I'm my own anecdotal rebuttal:
I've worn commercial N95 dust masks with the valve and full-face respirators with the cartridges for years while involved in fairly strenuous physical work [floor-sanding, tile work (mixing mortar and grout) and drywall installation/repair].
I can work a full day in that get-up. I have to peel off the face diapers after 15 minutes to get air, even just walking around a store.
Actually, I'll do a "chin pull", where I pull the mask down off my nose with my chin, to get air when I'm by myself in a store aisle.
The years of working in masks and respirators trained me to breathe through my nose and not through my mouth, so my air intake is restricted by the diapers.
I suppose Lefty mouth-breathers are more used to their method of air intake...
And lots of workers aren’t permitted to take breaks every 15 minutes.
The Left is Deceit.
Nov 3rd