Figure 1.

(a) An example of the particle-size dependence of penetration for charged and discharged wool/polypropylene (Wool–PP, WP) and melt blown polypropylene (Meltblown PP, MBP; Shanghai Da Sheng [5]) mask media when tested at a face velocity of 0.15 m/s. Pressure drop, thickness, fabric areal density, maximum penetration, and most penetrable particle size (MPPS) of MBP: 200 Pa, 3.0 mm, 280 g/m², 0.5%, 48 nm; WP: 50 Pa, 8.8 mm, 600 g/m², 2.2%, and 46 nm, respectively. The particle diameter size range used for measuring penetration P_0.3 has been highlighted in green. Trendlines (B-Spline) have been added for illustration purposes to measurements represented by dots. (b) Fiber-polymer specific charge distribution in electrostatically enhanced media of the tribo-electric type. (c) Charge distribution resulting from DC corona charging using a unipolar electrode configuration (example for unipolar, positive electrode configuration [8]).