[lemmox]

FWIW I found reading about the process of making respirators quite fascinating. It opened up a whole world of reading about nanofibers and the melt blown process that I'd not previously stumbled upon. Turns out good masks aren't just any old fabric - producing unwoven sub-micron nanofiber fabric is quite involved and that fabric is in short supply.

[serf]

Exactly this. Parent to your comment has no firm grasp on how difficult and expensive it is to place and maintain a melt-blown-fiber shop outside of a crisis, let alone during one.

That said : cotton DIY masks can be quite effective. I recommend buying a box of shop towels, which are made with a similar blowing mechanism that creates a random fiber orientation.