Using inexpensive and widely available resources, scientists have developed a simple approach to visually evaluate how effectively different kinds of masks to prevent the spread of droplets that could contain SARS-CoV-2 virus particles, according to a new study. While the authors note their job remains in the early stages, and their method has so far only been tested in a small group of individuals, these preliminary, proof-of-principle findings suggest that professional-grade N95 masks, surgical or polypropylene masks, and handmade cotton masks may all block much of the spray produced when wearers speak.

Bandanas and throat fleeces, nevertheless, likely provide little protection, as the investigators observed that the more droplets are expelled through these substances - likely because the substances divide larger droplets as they pass through the material, the researchers speculate. Emma Fischer and colleagues recommend that non-experts might easily construct and operate this setup to appraise masks at the neighborhood level, for example mask manufacturers could use the method to optimize mask designs, and community and educational outreach organizations may demonstrate proper mask fitting processes.

As nations worldwide have instituted mask mandates to suppress the spread of COVID-19, international industrial suppliers have encountered shortages in the face of unprecedented demand. To compensate, many individuals have turned to homemade masks and mask options, but these do-it-yourself variants have yet to be tested systematically.
To assess the potency of 14 different kinds of masks and other often substituted face caps, Fischer et al.. Designed a very simple approach in which one male speaker or, in some cases, four speakers wore every mask whilst standing in a black enclosure. The speaker would say the term"stay healthy, people" five times in the path of a laser beam, which scattered light from the droplets published during speech. A cell phone camera recorded the droplets and a very simple computer algorithm counted them. The installation was deliberately designed to be simple and inexpensive so that it could be reproduced by non-experts - that the hardware it requires, including laser equipment, is commonly available and can be purchased for significantly less than $200. The findings imply that bandanas and throat fleeces (like balaclavas), nevertheless, probably provide little protection.
<blockquote><em>Our work was a demonstration of a simple measurement method, not a systematic mask study. More work is required to investigate variations in masks, speakers, and how people wear them. We also want to extend our method to other droplet-generating actions, like coughing and sneezing. Further, we want to explore effects of incorrect placement and moisture saturation."-</em>Martin Fischer, study's corresponding author</blockquote>
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<span style="color: #ff6600;"><a style="color: #ff6600;" href="https://www.aaas.org/" target="_blank" rel="noopener noreferrer">American Association for the Advancement of Science</a></span>

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