The article, expected to be published in the Aug. 26 issue of the Journal of the American College of Cardiology, looks at previous research that finds inhaled pollutants set off an increase in "reactive oxygen species" -- superoxiding molecules that damage cells -- that cause not only inflammation in the lungs, but also trigger harmful effects in the heart and cardiovascular system.

"We used to think air pollution was a problem that primarily affects the lungs. We now know it is also bad for the heart," Dr. Robert A. Kloner, director of research at the Heart Institute of the Good Samaritan Hospital in Los Angeles, said in a journal news release.

Ultrafine air pollutants, such as those from car exhaust, may pass into the bloodstream and damage the heart and blood vessels directly, recent research has suggested. Studies conducted at the Heart Institute found that ultrafine air pollutants can cause an immediate drop in coronary blood flow and the heart's pumping function, and tend to cause arrhythmias to develop.

Researchers have also found increased levels of air pollution are tied to emergency hospital admissions for heart attack, chest pain and congestive heart failure, and even to death from heart disease, arrhythmias, heart failure and cardiac arrest.

"Air pollution can be dangerous at levels that are within the accepted air quality standards," said Dr. Boris Z. Simkhovich, a senior research associate at the Heart Institute of the Good Samaritan Hospital.

The report takes on special urgency given air pollution has been a major concern of athletes and spectators at the recent Beijing Olympics.

"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," Kloner said. "Of course, the real solution is to reduce air pollution."

More information

The American Academy of Family Physicians has more about the possible effects of air pollution.

SOURCE: American College of Cardiology, news release, Aug. 13, 2008

-- Kevin McKeever