lack comprehensive information on the health, economic and other quality of life impacts of all the environmental burdens that they’ve studied. But new data is constantly being generated and collected, and that data has become much more accessible in recent years because of tools supported by state and federal governments.

These developments enabled Mohai and his colleague Charles Lee, an environmental justice trailblazer who is currently a visiting scholar at the Howard University School of Law, to publish a related recent study in the journal Environmental Research Letters.

In this companion piece, Mohai and Lee showed that the simultaneous concentration of multiple environmental burdens were most likely to disproportionately accumulate in communities of color and where residents had limited English fluency. The study was made possible by data from the U.S. Environmental Protection Agency’s EJScreen tool, which is now offline, but its data has been preserved for others to use by nongovernment organizations.

“Paul and Charles have been able to show that, on a national scale, environmental and socioeconomic vulnerability in American communities are highly associated,” said Andrew Geller, who was a senior science adviser with the EPA before retiring in 2025. Geller was not involved in either of Mohai’s recent studies.

“While the particular pollutants and social stressors may vary from place to place, the moral of the story Paul tells is clear: Environmental protection has not been evenly distributed across America’s communities, and action to reduce the environmental burden in places with multiple sources of pollution will likely benefit the most vulnerable among us.”

The work showed how a matrix approach could support academic research and the construction of decision-making tools where cumulative environmental impacts are a concern. The article stressed that there are already multiple matrix approach decision-making tools in existence, although they were not recognized as such at the time of their creation.

That includes the White House Council on Environmental Quality’s Climate and Economic Justice Screening Tool, or CEJST, which was created under the Biden administration and has since been discontinued. New Jersey’s Environmental Justice Mapping, Assessment and Protection Tool, or EJMAP, also uses a matrix approach. In his newest report, Mohai examined these and other tools to highlight the advantages and outlook for matrix approaches moving forward.

“Dr. Mohai’s article provides an excellent introduction and overview of how matrix approaches can enhance cumulative impact assessments and improve environmental decision making,” said Professor Jayajit Chakraborty, the Mellichamp Chair in Racial Environmental Justice at the University of California, Santa Barbara, who was not involved in the study.

“It demonstrates how matrix approaches provide a sound methodological foundation that can lead to a new generation of techniques and tools for measuring cumulative impacts, as well as the investigation of new questions relevant to environmental justice research and policy.”

Mohai’s new study was selected for a special issue of the Environmental Justice journal, which featured him, Lee and Megan Cunningham as guest editors. Cunningham is the vice president for programs at the nonprofit organization Alliance for the Great Lakes.

From data to decision-making

Over the past several decades, community leaders and researchers like Mohai have shown that vulnerable communities—for example, communities of color and low-income communities—are the most likely to shoulder the impacts of environmental burdens.

This work has also enabled experts to start mapping where environmental burdens exist and to what extent, then couple that data with sociodemographic information at the census-tract and block group levels. These data-rich maps have become tools that allow people to see where environmental and social stressors combine, which can identify which communities face the greatest accumulation of risk factors.

In 2013, the state of California took a pioneering step in coupling its statewide assessment tool, called CalEnviroScreen, with legislation to aid the most disadvantaged communities.

“What California does is take all of these diverse indicators for environmental burdens and social vulnerability—air pollution concentration, proximity to hazardous waste sites, unemployment—and they have a formula to combine those factors into a single score,” Mohai said. “If a score reaches the 75th percentile or higher, that community is considered disadvantaged and qualifies for special funding.”

The U.S. unveiled a similar policy plan during the Biden administration for its Justice40 Initiative. The initiative aimed to ensure that disadvantaged communities—as determined by the Climate and Economic Justice Screening Tool, or CEJST—received 40% of federal investments made in alleviating certain environmental and social stressors.

The federal approach, however, added an important layer of nuance compared with its predecessor in California. While the state combined different burdens to yield a single score to determine qualifications for funding, CEJST instead used an array, or matrix, of 30 different climate, environmental and other burdens. If any one of those burdens met specified thresholds in a community, including socioeconomic thresholds, it would qualify for consideration of the initiative’s special funding.

Although the U.S. scuttled the CEJST, the Justice40 program and EPA’s EJScreen when Trump took office in 2025, CalEnviroScreen is turning 13 and launched a version 5.0 in draft form this past January. Several other states and even cities, including Michigan, Maryland and Chicago, have launched their own assessment tools (and a national assessment tool maintained by the Centers for Disease Control and Prevention is still currently online because of a court order).

New Jersey is also part of that list, yet it stands out for two key reasons, Mohai said. First, the EJMAP tool itself uses a matrix approach like CEJST, but adds another layer of nuanced analysis. The tool not only determines if any one of the 26 environmental and public health stressors that are tracked exceed their threshold values, it also keeps a running total of the ones that do.

“That number matters and makes EJMAP a genuine cumulative impact decision-making tool,” Mohai said.

If that stressor count exceeds the median count for the geographic point of comparison—which is either the state or county—the community is officially considered disproportionately impacted. With rules that went into action in 2023, the state is implementing its environmental justice legislation in an innovative way.

“Basically, the law says if a community is found to be overburdened and disproportionately impacted, we’re not going to allow any new sources of pollution in that community,” Mohai said. “The law itself is groundbreaking—I’m not aware of anywhere else in the country where it has been done like that.”

In a separate study in the same special issue of Environmental Justice, researchers led by Ana Baptista, an associate professor with the New School, analyzed the extent to which states were considering cumulative impacts in their assessments (Baptista’s earlier work helped pass New Jersey’s legislation). They found that, by the end of 2024, only New Jersey and Massachusetts had implemented regulations for permitting based on cumulative impacts. But eight more states had passed laws around it and 11 more states had seen similar legislation introduced.

“There are many possibilities for action on environmental justice at the state level even while the federal policy landscape seems bleak,” Baptista said. “State policies, even when they don’t pass, give us an opportunity to innovate and grow the momentum and ambition of our work on cumulative impacts.”

Mohai agreed and is excited for what’s to come because history has already shown that people working in this field are more than willing to build on what came before to create something new.

“We’re not just repeating the same things, and I think that’s important because we can find more ways to build on and expand these tools in order to cover as wide a range of decision-making contexts as possible,” he said. “Many states have done some really promising things and they’re showing the way for other states. And, at some point in the future, I think they’ll be very valuable in showing the way for federal policy.”

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