LOS ANGELES, Nov. 28 (Xinhua) -- A new study has found that breathing unfiltered air from rush-hour traffic significantly increased people's blood pressure, both while in the car and up to 24 hours later.
Researchers from the University of Washington drove healthy participants between the ages of 22 and 45 through rush-hour Seattle traffic while monitoring their blood pressure.
On two of the drives, unfiltered road air was allowed to enter the car. On the third, the car was equipped with high-quality HEPA filters that blocked out 86 percent of particulate pollution.
Breathing unfiltered air resulted in net blood pressure increases of more than 4.50 mm Hg (millimeters of mercury) when compared to drives with filtered air, according to the research, published Tuesday in the Annals of Internal Medicine.
The increase occurred rapidly, peaking about an hour into the drive and holding steady for at least 24 hours, the study suggests.
The research was funded by the U.S. Environmental Protection Agency and the U.S. National Institutes of Health.