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 standard varies a little by country, however they are broadly similar.
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.
EN 149:2001+A1:2009 / ASTM F2100 / NIOSH
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.
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.
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.
Content retrieved from: https://smartairfilters.com/en/blog/comparison-mask-standards-rating-effectiveness/.