As the Omicron variant continues to drive rapid spread in Canada, experts and public health officials are once again driving home 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 health-care professionals, a growing number of retailers are advertising KN95 and KF94 masks as alternatives.
These masks鈥攎ore commonly referred to as respirators in the medical realm鈥攁re more effective at filtering out particles in the air, prompting 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 鈥渒nock off鈥 N95 masks. So, what鈥檚 the difference between the two?
SIMILAR LEVELS OF FILTRATION, DIFFERENT FIT
When it comes to respirators, the number associated with the model indicates the filtration efficacy. Both the KN95 and the KF94 mask come very close to the level of filtration found in an N95 mask鈥攖hey鈥檙e simply different equivalents.
The KN95 mask is the Chinese equivalent to the N95, both having 95 per cent filtration efficacy.
The KF94 mask is the Korean equivalent, with a 94 per cent filtration efficiency for filtering out particles 0.3 microns in size, according to Dr. Gerald Evans, chair of Queen's University's infectious diseases division in Kingston, Ont.
鈥淏oth of them are thought to be to be equivalent to the N95 that are designated here in North America, and in the 'N' there stands for NIOSH, which is the National Institute of Occupational Safety and Health,鈥 Evans told CTVNews.ca
鈥淭he only thing that's really different is that the N95 mask has two elastics that go around your head鈥 the KN95 and KF94 have the ear loops that we鈥檙e used to seeing on cloth masks.鈥
For reference, a regular blue surgical mask has a filtration capacity of about 80 per cent, providing that it鈥檚 fitted to the face well without too much gaping at the sides.
But here鈥檚 where fit鈥攖he most important component鈥攃omes in.
While the N95, KN95 and KF94 masks boast high filtration capacities, their efficiency is entirely based on how it fits.
In medical settings, doctors are put through 鈥渇it tests鈥 to ensure their mask has a seal. This includes tests like smelling something through the mask (if you can鈥檛 smell something you should be able to smell without a mask the seal is working).
Due to the range in shape, size and length of ear loops, not every model of respirator is going to fit properly on every face.
鈥淚 do not believe there have been any tests to compare which is better, but the more critical aspect is which provides a better seal around the nose and mouth,鈥 Stephen Hoption Cann, an expert in infectious disease prevention at the University of British Columbia, told CTVNews.ca via email.
鈥淭he KN95 is more of a bird鈥檚 beak shape vs the KF94 is a little flatter.鈥
Brian Fleck, professor of mechanical engineering at the University of Alberta, says the effectiveness of masking comes down to basic engineering.
鈥淲hen a filter isn鈥檛 very well fitted鈥 the way pressure and airflow works it goes through the path of least resistance,鈥 Fleck explained over the phone.
鈥淕enerally, if the air can find a way around the filter, a lot of it will. So, you can have an extremely effective filter material, but if the air isn鈥檛 forced through it, it鈥檚 not as effective.鈥
Fleck notes that a good test when wearing a mask is to put on a pair of glasses鈥攊f they fog up when they breathe or come in from outside, the mask isn鈥檛 producing a proper seal.
鈥淔or people who want to be safe, in other words, they want to reduce the number of particles they breathe in, they should really pay attention to how their mask fits their face,鈥 he said, noting this goes for both medical-grade masks and cloth masks.
鈥淔ind the mask where no matter what you鈥檙e doing the elastics are tight and it鈥檚 not letting any air escape around the edges. Otherwise, you鈥檙e really just wearing it for optics.
Hoption Cann says it should be noted that many masks that are sold as KN95 or KF94, when tested, fail to meet their advertised filtration efficacy.
Health Canada, the U.S. Federal Drug Administration (FDA) and the U.S. Center for Disease Control and Prevention (CDC) as well as those found to be inadequate.
