Particulate matter (tiny particles) with a diameter of less than 10 microns is a common component of motor vehicle exhaust. In a study involving 2080 people, 870 of whom had developed blood clots in the legs (deep vein thrombosis or DVT), Italian researchers found that the risk of developing DVT  increased by 70% for each increase of 10 micrograms per square meter in air particulate matter concentration. In addition, people with higher exposure to particulate matter had the fastest blood clotting times.

The researchers are quoted as saying that a link between air pollution, heart attack and stroke is well established, but this is the first time that a connection has been made between air pollution and DVT. They caution that more work is needed to confirm these findings. However, if the results are verified, it could indicate that the adverse effects of air pollution may be even greater than is currently estimated.

References

Conlon, M.   2008   Study links air pollution to blood clots in veins   Reuters. Online, available at : http://www.reuters.com  (Viewed on 15.5.08)

Edelson, E.   2008   Air pollution linked to blood clots in legs   BusinessWeek. Online, available at : http://www.businessweek.com  (Viewed on 15.5.08)