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KN95 vs KF94 masks: what’s the difference?

As the Omicron variant continues to spread rapidly in Canada, experts and public health officials are once again reiterating the importance of wearing a properly fitted, medical-grade mask to prevent transmission of COVID-19.

But with N95 masks in short supply and largely reserved for healthcare professionals, a growing number of retailers are advertising KN95 and KF94 masks as alternatives.

These masks, more commonly referred to as respirators in the medical field, are more effective at filtering particles in the air, which has prompted a growing number of experts and public health officials to recommend their use over fabric masks. .

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

SIMILAR FILTRATION LEVELS, DIFFERENT ADJUSTMENT

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

The KN95 mask is the Chinese equivalent of the N95, both of which have a filtration efficiency of 95%.

The KF94 mask is the Korean equivalent, with a filtration efficiency of 94% to filter out 0.3 micron particles, according to Dr. Gerald Evans, chair of the division of infectious diseases at Queen’s University in Kingston, Ont. .

“The two are believed to be equivalent to the N95 which are designated here in North America, and in the ‘N’ stands for NIOSH, which is the National Institute of Occupational Safety and Health,” Evans told CTVNews .that.

“The only thing that’s really different is that the N95 mask has two rubber bands that go around your head … the KN95 and KF94 have the earrings we are used to seeing on masks in tissue.”

For reference, a regular blue surgical mask has about 80% filtration capacity, provided it fits snugly to the face without too much open space on the sides.

But this is where the fit comes in, the most important component.

While the N95, KN95 and KF94 masks have high filtration capacities, their effectiveness depends entirely on their fit.

In medical settings, doctors go through “fit testing” to make sure their masks are waterproof. This includes tests like feeling something through the mask (if you can’t smell something you should be able to smell without a mask, the seal is working).

Due to the variety of earring shapes, sizes and lengths, not all models of respirators will fit all faces properly.

“I don’t think there have been any tests to compare which is the best, but the most critical aspect is which one provides a better seal around the nose and mouth,” Stephen Hoption Cann, prevention expert of infectious diseases at the University of British Columbia. CTVNews.ca told via email.

“The KN95 is more bird’s beak shaped than the KF94 is a bit flatter.”

Brian Fleck, professor of mechanical engineering at the University of Alberta, says the effectiveness of masking comes down to basic engineering.

“When a filter isn’t installed very well… the way the pressure and airflow works, it goes down the path of least resistance,” Fleck explained over the phone.

“Typically, if the air manages to bypass the filter, a lot of it will. So you can have an extremely efficient filter material, but if the air is not forced through it, it is not as efficient.

Fleck notes that a good test when wearing a mask is putting on a pair of goggles – if they fog up when they breathe or come in from the outside, the mask is not providing a good seal.

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

“Find the mask where no matter what you do, the rubber bands are tight and it doesn’t let air escape around the edges. Otherwise, you really only wear it for the optics.

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

Health Canada, the United States Federal Drug Administration (FDA), and the United States Center for Disease Control and Prevention (CDC) provide information on approved products as well as those deemed unsuitable.