Particulates Can Cause Heart Attacks
By Cat Lazaroff
(ENS)-As few as two hours after being inhaled, tiny, invisible air
pollutants can penetrate the lungs’ natural defenses and trigger a
heart attack, says a recent report in Circulation: Journal of the
American Heart Association.
Previous studies have shown that long-term exposure to air
particulates can initiate a chain of events that trigger a heart
attack in individuals with cardiovascular disease or cardiovascular
risk factors. The current study is the first to examine short-term
effects of air pollution on the risk of heart attack.
Between January 1995 and May 1996, researchers interviewed 772
Boston-area heart attack patients about four days after their heart
attack to establish when their symptoms began. Researchers compared
the times heart attack symptoms began with daily air pollution
measurements, paying special attention to levels of the smaller
pollutants.
“These tiny particles are known as PM2.5 because they measure less
than 2.5 micrometers in diameter,” explained study coauthor Dr.
Douglas Dockery, professor of environmental epidemiology at the
Harvard School of Public Health. “They are so small that they can get
past the normal defense mechanisms in the lungs and penetrate deeply
into the air exchange regions, or alveoli.”
The study concluded that there was a 48 percent higher risk of heart
attack when PM2.5 concentrations increased by 25 micrograms per cubic
meter of air in the two hours before symptoms began. Fine particulate
air pollution is produced primarily by automobile engines, power
plants, refineries, smelters and other industries. Larger, more
readily noticed particles of airborne dust and debris from farming,
construction work and mining are less likely to trigger heart attack.
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