Daily Dose

Boston 4th for racial disparity in pollution exposure

People of color in Boston and most major American cities are exposed to more air pollution than whites, according to a new study from the University of Minnesota.

On average, across the country, nonwhites are exposed to 38 percent higher levels of nitrogen dioxide than whites, the study found.

That extra exposure leads to an additional 7,000 deaths a year among nonwhites from heart disease alone, according to the research, published in the April 15 issue of PLOS ONE.

Boston ranks worse than its size would suggest, said Julian Marshall, a study author and civil engineering associate professor at the University of Minnesota. Boston, the 10th largest metropolitan area in the country, has the 16th worst pollution level, but the 4th biggest gap between white and minority exposures, he said.


Overall, the tiny group of black hispanics is the most exposed to air pollution, followed by Asian-Americans, Hispanics of any race, and then blacks. Neighborhoods with mainly non-Hispanic whites saw the least exposure, regardless of income, with the lowest-income whites exposed to less than even the highest-income Asians, Marshall said.

His team’s study is the first to use satellite observations, measurements by the Environmental Protection Agency, and land use maps to examine disparities in air pollution exposure.

The biggest sources of nitrogen dioxide are car and truck emissions, followed by construction equipment and electricity generation, Marshall said. It makes sense, he said, that the highest levels of the pollution would be found in urban centers and along highways.

Rates of pollution generally go down with city size, and the gaps get smaller, the study shows. In rural areas, whites are exposed to more pollution than blacks, though Hispanics are exposed to substantially more than both those groups, regardless of income.

Lifestyle factors -- such as smoking, diet, drinking habits, and exercise -- have a bigger effect on health than pollution exposure, though, Marshall said.


Karen Weintraub can be reached at