Overall air pollution in the United States has decreased since 1990, but people of color are still more likely to be exposed to pollutants than white people, regardless of income level, new research shows.

Air pollution is linked to multiple health conditions, including heart disease, cancer, and cognitive decline. These effects vary depending on the source of air pollution. And not everyone is equally exposed to poor air quality.

For the new study in Environmental Health Perspectives, researchers investigated disparities in exposure to six major air pollutants in 1990, 2000, and 2010 by comparing models of air pollution levels to census data—including where people live, their racial/ethnic background, and their income status.

Disparities varied from location to location, but for all years and pollutants, a racial/ethnic minority group had the highest level of exposure. This trend continued in 2010, despite cleaner air overall. One limitation to this approach, the researchers say, is that the pollution models reflect national averages, so they might not be as good at catching unusual pollution events in some communities.

“Essentially, our research is showing these disparities exist,” Liu says. “We’re trying to catch people’s attention and show what is happening now. We hope this information will motivate change.”

Read the full article about air pollution racial disparities by Sarah McQuate at Futurity.