As scientists continue to learn more about the risks associated with indoor air pollution—including effects on blood pressure and sleep—it may seem like using an air purifier overnight would be a simple solution. But what impact does running an air purifier nightly actually have on these aspects of health? Here’s what to know.
There’s good reason to believe that sleeping with a nightly air purifier may improve both sleep quality and duration.
The bulk of past scientific literature focused solely on air pollution’s negative effects on sleep apnea, finding that it triggers upper airway irritation and edema (swelling of body parts), explained Thomas Kilkenny, DO, the director of the Institute Sleep Medicine at Northwell Health’s Staten Island University Hospital. More recent studies, however, have examined the connections between indoor air quality and sleep more generally, and the results have been consistent. “In general, they have shown that the cleaner the air quality in the bedroom, the better the quality of sleep,” Kilkenny said.
A study published in 2023, for example, found that people who slept with a HEPA air purifier, which can remove 99.97% of dust, pollen, mold, and bacteria from the air, slept longer and spent more time in bed compared with those who didn’t use a HEPA air filter.
Another 2023 report found that increasing the movement of bedroom air reduced carbon dioxide concentrations and levels of particulate matter—mixtures of solid and liquid particles that form particularly tiny and potentially dangerous droplets suspended in the air. At the same time, sleep also improved.
Researchers attribute air pollution’s effects on sleep to its ability to cause nasal and throat inflammation and possibly trigger oxidative stress, said Robert Satriale, MD, FAASM, a sleep medicine specialist at Temple Health. Oxidative stress is a condition that causes cell and tissue damage.
Research suggests that regular exposure to air pollution can cause inflammation and impair blood vessels, eventually raising blood pressure and the risk of adverse cardiac events like heart attack or stroke, said Sabrina Islam, MD, MPH, FACC, FAHA, FASE, an associate professor of medicine in the section of cardiology at the Lewis Katz School of Medicine at Temple University.
On the flip side, she added, studies have linked the use of an air purifier with improved blood pressure levels. This is particularly true for people living in areas with heavier pollution, such as those with high traffic, poorly ventilated spaces, or places prone to smog or wildfires.
A 2021 meta-analysis examined studies measuring the systolic blood pressure of people living in higher-pollution areas before and after using an air purifier—some in their bedrooms—for periods generally ranging from a week to several weeks. It found that, on average, using an indoor air purifier significantly decreased blood pressure.
Another paper, published in 2024, found that using an indoor air purifier in the main activity room for a year was linked to a large drop in diastolic blood pressure among older adults.
“Filtering systems are able to reduce exposure to outdoor and indoor sources of air pollution, thus reducing the development or worsening of cardiometabolic disorders, including hypertension,” Islam told Health.
If you’re looking to clean up the air in your bedroom in pursuit of a better night’s sleep or lower blood pressure, you may want to consider investing in a HEPA air filter.
But follow Satriale’s advice: Choose a product designed to purify the size of your room, and clean the filter on a monthly basis.
Air purifiers are most important for people with pre-existing respiratory and cardiac conditions, including allergies, asthma, obstructive sleep apnea, lung disease, and heart disease. However, cleaner air can directly lead to better health regardless of overall health status.
“In general, everyone could benefit by having a HEPA filter in the room to improve the quality of the air that they breathe,” Kilkenny said.
