Long-term exposure to traffic pollution could be linked to kidney damage, according to a new study.

Scientists looked at the kidney function of 1,100 stroke patients at a hospital in Boston, Mass., half of whom lived within 1 kilometer (about two-thirds of a mile) of a major road and half of whom lived between 1 and 6 k.m. of a major road. They found the patients who lived closest to a road had the worst kidney function, and that the difference between the two groups was comparable to adding four years onto the kidneys of the group who lived closest to traffic pollution.

The study joins a wealth of research linking air pollution to a range of health problems. Long-term exposure to air pollution has been found to increase a person’s risk of heart attack and stroke — a finding that may help explain traffic pollution’s ties to kidney health, as the health of the two organs is often related. In addition to that, women’s exposure to high levels of traffic pollution in the first two months of pregnancy greatly increases the risk of severe birth defects in the unborn child. Traffic pollution has been cited as causing nearly 5,000 deaths per year in the United Kingdom, and in China, where the smog is so bad it often obscures Beijing buildings, air pollution exposure contributes to 1.2 million early deaths per year.

Despite the well-documented negative side effects of air pollution, it continues to be a pervasive problem in the U.S. In its recent State of the Air report, the American Lung Association found more than 40 percent of Americans live in areas where air pollution counts often reach dangerous levels.

And dirty air often disproportionately affects low-income people and minorities. Last year, a report found people living in poor neighborhoods breathe in more toxic particles from air pollution than people in wealthy neighborhoods, and a study of metro Atlanta, Ga. counties found areas with 75 to 100 percent minority populations contained more than twice the amount of pollution sources as areas that were mostly white. That means that low-income and minorities are more subject to the health effects of dirty air, too — in 2011, according to a Centers for Disease Control and Prevention report, nearly one in four low-income Hispanic or Puerto-Rican children had been diagnosed with asthma, a condition exacerbated by air pollution, compared to about one in 13 middle-class or wealthy white children.

via Why Air Pollution Is Bad For Your Kidneys | ThinkProgress.