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Friday, 15 March, 2002, 23:53 GMT
Pollution strangles blood supply
Pollution causes changes to the body

The finding may explain why air pollution appears to increase the rate of heart attacks and other cardiovascular problems among people with heart and blood vessel disease.

In the study at the University of Toronto, 25 healthy people inhaled elevated concentrations of fine particles plus ozone for two hours.

After exposure, volunteers' blood vessels constricted between 2% and 4% on average.

However, their vessels did not constrict when they were exposed to ozone-free and particle-free air.

Tiny particles

Researcher Dr Robert Brook said: "There have been some suggestions in previous studies that people with atherosclerosis (furring of the arteries) tend to respond with greater-than-normal constriction, or narrowing of blood vessels, in response to certain hormones in the body.

The heart is directly affected by air pollution
"Could it be that their blood vessels also have enhanced constriction in response to air pollution?"

The researchers focused on ozone and fine particulate matter.

Fine particles are those with a diameter of less than 2.5 micrometers. They are emitted from burning fossil fuels, mostly from car engine exhaust, power generation and many industrial processes.




Rush hour pollution

The volunteers breathed in a level of pollution similar to that found in urban areas during peak air pollution times such as rush-hour traffic.

The degree of blood vessel constriction produced by exposure to pollutants is unlikely to produce significant problems in healthy indviduals.

However, Dr Brook said that it could conceivably trigger cardiac events in people who are at risk of heart disease.


A spokesperson for the British Heart Foundation said that air pollution was known to increase the risk of heart disease in those at risk.

However, she said that the study focused on too few people to draw firm conclusions.


See also:

06 Mar 02 | Health
Air pollution cancer fears grow
30 Dec 01 | Health
Pollution linked to birth defects
11 Jun 01 | Health
Air pollution heart attack link
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