A new study by the U.S. Environmental Protection Agency (EPA) has found
associations between tiny particles in the air inside automobiles and
cardiovascular health. The study, published in the second issue of the
April 2004 American Journal of Respiratory Health and Critical Care
Medicine, is a part of EPA’s ongoing efforts to reduce the public’s
exposure to air pollutants.
In the study, healthy highway-patrol officers were monitored
during nine-hour shifts. Researchers measured the air pollutants inside
and outside their vehicles and examined their cardiovascular status
before, during and after their shifts. Monitors inside the patrol cars
measured the type and amount of several pollutants including particles,
ozone, nitrogen dioxide and carbon monoxide.
The results of the study show signs of cardiovascular stress
attributable to particulate matter inside, not outside, the vehicles.
Particulate matter are small particles (about 30 times smaller than the
width of a human hair) that are emitted from cars and trucks, coal-fired
power plants and industry. These particles are breathed into the lungs,
where they can stay for a long time, potentially causing significant
Researchers also found changes in heartbeat rhythm and changes in
the blood that can lead to the formation of clots — a risk factor for
heart attacks. While these small changes did not pose a health concern
to the younger troopers, researchers fear they may be a concern to the
elderly with heart disease.