Traffic
Photo: Tim McCaig/iStockphoto
"Within 100 to 200 meters of a major road is where you'll find elevated levels of a handful of major pollutants," says Jonathan Levy, ScD, associate professor of environmental health and risk assessment at the Harvard School of Public Health. Soot and nitrogen oxide from car and truck exhaust are most concentrated within this zone—though vehicle emissions can travel up to 500 meters. Stop-and-go driving—whether it's on city streets or suburban freeways—generates as much as three times the pollution of free-flowing traffic.

The health costs can be chronic respiratory problems like asthma and bronchitis. Other research suggests that car pollution may harm the cardiovascular system, triggering clots and inflammation in blood vessels, hardening the arteries, and elevating blood pressure. Exposure to exhaust pollutants has also been linked to cancer (breast, lung, leukemia) and preterm birth.

The Sound of Traffic

Besides cars and trucks, the churn of unwanted sound from construction, booming stereos, barking dogs—you name it—acts as a stressor, eliciting the body's fight-or-flight response, which can translate to higher blood pressure and heart rate. The World Health Organization estimates that roughly 3 percent of ischemic heart disease in Europe is attributable to long-term exposure to traffic noise.

Save Yourself

"Within 100 to 200 meters of a major road is where you'll find elevated levels of a handful of major pollutants," says Jonathan Levy, ScD, associate professor of environmental health and risk assessment at the Harvard School of Public Health. Soot and nitrogen oxide from car and truck exhaust are most concentrated within this zone—though vehicle emissions can travel up to 500 meters. Stop-and-go driving—whether it's on city streets or suburban freeways—generates as much as three times the pollution of free-flowing traffic.

The health costs can be chronic respiratory problems like asthma and bronchitis. Other research suggests that car pollution may harm the cardiovascular system, triggering clots and inflammation in blood vessels, hardening the arteries, and elevating blood pressure. Exposure to exhaust pollutants has also been linked to cancer (breast, lung, leukemia) and preterm birth.


The Upside to City Living

Urban dwellers can take comfort in the fact that their mean streets also give them plenty of opportunities to improve their health. "People who live in walkable communities have exercise built into their daily life, as opposed to those who are dependent on the automobile," says Andrew Darrell, New York regional director of the Living Cities program at Environmental Defense, a national nonprofit dedicated to finding solutions to environmental problems. A study in the American Journal of Preventive Medicine found that people living in neighborhoods with a mix of shops and businesses in easy walking distance were 35 percent less likely to be obese.

There's also virtue in a city's social density: "Because people live so close to each other, they tend to develop deeper social networks," says Darrell. It's hard not to make friends or find supportive individuals when you're so tightly packed, he says.

Ultimately, where you live may be a matter of environmental trade-offs. "If you're near a major road but, in exchange, you're able to walk a lot, you may be getting net benefits for your health," says Levy.