HEALTH
Traffic congestion linked to heart attacks
September 9, 2009
Joseph Hall
HEALTH REPORTER
Fuming Gardiner Expressway congestion might spew out enough pollution to cause heart attacks in people with coronary artery diseases, a new University of Toronto study suggests.
The research showed that particulate pollution at levels that might be generated by a Gardiner backup could significantly raise blood pressure and cause vessels to constrict – a potentially fatal circumstance for people with clogged coronary arteries, one of the paper's authors says.
"People who are close to having problems, when they're exposed to the pollution, it sort of tips you over the edge," says Bruce Urch, an air pollution expert at U of T and a co-author of the study.
Urch says people with arteriosclerosis – hardening of the arteries – could be placed in particular danger by high pollution levels.
"It can constrict your coronary blood vessels and if you're 95 per cent blocked ... then that's going to be a severe thing to happen," he says. "A little bit more (artery shrinkage) would be deadly."
Alternately, sudden, arterial inflammation could cause plaque deposits lining the vessels to break off into clots, creating heart attack or stroke dangers.
The paper appears in the current edition of the journal Hypertension, published by the American Heart Association.
While the study subjected participants to noxious levels of pollution found in places like Mexico City, Urch says that a jammed up Gardiner or Don Valley Parkway could generate such eye-searing, atmospheric soups.
The study was conducted on 83 healthy students – 33 in Toronto and another 50 at the University of Michigan, which collaborated on the paper.
Using special, pollution-generating equipment, air was sucked in from outside Urch's downtown College St. lab, where many of the natural gases were removed to concentrate the small particles that typically contaminate this city's air.
Ozone, another pollutant, was also added to the mix, creating air that was about twice as smoggy as you'd find on a particularly smoggy day in this city.
Sitting in Plexiglas booths, student volunteers were then subjected to the high-octane ooze, breathing it in through face masks for two-hour stretches.
During that time, the subjects' diastolic pressure – the bottom number on standard blood pressure readings – climbed an average of five points.
"In a healthy, normal subject that's nothing, it wouldn't do anything," Urch says.
"But if you had hypertension, or you had a respiratory condition or a heart condition ... then that may be more of an issue."
Past studies have shown the connection between smog and heart attacks. But the most recent paper broke down the dirty air into its particulate and ozone components, Urch says.
"What we found was the effects we saw were mainly due to the particles and not due to the ozone," he says. "So it just helps with assessing what's the main thing that's causing events."
While the particles don't actually enter the bloodstream, Urch speculates that they might trigger inflammatory enzymes in the body that cause vessels to constrict.
Toronto Star
Featured Sponsored Listings