Late last year, the Trump administration moved to roll back Obama-era regulations designed to improve air quality and limit pollution. No one thought of it as an education story.

But new research suggests it is, at least in part. While the health risks of air pollution have long been documented, two recent studies are among the first to directly connect two different forms of pollution to lower test scores and higher absence rates among exposed schoolchildren.

Schools across the country — particularly those serving more low-income students of color — are often located near hotbeds of pollution, like highways.

“The results are pretty damning,” said Claudia Persico, a professor at American University and one of the researchers behind both of the studies. “These papers suggest that pollution might play a much bigger role in inequality in outcomes between rich and poor kids and between black and white kids than we previously realized.”

The two studies both examine Florida in the 1990s and 2000s.

In one, researchers Persico, Jennifer Heissel, and David Simon look at whether being exposed to pollution from a major highway affects school performance. To do that, they compare students who switch to a school downwind from a highway to similar students moving to schools upwind (and thus less exposed to that pollution).

Downwind students performed slightly worse on state tests, were 4 percentage points more likely to have a behavioral infraction and half a percentage point more likely to be absent.

In the other study, Persico and Joanna Venator examine Florida schools within a mile of toxic chemical release sites, through factories or manufacturing plants for example, which are reported to the Environmental Protection Agency.

Compared to similar students who go to school farther away, those who are closer see drops in test scores and were 1.4 percentage points more likely to frequently miss school.” The test score declines were significant enough to cause some schools to get lower grades under Florida’s high-stakes accountability system.

It’s the latest research underscoring the myriad of factors — like poverty, heat, and lead poisoning — that affect how well students do in school. These studies do not suggest that teacher or school quality doesn’t also matter for student success — a substantial body of other research show that those things are also very important.

In both studies the effect on test scores was fairly small, but the amount of pollution was not huge either.

Schools across the country are frequently located near highways or chemical release sites.

More than one in five public schools across the country are within a mile of a toxic release site, according to calculations by Persico and Venator. And a 2017 analysis found nearly one in 11 public schools nationally, enrolling 4.4 million students, are located within 500 feet of a major road.

In neither Florida study was there any evidence that students of color or low-income students suffered more from pollution exposure. However, those children are much more likely to exposed in the first place both in and out of school.

Whereas only 4 percent of schools serving predominantly white students sit next to major roads, 15 percent of those serving largely students of color do, according to the 2017 report.

There are also disparities in exposure to toxic release sites. “Part of this might be because [toxic release] sites are located in major cities very often, and where they’re located is often a legacy of residential segregation,” said Persico.

The studies appear to be among the first to directly examine the consequences of pollution over time on school-age kids in American schools. Other research, for instance, has shown how levels of air pollution on a given high-stakes test day can lower students performance on that test. But the latest studies show that pollution doesn’t just matter for how students perform on a given day, but how much they learn throughout the year.

Still other work has shown how toxic chemicals severely affect very young children. An older Florida study by Persico looked at children conceived within two miles of a toxic waste site. Compared to their siblings who were conceived after the site was cleaned, those children had lower test scores were 7.4 percentage points more likely to repeat a grade and 6.6 percentage points more likely to have a discipline infraction. Again, black and low-income children were substantially more likely to face such exposure.

“Pollution shapes the lives of children in ways we’re just starting to understand,” said Persico. “Adopting cleaner technologies and cars … might lead to pretty substantial improvements in children’s test scores and outcomes.”