Environmental justice advocates have long maintained that people of color live in communities with high pollution or toxic air contamination in much higher numbers than Whites. And a new study is now revealing one reason why: Because real estate agents encourage them to move into these areas.

Sorting or Steering: Experimental Evidence on the Economic Effects of Housing Discriminationwas released this month by the National Bureau of Economic Research, an independent economic research group. It examined what discrimination people of color face as they work with real estate agents to find homes and found that these agents are much more likely to show them houses in high-pollution areas. Per ThinkProgress:

The researchers of the new study looked at data on White, African American, Asian and Hispanic households. Information about the recommended homes to these groups was merged with information about local pollution sources from monitoring programs conducted by the U.S. Environmental Protection Agency (EPA).

“These results are the first that we know of to demonstrate housing discrimination by real estate agents to pollution exposures and to a range of other economic disadvantages,” Peter Christensen, a professor of economics at the University of Illinois, Urbana-Champaign and one of the authors of the study, told ThinkProgress.

Their findings are supported by a number of previous reports on housing, race and pollution. A joint study from November 2017 by the National Association for the Advancement of Colored People, Clean Air Task Force and National Medical Association found that the air Black Americans breathe is nearly 40 percent more polluted than that of their White counterparts. And other studies show that inhaling toxic air leads to higher rates of asthma, heart attacks and lowered life expectancy rates.

A 2017 study by the federal government looked at who is affected by the air contaminant nitrogen dioxide by race, ethinicity and socioeconomic factors. Per The Guardian:

In 2000, concentrations of [nitrogen dioxide] in neighborhoods with the smallest proportions of White people were 2.5 times higher than in areas that are overwhelmingly White. In 2010, this discrepancy increased to 2.7 times higher. The gap between White and nonwhite people is starkest in the Midwest and California.

The latest study’s authors determined that in order to address how housing discrimination leads to exposure to toxic pollution, fair housing laws must be updated to address environmental justice issues. In addition, the researchers urge elected officials to address issues of affordable housing to give lower-income earning people more options that are not in high pollution neighborhoods.