A commercially available particle trap can filter microscopic pollutants in diesel-engine exhaust and prevent about 98 percent of them from reaching the air, according to research reported in Circulation: Journal of the American Heart Association.
Inhaling exhaust particles increases the risk of dying from heart and lung diseases. Air pollution, including diesel exhaust as a major contributor, causes 800,000 premature deaths annually in the world, according to the World Health Organization.
* Traps installed on diesel engines can cut heart-harmful microscopic exhaust particles by 98 percent.
* Men breathing filtered diesel exhaust had significantly greater blood vessel dilation and fewer blood clots than those inhaling unfiltered diesel fumes.
* If confirmed in larger studies, the findings could result in changes that lead to a major reduction in cardiovascular deaths.
The volunteers breathed filtered air, unfiltered dilute diesel-engine exhaust and dilute diesel-engine exhaust after it passed through a particle trap. Participants inhaled each gas for one hour in an exposure chamber during which they did two 15-minute periods of moderate exercise. At least one week separated each inhalation session. Researchers randomized the order in which each man breathed the three gases.
The particle trap oxidized nitric oxide (NO) into nitrogen dioxide (NO2), both important nitrogen-containing reactive gases in diesel exhaust.
“We have previously exposed people to nitrogen dioxide alone and seen no effect on the body,” Newby said.
Among the study’s findings:
The particle trap removed about 98 percent of all particles in the diesel exhaust and 99.8 percent of the smallest and most damaging particles (less than one micrometer).
Compared to filtered air, artery dilation (widening) was significantly reduced six to eight hours after exposure to unfiltered diesel exhaust when the men were tested with bradykinin, acetylcholine and verapamil – compounds that cause arteries to widen, or dilate (vasodilators).
The blood’s tendency to clot differed between groups. Compared to men inhaling unfiltered diesel exhaust, those breathing filtered exhaust showed significantly greater release of tissue plasminogen activator (t-PA), a naturally occurring protein that dissolves blood clots – one of the body’s built-in mechanisms for preventing heart attacks or strokes.
In another test for blood-clotting ability, a significant increase in blood clotting occurred in men who had breathed diesel exhaust versus those who inhaled filtered air. There was no difference in the blood’s clotting ability between men who inhaled filtered diesel exhaust and filtered air.
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