Â- Bacteria filtration efficiency (BFE): the higher the value the better, representing the ability to block bacteria; bacteria diameter is generally 0.2-2 microns. Particle Filtration Efficiency (PFE)

Â- Bacteria filtration efficiency (BFE): the higher the value the better, representing the ability to block bacteria; bacteria diameter is generally 0.2-2 microns.Particle Filtration Efficiency (PFE): the larger the value the better, representing the ability to block micro particles; here the diameter of micro particles generally refers to particles below the diameter of bacteria; so the particle filtration efficiency is high, then the bacterial filtration efficiency must be high.Synthetic blood penetration resistance: the higher the value, the better, representing the ability to block liquid spatter.Pressure difference: the higher the value the better, representing the pressure difference between the inside and outside of the mask, the higher the pressure difference, the better the seal and also the higher the protection capacity.The focus is different, with respiratory masks focusing more on high particle filtration efficiency and surgical masks focusing more on protection against liquids such as blood spurts (high synthetic blood penetration resistance); however, respiratory masks are often in short supply in times of major epidemics and surgical masks can be used as basic respiratory protection when necessary.