For this demonstration, Dr. Davis held agar cultures near his face and sneezed, sang, talked, and coughed at them. For one set, he wore a standard surgical mask, and for the other, he wore no mask.

Check out the video on the masking debate. We are officially living in a Parks and Rec episode.
https://www.buzzfeed.com/andyneuenschwander/microbiologist-mask-bacteria-demonstration