Heart disease is not only a product of genetic factors or lifestyle choices, air pollution also puts people at an increased heart attack risk, suggests a study led by Aruni Bhatnagar of the University of Louisville.
Evidence has shown that increase in particulate air pollution is also associated with an increase in heart attacks and deaths.
During the study, Bhatnagar found that risk of heart attack increases in parallel with time spent in traffic.
In animal experiments, she has found that aldehydes -- a toxic class of chemicals present in most forms of smoke, including cigarette smoke and car exhaust-can increase blood cholesterol levels and activate enzymes that cause plaque in the blood vessels to rupture.
When the plaque ruptures, it can cause a blood clot that may, in turn, block an artery and lead to a heart attack.
In another study, researcher Robert Brook of the University of Michigan found a link between air pollution and hypertension.
He said that fine- and ultra-fine particles that get into the lung might make their way into the blood vessels, and within 15 minutes of inhaling pollutants, there is a very rapid increase in blood pressure.
For people living in areas with high levels of air pollution, Brook recommended to exercise indoors, because indoor air is filtered.
He also advised to avoid peak traffic times.
The researchers are trying to find out which pollutants are harmful, and how the harmful pollutants work to damage the cardiovascular system.
They have focused on smaller, microscopic particles that can get into the lungs, and may gain entrance to the blood stream.