I'd like to see a comprehensive, rational study of mask reuse.

Out in the environment COVID-19 is very fragile, it needs people to survive. The virus does not live long on most surfaces or in the air. Masks need to trap particles of approximately five microns and smaller because our nasal passages are reasonably effective at filtering larger particles, preventing them from reaching the lungs. The small particles pass through our nasal passages to the lungs.

With any passive air filter, particles will eventually diffuse through. This is why we regularly change air conditioning filters. In a high concentration area, such as an ICU filled with COVID patients, I can imagine that a 20 minute effective mask life is the norm. Out in a properly social distanced meeting room, I don't think that the 20 minute mask change rule is necessary, but I don't have the data to prove this.

Since the virus is so fragile out of the body. soap and water is very toxic to the virus, but soap and water might degrade a mask. I think that a sterilization routine could be developed to allow mask reuse for regular folk. Storing the masks in a virus hostile temperature and humidity environment for a few days would probably suffice. A more stringent process would be required for ICU masks.

Regardless, I see too many masks dangling under the chin.