Recent research has provided increasing evidence to prove that air pollution can both increase the risk of cardiovascular diseases in the long run and trigger a heart attack within hours of traffic exposure.
Previously it was thought that fine sooty particles in exhaust fumes caused hardening of arteries. Now fresh studies have come out with more reasons to explain the recurring link between air pollution and heart disease.
Scientists have now found fresh evidence linking smoke from fires and tobacco to heart attacks, cardiovascular disease and clogged arteries.
It is feared that the compounds, which are found in petrol, coal and diesel fumes could cause irregular heartbeats - a potentially life-threatening condition that can raise the risk of stroke.
US government scientist John Incardona, a developmental biologist, warned the chemicals were "ubiquitous in urban air".
John Incardona, of the National Oceanic and Atmospheric Administration, reported research on a type of polycyclic aromatic hydrocarbon (PAHs) that is produced when substances such as coal, tobacco, or wood are burned. Some larger types of PAHs are known to be carcinogenic. The smaller ones have largely been considered harmless. Now research shows they may be toxic to the heart.
The link was first made after the Exxon Valdez oil spill of 1989, when salmon and herring embryos caught up in the slick were found to develop heart defects.
For further study on the effects of PAHs, Dr Incardona turned to the zebra fish, a tiny tropical fish with heart that was much similar to the human heart.
Studies on zebra fish embryos showed smaller PAHs had dramatic effects on the developing heart, causing swelling and irregular heartbeats or arrhythmias.
This led Dr. Incardona to believe that, "In essence, people in big cities are breathing in an aerosolized oil spill."
Speaking at the American Association for the Advancement of Science annual meeting in Boston, researchers argued that more regulation was needed to curb the potential harms of pollution.
"In rapidly modernizing regions, environmental regulations are frequently avoided in the interest of improving economic growth," said Matt Campen, of the Lovelace Respiratory Research Institute in Albuquerque, New Mexico. "Thus, the global cardiovascular health burden from air pollution is likely to escalate dramatically over the coming decades," he added.
Professor Peter Weissberg, of the British Heart Foundation, said: "It is a long way to extrapolate from something shown in the development of zebra fish to something that would affect healthy adult human beings...We do not see a lot of spontaneous, unexplained heart disease and arrhythmia in adults."
He said it was an interesting study, though. It suggested that these chemicals clearly have an important effect on these "developmental chemical interactions in the heart."
"So if adults were exposed to doses of these chemicals as large as the fish were, maybe we might see an effect," he said.