Not sure why anyone doesn't know this by now, but coughing, sneezing, and even speaking generates droplets that can come in contact with others within a certain range. That's why the 6 feet "safe" radius. A number of tests were done, one on this short video below, showing those lovely droplets spreading out. So wearing the mask does help to a degree, and to be most effective it should be used by all around not just one wearer in a sea of non-wearers. It ain't gonna help much if you're the mask wearer and someone without one is talking or sneezing in the air close to you. That's pretty much how airborne diseases spread. So that's why all the mandate stuff.
https://www.youtube.com/watch?v=DNeY...b_channel=UNSW