Making masks at home? Cotton with silk, chiffon best materials, says new study

The study says that the combination can filter out aerosol particles, provided the mask fits well.

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The researchers said tightly woven fabrics, such as cotton, can act as a mechanical barrier to particles, whereas fabrics that hold a static charge, like certain types of chiffon and natural silk, serve as an electrostatic barrier. (Representative image)
WASHINGTON: As people resort to making their own cloth masks due to shortage of surgical and N95 varieties in the wake of the COVID-19 pandemic, a new study says a combination of cotton with natural silk or chiffon can filter out aerosol particles provided that the mask fits well.

According to the researchers, including those from the University of Chicago in the US, SARS-CoV-2, the new coronavirus that causes COVID-19, is thought to spread mainly through respiratory droplets when an infected person coughs, sneezes, speaks or breathes.

They said these droplets form in a wide range of sizes, but the tiniest ones, called aerosols, can easily slip through the openings between certain cloth fibers, leading some experts to doubt if cloth masks can actually help prevent disease.


In the study, published in the journal ACS Nano, the scientists assessed the ability of common fabrics, alone or in combination, to filter out aerosols similar in size to respiratory droplets.

They used an aerosol mixing chamber to produce particles ranging from 10 nanometres to 6 micrometrs in diameter, which is tens to hundreds of times smaller than the width of a single human hair.

A fan blew the aerosol across various cloth samples at an airflow rate corresponding to a person's respiration at rest, and the research team measured the number and size of particles in air before and after passing through the fabric.
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The scientists found that one layer of a tightly woven cotton sheet combined with two layers of polyester-spandex chiffon, a sheer fabric often used in evening gowns, filtered out the most aerosol particles -- 80-99 per cent, depending on particle size.

They said the performance of these fabric layers was close to that of an N95 mask material.

According to the study, substituting the chiffon with natural silk or flannel, or simply using a cotton quilt with cotton-polyester batting, produced similar results.

The researchers said tightly woven fabrics, such as cotton, can act as a mechanical barrier to particles, whereas fabrics that hold a static charge, like certain types of chiffon and natural silk, serve as an electrostatic barrier.
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However, they cautioned that even a small gap, by as much as one per cent, reduced the filtering efficiency of all masks by half or more, emphasising the importance of a properly fitted mask.

"Our studies also imply that gaps can result in over a 60 per cent decrease in the filtration efficiency, implying the need for future cloth mask design studies to take into account issues of “fit” and leakage, while allowing the exhaled air to vent efficiently," the scientists wrote in the study.
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Therapeutic Music, Immunity-Boosting Foods & More: How Tom Hanks, Prince Charles & Idris Elba Recovered From Covid-19
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Politicians, princes and the who’s who of Hollywood — a number of famous faces have been diagnosed with Covid-19. But the good news is that they recovered. We round up the tips they shared.

Politicians, princes and the who’s who of Hollywood — a number of famous faces have been diagnosed with Covid-19. But the good news is that they recovered. We round up the tips they shared.
That’s what Prince Charles (in pic), 71, followed down to the T when he was diagnosed with the virus. After it was claimed that he was following homeopathy and Ayurvedic treatment for the virus, Clarence House quickly issued a statement: “This information is incorrect. The Prince of Wales followed the medical advice of the NHS in the UK and nothing more.”
That’s what Prince Charles (in pic), 71, followed down to the T when he was diagnosed with the virus. After it was claimed that he was following homeopathy and Ayurvedic treatment for the virus, Clar..
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Author JK Rowling (in pic), 54, credits a breathing technique she learnt from a doctor at Queens Hospital in England for helping her. It involves taking five deep breaths, holding each breath for five seconds, and then taking a sixth breath and then immediately coughing [cover your mouth please]. Rowling said, “I’m fully recovered and this technique helped a lot.”
Author JK Rowling (in pic), 54, credits a breathing technique she learnt from a doctor at Queens Hospital in England for helping her. It involves taking five deep breaths, holding each breath for fiv..
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Tom Hanks (L) and his wife Rita Wilson (both 63) were filming in Australia and had to be quarantined there. But they used the time to try Aussie favourites while they were unwell, including Vegemite. Hanks posted a picture of his meal, two slices of toast with a thick layer of the immunityboosting extract that is said to reduce fatigue, anxiety, stress and heart disease risk. On his return to America, Hanks said he has learnt “not to spread his Vegemite on so thick”.
Tom Hanks (L) and his wife Rita Wilson (both 63) were filming in Australia and had to be quarantined there. But they used the time to try Aussie favourites while they were unwell, including Vegemite...
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Prince Albert II (in pic), 62, of Monaco has just come out of quarantine after being diagnosed with Covid-19. The royal, who will be joining his wife and children soon, is back in good health, but he says he still plans to take it easy when it comes to work and obligations. He was quoted saying, “The only meetings I will be having are video conference calls.”
Prince Albert II (in pic), 62, of Monaco has just come out of quarantine after being diagnosed with Covid-19. The royal, who will be joining his wife and children soon, is back in good health, but he..
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When in doubt, belt it out. That’s what actor Idris Elba (in pic), 47, did when he and his wife Sabrina Dhowre (30) tested positive for Covid-19. Elba said he didn’t have many of the common symptoms, and made the most of his time in isolation by getting his creative juices flowing. He shared a music track that he created while in quarantine on his social media account.

Titled ‘The Long Road 2’, the song starts with Elba discussing self-isolation. He said that creating the song was music therapy to him. “Creating is living right now,” he said.
When in doubt, belt it out. That’s what actor Idris Elba (in pic), 47, did when he and his wife Sabrina Dhowre (30) tested positive for Covid-19. Elba said he didn’t have many of the common symptoms,..
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