[ad_1]
You’ve heard of the N95 and KN95 masks – but have you heard of the KF94 and what’s the difference between the three?
There are many high quality masks on the market with different letters and numbers. Of course, this can be confusing. However, to decipher their differences and how each one works, one needs to understand what the different letters and numbers represent.
“The number on all of these refers to its filtration efficiency, therefore the percentage of items it keeps from passing,” said Dr. John Volckens, professor of mechanical engineering at Colorado State University.
A KN95 filters 95% of particles, just like an N95. A KF94 filters 94% of particles. The difference between the letters is the standard government certification.
“The N in N95 stands for NIOSH [The National Institute for Occupational Safety and Health], and this is the American standard, and it is a professional standard, “Volckens said.” KN95 is a Chinese standard which is close to the American standard and KF94 is a Korean standard.
“N” is also a NIOSH rating 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 small as only seven patients infected with SARS-CoV-2 participated in it.
“The KF94s seem to be more readily available than the cheaper N95s [generally under $2 each] and easier to use for many people, ”said Sonali Advani, assistant professor of medicine at Duke University. NPR. “The KF94 is actually for public use. In Korea, they are often worn by ordinary citizens to filter out dust or pollution.”
Volckens explained that N95 masks are only certified by a lab that’s part of the Centers for Disease Control and Prevention (CDC), and that’s part of why supply can’t meet demand at the moment.
“They’re very strict about who they let become an N95, which is why you don’t see a lot of them in the market anymore because they’ve all been bought,” Volckens said. “The problem with the KN95s and KN94s is that there are a lot of impostors out there, and we don’t know what you’re buying.”
As for N95 masks, each mask has a stamp indicating that it has been certified by NIOSH with a certification number which you can search online. Volckens added there are also masks which have ASTM [American Society for Testing and Materials] standards that are “nearly equivalent” to N95 masks – like FFP2, which stands for “two-level filter mask”.
In parts of Europe, such as Germany, state and federal governments are requiring that FFP2 masks now be used in shops and on public transport. According to NPR, Austria makes similar recommendations. In France, the Haut Conseil de la santé publique announced that it is also recommending that people wear surgical masks in public – instead of cloth masks.
In the United States, the CDC continues to recommend sheet masks for the general public, as long as they have at least two layers.
Volckens said that if you are buying a sheet mask, there are three key features you should look for: fit, filtration and breathability.
“Filtering ability of the fabric, you want a very efficient filter, you want a fit – and that’s a personal thing, but you want the mask to fit tightly all over your face, then the breathability you have to be able to breathe normally through the mask, “Volckens said.” Otherwise, if it’s uncomfortable to breathe, you’re not going to wear it, and that could be dangerous. “
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 who has been filter tested. Regarding mask fit, this can be reconciled by double masking.
“That’s why you can double the mask because you can buy a mask that doesn’t fit well, but then use something else to keep that mask closer to your face,” Volckens said. “This is what we are talking about the effective double masking on the fit.”
[ad_2]
Source link