[mensetmanusman]

To clarify:

There are many different types of masks. Masks in the health care context are designed to protect the wearer. N95 masks block 99.9% of incoming nanoscale particles, but are designed to be easy to breath, so have valves or release-seals on the perimeter so that you can breath out with no resistance.

i.e. they are not at all designed to protect others from yourself, but they do help.

Cloth masks provide <10% filtration efficacy for breathing in, so they are not appropriate for the industrial/medical arenas.

Anything in front of your face helps stop large droplets.

Medical people wear eye protection because covid enters through the eyes as well.

[scoutt]

Thanks. Yes, I clarified some points in other answers.

My message was intended to be as simple as possible, because a healthcare worker won't be even questioning all these facts after six months of life/death struggle.