A team of chemical engineers at Northeastern University, Boston, evaluated over 70 different multi-layer material combinations and masks for their ability to reduce the risk of viral-aerosol inhalation.  Infected individuals, whether symptomatic or not, emit invisible viral aerosols when talking.  Several of the combinations tested were found to be excellent at filtering out virus-like particles, along with two types of N95s tested for comparison.

     Top-performers were made up of both absorbent, wicking layers, and water-repellant barrier layers. Examples of repelling-type layers included nonwoven polypropylene, polyester, and polyaramid.  Those layers may also repel droplets from nearby absorbing layers, such as terry cloth cotton, quilting cotton, and flannel, and help prevent wicking across the mask’s “sandwich”, the paper explained.  See the chart of high performers below.

 

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