This video explains how virus particles 20 um in size can go when someone coughs.

This video explains how far small particles can go when a human coughs. And this explains why we should wear a mask AND keep a distance of at min 6 feet. (9ft is better and we need to keep a distance from an infected person)

https://www.cnn.com/2020/11/06/healt...ess/index.html