Our inner layer fabric filter design is effective against particle size of 300 nano meters and above. WHO (World Health Organization) indicates that the primary air borne transmission of COVID-19 virus is through respiratory droplets of the size > 5000 nano meters.  

More Information

https://www.who.int/news-room/commentaries/detail/modes-of-transmission-of-virus-causing-covid-19-implications-for-ipc-precaution-recommendations