Choice of mask is very important. Surgical masks worn correctly are the best. They are water proof on the outside and absorbent on the inside, ONLY if WORN CORRECTLY.
To wear your mask correctly, make sure the blue side is on the outside. It is water proof and will protect outside germs from coming into your respiratory system and will protect others by absorbing your respiration on the inner absorbent side.
To be effective, your mask MUST cover your nose as well as your chin. Pull it down under your chin. Crimp or squeeze the metal strip on the upper side to fit securely over your nose.
Tie the ends firmly behind your ears.
Incorrect, mask is inside out.
If you see anyone wearing their mask incorrectly, mention this to them and advise them how to wear the correctly. Do so without touching other peoples masks.