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.

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.

A study conducted over 2 years on 861 asthmatic inner-city U.S. children, aged 5 to 12 years, has found that  the children’s lung function was significantly reduced following exposure to higher levels of air pollutants such as sulphur dioxide, fine particulate matter and nitrogen dioxide. 

A study published in the American Journal of Epidemiology has found some association between long term (20 year) exposure to air-borne particulates and sub-clinical atherosclerosis (the formation of fatty deposits in artery walls).

According to researchers in the U.S., breathing air that is heavily contaminated with traffic pollution may be associated with reduced memory, learning ability and I.Q. in children.