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Indoor air filters can cut pollution in half, Utah pulmonologist’s research shows

By Jed Boal, KSL TV | Posted - Sep. 26, 2018 at 10:05 a.m.

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MURRAY — The past few weeks, Utahns have breathed in some of the worst air emitted by wildfires in years. The smoke is just as dangerous for our lungs as our winter pollution. But, new research from a pulmonologist at Intermountain Medical Center shows standalone indoor air filters can cut the pollution in half.

Outdoor air pollution dirties the air we breathe inside, too. But, do indoor air filters make enough of a difference to make the investment?

“Every winter, my patients would come in complaining of worse symptoms during inversions,” said Dr. Denitza Blagev, a pulmonologist at Intermountain Medical Center and principal investigator on the study.

And, every winter Dr. Blagev wanted to offer some relief.

“We would have people asking, ‘what can we do, what can people do to try to protect themselves from this?’”

But, the pulmonologist was hesitant to recommend high-efficiency particulate air filters, or HEPA filters, without the science to back it up.

“Does it make enough of a difference?” she wanted to know.

For the study, researchers put $300 HEPA air filters in 52 homes of enrolled patients with respiratory problems. After monitoring air quality for 12 weeks during the last two winters, Dr. Blagev and her research team had their answer.

“Yes. Having a high-efficiency, HEPA filter does remove particulates significantly,” she said.

Those fine particulates — PM 2.5 — are the most dangerous for our lungs, she said.

“Those are significantly reduced when you have the HEPA filter on, versus not,” she said.

Dr. Denitza Blagev, a pulmonologist at Intermountain Medical Center, and principal investigator on the study. Photo: KSL TV

The filter reduced fine particulate matter 55 percent. It cut the pollution outside coming inside by 23 percent.

“It was really validating to be able to see how much air pollution is really cleaned up by these filters,” said Blagev.

She presented the study Sept. 16 at the European Respiratory Society’s International Congress in Paris.

“People were excited about the results,” she said.

Each household can weigh whether the expense of the filter is worth it. Blagev suggests respiratory patients, or families with newborns, might find the filters most valuable. But, she points out; we all breathe the same pollution.

“It gives people an option of something they could do to really reduce their risk of air pollution exposure,” she said. “Usually, a filter of that size is really only going to be able to filter out the one room that it’s in.” But, we spend about a third of our lives breathing air in the bedroom.

That’s why it’s also important to regularly change the filter on your home heater, and eliminate wood and cigarette smoke from your home, she said.


“Those are simple things that you could avoid doing that would really improve things,” said Blagev.

Air filters are only bandages for the bigger problem, she said. Everyone should try to improve the overall outdoor air quality in their communities.

Researchers are still gathering data for the second part of the study, which will measure whether the reduction in pollution actually makes the patients feel better.

“Our next steps will be to look at whether the HEPA filter cleans the indoor air enough to help alleviate symptoms in patients with COPD or asthma during poor air quality days,” said Blagev. “We often encourage our patients with respiratory illnesses to stay indoors on days when PM 2.5 is high outdoors, but we hope to identify ways to help improve the indoor air quality and relieve symptoms in our patients, which will protect our lungs from dangerous air pollutants.”

The study was funded by the Intermountain Research and Medical Foundation. The Intermountain Medical Center research team includes: Daniel Bride, Danielle Babbel, and Benjamin Horne, PhD, and Daniel Mendoza, PhD, from the University of Utah.

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Jed Boal


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