Wrong.....NOT a tight fit, & will not filter the very fine virus particles when it disperses from the water droplets you cough/sneeze out....you need a A2 twin cartridge filter for organic vapours...
I'm a qualified Technical Architect so know building ventilations systems, sick building syndrome, & why you get flu/virus traveling through a buildings ventilation system…....& also the number of air changes required in a space ..in an ideal system...which usually doesn't happen as there are dead spaces etc...
In the right atmosphere the virus if coughed/sneezed out into the air will travel further than 2m...& will hang in the air for longer & be taken to different areas......one of the first deaths in UK was from a man who went to a restaurant..& at the same place was a man just back from Italy who had it....so the person who got infected did so by being in the same contaminated air space & outside the 2m zone......the more moist & still the air the longer it will "hang" there....also bright sunlight will still kill it...so out in the sun on a windy day is great!!
How the feck do people think Doctors with all the plastic sheeting/disposable gloves/aprons etc. & even those wearing the fine dust/water mist masks (FFP3) are still getting the virus??....all down to the air being heavily contaminated...& the mask not upto the job when spending so long in the bad air..
Basically spend NO more than 15mins in any enclosed office/space/shop etc......unless you have a grade A2 mask......I don't have one as all sold out where I am...so play "supermarket sweep".....high speed shopping!!..if big lines of people I come back later on...
linky to an article on the MIT report into flu germs spreading .....
https://www.businessinsider.com/how-far-sneeze-cough-germs-can-travel-2018-10?r=US&IR=T