How many times can you reuse your N95 or KN95 mask?

With COVID-19 cases still high in much of the country thanks to the continued spread of omicron, it’s important to be equipped with an effective mask.

And, considering that N95s and KN95s can still be difficult for the general public in the U.S. to find on a consistent (or affordable) basis, you may be considering re-wearing one of those that you already have.

Experts say there is a way to reuse N95 masks safely — as long as you follow some key guidelines.

With omicron circulating, should you upgrade to an N95 or KN95?

The Centers for Disease Control and Prevention recently updated its mask recommendations to clarify that, while all masks can be helpful, N95s (technically respirators, not masks) will offer the “highest level of protection” against particles in the air — including those that may contain the coronavirus. But whether or not you as an individual absolutely need to get a better mask isn’t so clear cut, experts said.

Upgrading your mask right now “certainly makes sense and it doesn’t necessarily hurt,” Dr. Bernard Camins, medical director for infection prevention at the Mount Sinai Health System, told TODAY. “The only potential issue is that the better masks are certainly more uncomfortable.”

Any mask is better than no mask, Dr. Raed Dweik, pulmonologist, critical care specialist and chair of the Respiratory Institute at the Cleveland Clinic, told TODAY. But he agreed that N95s and KN95s tend to be less comfortable. “So you have to find the right balance,” he explained.

You should “wear the most protective mask you can that fits well and that you will wear consistently,” the CDC explained. So if you’re choosing between a comfortable cloth mask you can wear without issues for a few hours at a time and a KN95 that might be more effective but you can’t keep it on for more than 10 minutes because it’s digging into your nose, the cloth mask might actually be a better choice.

And, for those who can’t get their hands on respirators, don’t forget the power of double-masking by wearing a cloth mask over a surgical mask.

The context around why you’re wearing the mask matters as well, Dr. Richard Martinello, associate professor of medicine in the department of infectious diseases at the Yale School of Medicine, told TODAY. If you’re going into a higher-risk environment, like on a flight or spending time in crowded elevators, it might be more important for you to wear a mask with a higher degree of protection — and you might be more willing to put up with a less comfortable mask under those circumstances. (And, of course, many people — including children — don’t have easy access to well-fitting respirators.)

But, ultimately, “the only mask or respirator that’s going to work is the one that you’re going to wear,” Martinello said.

How many times can you reuse an N95 or KN95 mask?

You can keep wearing an N95 or KN95 respirator until it loses its shape, gets visibly soiled or gets wet. And, of those, the most important thing to pay attention to is the fit of the mask.

Martinello said that in his hospital, staff members do a “fit check” in which they take a deep breath in and out to feel for any gaps between the edges of the mask and their skin where air might be able to pass through.

“What people will find is that the more they use the respirator — and, in particular, the more they take it off — the less likely it is to fit well and past that fit check,” he said. “We (tell) people in the health care setting that if the respirator doesn’t pass that fit check, both on inhalation and exhalation, they should discard it and get a new one.”

Health care workers may go through one, two or even more masks per day. But for most people outside of that setting who are using an N95 or KN95 for several hours a day, it will last somewhere around five days of use, Camins and Martinello said. If you’re only using it for weekly errands or the occasional visit with friends, it will likely last much longer than that.

“If you’re wearing it for an hour a day, you can probably wear it for a couple of weeks,” Dweik said. “But if you’re wearing it for eight hours a day, the chances are it will get soiled or it will get wet from your breath, and you’ll have to replace it. So you really have to take those (factors) into consideration.”

What’s the best way to store an N95 or KN95?

Once you’ve used them, you should keep your masks in a dry, safe space. The experts we spoke to all suggest keeping them in a plain old brown paper bag, which will allow the mask to dry off and keep it out of the way.

“We prefer a paper bag over a plastic bag because the plastic bag is going to retain the humidity,” Martinello explained. “If you just took it off, for example, it may be a little bit moist from wearing it for a prolonged period of time. And a plastic bag or container won’t allow (the mask) to breathe, but a paper bag will allow that.”

If you’re traveling or keeping your mask in your bag, you could try cutting some holes in the lid of a plastic container. Storing the mask in there will help protect it from getting misshapen in transit, Martinello added. At home, you could also hang it up somewhere out of the way, Camins said. “You just need to protect it because you don’t want it just lying around.”

In the early days of the pandemic when even health care workers had to ration their N95s, the recommendation was for them to keep reusing the same few masks and to let them sit in paper bags for a few days in between uses to allow any virus that might be lingering on them to die off, Camins explained.

But the experts told TODAY that, outside of a health care setting (where you might frequently come into contact with people who have confirmed COVID-19), you don’t really need to worry about the downtime between uses. These days, the general public can absolutely use the same mask on consecutive days — just be sure to let it air out overnight.

Signs that it’s time to replace your N95 or KN95:

Really, you can keep using the same mask for quite a while. But there are three key signs that it might be time to replace your mask, the experts said:

Does it still hold its shape? The most important issue is that it keeps its shape because that’s where the N95’s true filtration powers come from. “If it’s all scrunched up and when you put it on your face there are holes between the mask and your skin, then it’s misshapen and you shouldn’t be wearing it,” Camins said.

Is the mask soiled? If the mask is visibly soiled (like, there’s dirt or several days’ worth of makeup caked on there) you should swap it out.

Does the mask feel wet? If the mask gets a little bit moist, it can still be used as long as it dries out and is still able to fit tightly to your skin. But if it feels really damp (like from sweat or rain), it’s time to get a new one because once it gets wet, it’s less able to hold its shape. And if you start to notice a weird smell, it’s probably a good idea to use a new mask.

But the shape of the mask is the most important factor. And even if the shape isn’t perfect, a slightly misshapen N95 can still provide some protection — especially if the alternative is no mask at all.

“While in the health care setting we would tell people to throw it out,” Martinello said, “for any individual who doesn’t have as much access to personal protective equipment as we do, they can continue to use it recognizing that its ability to protect them is a little bit less.”