People of color are exposed to more nitrogen dioxide pollution than whites in the United States. And now, research from the University of Washington has found that little progress was made in lessening the gap between 2000 and 2010.
Nitrogen dioxide (NO2) is emitted from vehicle exhaust, power plants, and off-road equipment. It is one of six principal air pollutants monitored by the Environmental Protection Agency. NO2 has been linked to asthma and increased risk of respiratory problems and heart disease.
A nationwide study was launched to investigate how much people are exposed to NO2 based on the neighborhoods where they live. The researchers estimated the outdoor concentrations of NO2 in both 2000 and 2010. The results showed a larger imbalance in NO2 exposure by race and ethnicity than by income, age, or education.
For their study, the researchers developed a model that is the first of its kind to combine satellite and regulatory measurements with land use data in order to predict pollution at a neighborhood level. Measured in parts per billion, or ppb, average annual NO2 exposure decreased from 17.6 to 10.7 ppb for nonwhite populations, and from 12.6 to 7.8 ppb for white populations between 2000 and 2010.
Despite this significant drop, the gap in exposure among races narrowed by very little. Nonwhites were exposed to 40 percent more of the pollutant in 2000, which only dropped to 37 percent by 2010. In addition, concentrations of NO2 in neighborhoods with the highest numbers of nonwhite residents were 2.5 times higher in 2000. This value increased to 2.7 times higher by 2010.
The experts estimated that 5,000 premature deaths from heart disease among the nonwhite group would have been prevented if people of color had breathed the lower NO2 levels experienced by whites in 2010.
“The finding that shocks us is that when it comes to how much NO2 a person breathes, it’s still race that matters,” said senior author Julian Marshall. “At any income level — low to medium to high — there’s a persistent gap by race, which is completely indefensible. It says a lot about how segregated neighborhoods still are and how things are segregated.”