KN95 vs. KF94 masks: What’s the difference?

As the Omicron variant continues to drive the rapid spread in Canada, experts and public health officials are once again pushing home the importance of wearing a proper medical mask to prevent transmission of COVID-19.

But with the supply of N95 masks largely intended for medical professionals in short supply, an increasing number of retailers are advertising KN95 and KF94 masks as alternatives.

These masks — commonly referred to as ventilators in the medical field — are more effective at filtering particles in the air, leading a growing number of experts and public health officials to recommend their use over cloth masks.

Contrary to some claims on social media, KN95 and KF94 are not “stop working” N95 masks. So, what’s the difference between the two?

Similar levels of filtration, different fit

When it comes to respirators, the number associated with the model indicates filtration effectiveness. The KN95 and KF94 mask are very close to the level of filtration found in the N95 mask – they are simply two different equivalents.

The KN95 mask is the Chinese equivalent of N95, and both have a 95 percent filtration efficacy.

The KF94 mask is the Korean equivalent, with a 94 percent filtration efficiency to filter 0.3-micron particles, according to Dr. Gerald Evans, chair of the Department of Infectious Diseases at Queen’s University in Kingston, Ont.

“Both are thought to be equivalent to the N95 designed here in North America, and in the letter ‘N’ is NIOSH, which is the National Institute for Occupational Safety and Health,” Evans told CTVNews.ca.

“The only thing really different is that the N95 mask has two rubber bands that go around your head… The KN95 and KF94 have the ear loops we’re used to seeing on cloth masks.”

For reference, an ordinary blue surgical mask has a filtration capacity of about 80 percent, provided that it fits the face well without large gaps in the sides.

But here comes the right place – the most important element – comes.

While the N95, KN95 and KF94 masks have high filtration capabilities, their efficiency depends entirely on how they are fitted.

In medical settings, doctors undergo “fitness tests” to make sure their masks are sealed. This includes tests such as smelling something through the mask (if you can’t smell something, you should be able to smell it without a mask, the seal works).

Due to the range, size, and length of earloops, not every model of respirator will properly fit every face.

“I don’t think there have been any tests to compare which one is better, but the most important aspect is to provide better sealing around the nose and mouth,” Stephen Hope Kahn, an expert in infectious disease prevention at the University of British Columbia, told CTVNews.ca via email.

“KN95 is closer to the shape of a bird’s beak while the KF94 is a bit flatter.”

The mask’s effectiveness is due to the underlying engineering, says Brian Fleck, professor of mechanical engineering at the University of Alberta.

“When the filter is not properly fitted … the way pressure and airflow operate goes through the path of least resistance,” Flick explained by phone.

“In general, if air finds a way around the filter, there will be a lot of it. So, you can have a very effective filter material, but if the air is not being pushed through, it will not be as effective.”

Flick notes that a good test when wearing a mask is to wear a pair of glasses—if they mist when they breathe in or get in from outside, the mask doesn’t produce a proper seal.

“For people who want to be safe, in other words, who want to reduce the number of particles they breathe in, they should really pay attention to how their masks fit their face,” he said, noting that this applies to both medical-grade masks and cloth masks.

“Look for the mask where no matter what you do, the rubber bands are taut and don’t allow any air to escape the edges. Otherwise, you’re really wearing it for the optics.

Hoption Cann says it should be noted that many masks sold as KN95 or KF94, when tested, fail to meet their advertised filtration efficacy.

Health Canada, the Federal Drug Administration (FDA), and the US Centers for Disease Control and Prevention (CDC) provide information on approved products as well as those found to be inadequate.

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