A month with a HEPA air purifier at home may do a little more than clean the air.
Researchers reported that adults aged 40 and older performed about 12 percent faster on a test of executive function after using a HEPA purifier for one month, compared with a sham purifier that looked the same but had no air-cleaning filter. The findings come from a new study in Scientific Reports, based on data from 119 people aged 30 to 74 living in Somerville, Massachusetts.
The study was co-authored by Nicholas Pellegrino, Misha Eliasziw, Richard Fortinsky, Hunter Gates and Doug Brugge.
HEPA stands for high efficiency particulate air. The filters remove particulate matter from the air. The source article said exposure to particulate matter has been linked to respiratory and cardiovascular illnesses, as well as neurological diseases such as Alzheimer’s and Parkinson’s.
Researchers said Somerville was a useful place to test the effects of air purifiers because it sits along Interstate 93 and Route 28, two major highways associated with relatively high levels of traffic-related air pollution.
Participants were randomly split into two groups. One group used a HEPA purifier for one month, then a sham purifier for one month, with a month-long break in between. The second group used the devices in the reverse order.
After each month, participants took a test of mental function. The test measured visual memory and motor speed by timing how quickly people could draw lines between sequential numbers. It also measured executive function and mental flexibility by asking them to draw lines between alternating sequential numbers and letters.
Researchers found the improvement in adults aged 40 and older, who made up about 42 percent of the sample. The source article said the result held even after accounting for differences including time spent indoors, time spent with either filter and how stressful participants found the test.
The article said, “This improvement may seem small, but it is similar to the cognitive benefits that people experience from increasing their daily exercise.”
It also said, “While you may not experience a sudden increase in clarity from a 12% boost, preventing cognitive decline is vital for long-term well-being.”
The researchers said studies have shown air pollution can affect mental function after only a few hours of exposure, but there has been limited research on people living near major sources of air pollution such as highways.
The article said people living near highways or major roadways face higher exposure to air pollution and higher rates of air pollution-related disease. It also said, “People of color and low-income people are more likely to live near highways or areas with heavy traffic.”
The study did not examine older age groups in depth, because fewer than 10 of the 119 participants were over 60. Participants also used a HEPA purifier for only one month, so the study did not test longer-term effects.
The article said, “We plan to study whether reducing particulate matter by using air purifiers is indeed protecting the brain’s white matter, and whether it could reverse some cognitive decline.”
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