The only mask I can think of that actually would protect you very well from breathing in the virus particles ejected from others while at the same time protecting everyone around you from possibly becoming contaminated by you in case you have the coof is a positive-pressure filter system.
A somewhat heavy device carried on a shoulder strap that has two pumps, one pump pulls in air from your immediate surrounding and passes it through a very good filter that CAN capture all the virus particles and feeds the filtered, clean air under pressure to your full-face mask...clean air comes in when you inhale and cause a valve to switch to inward flow and when you exhale a valve sends your exhaled air back to the device that filters your exhaled air before it is ejected into the surrounding air.
No virus coming in, no virus going out and none leaking in or out from your mask which is very tightly fitted to your face.
While it might be possible to have a very tightly fitted full-face mask without the pumps but with valves that could perform the same function I think it might be difficult for some to suck in air through an adequate filter and then have to also force the air in the mask back out through another filter. It might be possible if the filters were quite large as generally the larger the filter the easier to push air through them... such a mask might find many customers given the current level of hysteria.
If you did not have to worry about putting your possibly contaminated exhaled air into your surroundings a system could be more easily constructed.
Some modern military vehicles use a positive pressure system that sucks air from the outside through a filter and keeps the inside air at all times at a high enough pressure that no external air can seep in through any cracks.. They do NOT have the problem of having to filter the inside air before ejecting it back outside. .. biological warfare systems...
Paper and cloth masks can have an effect on virus particles going in and out but are somewhat like standing on one side of a picket fence while someone on the other side with a hose tries to wet you down. Yes, you will be a bit less soaked... it seems to me that a paper or cloth mask might lower the amount of particles for someone if you were close to them and exhaling in their direction as your breath mostly seems to eject from the sides... if someones smokes and exhales through a cheap mask an awful lot of the smoke goes out the sides... the victim of your exhaled viral particles might wind up with a lesser viral load than if you just breathed on them at close range with no mask at all..
It’s not my place to guess if the effort and inconvenience of wearing paper masks and risking the bacteria that can build up in them is a sensible thing...
With the possibility of a serious viral pandemic always hanging over us all why hasn’t very extensive testing been done re the efficacy of cheap masks???
Level 4 labs feed air under pressure to a full-body protective suit that ensures no air from inside the lab reaches inside your suit. The air ejected from the level-4 areas of the lab is filtered before it reaches the outside air.
And don’t you just love the DIMWITS with a paper or cloth mask, OVER A FULL BEARD!
I tell everybody who asks me about masks, that the ONLY TIME YOU WILL SEE ME WEARING A MASK IS IF I AM GOING TO ROB A BANK!
Unfortunately, even hazmat suits are not infallible.
Remember where this came from - (Wuhan Institute of Virology)