[alexander_busek]

That’s how I interpret it. Cheesecloth is pretty “breathable”, even two layers of it, so that would be my solution if I were to go on any form of public transportation, which I’m not.

Air resistance increases quadratically to (according to the square of) the speed.

Thus, if you're taking shallow breaths (e.g., when sitting quietly in a chair), your mask may not significantly impede breathing.

If, however, you are exerting yourself (e.g., walking briskly), the resistance caused by the mask could easily increase 16-fold.

Regards,

[HartleyMBaldwin]

If I’m on an airplane or a bus or whatever, I’m not likely to be walking briskly.