What’s the difference between an N95 and a KN95?

Summary: There’s virtually no difference. It’s just what different countries call the same thing.

Let’s use an analogy.

Let’s say your name is Jonathan. (That's him on the left.)

People like you because you’re just the right blend of (approximately) 95% sweet and 5% spice.

Your mom totally agrees, so her pet name for you is Jonny.

Your grandpa thinks you’re great from experience, so he calls you Jon-boy.

Your best friend can attest to you being 95% sweet (picks up the tab) and 5% spice (can tell a risque joke every once in a while), and calls you Jon-Jon.

They all love you equally (with minor variations).

Does Jonathan pass the pet name test?

But just like real life, their expressed affection for you is conditional on you being 95% sweet and 5% spice. Your mom may love you unconditionally, but she might not call you “Jonny” at the Thanksgiving table, instead opting for a chilly ‘Jonathan.’ Ouch.

But no matter what you’re called, you’re still you.

You can be BOTH Jonny and Jon-boy to your mom and grandpa. 

But maybe you’ve never left your house since birth so no friends for you. As a result, nobody calls you Jon-Jon.

That doesn’t mean you fundamentally change. You’re still approximate 95% sweet, 5% spice.

So does a mask by another name work as well?

If it’s well-vetted and certified by one country, it’s almost identical, since the requirements to be called the ‘pet name’ for that country are the same. (Link goes to explanation by 3M)

Turns out you just need to have the same high reliability and basic sense of humor in every relationship to pass the test! (Or 95% filtration and level of breathability)

So Europe’s ‘pet name’ for masks with 94% filtration capabilities is called FFP2. Their test is called EN149:2001. It's 94 rather than 95%, since Europe took a nap during lunch. 

China’s ‘pet name’ is KN95. Their test is called GB2626-2006. It looks virtually identical to the other countries. China really liked how America's pet name N95 sounded so they threw a K in front of it.

America’s ‘pet name’ is N95. Their test is called being anointed by NIOSH (an agency that protect worker safety, generally speaking - construction workers too!) as a NIOSH-approved N95.

For that reason, there’s not reallllyyy such a creature as a plain old N95. It’s almost always a NIOSH-approved one. (See footnote for further explanation.)

And there’s not a lot of places that make these little unicorns - the NIOSH N95's. You're pretty unlikely to encounter them on the internet for anything less than $15-20.

So Jonathan is still Jonathan? N95's are KN95's?

These pet names are like gold stars of approval handed out by each country’s regulatory agency, so you can have multiple gold stars from different countries.

The crazy thing? The standards are virtually identical. Hence why the FDA has said during this shortage, the alternates are ok to use.

But don’t worry Jonathan: to us you’re always Jon-Jon, Jonny, and Jon-boy, screw all the haters.

I don’t care! I want an N95!

You’re actually asking for a NIOSH-certified N95.

Remove the naked “N95” without its codependent partner “NIOSH.”

There’s no certified N95 except for a NIOSH N95.

Because, well, the way you get certified as an N95 in the USA is through NIOSH.

So no NIOSH, no N95. (See further discussion below for more detailed explanation.) 

Well, I want a NIOSH-certified N95 then! Listen to me! None of that China crap!

It’s tough. This is precisely why we have a PPE shortage.

It’s not so much that hospitals lack any available Jonathans, it’s that they only trust the judgement of Mom but not Grandpa or Best Friend.

So they want Jonny’s only, no Jon-Jons or Jon-boys.

So even though the FDA has said it’s ok to trust other people in Jonathan’s life who show affection for him and can vouch for his 95% reliability, hospitals are really stuck on mom’s judgement.

They’re worried that if they take the word of Grandpa or Best Friend, they might get sued.

They’re just sort of scared in general. And bad at changing their minds in a pinch.

So they’re like, we want NIOSH N95 only! But there’s very few of those out there, and they’re quite expensive.

So by purchasing FFP2 and KN95’s, you’re actually increasing the availability of masks, not necessarily taking them away from healthcare workers whose bosses are momma’s boys.

(Boo, hiss. A discussion for another day.)

How do I know I can trust KN95’s and FFP2/FFP3?

Humans have diplomas and report cards. Masks have certificates and test reports.

Remember: if something passes the test for one country, it’s pretty much the same thing as passing the test for another country.


But what if those are faked? Or how can I figure out if a mask REALLY works?

Here’s a link to a fit test.

You can also cut open a mask and look at the internal layers. One of the layers should be bright white and have an unusual texture - thin and springy, almost like plastic wrap. That’s called meltblown fabric.

That’s the layer that’s responsible for the whole “95% filtration” thing.

If it doesn’t have that layer, it’s not an N95.


What's that thing about N95's being more complicated in the USA?

In the USA, we add one extra 'personality factor' - liquid resistance - that splits N95’s into ‘standard’ (construction worker protected from dust) and ‘surgical’ (filters dust and also resists a splash of blood during, say, surgery).

Because we’re a nation that likes to collect degrees, NIOSH awards certification for ‘standard’ and the FDA awards certification for ‘surgical’. NIOSH protects general workers on the job and the FDA protects the general public.

You can also be both. It’s confusing, sort of like how bisexual people confuse straights. (Just choose, dammit!)

Or how you can collect a Biology degree, an English degree, or do a really impressive thing and double major.

It’s why the gold standard for N95 masks in the US is the 3M 1860 blue mask - it’s approved by both NIOSH *and* the FDA! Dust or blood, it gets ‘em all. It’s a NIOSH-approved N95 surgical respirator.

(BTW, the word ‘respirator’ is often used so people don’t confuse these weird looking, tight fitting things with those square blue ‘surgical masks’ with open sides. I know. They were not very helpful with clear names.)