Dodging Traffic Pollution's Lung Effects
The Scenic Route May Beat City Streets for Asthma Patients' Lungs
Dec. 5, 2007 -- Your lungs may thank you for limiting your exposure to
traffic pollution, especially if you have asthma, two new studies show.
Here's the quick version of the findings:
- Asthma patients had more lung inflammation while strolling a busy street
than in a park.
- If the air gets cleaner, lungs tend to act younger longer, even in people
The studies are a "remarkable" look at air pollution's effects in
the real world, states an editorial published with the studies in tomorrow's
edition of The New England Journal of Medicine.
Asthma and Diesel Fumes
The first study took place in London's bustling Oxford Street and Hyde
Oxford Street, London's busiest shopping area, only allows diesel-powered
buses and taxis. Hyde Park doesn't allow any traffic on its 350 acres.
In the study, 60 adults with mild or moderate asthma spent two hours
strolling along Oxford Street. More than three weeks later, they spent two
hours walking in Hyde Park.
The researchers monitored the patients' lung function before, during, and
after each walk. Those tests show more lung inflammation on Oxford Street than
in Hyde Park.
During those walks, the air along Oxford Street was also grittier than the
air in Hyde Park, based on real-time checks of fine particulates (a type of air
The patients didn't report any asthma symptoms during either
walk. But people with more severe lung problems might be more affected,
according to the researchers.
Imperial College's James McCreanor, MRCP, and colleagues aren't telling
asthma patients to steer clear of Oxford Street.
But they say their study shows that the degree of traffic exposure matters
in asthma patients' lung function.
Other factors -- including city stress on Oxford Street and the
soothing scenery of Hyde Park -- may have affected the results.
Lungs Like Less Air Pollution
Don't have asthma? Your lungs may also appreciate a drop in air
Lung function typically declines with age. But that decline may happen more
slowly when air pollution eases.
Swiss scientists report that news based on an 11-year study of more than
4,700 adults in Switzerland.
At the start and end of the study, participants took lung function tests.
The researchers also checked air pollution levels in each participant's
Air pollution levels fell during the study. And the decline in lung function
slowed with the decline in air pollution.
It didn't take a massive drop in air pollution for that to happen. Even
"relatively small reductions" in particulates have "measurable
benefits for lung function," write the researchers.
They included Sara Downs, PhD, of Switzerland's University of Basel.
In both studies, pollution levels were below the levels set by the World
Health Organization and U.S. Environmental Protection agency, notes a journal
"These studies provide additional biologic data indicating that
relatively low levels of airborne particles have adverse effects on human
health. Are our standards too high?" asks Morton Lippmann, PhD, in his
Lippman works in the environmental medicine department at New York
University's medical school.