"Polypropylene is a commonly used material for N95 type respirators. In order for small particles to get through a filter composed of interlaced layers of polyp

"Polypropylene is a commonly used material for N95 type respirators. In order for small particles to get through a filter composed of interlaced layers of polypropylene fibers, they have to wind through a rather tortuous path and as a result would likely be trapped in the material." [0] [0] https://qcmask.com/pages/the-science-of-masks https://qcmask.com/pages/the-science-of-masks