Do we really all breathe the same air? Pollution is segregated, too

From [HERE] Studies dating back to the 1970s have pointed to a consistent pattern in who lives near the kinds of hazards --  toxic waste sites, landfills, congested highways -- that few of us would willingly choose as neighbors. The invariable answer: poor people and communities of color.

This pattern of "environmental injustice" suggests that minorities may contend every day with disproportionate health risks from tailpipe exhaust or coal plant emissions. But these health risks are harder to quantify than, say, the number of power plants in a city. And most of the research that has tried to do this has been limited to a single metropolitan area, or to those few places that happen to have good monitoring data on pollution.

Now, however, researchers at the University of Minnesota, writing in the journal PLOS ONE, have created a sweeping picture of unequal exposure to one key pollutant -- nitrogen dioxide, produced by cars, construction equipment and industrial sources -- that's been linked to higher risks of asthma and heart attack. They've found, all over the country, in even the most rural states and the cleanest cities, that minorities are exposed to more of the pollution than whites.

"The biggest finding is that we have this national picture of environmental injustice and how it varies by state and by city," says Julian Marshall, a professor of environmental engineering at the University of Minnesota and one of the authors of the study along with Lara P. Clark and Dylan B. Millet. "The levels of disparity that we see here are large and likely have health implications."

Specifically, they found that minorities are on average exposed to 38 percent higher levels of outdoor NO2 than whites in the communities where they live, based on demographic data from the 2000 census. That gap varies across the country, though, and it's substantially wider in the biggest cities. Nationwide, the difference in exposure is akin to approximately 7,000 deaths a year from heart disease.

"It’s a shockingly large number," Marshall says. "You’re taking what's a major killer of people [in heart disease] and increasing it slightly, by a few percent. But that’s a lot."

Regionally, the disparities are largest in the upper Midwest and the Northeast, but the model Marshall and his coauthors developed can drill down from there. These maps show the differences in average exposure to NO2 between low-income nonwhites and high-income whites: [MORE]