Abstract
During the global pandemic of COVID-19, the term ‘N95’ is frequently encountered in our daily life. ‘N95’ is the abbreviation of facepiece respirators that meet the class 95 standard of US National Institute for Occupational Safety and Health (NIOSH). The number ‘95’ means that the N95 respirator can filter >95% of airborne particles. Numerically, 95% or 0.95 is very close to the function value of when Intuitively, there might be some underlying relationship between and the filtering rate 0.95. In this paper, a constant-law model is presented, giving clear physical picture for the filtering rate of non-woven fabrics. The derived physical model may also be used as a standard for particulate-filtering non-woven fabric products such as facepiece respirators.
Disclosure statement
The authors declare no known conflict of interest.
Data availability statement
The data that support the findings of this study are all enclosed in this paper.