Pollution levels inside kids' bedrooms were up to two-thirds lower when HEPA filters were used, a new study found. Photo by M. Dykstra/Shutterstock
A bedroom air filter can significantly improve breathing in kids with asthma, new research shows.
The study included 43 children with mild to moderate asthma, and was conducted during a period of moderately high fine particulate matter (PM2.5) air pollution in Shanghai, China.
Particulate matter pollution originates from fossil fuels and can be found in various sizes. PM2.5 are about 30 times smaller than the width of a single human hair, and can be inhaled into the deepest areas of the lungs.
For the study, two air filters were tested in the children's bedrooms. One was a high-efficiency particulate air (HEPA) filter capable of removing PM2.5, and the other was a fake filter. Each filter was used for two weeks with a two-week gap in between. Families didn't know which filter was which.
PM2.5 levels inside the kids' bedrooms were up to two-thirds lower when the real HEPA filters were used, compared to the fake ones. And those reductions resulted in significant improvements in how easily air flowed in and out of the children's lungs.
On average, there was a 24 percent reduction in total airway resistance; a 43.5 percent reduction in small airway resistance; a 73 percent increase in airway elasticity; and a 28 percent reduction in exhaled nitric oxide, a marker of lung inflammation, the investigators found.
The breathing benefits lasted only as long as the real air filters were used. But study leader Junfeng Zhang said that "it's probable that if children use the filters on an ongoing daily basis they will see continued benefits."
Zhang is a professor of global and environmental health at Duke University in Durham, N.C.
The findings -- published April 6 in JAMA Pediatrics -- are the first of their kind, according to the researchers.
"Pharmaceutical companies have spent large amounts to develop drugs that can work on lower airways, but they are very expensive," Zhang said in a university news release. "Our results show that using an air purifier to reduce the exposure of lower airways to pollutants could help asthmatic children breathe easier without those costly drugs."
If clinical trials confirm the findings, air filters could help manage asthma in polluted outdoor or indoor locations, and could even be lifesavers during wildfires, he said.
"Look at the high PM2.5 pollution levels that occurred in San Francisco last year as a result of smoke from the California wildfires, and at the air-quality problems happening this year from the bushfires in Australia," Zhang said. "People should really consider using one of these devices during wildfires."
The American Lung Association has more on children with asthma.
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