Fig. 2.
Filtration efficiency at 0.3 μm, overall number-based filtration efficiency, and corresponding pressure drops of the tested medical and non-medical filter materials. (a) Filter pressure drop and filtration efficiency for 0.3 μm particles measured at a face velocity of 23.2 cm s−1; (b) Filter pressure drop and overall filtration efficiency measured at a face velocity of 23.2 cm s−1; (c) Filter pressure drop and filtration efficiency for 0.3 μm particles measured at a face velocity of 15.3 cm s−1; (d) Filter pressure drop and filtration efficiency for 0.3 μm particles measured at a face velocity of 9.2 cm s−1. Dashed lines mark the approximate boundary between fibrous and fabric filters.