I am an immune compromised person, and have significant experience with masks and "staying safe".  Mandating a  random face covering is useless.  Anything can cover your nose and mouth, but it requires a special mask, that is changed often to be of any significant value.  Most of the masks people are wearing will only keep viruses and germs close to their nose and mouth - a point of entry for COVID.   If you are serious about people wearing masks to prevent COVID, then you need to supply people with effective masks that will keep them and anyone around them safe.  Telling people to wear "something" over the nose and mouth is just irresponsible, and will likely just encourage the virus by giving it a free ride to someone's nose and mouth via an infected mask.