Wearing a mask is to protect others from your own droplets. This is CDC protocol: if a doctor suspects covid, the patient is given a mask to put on. If that is enough to protect the doctor in close proximity, it is good enough to protect the general public. Like herd immunity if we all wear masks in public, the chance of droplet exchange is greatly reduced. The quality of mask and the manner of mask wearing become irrelevant. This is why we need universal mask wearing. It is the fastest and cheapest way to get the economy back on its foot again.