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Which Materials Make the Best Face Masks?

Which Materials Make the Best Face Masks?

Researchers explore which fabrics are best at preventing virus particles from spreading, and look to improve PPE

Rachel Muenz

Editor’s note: COVID-19 is a rapidly evolving situation and the materials mentioned in this article have not been extensively tested for their safety and effectiveness. Be sure to check the CDC website or that of your local health authority for the most current recommendations on preventing and protecting yourself from COVID-19 transmission. This press release was updated with new information on Apr. 29.

With health authorities now recommending that the general public wear cloth face masks in public areas, which homemade options are best for the general public?

Missouri University of Science and Technology researchers may soon help answer that question definitively. Dr. Yang Wang, assistant professor of environmental engineering, and his PhD student, Weixing Hao, recently tested some common materials to see how well they did in preventing particles from being transmitted.

Wang got plenty of attention when he shared the initial results of the research on Twitter on Apr. 3. According to the researchers’ findings presented in a press release, scarves and bandanas aren’t so great at filtering aerosols, and, when it comes to using pillowcases, a higher thread count is more effective. The best materials were household air filters such as furnace filters, but the researchers faced some challenges in terms of breathability. There could also be safety issues with using furnace filter materials, they added.

Wang suggested in his Twitter post that a combination of pillowcase fabric and furnace filter material may be the best option. He and Hao are continuing their investigation into such materials and have received plenty of feedback from other researchers doing similar work. As with many US universities, Missouri S&T is also working at producing needed personal protective equipment (PPE) for medical workers.

Elsewhere, Indiana University origami artist and professor Jiangmei Wu has created and shared patterns for making origami face masks for the general public, suggesting using household HEPA vacuum filters. The plans advise avoiding filters containing fiberglass, as these are hard to breathe through, using PTFE ones instead.

Improving PPE for health care workers

There are also several efforts at a number of universities to improve the current PPE offered to health care professionals. A team at West Virginia University has developed extenders for surgical masks to make them more comfortable to wear, while a researcher at the University of Kentucky’s College of Engineering is using his expertise in producing membranes to develop a face mask for health care workers that not only prevents transmission of SARS-CoV-2, but also deactivates the virus when it contacts the material.

“We have the capability to create a membrane that would not only effectively filter out the novel coronavirus like the N95 mask does, but deactivate the virus completely,” said Dibakar Bhattacharyya in a University of Kentucky press release. “This innovation would further slow and even prevent the virus from spreading. It would also have future applications to protect against a number of human pathogenic viruses.”

Bhattacharyya and his collaborators plan to submit their initial work to the National Institutes of Health. Their project is expected to take roughly six months to complete.

Similarly, Rensselaer Polytechnic Institute researchers recently received National Science Foundation funding to develop a coating that gives antiviral properties to existing N95 masks and makes them easier to decontaminate. They plan to test the finished product in New York's Mount Sinai hospital to determine that it works properly in a real-world setting.

“As soon as we can have modified masks validated and certified, we hope to disseminate a DIY kit for application of the coating to existing masks,” said Edmund Palermo, an assistant professor of materials science and engineering at Rensselaer, in a press release.

In another project, researchers from Binghamton University in New York state are working on improving a design for a reusable plastic N95-style face mask that could help combat shortages of this key piece of PPE. And, in just one example of commercial groups helping solve the PPE challenge, ExxonMobil announced Apr. 2 that they have partnered with the Global Center for Medical Innovation—a medical device innovation center—in several projects to develop reusable PPE, including masks and face shields.

“Expediting advanced technologies to help those who are combating this global pandemic is absolutely critical for society,” said Karen McKee, president of ExxonMobil Chemical Company in a recent press release. “We’re proud to do our part by sharing our expertise and experience in material technologies, and energy supplies needed to support our health care workers. It’s just one example of ExxonMobil employees working around the clock to help keep our communities safe and limiting the spread of COVID-19.”

With researchers and their partners working hard at such solutions, the US may soon not only tackle the lack of PPE health care workers are struggling with, but provide better protective options than those currently available.