I work in an industry that takes safety very seriously. Our staff are exposed to incredible danger every day.
One of those dangers is respiratory illness, caused by inhalation of contaminants.
These staff are provided with FFP3 masks and have to be "face fitted" by someone who knows what they're doing. This is because they do actually work when fitted properly.
The thing is, they do not form a tight fit on anyone with facial hair. Some parts of the business actually mandate that everyone's face is completely clean-shaven; not even a Homer Simpson shadow is permitted because otherwise your face mask is rendered useless.