How Many Times Can You Wear N95 and KN95 Masks? Experts Weight In.
The Centers for Disease Control and Prevention (CDC) made a huge change to its masking recommendations in mid-January following the identification of the new Omicron variant, announcing that there are no longer concerns about supply for N95 respirators. As a result, the CDC says, people who aren’t medical professionals can choose to wear N95 masks to protect themselves against COVID-19 if they want to.
The new CDC guidance clarifies that masks labeled as “surgical N95s” should still be reserved for healthcare settings. But, other than that, if you happen to spot an N95 for sale, you should feel free to snatch it up.
KN95 masks have been widely circulating in the U.S. for months, but it can be tricky to get your hands on reputable masks of either type. And, when you do, it’s understandable to want to extend the life of them.
KN95s and N95s are disposable masks, and they’re not something you can wash like a cloth face mask. That said, plenty of people are wondering how many times you can wear an N95 or KN95 mask before you need to ditch it because these masks a) aren’t cheap and b) are tough to find.
So, how many times can you wear an N95 and KN95 mask before it needs to be tossed, and what can you do to extend the life of your mask in the meantime? Experts break it down.
What are N95 and KN95 masks, again?
An N95 (also known as an N95 respirator) is a type of face mask that filters out at least 95% of airborne particles, per the CDC. N95 masks have traditionally been used in healthcare settings to protect doctors and other medical staff from airborne pathogens.
A KN95 mask is the Chinese equivalent of an N95—it also filters out at least 95% of airborne particles. In order to be classified as a true KN95 respirator, these masks must be manufactured in China and authorized for use by the Chinese government.
KN95 masks have become more popular in the U.S. during the pandemic because of the shortage of N95 masks, but the CDC warns that up to 60% of those on the market don’t work as well as they claim. Still, there are some KN95 masks for sale that have been granted an emergency use authorization (EUA) from the Food and Drug Administration and do work well for blocking airborne particles.
How many times can you wear an N95 and KN95 mask?
It’s important to point out that there’s no hard and fast rule on this one. In pre-pandemic times, when N95 respirators were mostly used by healthcare and construction workers, N95 respirators were tossed after one use. “Initially, people would say that these types of masks were one and done,” says Thomas Russo, M.D., professor and chief of infectious disease at the University at Buffalo in New York. “But now, given pandemic shortages, that’s not very pragmatic.”
People often cite 40 hours of use for N95s but it’s not set in stone, says William Schaffner, M.D., an infectious disease specialist and professor at the Vanderbilt University School of Medicine.
There has been some research on this. One study published in the journal Medicine had volunteers wear N95s for eight hours a day and found that the average filtration efficiency of the masks was still 97% after three days of use.
The CDC says that N95 masks can be used up to five times before they need to be tossed “but this is for healthcare professionals,” says Aaron Collins, a mechanical engineer in Minnesota and self-described "citizen engineer" who has been studying mask efficiency. “I find that, depending on the mask, you can go longer,” he adds. “Straps begin to start to stretch and the mask loses shape around a week of total wear.”
Collins points out that this is usually true for N95s, KN95s, and KF94s, which are the Korean equivalent of N95s and KN95s.
It’s important to separate what the average person is exposed to when they’re going about their daily life, wearing a mask to the grocery store or work, from the bodily fluids and other contaminants that healthcare workers are regularly exposed to, Dr. Schaffner says.
“The average person can reuse these masks until they become distorted, dirty, and no longer have integrity,” he says. “For people who put these masks on for relatively short period of time, that can be several days.”
Robert Laumbach, M.D., associate professor of clinical research and occupational medicine at the Rutgers University School of Public Health, says that “people might have concerns that the virus particles will penetrate the respirator more with repeat use, but that’s not true.” He adds, “it doesn't lose its efficiency unless it’s damaged or no longer a good fit.”
That’s why Dr. Russo suggests tossing your mask if the straps become loose or frayed, you notice loose threads forming inside your mask, or it starts to look damaged.
How to extend the life of your N95 and KN95 mask
Experts generally recommend rotating through different masks during the week if you can. When you’re done wearing a mask, Dr. Schaffner suggests keeping it “in a dry place between uses.”
Dr. Russo has his own hack, which involves putting his used mask in an open sandwich baggie (it's open to prevent moisture from building up) and rotating his masks every few days. SARS-CoV-2, the virus that causes COVID-19, can’t last on inanimate objects like masks for very long, he explains, “so after three days, you’re fine.”
Dr. Russo says this method works well for him, adding, “I don’t usually count the hours that I’ve worn the mask.”
The CDC also recommends a similar method (for healthcare workers), suggesting that N95 respirators be stored in a “breathable paper bag” at the end of each shift “with a minimum of five days” between each use. “This will provide some time for pathogens on it to ‘die off’ during storage,” the CDC says.
Should you clean or disinfect your mask to extend its life?
While there have been studies that found that putting your mask in the oven or a pressure cooker (like an Instant Pot) can decontaminate it, experts really don’t recommend this.
“There’s a risk that you could damage the integrity of the mask,” Dr. Russo says. Dr. Schaffner agrees. “For the average user, don’t bother with that,” he says. “Just make sure the mask still fits well over your face.”
If you're worried about germs from your mask after you take it off, Dr. Laumbach says you can wash your hands after handling your respirator "if you want to be cautious."
How to properly dispose of your mask
N95 and KN95 masks don’t last forever and, at some point, it’s going to be time to throw yours out. Experts say getting rid of your mask is as simple as tossing it in the trash.
“Don’t make an opera out of this,” Dr. Schaffner says. “If there are viruses embedded in the fabric, they’re not going to jump out of the trash and infect anybody else. Just put them in the trash.”
Experts stress the importance of taking good care of your N95 and KN95 masks, if you can get your hands on them. “They can actually last a considerable period of time if you take care of them,” Dr. Schaffner says.
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