Avram
>> FIRST ARE THESE COMMERCIAL OR MEDICAL? COMMERCIAL ARE NOT THE RIGHT ONES.”
> Why not?
My understanding is that medical standards call for different filtration. Masks include special materials, such as electrostatic layer. I did not study this in depth. Look it up.
Overall, I agree that it looks like there are enough cases where wearing a valve makes sense. Maybe worth to revisit the original message. Tzarich Iyun.