Why our mouth masks?
Bacterial Filter Efficiency or BFE of a mouth mask gives the percentage of the number of 3µ particles that are retained. The Particulate Filtration Efficiency PFE is the percentage of the 0.1µ sub micron particles that are filtered from the air. These particles can be, for example, dust particles or aerosols. Aerosols are fine droplets that can contain bacteria. The BFE and PFE are also directly related to the amount of bacteria that are inversely released from the wearer through the mask into the ambient air. The higher the BFE or PFE, the better the carrier is protected from particles and the less the carrier transmits particles or aerosols.
The breathing resistance or the pressure difference of the mask must also remain low ≤ 60 Pa. The lower the pressure drop, the higher the comfort of the mask. The pressure drop is the resistance that the air experiences while it moves through a medium. Homemade cotton masks have too low a BFE and too high a pressure drop. Research has shown that as a result, emissions pass less longest through the mask, but more via other routes. Especially through the back, so that people behind the person can be contaminated.
Due to the growing evidence that individuals with mild or no symptoms can contribute to the spread of COVID-19, face masks and other face covers can be considered a source of control, complementary to other measures already in place to prevent the transmission of COVID-19. Evidence is growing that the viral spread of COVID-19 is higher just before the onset of symptoms and during the first 7-8 days after onset.
Public use of facial masks can serve as a source of control to reduce the spread of the infection in the community by minimizing the excretion of respiratory droplets from infected individuals who have not yet developed symptoms or remain asymptomatic. It is not known how much community use of masks can contribute to a decrease in transmission alongside the other countermeasures.
Learn more about the different types of masks we offer