A growing body of evidence showed that air pollution is associated with heart failures, strokes and cardiovascular deaths.

According to an updated American Heart Association (AHA) scientific report, individuals, mainly those at high cardiovascular risk, should limit their exposure to air pollution.

The expert group of researchers who updated the AHA 2004 initial statement on air pollution stated that the proof is strongest for fine particulate matter (PM2.5) having a fundamental association to heart disease,

There are many ways by which PM2.5 could have an effect on the cardiovascular system; however, one main explanation hinted that several components of PM2.5, once breathed in, can lead to swelling and irritate nerves in the lungs.

These reactions can start a cascade of modifications, which adversely affect the remaining parts of the body.

Robert D. Brook, associate professor of internal medicine University of Michigan (U-M), Ann Arbor said, "It's possible that certain very small particles, or chemicals that travel with them, may reach the circulation and cause direct harm."

"The lung nerve-fibre irritation can also disrupt the balance of the nervous system throughout the body. These responses can increase blood clotting and thrombosis..., elevate blood pressure, and disrupt proper cardiac electrical activity which may ultimately provoke heart attacks, strokes, or even death," Brooks added.

The main source of PM2.5 is fossil fuel burning from industry, traffic, and power generation. Biomass burning, heating, cooking, indoor activities and forest fires may also be relevant sources, particularly in certain regions.

"These studies also indicate that there is no 'safe' level of PM2.5 exposure," he said.

The results of the study were also published in Circulation: Journal of the American Heart Association. (With Inputs from Agencies)