Name:   MartiniMan - Subject:   Just a restatement of facts Date:   7/14/2020 9:29:16 AM (updated 7/14/2020 9:30:13 AM)

It is of limited value for aerosols because they pass right through and float around in the air.  For water droplets it will help but so does covering your mouth when you cough and sneeze.  And the droplets fall to the ground rapidly and over a short distance anyway so unless someone is sneezing or coughing right next to you they are not a significant source of transmission anyway.  If particles can get in when you inhale they will go out when you exhale. It is basically the same fluid dynamics in either direction.  You exhale through the mask and the particles are then free to float around.  And this doesn't include the inhaled/exhaled air that escapes from the sides of the mask because it is not properly designed, fit tested and worn.  Those enter and escape unimpeded. The masks are near on useless for the average person.

And again, as the study referenced above demonstrates, after two hours of wear there is close to zero effect of a mask.  Wear a mask if you want but to really be safe do all the other things.