We spend about a third of our lives sleeping, and most of that occurs in a bedroom.
Unfortunately, the upholstered surfaces, curtains, and other surfaces that make for a pleasing aesthetic also make most bedrooms the ideal gathering places for allergens and respiratory irritants like dust, mold, pet dander, and pollen.
According to the Environmental Protection Agency (EPA), indoor air — including the air in our bedrooms — can be two to five times more polluted than the outdoor air, and sometimes up to 100 times more polluted. Many of us have physical reactions to those irritants, including congestion, coughing, sneezing, and other reactions that can rob us of a good night’s sleep. In fact, research published in the journal Current Medical Research and Opinion found that nasal congestion increases the likelihood of not just sleep problems, but also fatigue, headache, and daytime drowsiness.
Anyone blaming the air quality may be wondering: Could an air purifier help? Experts say yes, but it depends on the type, where it’s placed, and how it’s maintained. Here’s what you need to know.
How air purifiers work
Air purifiers are air-cleaning machines that filter out even tiny particles of the air that passes through them.
They typically have a fan that draws the indoor air in, passes it through a filter (or several filters) that traps pollutants and then pushes the cleaned air back out. According to one review of studies on air purifiers, a good air purifier can help rid the air of fine particulate matter (microscopic particles that can be inhaled and cause damage to yourhealth) by 22.6 to 92%.
Air purifiers with HEPA (high-efficiency particulate air) filters are the gold standard. According to the EPA, they can remove 99.97% of dust, pollen, mold, and particles measuring 0.3 microns (a micron is one-millionth of a meter; 0.3 microns is the most difficult size particle to capture with mechanical filtration).
“HEPA filters that clear the smaller particle size (PM2.5) are likely to have a bigger effect on the lungs, as it is the smallest particles that enter further into the lungs,” says Dr. Naomi R. Kramer, a pulmonologist and sleep medicine physician with Care New England Medical Group and a clinical assistant professor at Brown University’s Warren Alpert Medical School.
It’s important to remember, though, that an air purifier can only remove matter circulating in the air. “Heavier particles, such as dust mite allergens and pollen, settle down onto surfaces, so filtering the air is not likely to be very effective in removing them unless they have been disrupted and are floating,” Kramer notes.
Which air purifiers to avoid
The EPA cautions against using air purifiers that clean with ions or UV light, as they have been shown to produce ozone, a known lung irritant. The Association of Home Appliance Manufacturers has a list of air cleaners that produce little to no ozone.
How an air purifier can help your sleep
If you’ve ever tried to sleep with a stuffy nose or in a room that smells — whether from stale smoke, cooking odors, pet smells, or just stale air — you know that when you can breathe easier, you can usually sleep easier, too.
In one small study looking at whether air purification can improve sleep, researchers asked 30 healthy adults to use an air purifier with a filter for two weeks and one with a placebo filter for another two weeks. They found that when they used the purifiers with the air-cleansing filter, they slept 12 minutes longer at night and spent an average of 19 minutes longer in bed.
That may not seem like all that much, but that’s an additional 84 minutes of sleep every week, which adds up to 73 hours (or more than three full days) of sleep per year. “And the study was conducted on healthy adults,” notes Dr. Faisal Zahiruddin, a sleep specialist and pulmonologist at Houston Methodist, “so perhaps people with allergies and asthma may benefit more. Further studies will be needed.”
A study published in Sleep Health in April 2023, conducted by researchers at the University of Pennsylvania and the University of Louisville, found that air pollution may adversely affect sleep. The study examined the effects of air pollution, warm temperatures, high levels of carbon dioxide, and ambient noise. The study found that each diminished sleep efficiency; high particulate matter was associated with a 3.2% decline in sleep efficiency.
Improved air quality may also help other sleep issues. There’s some research showing that poor air quality can contribute to snoring. While the study didn’t introduce air purifiers as a specific solution, experts note that it’s not a huge stretch to think that when air quality improves, so, too, does snoring.
“I haven’t seen high-quality studies (randomized, controlled, double-blind) specifically documenting change in snoring with air purifiers, but intuitively it seems logical,” says Kramer. “If there are more irritants in the air — particulate matter or noxious fumes — these could contribute to inflammation in the nasal tissues and thus impact snoring.”
Other health benefits of air purifiers
Air purifiers can improve breathing and lung issues like asthma. But research shows they can have more far-reaching health benefits as well.
One small study conducted on older adults in China found that after just 48 hours using an air purifier, the study’s participants had decreased concentrations of inflammatory and coagulation biomarkers (measurable molecules in the body), which researchers say points to improved cardiopulmonary function.
In another review of literature looking at air purifiers and blood pressure, researchers found that using an air purifier for a median of 13.5 days could decrease systolic blood pressure (the first number used in a blood pressure reading; it measures the pressure in your arteries when your heart beats) by 4 mmHg. They also note that decreasing systolic blood pressure by just 5 mmHg can reduce mortality from stroke by 14% and coronary heart disease by 9%.
“This is likely a very complex process and may have to do with inflammation being generated by irritant particles and glasses,” Kramer explains.
How to choose an air purifier
Air purifiers can be a boon to your breathing, and, consequently, your sleep.
Though no air purifier can remove 100% of the pollutants in your home, they can make a big difference, particularly for those with allergies, those with pets, and those living in urban areas with poor air quality.
For those with acute conditions like asthma and diagnosed sleeping problems such as insomnia, it’s best to consult a health care provider for specific treatment options beyond an air purifier.
Here are some tips for how to choose an air purifier and how best to use it.
- Make sure the air purifier you select is filtering what you want. Some air purifiers only filter particulate matter. Others do that as well as gasses that have odors (usually via the help of an activated carbon filter). Check out the product’s packaging to see what exactly it does. As we shared above, air purifiers with HEPA filters can capture the smallest particles, so may be most effective in purifying your room.
- Get a purifier that’s big enough for the room in which you’ll use it. According to the EPA, the higher the clean air delivery rate (CADR), the more particles the unit can sweep from the air. Again, check the purifiers packaging to make sure it’s big enough for your room.
- Be careful where you place the unit. “The best location is somewhere where the air purifier has a few feet of clear space around the top and all four sides,” says Zahiruddin. Make sure to keep it clear of bedding, curtains, and furniture.
- Run the air filter for long periods and at a high fan speed. Both will increase how much air is filtered.
- Clean or replace the filters according to the manufacturer’s directions. A blocked filter won’t do much to create clean air. “HEPA and carbon filters need to be changed every six months to one year, whereas washable filters need to be cleaned every 10 days,” says Zahiruddin.
Following a cleaning routine or schedule can also help keep dust, pollen, and other allergens at bay, especially during high-pollen-count seasons or times when smoke, smog, or other irritants worsen air quality.