Ultrafine particles in diesel exhaust fumes can harm blood vessels, leading to a greater chance of blood clots developing in the arteries, resulting in a greater risk of heart attack or stroke, researchers from the University of Edinburgh, Scotland revealed in the European Heart Journal.

The scientists measured the diesel exhaust fume impact on healthy individuals at levels similar to those found in highly polluted cities. They compared how each volunteer reacted to diesel fume gases, such as nitrogen dioxide (NO2) and carbon monoxide (CO), versus those caused by tiny chemical particles from exhausts.

This British Heart Foundation funded study demonstrated that it was the ultrafine particles, rather than the gases that undermined blood vessel function, particularly how they control bloodflow to the body’s organs.

These ultrafine particles are less than one millionth of a meter wide. Special filters can be fitted to cars which trap them. This is already being done in US public transport vehicles.

Dr Mark Miller said:

“While many people tend to think of the effects of air pollution in terms of damage to the lungs, there is strong evidence that it has an impact on the heart and blood vessels as well. Our research shows that while both gases and particles can affect our blood pressure, it is actually the miniscule chemical particles that are emitted by car exhausts that are really harmful.

These particles produce highly reactive molecules called free radicals that can injure our blood vessels and lead to vascular disease. We are now investigating which of the chemicals carried by these particles cause these harmful actions, so that in the future we can try and remove these chemicals, and prevent the health effects of vehicle emissions”

The scientists say that measures should be taken, aimed at reducing exhaust emissions. They should be carefully tested to see whether they can reduce heart attack rates.

Associate Medical Director at the British Heart Foundation, Professor Jeremy Pearson,, said:

“We’ve known for a long time that air pollution is a major heart health issue and that’s why we’re funding this team in Edinburgh to continue their vital research. Their findings suggest that lives could be saved by cutting these harmful nanoparticles out of exhaust – perhaps by taking them out of the fuel, or making manufacturers add gadgets to their vehicles that can trap particles before they escape. The best approach isn’t clear yet.

For now our advice remains the same – people with heart disease should avoid spending long periods outside in areas where traffic pollution is likely to be high, such as on or near busy roads.”

“Combustion-derived nanoparticulate induces the adverse vascular effects of diesel exhaust inhalation”
Nicholas L. Mills, Mark R. Miller, Andrew J. Lucking, Jon Beveridge, Laura Flint, A. John F. Boere, Paul H. Fokkens, Nicholas A. Boon, Thomas Sandstrom, Anders Blomberg, Rodger Duffin, Ken Donaldson, Patrick W.F. Hadoke, Flemming R. Cassee, and David E. Newby
Eur Heart J (2011) doi: 10.1093/eurheartj/ehr195

Written by Christian Nordqvist