This increases the amount of surface area that an aerosol can stick to. Seen up close, cotton fibers have kinks and bends. The Star Destroyer couldn’t make it through. Only the smaller ships could turn fast enough. NIST researcher Chris Zangmeister likens this to the scene in Star Wars: The Empire Strikes Back when starfighters are streaking through the asteroid field. As the air bends and twists around the fibers, some of the aerosols can’t turn fast enough and smash into and stick to them. The aerosols can be very small, but they do have some mass.
When you breathe through a mask, the air flows around these fibers and the aerosols are pulled along for the ride. This image shows the individual fibers in cotton flannel. Vicenzi/Smithsonian's Museum Conservation Institute and NIST And they can give us all a sense of the beautiful, textured, woven world right in front of our faces.Į.P. His images gave the scientists important insights into the particle-filtering properties of different fabrics. He is also a visiting researcher at NIST. Vicenzi works at the Smithsonian’s Museum Conservation Institute, where he studies the history and origin of objects in the museums’ collection. After being exposed to the moisture in a person’s breath, cotton fabrics perform better still.Īs part of this research, one team member, Edward Vicenzi, used a scanning electron microscope to examine the fabrics up close. Their research indicates that that cotton fabrics tend to perform better than synthetics, with cotton flannels being particularly effective. The researchers wanted to know how well different fabrics filter out those particles and what makes some fabrics better filters than others. Those masks work by blocking some of the virus-filled droplets and smaller particles, called aerosols, that an infected person exhales, and they also offer some protection to the wearer by filtering incoming air. There are a lot of rules to consider here, so if you only remember one thing, make it this: any mask is better than no mask.To understand how something works, it helps to see it up close.Ī team of researchers took this approach when studying the fabric masks that people wear to slow the spread of COVID-19. In a January interview, he said if you don't mind extra layers of material over your mouth and nose, you can opt for a cloth mask that uses filtration inserts for extra protection, instead. Dave Hnida, the medical editor at CBSN Denver. That led the researchers to conclude the magic of double masking all comes down to a more snug fit.īut you shouldn't wear three masks, as the triple layer of fabric starts to make it difficult to breathe, according to Dr. However, the results were not the same in the opposite scenario: wearing a surgical mask over a neck gaiter. They found the best coverage came from wearing a neck gaiter or a bandana over a surgical mask. In a research letter published last April in JAMA Internal Medicine, scientists at the University of North Carolina at Chapel Hill compared the filtration efficiency of commonly available masks "worn singly, doubled, or in combinations."
"Furthermore, the performance of the valved N95 mask is likely affected by the exhalation valve, which opens for strong outwards airflow," the Duke scientists say.
According to the CDC, counterfeit respirators are on the rise amid the COVID-19 pandemic. However, this is with the caveat that N95s don't necessarily protect others around you if they use a valve. Those masks had a droplet transmission rate of less than 0.1 percent. The Duke researchers found N95 respirators were most effective in filtering out particles.
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