A constant-law model for the filtering rate of non-woven fabrics

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 $f(x)=1-e^{-x},$ when $x=3.$ Intuitively, there might be some underlying relationship between $f(3)$ 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.

Keywords:

• Filtering
• non-woven fabric
• modeling
• analysis

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.

Additional information

Funding

This work is partly supported by the National Natural Science Foundation of China (NSFC) under grant No. 12104405 and the Science Foundation of Zhejiang Sci-Tech University under grant No. 21202242-Y (both to X.Q.).