WebMD Medical News
Elizabeth Klodas, MD, FACC
Aug. 13, 2008 -- Researchers say breathing in polluted air does more than
damage the lungs; it harms the heart, too.
Air pollution levels do not need to be very high to cause harm, researchers
report in the Aug. 25 issue of the Journal of the American College of
Cardiology. Air pollution -- even at levels deemed
"acceptable" by the Environmental Protection Agency -- leads to short-
and long-term injury to the heart and blood vessels, increases rates of heart
disease-related hospitalizations, and can even cause death.
"There doesn't have to be an environmental catastrophe for air pollution
to cause injury," Boris Z. Simkhovich, MD, PhD, a senior research associate
at the Heart Institute of the Good Samaritan Hospital and an assistant
professor of research medicine at the Keck School of Medicine, University of
Southern California, says in a news release. "We're talking about very
modest increases. Air pollution can be dangerous at levels that are within the
accepted air quality standards."
Air quality levels in the U.S. are based on five major pollutants:
ground-level ozone, particle pollution (including smoke from wildfires and
emissions from vehicles and power plants), carbon monoxide, sulfur dioxide, and
nitrogen dioxide. The air quality index (AQI) runs from 0 to 500. The higher
the number, the more toxic the air and the greater the health concern. An AQI
under 100 is generally considered acceptable.
Data documenting the ill effects of air pollution dates back more than a
century. In 1872, one of the first air-pollution studies detailing the toxic
components of urban air was published.
Recent studies show that the ultrafine particles found in polluted air can
pass into a person's bloodstream and travel to the heart, where they can cause
an inflammatory response. This may reduce the ability of the heart to pump
blood effectively to the body, raise blood pressure, and diminish blood flow
through coronary arteries -- the vital blood vessels which supply the heart
with its oxygen and nutrient supply. Exposure to pollutants can also predispose
individuals to experience irregular heartbeats.
Simkhovich and colleagues published their report after reviewing data from
numerous studies regarding air pollution's dangerous health effects. The
researchers write in the journal report that the evidence "unequivocally
indicate[s] pollution is directly linked to the adverse cardiovascular outcomes
in the general population, and effects are seen at levels at or below existing
air quality standards."
Specifically, both animal and human studies have shown that breathing in bad
Long-term studies involving a large group of people have linked spikes in
air pollution to emergency hospital admissions due to heart attacks, chest
pain, heart failure, and even heart-related death.
The elderly and people with existing heart disease or diseases that damage
the blood vessels (such as diabetes) are especially vulnerable to the harmful
heart-related effects of air pollution. In the U.S., air quality index levels
over 100 are considered dangerous for sensitive individuals, such as those with
heart or lung disease.
"Patients with cardiovascular disease shouldn't exercise outside on days
with increased air pollution levels. On very polluted days, they should
consider staying inside, and during the winter, they should limit exposure to
fireplace smoke," Robert A. Kloner, MD, PhD, director of research at the
Heart Institute of the Good Samaritan Hospital and a professor of medicine at
the Keck School of Medicine, University of Southern California, says in a news
release. "Of course, the real solution is to reduce air pollution."
SOURCES:News release, American College of Cardiology.Simkhovich, B. Journal of the American College of Cardiology, Aug.
26,2008; vol 52: pp 719-726.
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