Comparison of Mask Standards, Ratings, and Filtration Effectiveness

Mask Rating N95 N99 FFP1 FFP3 Surgical Respirator Mask Comparison

Mask standards can be confusing: N95, KN95, FFP1, P2, or surgical mask? This quick run-down covers mask types, mask ratings, and their effectiveness at filtering particles.

First off, let’s start with mask types (or certification types). In general, there are 3 (or sometimes 4) types of commonly used, disposable masks. They are single-use face masks, surgical masks, and respirators.

Surgical Mask Filtration Standards

Mask Standards and Effectiveness Bottom Line

  1. Single use masks (normally one layer, very thin) are typically only effective at capturing larger dust particles, but can do so fairly well.
  2. Surgical mask standards have higher requirements for capturing virus-sized (0.1 micron) particles, however they vary by region.
  3. Pollution masks (respirators) typically capture >90% of virus-sized particles. You can use the rating system in the table above to see the exact proportion each certification requires. This includes ratings such as N95, KN95, FFP1, FFP2 and FFP3.

Mask Standards Vary by Country

Each country has their own certification standard for each mask type. For example, Europe uses the EN 14683 standard for surgical masks, whereas China uses the YY 0469 standard. Each standard varies a little by country, however they are broadly similar. For respirator masks, China uses the KN standard (e.g. KN95) and the US uses the N standard (e.g. N95).

Read more: what’s the difference between KN95 and N95 masks »

Requirements Are Lowest for Single Use Face Masks

The standard with the lowest requirements on filtration effectiveness are the single use face masks (not to be confused with surgical masks). Surgical masks have higher requirements, and respirators have the highest requirements. Respirators also usually fit tighter around the face (data shows they score higher on fit effectiveness) than surgical masks and single-use face masks.

N95 Mask Fit Test Filtration Effectiveness

Coronavirus & Mask Livestream

Wondering whether masks work to protect you against the coronavirus? Check out our livestream recap covering all the info here!


3M or FFP1 or N95 or KN95? What Do Mask Numbers and Letters Mean?

A visitor to the website asked this in the comment section on coronavirus and Pitta masks a few days back:

Could you please explain: if a mask is FFP2 or 3, but NOT 3M – what does it mean exactly concerning coronavirus? thank you!

Here’s an explanation on the difference between N95, 3M and PM2.5, to help you out.

N95, N99, FFP1, FFP2 and FFP3 Masks

The ratings cover (most importantly for us) the filtration level, among other things. You can think of them like G, PG, PG-13, R ratings for movies. The movie ratings cover who can watch them.

Movie rating system like ffp1 ffp2 n90 n95 n100 respirator rating system

EN 149:2001+A1:2009 / ASTM F2100 / NIOSH

These are standards for masks. They specify the rules and testing methods companies should follow to rate their masks. These standards define the N95, FFP1, and FFP2 ratings above. Using the movie rating analogy, you can think of it like this: the people reviewing movies and choosing the appropriate movie rating must have a set of rules to decide if the movie is considered PG-13 or R. They’ll follow these rules to rate the movie. These standards are the set of rules for masks.

Why are there so many? Standards labelled “EN” are for the EU. ASTM F2100 (NIOSH) is for the US. Many other countries will have their own rating systems too.

3M Masks?

3M is a company that manufactures masks. They generally produce masks that meet KN95 or N95 standards

PM2.5 vs. N95

As we now know, N95 is a mask rating. PM2.5 refers to “particulate matter” or a fancy way of saying “pollution particles” that are in the air. The 2.5 refers to the size of these particles as being 2.5 microns or smaller. This picture can give you a visual example of how big PM2.5 particles are.

Size of coronavirus particle pm2.5 and bacteria


Bottom Line: To Understand Mask Ratings

1. Three randomized studies have found surgical masks are just as effective as N95 masks at preventing virus transmission. They hypothesize the main reason for this is that any mask can reduce the hand-to-face contact, although we don’t know this for sure.

2. If you’re wearing a mask with a valve, you are protected. The valve does not bring in any outside air into the mask. Fit-test data has found that masks with valves are often among the highest scoring.

Mask Fit Effectiveness Valve vs No Valve

However, valves will not protect other people as well. If you are sick, and you breathe out, some of the moisture from your breath can expel through the valve, potentially putting others in danger.

3. Tests have found that DIY masks can filter a percentage of virus-sized particles. While they’re not as effective as surgical or N95 masks at filtering viruses, they can still provide some benefit. They can also reduce hand-to-face contact.

Covid19 coronavirus best masks materials fundraiser

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I’ve been re-using my surgical mask enclosed in a sleeve. The sleeve is to prevent the surgical mask from getting dirty.

After each use, I wash the sleeve and disinfect both sides of surgical mask with hydroxyl ions generated by my Winix air puriifier, which is the PlasmaWave function. I do wonder whether I should get rid of the inner most and outer most layer of surgical mask, so that the hydroxyl ions can get to the melt-blown material easier.

Would be nice if somebody can verify such practice.

Adele Cerrelli

I see disposable face masks that say they are “FDA registered” or “FDA Approved” or “FDA certified”. Is any of that true? And where can I find a what official standard a disposable face mask has met?

Liz - Smart Air

Hi Adele, Liz here. FDA approved is applied on medical devices. So if you see a mask is FDA approved, it means that the mask is exempt from premarket notification requirements.But FDA approve doesn’t say the grade of the masks. The standards listed in this article tells how well your mask would do for filtering particular sized particles.



In South Africa we have very expensive NanoWave masks. It’s a sponge type mask with a filter and it says EN 149:2001 + A1:2009 on the mask. From your article this does not seem to mean anything. Do you know anything about them?


Liz - Smart Air

Hi Dianne, EN is the standard for European standard, and EN149:2001 are designed to protect against solids, water-based aerosols, and oil-based aerosols. In contrast, there is also a standard EN149:1991 which is allows for the testing of respirators against solid aerosols only. A1:2009 is the amendment version (likely the 2009 is the amendment year). You can find the standard full info online.


Please let me know the correct side of surgical mask (blue layer touching the skin)

Liz - Smart Air

Hi Felix, Liz here. Our engineer just wrote an article on how to wear your surgical mask:

Eduardo Jeldres

What about electrical masks? I d just buy the Xiaomi Q5 pro and I dont have enough evidence on how this mask can protect from coronavirus. It suppose it filter 2.5 ppm enforced for additional filters.
Do you have more information please?

Liz - Smart Air

Hi, Eduardo, Liz here. I looked it up and seems like Xiaomi doesn’t sell this model in major Chinese online shopping sites. Anyway, I still did some dig in and found the mask has four layers and basically like a N95 mask with a carbon filter layer. The fan (the part you can charge) is helping to breath easier, not to help on increasing filtration rate. So, I’d say if it works well, it should have about the same filtration rate as a N95 mask or a surgical mask. However, we never tested the model so I don’t have the… Read more »