Everything You Need To Know About Korean KF94 Masks

Everything You Need To Know About Korean KF94 Masks
South Korea's KF94 face mask is comparable to both the American N95 and Chinese KN95.

Monica Torres
02/02/2021 05:45am EST | Updated February 2, 2021

In the fight against the coronavirus, wearing a good mask is critical for preventing the spread of COVID-19. But due to ongoing shortages, finding medical-grade N95 respirators, the gold standard of protection in the U.S., is still difficult for health care workers ― let alone laypeople.

As more contagious variants of the coronavirus are spreading throughout the world, getting a high-quality mask is more important than ever. If you’re hunting for an everyday face mask that’s an upgrade from cloth, consider the KF94.

What exactly is a KF94 mask?
KF94 masks are the South Korean equivalent of the N95. The “KF” stands for “Korean filter,” and the “94” means that according to South Korean government standards, it is 94% effective at filtering out airborne particles.

“Comparing it to an N95 which has 95% filtration efficiency, this is 94% good at filtering out particles. So pretty comparable to the N95 mask,” said Ravina Kullar, an infectious disease specialist and epidemiologist.

The FDA has not authorized KF94s for emergency use by U.S. health care workers like it has with certain KN95 masks that meet the Chinese government’s standards of certification. But for everyone else, KF94s may be a good upgrade option –– especially for other essential workers who are consistently around other people.

“It definitely is better than a cloth mask,” Kullar said. “It gives you more protection.”

Many KF94s look like a mashup of an N95 and a cloth mask. Similar to an N95, there is an adjustable nose bridge. But instead of elastic headbands, the KF94 has ear loops. “They also have side flaps to contour [to] your face as well, so that’s going to help close the gaps around the face, and also limit unfiltered air entry as well,” Kullar said.

Unlike a cloth mask, the KF94 is meant to be disposable, so don’t launder it. “The synthetic materials are going to get ruined in the wash, so I would see this as one-and-done. Use it once, get rid of it, and get a new mask,” Kullar said.

Russo noted that although the masks are intended to be single-use, “given the circumstances we’re in, that’s not pragmatic.” To stretch out your supply, “the best way to do it is rotate them.” He recommended leaving your KF94 mask in an open paper bag or Ziploc bag, so that the moisture on the inside of the mask evaporates, and that you can reuse them after any viable virus is no longer viable.

How effective are KF94 masks at blocking COVID-19?
In a small, limited study published in the journal Infectious Disease in August, both KF94 and N95 masks were effective at stopping viral particles when tested on coughing coronavirus patients. Both types performed better than surgical masks.

Although there is a 1-point difference in the filtration efficiency of N95s and KN95s and KF94s, “functionally, they’re all equivalent,” said Thomas Russo, chief of the infectious disease division at the University of Buffalo.

“To me, that’s the same ballpark,” Russo said, suggesting that instead of focusing on the small difference in filtration efficiency, people pay the most attention to how this type of mask fits their face. “You can have a N95, but if it doesn’t fit well, that’s problematic,” he noted.

Fit is the most important factor in making a mask like the KF94 effective. If you buy a KF94, make sure it feels comfortable to wear without needing to be adjusted all the time. Kullar said wearers should pull on the ear loops to get them as tight as possible so the mask fits close to the face.

“If you keep moving it around, you’re obviously going to leave some leeway for particles to come through, come out, and that’s not going to protect other people,” Kullar said.

One quick test for glasses-wearers: If your glasses are fogging up while you wear your mask, that’s a sign you don’t have an optimal fit, Russo said. “That means the humidified air is sort of escaping” from under your mask, he said.

How can I tell if a KF94 mask is fake or legit?
Counterfeit masks are an ongoing problem on Amazon, the world’s largest e-commerce retailer. Experts say you should check seller ratings, double-check a listing’s URL to be sure it matches the item on sale, and be wary of new sellers if you choose to buy masks through Amazon.

Kullar suggests going to a well-known retailer if you’re looking for KF94s. “If you go to Target, you go to Lowe’s, you go to Ace Hardware, you know there was someone affiliated with the company who purchased those,” she said.

The Centers for Disease Control and Prevention keeps a list of manufacturers whose KF94s and KN95s have passed a filter efficiency test similar to the one used on N95s. When in doubt about your mask, add a cloth one on top.

“Spotting counterfeits is very difficult, and if there’s any question about the quality of the mask, and you don’t think it’s up to snuff but you have no alternative, that may be a scenario where you want to double-mask with a good cloth mask over it,” Russo said. “If you’re not certain, [it] will give that bit of extra protection.”