Hello Meno_.
My wife has been on a CPAP machine as well. I’ve looked at it from the respirator perspective but I’m not seeing how that would work.
To the best of my awareness the ventilators used in hospitals simply filter the exhaled air and I don’t know what size particle that filter was designed to trap. That’s one of the problems requiring the use of PPE in the care of individuals hospitalized. I think it is a problem of isolation at the source. Masks and filters for that matter simply attempt to stop the spread through entrapment, yet make no attempt to render the bug incapable of reproducing else where.
If sick and must wear a mask, that person is forced to re-inhale the problem causing virus over and over again. It would seem like that could be making it harder to recover from. What would, I think be helpful, is a mask that traps the bug and an renders it incapable of reproducing on contact within the “trap”. For those not infected, a mask that entraps the bug and renders it harmless before it is breathed into the lungs to reproduce. If we could do that it would not be the bug it is.
Many countries have gone so far as to go out in the world and attempt to sanitize the outside surroundings.
The effectiveness of an N-95 mask. When properly fit, is designed to catch 0.3 micron particles, 95% of the time. *
I’m not thinking making your own mask out of denim and curtain lining is going to provide much protection. But maybe if you used a HEPA vacuum cleaner bag you might have more luck.
Another note is the virus travels on larger molecules or clumps of cells like mucus, and even T-shirt cotton when folded a few time can catch material that large. Like I said it would be helpful to render the bug harmless as well in these forms of traps.