Study: Household fabrics masks effective against coronavirus transmission

In a new study, scientists found that the masks designed out of the household fabrics with a single layer are proven effective against the novel coronavirus transmission. Researchers at the University of Illinois, Urbana-Champaign, US conducted an experiment to find the effectiveness of the homemade masks that largely curbed the virus particles in the bigger droplets while coughing and sneezing. A mechanical science and engineering professor at the University of Illinois said that the homemade cotton face coverings can stop the contagious droplets from spreading up to great extent, while surgical or the N95 masks curbed the coronavirus spread by 100 per cent. 

"We found that all of the fabrics tested are considerably effective at blocking the 100-nanometer particles carried by high-velocity droplets similar to those that may be released by speaking, coughing and sneezing, even as a single layer," Saif said, in a study published in the Extreme Mechanics Letter and American Association for the Advancement of Science journal on September 18.

In the experiment, the team of researchers segregated the particles, as ones less than 5 micrometers that spread up to a range of hundreds of nanometers, and the larger droplets with approximately 1-millimeter diameter. According to the researchers, it’s the larger droplets that tend to spread farther with sufficient momentum, at times breaking into the smaller droplets transforming into airborne aerosols. They can spread when the person positive to COVID-19 communicates, but with fabric, the mask can be prevented as they get sucked into the pores of some fabrics. 

“A mask made out of a low-breathability fabric is not only uncomfortable but can also result in leakage as the exhaled air is forced out around contours of a face, defeating the purpose of the mask and providing a false sense of protection,” Saif said. “Our goal is to show that many common fabrics exploit the trade-off between breathability and efficiency of blocking droplets – large and small.” The team recommended 11 best options in the household fabrics to design masks. New and used garments, quilted cloths, bedsheets, and dishcloth material would make masks that would be ideal basis construction, fiber content, weight, thread count, porosity, and water-absorption rate, the researchers said in the study. 

Read: Coronavirus Will Become Seasonal Flu Once Herd Immunity Is Achieved: Study

Read: NASA Mulls Planetary Missions to Study Venus After 'phosphine' Discovery

[Mechanical science and engineering professor Taher Saif, right, and students Onur Aydin, left, and Bashar Emon test common household fabrics used to make masks to help stop the spread of the coronavirus. Credit: Illinois University/ Taher Saif]

Droplets with diameters 0.1 -01 stopped

To prove its efficacy,  researchers designed a set up in a laboratory and filled the nozzle of an inhaler with distilled water seeded with easy-to-find 100-nanometer diameter fluorescent particles. Further, they generated high-momentum droplets from the inhaler imitating the coronavirus and collected samples of high-momentum droplets on a dish. Researchers repeated this experiment using variety of fabric masks and found that it was effective against droplets with diameters in the 0.1 to the 1-millimeter range. “We found that all of the fabrics tested are considerably effective at blocking the 100-nanometer particles carried by high-velocity droplets similar to those that may be released by speaking, coughing, and sneezing, even as a single layer,” Saif said. “With two or three layers, even the more permeable fabrics, such as T-shirt cloth, achieve droplet-blocking efficiency that is similar to that of a medical mask, while still maintaining comparable or better breathability,” he added. 

Read: Indian Monsoon Can Be Predicted Better After Volcanic Eruptions: Study

Read: COVID-19: Most Homemade Masks Block Large Cough Droplets, Even As Single Layer, Says Study