Following my @guardianopinion article, people asked which #mask I recommend. I won't recommend a specific brand or model but I can recommend features of masks that will enhance comfort and fit. This🧵relates to industry-certified masks. 1/ theguardian.com/commentisfree/…
#BetterMasks
#BetterMasks
2/ Firstly, what do I mean by 'industry-certified'? These respirators conform to (and have passed tests for) industry standards of filtration efficiency (at a minimum). To cut a long story short, mainly #N95/N99 (US), #FFP2/FFP3 (Europe/UK) & KF94 (Korea). theguardian.com/commentisfree/…
3/ Although these masks pass tests for how well they filter (capture) particles & aerosol, and all are excellent at doing this, the actual effectiveness of your mask also depends on how well it seals to your face. This also depends on your face shape/size. sciencedirect.com/science/articl… 
4/ You may need to try several masks to find one that fits well and doesn't let air out of the edges of the mask. Air should only enter/exit through the mask's fabric - this is the filter. Facial hair also gets in the way of a tight seal. #LoseThe#Beard
5/ Masks come in different shapes. I find that bi-fold masks (with a vertical fold) don't make a great seal because the nose clip is bent in the middle. When you fit a mask, you should mould the clip to your nose, not pinch it, otherwise air escapes around your nose bridge.
6/ 'Hard-cup' masks often do not fit small or narrow faces and are the least flexible in terms of moulding them to your face shape.
7/ There are other shapes on the market (too many to go through!) but I really like the 'boat shaped' masks. They fit really well to different face shapes and I find them to be very comfortable. Photo: @3MUK
8/ Regarding earloops versus head straps, ear loops rarely provide sufficient tension (without hurting the ears) to maintain a good facial seal. Head straps are more comfortable, too. If you can't get masks with headstraps, consider using an 'extender head strap' with ear loops.
9/ Make sure the headstraps are not twisted. The upper one should sit at the crown of your head and the lower one should sit on your hairline.
9/ An excellent mask might also have foam around the edge, to make a really good and comfortable facial seal, especially around the nose. This really helps prevent misting of glasses, too.
10/ Note: none of the masks I've shown has a valve on the front or side (image below, for reference). These valves are designed to improve comfort. They let a portion of your breath out unfiltered, so they give insufficient #Covid_19 protection to those around you. Photo:@3MUK
11/ For information on how to fit an N95-style mask, you might like this video that we (#IVHHN) produced for the public, to protect people from volcanic ash. Different exposure scenario, but no difference in need for excellent masks or how to fit them!
13/ Disclaimer: Neither I nor #IVHHN endorse any brands that may be shown in the images in this thread.
All mask photos not credited in the thread are free to use from unsplash.com or were taken by me.
All mask photos not credited in the thread are free to use from unsplash.com or were taken by me.
14/ If you've found this🧵useful, you might also like this one, on how you can re-use your #N95/#FFP2 #masks:
https://twitter.com/claire_horwell/status/1466400270137630727?s=20
15/ And this🧵on how the public do not need to be fit-tested in order to wear industry-certified masks:
https://twitter.com/claire_horwell/status/1414497913435209730?s=20
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