How Long Do N95 Masks Last?

The N95 mask has a long, fascinating history that began with a bra cup designed by Sara Little Turnbull in the 1950s. But your burning questions might be less about its origins and more about how long you can wear one before it belongs in the trash.

Like certain foods, N95 masks don’t have a hard-and-fast expiration date—you’ve got to make a judgment call based on the situation and the state of the mask itself. That said, there are some guidelines to follow.

As the San Francisco Chronicle reports, any sign that your mask is dirty or deteriorated means you should throw it away. Maybe it’s wet or has a stain on it. Maybe the mask is dry and spotless, but its straps are stretched out and it feels loose on your face.

If your mask still looks (and feels) to be in mint condition, it can probably live to see another day. Many experts recommend storing your mask in a paper bag or some other “breathable” container that’ll prevent it from getting contaminated—or contaminating someone or something—between uses. The idea is to allow any virus particles on the mask to die out between uses.

“It's not the bag that’s doing the magic trick,” Verywell Health chief medical officer Dr. Jessica Shepherd told 4WWL. It's more about “keeping a dry environment in order for the virus to not spread or stay on the mask.”

In October 2020, the CDC published advice for health care workers who needed to optimize the longevity of their N95 masks during PPE shortages. According to those recommendations, each person should have at least five N95s in the rotation, which they would store in separate paper bags between uses. That way, any pathogens that had landed on a mask would have a good several days to die off in the paper bag before someone needed to wear the mask again. When there isn’t a PPE shortage, health care workers are generally advised to toss their mask after one day.

But for the rest of us, mask rotation can be a good idea. “For an N95, we'd recommend you switch [the mask] every day,” Dr. Sabrina Assoumou, an infectious diseases physician at Boston Medical Center, told USA TODAY. “If you have three masks, [for example], you could number them and switch them around.”

As for how long you should keep a mask in the rotation before throwing it away, it depends on whom you ask. The CDC and other experts have said that five wears is a good rule of thumb. But, again, if your N95 is misshapen or stained after just the first wear, don’t try to make it last for four (or even one) more.

[h/t San Francisco Chronicle]