Abstract

Nonwoven fabric sheet is usually used as mask due to the comparatively high particles removal performance and ease of breathing. The diameter of the SARS-CoV-2 (COVID-19 virus), including various mutants, is considered to be about 50nm to 150nm which is a size that can be removed by the nonwoven fabric sheet mask according to the particle collection Air Filter Mechanism Theory (AFMT) as shown in Figure 1. The most disturbing problems are that large amounts of aerosols of various sizes, including many viruses, are released from the mouth by coughing, and those around the diameter of 300nm slip through the mask according to the AFMT. In order to solve the problem, the electric charge is usually given to the mask. Such modification, however, loses the effectiveness in the presence of water molecules in the breathing.