People whose homes are near busy highways may be able to reduce their blood pressure by running an air purifier with a HEPA filter, a study found.

The Instant Brand Quiet HEPA Air Purifier works to filter out dust, pet hair, pollen, mold, smoke and other particles as small as 0.3 microns.

The vast majority of car air purifiers are powered by the 12-volt cigarette lighter or a USB outlet, though sometimes this means that wires hang all over your dashboard.

We've tested and reviewed products since 1936. Read CR's review of the Avari EG air purifier to find out if it's worth it.

“When I started Smart Air, in a way I was really angry at larger purifier companies, because they’re out here trying to convince people it costs $1,000 to protect your health,” Talhelm said.