" In any case, the mask is a barrier. Anyone wearing a mask in a pandemic context should consider that their mask may be infected. If you are asymptomatic, you would have covid-19 particles on the inside surface of the mask. If you meet a person that is infected with the covid-19, you may have some particles on the outside of the mask. For these reasons, you should never place back the mask inside the cap after wearing it. I believe that this 'hiding-back-mask' is a bad design for a pandemic context."