1. Jim Brady Jim Brady United States says:

    The physicist in me agrees with the mask fit and the KF94 (I use an industrial N95 with the valve taped over) and that most mask are worn improperly (if at all).  When I go to medical facilities, I find that the majority of mask are worn improperly with the "tip of the nose" version being the most popular, then the "don't pinch my poor nose" version, and finally "the chin warmer".  

    As to the cloth  mask, homemade or commercial, most fail to be very effective by being made of soft and porous materials.  Comfortable, but you are working at breathing the mask is NOT working at stopping Covid.

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