Breathing. It is easy for most of us, but not for the 25 million Americans with asthma. Being black or Hispanic, poor, and young are among the risk factors for asthma. African Americans were three times as likely to die of asthma-related causes in 2009 as whites. Research reported recently in PLOS One, the open-access, peer-reviewed, online scientific journal, provides some interesting data to help explain why.

The study, by researchers at the University of Minnesota, with funding from the National Science Foundation, found that outdoor nitrogen dioxide exposure is 38 percent higher for nonwhites than for whites. And nitrogen dioxide exposure is linked to asthma, as well as to heart disease, low birth weights, and other negative health effects. Young children and the elderly are particularly vulnerable to its harmful effects on the lungs. Nitrogen dioxide comes from cars (specifically internal combustion engines) and from power plants. In plain language, if you live near a highway or a power plant, you are more likely to end up in the emergency room or the hospital.

A map (below) based on the PloS One study shows that Pennsylvania ranks No.1 among contiental states with the largest race-and-income pollution gap (or No. 2 based on race alone). New Jersey is No. 3 (or No. 5 based on race alone). The reasons have to do with the location of environmentally hazardous facilities–near poor, minority communities. The data present a pretty clear case of environmental injustice and inequality. This isn't just about pleasant-smelling air; disparities in exposure translate to serious health problems and higher rates of mortality.

Environmental justice is defined by the Environmental Protection Agency as “the fair treatment of and meaningful involvement of all people regardless of race, color, national origin, or income with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies.” Nice goal, but how do we get there?

Just knowing is a start. The California Environmental Protection Agency, for example, has compiled a list of the most-polluted census tracts in the state, along with a mapping tool to help locate and compare them. That would be useful here. There are no simple answers, however, to reducing neighborhood or urban pollution levels. Using zoning laws to prevent poor neighborhoods from being burdened with pollution-emitting plants and new highways, however, and the regulation of emissions, are important steps.

We can reduce mortality rates that are driven by environmental injustice. Clean air, after all, saves both lives and money. The new federal emission standards for cars and gasoline, issued by the Environmental Protection Agency in March, are aimed at reducing vehicle emissions, although they don’t take effect until 2017. You probably don’t want to read the new rules but you should breathe a sigh of relief that they have finally been enacted. Then, we all need to take another breath and get busy addressing the problems of environmental injustice and outdoor air pollution that continue to face us today.

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