Fig. 1: Ultrathin, ultralight dual-scale fibrous filter with high protective capacity and wearing comfort.

a Preparation process and structural characteristics of dual-scale fibrous filter. b Optical image of the dual-scale fiber filter. c Scanning electron microscope (SEM) images of the dual-scale fibrous filter and human hair. d Weight of a piece of dual-scale fibrous mask. e The breathability of the dual-scale fibrous filter. f Comparison of heat dissipation of the dual-scale fibrous filter and N95 mask.