> N95 masks are not at all difficult to breathe in in my experience. Not at all.
My default assumption would be that if the mask doesn't make it more difficult to breathe then it is unlikely to be effective. The filtration mechanism should introduce friction which you then have to compensate for with additional pressure in your lungs.
This is a bad assumption that you can disprove for yourself in 10 seconds. You aren't pushing air up a slope you are creating a pressure differential. An impediment ought to at best result in a small decrease in the speed of filling and a tiny amount at that because your mask is very porous. Your mask is effective not in proportion to keeping air out but because larger items like globs of spit get stuck on it and because of electrostatic charge.
There is absolutely no reason to believe that effectiveness at preventing infection is linearly correlated with difficulty breathing or that to a degree that the additional friction induces difficulty must rise to the level of preventing breath in order to be effective. You aren't preventing 50% of particulates from getting in by preventing 50% of oxygen for example.
For example I imagine that you didn't believe that doctors wearing masks pre pandemic or construction workers weren't just going without breathing well for hours given paucity of air becomes an problem very very quickly
Thanks for the extra perspective. Without going into specifics like linearity it still seems like it could be the basis of reasonable public health advice. Forgive the tongue in cheekness but something along the lines of:
"Expect some discomfort - that lets you know the mask is working"
It’s a natural assumption!, and it’s important to address it. Basically the filter material is… almost indistinguishable from magic? It’s a beautifully balanced construction of materials science. From the perspective of gases, the mask is almost transparent. From the perspective of aerosolized particles, the mask is a wall of electrostatic forces and difficult luck rolls. It’s sort of like a wide reef that the tide may pass over but just isn’t traversible by boat; And all boats are steel and the reef is magnetized.
“Duckbill” type masks are great too, like Kimberly-Clark / Kimtech pouch respirators: https://www.kcprofessional.com/en-us/products/scientific-and... … These might be the most comfortable article of clothing I’ve ever worn? Like really seriously. Very easy to breathe through. No drag or inertia at all. The 3M Aura mask has the edge in breathability though – feels impossibly transparent. I believe it’s due to the material itself. The duckbill type gets its breathability through using more material and a bigger airspace. I’d love to try a duckbill made out of the material in the 3M Aura. (Secret tip: If the duckbill is creased just right it looks more like a Stormtrooper than a duck. The free bread is nice though.)
I’m reading the Wikipedia page on HEPA filters now. Trying to get a better feel for how the material works. Seems like part of how the close-fitting masks can be made so easy to breathe through is that the possible speed of air flowing through is limited. Anywhere in the range of airspeed that we can breathe aerosolized particles in or out, the filter material causes slight turbulence in the atmospheric gas, it flows and eddies around the filter material – the air flows around the material – but the aerosol particles have much more inertia and hit the filter. I actually hadn’t understood or appreciated this aspect before now.
