Over the years, a mountain of evidence has brought to light a stark injustice: Compared with white Americans, people of color in the United States suffer disproportionately from exposure to pollution.

Now, a new study on a particularly harmful type of air pollution shows just how broadly those disparities hold true. Black Americans are exposed to more pollution from every type of source, including industry, agriculture, all manner of vehicles, construction, residential sources and even emissions from restaurants. People of color more broadly, including Black and Hispanic people and Asian-Americans, are exposed to more pollution from nearly every source.

The findings came as a surprise to the study’s researchers, who had not anticipated that the inequalities spanned so many types of pollution.

“We expected to find that just a couple of different sources were important for the disparate exposure among racial ethnic groups,” said Christopher W. Tessum, an assistant professor in environmental engineering and science at the University of Illinois at Urbana-Champaign, who led the study. “But what we found instead was that almost all of the source types that we looked at contributed to this disparity.”

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These findings were consistent with the experiences of communities on the ground, said Robert D. Bullard, a professor at Texas Southern University who has written for more than 30 years about the need to redress environmental racism, and who was not involved in the study.

“If you go to communities of color across this country and ask them, ‘What’s the source of the environmental problems?’ they can point you to every one: the highway, the chemical plants, the refineries, the legacy pollution left over from decades ago, in the houses, in the air, in the water, in the playgrounds,” he said. “Empirical research is now catching up with the reality: that America is segregated and so is pollution.”

On Wednesday, the Environmental Integrity Project, a nonprofit group founded by former officials from the E.P.A., released a separate report that found that 13 refineries across the United States had released elevated levels of benzene, another harmful pollutant, into mostly minority and lower income neighborhoods in 2020.

These disparities have roots in historical practices, like redlining, under which the federal government marked certain neighborhoods as risky for real estate investments because their residents were Black. For decades, residents of redlined areas were denied access to federally backed mortgages and other credit, fueling a cycle of disinvestment and environmental problems in those neighborhoods.

“Communities of color, especially Black communities, have been concentrated in areas adjacent to industrial facilities and industrial zones, and that goes back decades and decades, to redlining,” said Justin Onwenu, a Detroit-based organizer for the Sierra Club. “And a lot of our current infrastructure, our highways, were built on — built through — Black communities, so we’re breathing in diesel emissions and other pollution just because we’re located right next to these highways,” Mr. Onwenu said.