Media release

From: American College of Cardiology

Air Purifiers May Reduce Heart Risks for People Exposed to Traffic Pollution

Study finds in-home HEPA air filters significantly lowered systolic blood pressure in adults with elevated readings

Using portable high-efficiency particulate air (HEPA) purifiers at home can significantly lower systolic blood pressure (SBP) in adults with elevated baseline readings — even in areas with relatively low overall air pollution levels, according to a study published today in JACC, the flagship journal of the American College of Cardiology.

Particulate matter (PM) is a major contributor to air pollution and is strongly associated with cardiovascular disease (CVD). People living near high-traffic roadways are frequently exposed to elevated levels of PM from vehicle emissions as well as tire and brake wear. These fine particles can infiltrate homes and affect residents, increasing the risk of hypertension and elevated blood pressure—both major CVD risk factors.

“High blood pressure remains one of the most important modifiable risk factors for cardiovascular disease,” said Douglas Brugge, Ph.D., M.S., Professor and Chair of the Department of Public Health Sciences at UConn Health and lead author of the study. “This research adds to growing evidence that simple interventions, like in-home air filtration, may help improve heart health for people at risk.”

In this randomized crossover trial of 154 adults living near highways, participants were randomly assigned to receive one month of either HEPA or sham filtration (the same air purifiers with the filter removed) in their homes, followed by a one-month “washout” period with no filtration and then the alternate treatment. Blood pressure measurements and participant questionnaires were collected at the start and end of each period.

Researchers found that participants who entered the study with elevated SBP (>120 mmHg) experienced an average 2.8 mmHg reduction in SBP after one month of HEPA filtration. In comparison, SBP increased slightly (0.2 mmHg) during a sham filtration period, resulting in a significant 3.0 mmHg difference in favor of HEPA filtration. There was no significant impact on diastolic blood pressure or among participants with normal SBP (<120 mmHg).

"Overwhelming evidence shows the harmful health effects of PM_2.5 exposure, even at levels below current U.S. standards,” said Jonathan Newman, M.D, M.P.H., Associate Professor of Medicine (Cardiology) at the Department of Medicine at NYU Grossman School of Medicine, Director of Clinical Research at the Center for the Prevention of Cardiovascular Disease and lead author of the accompanying editorial comment. “As healthcare professionals, we must educate the public and support policies that protect clean air and improve the health of all Americans."

Harlan M. Krumholz, M.D., S.M., Editor-in-Chief of JACC, noted that the study raises the possibility that even modest improvements in indoor air quality could have a meaningful impact on blood pressure for people at risk.

“While more research is needed, these results suggest that what we breathe at home may matter for our cardiovascular health,” Krumholz said.

Study limitations include limited generalizability due to a predominantly White, higher-income participant pool, exclusion of people on blood pressure medications, and a lack of data during hotter summer months or at times of higher indoor pollution.