A new study suggests that using portable high-efficiency particulate air (HEPA) purifiers at home can help lower blood pressure in people with higher-than-normal readings — even if they live in places where the overall air quality is already fairly good.
The research was published in JACC, the flagship journal of the American College of Cardiology.
Air pollution is made up of many harmful substances, but tiny particles known as particulate matter (PM) are some of the most dangerous. PM comes from sources like car exhaust, brake dust, and tire wear, and can easily enter homes, especially for people living near busy roads.
Breathing in these particles has been strongly linked to heart disease. One major risk factor is high blood pressure, which can damage the heart, arteries, and other organs over time.
According to lead researcher Douglas Brugge, Professor and Chair of the Department of Public Health Sciences at UConn Health, high blood pressure is one of the most important risk factors for cardiovascular disease that people can control.
“This research adds to growing evidence that simple interventions, like in-home air filtration, may help improve heart health for people at risk,” Brugge said.
The study involved 154 adults who lived near highways and were not taking blood pressure medication. It used a “randomized crossover” design, meaning each person tried both real and fake air purifiers at different times.
For one month, participants used either a working HEPA purifier or a sham purifier (the same device but with the filter removed). After a one-month break with no purifier, they switched to the other type. Blood pressure readings and questionnaires were collected at the start and end of each period.
The results were clear for people with elevated systolic blood pressure (SBP) — the top number in a blood pressure reading, which measures pressure when the heart beats. Those with an SBP over 120 mmHg saw an average drop of 2.8 mmHg after using HEPA filtration for a month.
In contrast, during the sham period, their SBP rose slightly by 0.2 mmHg. This means there was an overall difference of about 3.0 mmHg in favor of using a real purifier. There was no major change in diastolic blood pressure (the bottom number) or in people whose SBP started out in the normal range.
Jonathan Newman, Associate Professor of Medicine at NYU Grossman School of Medicine, said in an editorial that “overwhelming evidence shows the harmful health effects of PM2.5 exposure, even at levels below current U.S. standards.” He emphasized the need for public education and stronger policies to protect clean air.
Harlan M. Krumholz, Editor-in-Chief of JACC, pointed out that the results suggest even small improvements in indoor air quality could make a real difference for people at risk of high blood pressure. However, he and others noted that more research is needed.
The researchers did mention some limitations. Most of the participants were White and from higher-income households, so the results may not apply to everyone. The study also did not include people who were already taking blood pressure medicine, and there may have been differences in how often people used the purifiers.
Finally, the research didn’t capture results during the hotter summer months or times of higher indoor pollution, when air quality changes might have a bigger impact.
This study adds to the growing body of evidence that indoor air quality plays a role in heart health. Even a small drop in systolic blood pressure can reduce the risk of heart attack and stroke, especially across large populations.
While the blood pressure reduction seen here — around 3 mmHg — might seem small, it is meaningful from a public health perspective. The findings also suggest that people don’t need to live in highly polluted cities to benefit from better indoor air.
That said, this was a short-term study, and more research will be needed to confirm whether the benefits last over months or years, and whether they extend to more diverse groups of people. For now, portable HEPA purifiers appear to be a simple, accessible tool that could help some people protect their heart health.
If you care about blood pressure, please read studies that changing blood pressure readings is a hidden sign of heart disease and switching blood pressure drugs may treat the condition better.
For more information about blood pressure, please read studies about the arm squeeze test: could your blood pressure reading be wrong and bedtime medication more effective for high blood pressure.
The study is published in Journal of the American College of Cardiology.
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