Is building housing developments near major roadways a bad public health practice?
People may heart New York, but cities in general are hard on the ol' ticker. As previously reported by CityLab, exposure to traffic noise may increase rates of hypertension. Living near a foreclosed home could increase your risk of heart attack, too. Now, another heart-health risk factor has been added to the list: living close to major roadways.
New research from the Journal of the American Heart Association indicates that those living adjacent to large roadways may be at greater risk to develop high blood pressure. Among 5,400 San Diego women, high rates of systolic blood pressure were 9 percent more frequent among those living 100 meters or less from freeways, freeway ramps, and major arterial roads compared to those living 1,000 meters or farther. Given that one-third of American adults are estimated to suffer from high blood pressure, these results could have important urban planning implications. Could a move to build residences away from major roadways, for example, improve public health? (Even though that convenience factor might be what brought you to the city in the first place?)
“There are a lot of new developments going up right near highways,” says Gregory Wellenius, assistant professor of epidemiology at Brown University in light of the study’s findings. “One has to start thinking about what the associated health effects are with that."
Scientific constraints forced the researchers to speculate as to why households adjacent to roadways might experience greater rates of hypertension. Traffic-related air pollution, believed to attack the heart in a number of ways, is the most likely culprit.
“A large body of literature indicates that short-term exposure to traffic-related air pollution is associated with increased cardiac sympathetic nervous system activity, vascular resistance, and blood pressure,” the research team writes. Moreover, the toxicity of air pollutants doesn’t significantly diminish until they’ve traveled 150 meters or more from its source, according to a 2010 CDC report. Thus, homes 100 meters or less from a major roadway are in the direct path of highly potent chemicals.
The new study’s conclusions are upheld by a number of trial adjustments. When adjusting for variations in race, age, habitual smoking, education level, history of diabetes, and household income, their conclusions remained constant. (A factor they could not control—despite its possible impact on the results—is household diet.)
But these findings need not paint city life as inherently hazardous to your health. Many aspects of urbanity contribute to healthy lifestyles. Women that live in cities with robust vegetation are believed to give healthier births. CityLab’s recently conducted State of the City Poll found that most urban residents are happy with their access to parks. It’s hazardous externalities—like air pollution from a nearby highway—that reduce the quality of urban life.
The question is: How far can we keep those from our front doors while also being able to get to work on time?