‘The masks do stop most droplets of sputum coughed up by others.’
except sputum droplets, being moisture laden and thus heavier than air, drop to the ground at a certain distance; if you’re not within that distance of someone, these droplets become irrelevant...
it is acknowledged that virii, being microscopically small and nearly weightless, travel via aerosolization, and remain in the air much longer; if you can actually breathe through your mask, and you are infectious, you are contributing infection to your environs, and your mask is little more than a socially accepted talisman at that point...
“… if you’re not within that distance of someone..”
Like in a clinic or hospital? I read several reports, If you’re within 16-20 feet, there’s a higher chance. It’s true that most sputum droplets drop out within 3 meters, but a lot of them go well beyond that.
Clinics and hospitals are dangerous places for the healthy. More dangerous for those of us that are older with other problems.