Have you heard of the N95 and KN95 masks – but have you heard of the KF94, and what is the difference between the three?
There are many high quality masks on the market with different letters and numbers. Understandably, this can be confusing. However, to decipher their differences and how each works, you need to have an understanding of what the different letters and numbers represent.
“The number of all of them refers to his filtering efficiency, that is, the percentage of articles he misses,” said Dr. John Volckens, professor of mechanical engineering at Colorado State University.
A KN95 filters 95 percent of the particles, as does an N95. A KF94 filters 94 percent of the particles. The difference between the letters is the standard government certification.
“ON in N95 means NIOSH [The National Institute for Occupational Safety and Health], and that’s the US standard, and it’s an occupational standard, “said Volckens.” KN95 is a Chinese standard close to the US standard and KF94 is a Korean standard. “
“N” is also a NIOSH classification for non-oil resistant masks.
KF literally means “Korean filter”. Notably, a study published in 2020 showed that KF94 masks are comparable to N95 in blocking SARS-CoV-2 particles and more effective than a surgical mask. However, the study was quite limited, as only seven patients with SARS-CoV-2 infection participated in it.
“KF94s seem to be more available than the N95, cheaper [generally under $2 each] and easier for many people to use, “said Sonali Advani, assistant professor of medicine at Duke University. NPR. “The KF94 is actually intended for public use. In Korea, it is often used by ordinary people to filter out dust or pollution.”
Volckens explained that N95 masks are certified only by a laboratory that is part of the Centers for Disease Control and Prevention (CDC), and that is partly because the supply cannot meet demand now.
“They are very strict about who lets them become an N95, which is why you don’t see many of them on the market anymore because they were all bought,” said Volckens. “The problem with the KN95 and KN94s is that there are a lot of imposters on the market and we don’t know what you’re buying.”
When it comes to N95 masks, each mask has a seal that declares that it has been certified by NIOSH with a certification number that you can consult online. Volckens added that there are also masks that have ASTM [American Society for Testing and Materials] patterns that are “almost equivalent” to N95 masks – like FFP2, which means “two-level mask filter” mask.
In some parts of Europe, such as Germany, the federal and state governments are demanding that FFP2 masks be used in stores and on public transport now. According to NPR, Austria is making similar recommendations. In France, the Superior Council for Public Health announced that it also recommends that people wear surgical masks in public – instead of tissue masks.
In the USA, the CDC continues to recommend fabric masks for the general public, as long as they have at least two layers.
Volckens said that if you are buying a fabric mask, you should look for three main characteristics: fit, filtration and breathability.
“Filterability of the fabric, you want a highly effective filter, you want an adjustment – and that’s a personal thing, but you want the mask to fit perfectly across your face and then breathability, you must be able to breathe through the mask normally, “said Volckens. “Otherwise, if it is uncomfortable to breathe, you will not be using it and may be unsafe.”
Of course, it is difficult to know the fit of a mask until it is purchased. But Volckens said people should buy masks from a supplier whose filter has been tested. As for the adjustment of the mask, it can be reconciled by double masking.
“That’s why you can use the double mask, because you can buy a mask that doesn’t fit well, but use something else to hold it closer to your face,” said Volckens. “This is what we talked about about double masking being effective in adjusting.”