Tiny particles in exhaust fumes that cause big problems

Cars in smog

BHF-funded research has discovered the potential damage to heart health caused by air pollution including the discovery that diesel contains tiny particles that increase the risk of clots that can cause a heart attack.

International collaborators

Researchers at our University of Edinburgh Centre of Research Excellence including BHF Professor David Newby and BHF Intermediate Research Fellow Dr Nick Mills have made great strides into finding out how pollution affects heart health.

“People understand that air pollution can damage the lungs, but at Edinburgh we’ve found that pollution also has important effects on the heart and circulatory system,” said Dr Mills.

Sweden. They have also carried out testing in Beijing – one of the most polluted cities in the world – to see if reducing exposure to air pollution could have benefits for heart and circulatory health.

Pollution has important effects on the heart and circulatory system.

Dr Nick Mills
University of Edinburgh

In Beijing, local people with heart disease volunteered to walk around the city hooked up to portable blood pressure and heart rate monitors while wearing trendy backpacks. “But these backpacks were not just a fashion accessory; they contained specialist monitoring equipment that measured their heart function and exposure to air pollutants,” explained Dr Mills.

Dr Mills and his colleagues found that when the volunteers wore a highly efficient face mask that filtered out pollution particles, measurements showing their heart and circulatory health appeared to improve – their blood pressure was lower and their heart activity was healthier. The scientists have since found out which constituents of pollution could be having this negative effect on the heart and circulatory system.

Dangers of exhaust fumes

“We found that tiny ‘nano-particles’ in diesel exhaust produce highly reactive molecules called free radicals that can injure blood vessels and lead to disease,” said Dr Mills. These nano-particles – less than a thousandth of a millimetre wide – prevent blood vessels from relaxing and contracting properly, which is vital for keeping them free from disease. The disturbance to blood vessel function means there is increased risk of clots developing in coronary arteries, which can cause a heart attack.

“We are now looking at ways to remove these particles so that we can prevent some of the negative health effects of vehicle emissions,” said Dr Mills. In the future lives could be saved by designing equipment that filters these particles out of vehicle exhaust fumes or by finding ways to prevent the particles from being released when the fuel is burnt.

Find out more about our research by downloading out Lifesaving science booklet.