A team of researchers from the University of Cambridge and Northwestern University tested a range of  fabrics from t-shirts and socks to jeans and vacuum bags to determine what type of mask material is most effective at trapping the ultrafine particles that could contain viruses, according than article on the Lab Manager website.

The researchers, from the University of Cambridge and Northwestern University, tested the effectiveness of different fabrics at filtering particles between 0.02 and 0.1 micrometers—about the size of most viruses—at high speeds, comparable to coughing or heavy breathing, the article said. 

The study also looked at N95 and surgical masks. The results showed that most of the fabrics commonly used for non-clinical face masks are effective at filtering ultrafine particles. N95 masks were highly effective, although a reusable HEPA vacuum bag actually exceeded the N95 performance in some respects.

As for homemade masks, those made of multiple layers of fabric were more effective, and those which also incorporated interfacing, which is normally used to stiffen collars. However, this improvement in performance also made them more difficult to breathe through than an N95 mask.

American healthcare workers still face dangerous shortages of personal protective equipment as Covid-19 patients continue to fill hospitals, according to a Bloomberg article.  Many healthcare providers only got a single N95 mask per shift.

The nationwide demand for the N95 respirator masks that give is 300 million a year, up from 25 million prior to the pandemic.

Read the full Lab Manager article.