Air pollution is linked to increased risk of developing an irregular heartbeat and blood clots in the lung, according to a new study.

The research, carried out by researchers from the London School of Hygiene and Tropical Medicine and funded by the Department of Health, found that short-term exposure to small particulate matter – a form of air pollution linked to cars and other sources – is linked to a raised risk of death from these conditions.

Small particulate matter is known to be dangerous – because of its size (which can be 100 times thinner than a human hair), it can bypass the body's defences against foreign objects and affect the heart and the lungs.

Nevertheless, the study found no clear evidence of a link between air pollution and the risk of having a heart attack or stroke.

But the link found between irregular heartbeats (atrial fibrillation) and blood clots in the lungs (pulmonary embolism) is still a matter of concern, according to the report. Both conditions can cause serious complications, especially in vulnerable people with a pre-existing health condition.

The study reinforces the fact that people should not become complacent about the health dangers posed by all forms of pollution.