Fig. 5.
Functional prototype of a desk-top mask charger. a, The cross section, and b, the operation of the device. c, Polypropylene sheet electrostatics before and after charging (n = 10). In “polypropylene sheet”, the polypropylene sheet was extracted from surgical masks and the sheet was charged with the device. In “surgical mask”, the entire mask was charged. d, Examples of data used in c before averaging. e, The results from the Particle Filtration Efficiency (PFE) Test (n = 9).