In a pandemic, most people will move around, and many will want to use some kind of mask, anything that makes them feel they’re doing the best they can to protect themselves and their loved ones and their communities. If there are not enough high-tech masks (which will be the rule all over the World), then what is the best practical thing?
It boils down to (self)education: the mask not as a prevent-all but as one more element in the slow-down strategy, together with hand-hygiene, social distance, asynchronous transfer, etc. A handful of memes, possibly in an educational package.
If, say, 50% of people in a community contribute to slowing down transmission, we would be better off. The value of the slow-down strategy is easily explained: at any one time there would be more healthy people taking care of less ill. This would be useful whatever the CFR may be.
Quite possibly, having something sensible you can do is also valuable.
There’s http://www.cdc.gov/ncidod/EID/vol12no06/05-1468.htm which gave birth to this page. How can we improve on this?
We can focus on:
I once saw a recommendation for a “home-made” mask made out of Indian saree silk. That is silk which is very thin, extremely tightly woven and easy flowing. You can probably get hold of a few yards at the nearest Indian tailor or cloth shop. The description, if I remember correctly, was to fold it until you have 8 layers, then shape in a form that covers mouth and nose. It is nowhere near the quality of an N95 mask, but it is washable and cheap.