Comparison of Mask Standards, Ratings, and Filtration Effectiveness
Posted by HETUL THAKKAR
Mask Standards and Effectiveness Bottom Line
- Single use masks (normally one layer, very thin) are typically only effective at capturing larger dust particles, but can do so fairly well.
- Surgical mask standards have higher requirements for capturing virus-sized (0.1 micron) particles, however they vary by region.
- 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).
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.
Coronavirus & Mask Livestream
3M or FFP1 or N95 or KN95? What Do Mask Numbers and Letters Mean?
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.
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.
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.
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.
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