On November 25, 2021, the Centre for Health Protection (CHP) of the Department of Health of the Government of the Hong Kong Special Administrative Region announced that the transmission chain of the Omicron variant in The Regal Airport Hotel in Hong Kong was confirmed by genome sequencing. After an investigation by expert consultant Yuen Kwok-yung of the Hong Kong Government, it was confirmed that the Indian man who was first diagnosed was wearing a mask with air valve. Through the breathing, the infected air flowed out of the hallway, infecting the man in the room diagonally opposite. Referring to the valve masks as "selfish masks", Mr Yuen advised people not to use them, and use surgical masks instead.
Why are valve masks selfish masks?
Respirators with air valves ensure that dust or toxic and harmful substances in the air do not affect the wearer. Generally, they are used by people to prevent PM2.5. Its particle-barrier ability is similar to that of medical protective masks, which can be used for industrial dust prevention and haze protection.
However, it should be noted that the breathing valve is provided with a valve, which is closed when inhaling, and opened when exhaling. So when the wearer breathes, the air is released directly into the environment without being filtered.
Why are they called "selfish masks”?
Not all wearers of these masks with exhalation valve are guaranteed virus-free. Therefore, if in any case the wearer is a virus carrier, the exhalation valve could potentially be a channel of the virus also.
In other words, the mask protects only the wearer but puts in danger those that are close.
update : 20220109-Eng