Masks made from a combination of different fabrics such as cotton, silk, chiffon, flannel can provide 80% protection against infections, a new study has found.
The new study published in April and obtained by TheCable shows that type of fabric and its arrangement can help improve protection against viruses, including the novel coronavirus.
The research team in America’s Argonne National Laboratory found that cotton, natural silk, and chiffon provides above 50% protection against viral particles in aerosols, provided they have a tight weave.
Tightly weaved layers of cotton, the most widely used material for cloth masks, “could provide over 79% depending on particle size, while a combination of different fabrics such as cotton silk, chiffon, flannel can provide 80% filtration coverage”.
The report, titled “Aerosol Filtration Efficiency of Common Fabrics Used in Respiratory Cloth Masks”, has been published by the American Chemical Society.
The report added that cotton quilt laced with batting provides the best protection at 96 percent because of the “fibrous nature of the batting aids in the superior performance at small particle sizes.”
Earlier, researchers at Netherland’s National Institute for Public Health and the Environment, and Public Health England (PHE) found that in the event of surgical mask shortage, these masks are better than no mask at all.
“Any type of general mask use is likely to decrease viral exposure and infection risk on a population level,” the Netherland report had said.
PHE opined that “homemade mask should only be considered as a last resort to prevent droplet transmission from infected individuals, but it would be better than no protection”.
‘THE FIT IS ABSOLUTELY IMPORTANT’
The researchers compared with the performance of a standard N95 mask to those of the fabric masks and reported that “all three hybrid combinations performed well, exceeding 80% efficiency in the <300 nm range, and >90% in the >300 nm range”.
“These cloth hybrids are slightly inferior to the N95 mask above 300 nm, but superior for particles smaller than 300 nm.
“It is important to note that in the realistic situation of masks worn on the face without elastomeric gasket fittings (such as the commonly available cloth and surgical masks), the presence of gaps between the mask and the facial contours will result in “leakage” reducing the effectiveness of the masks.
“It is well recognized that the “fit” is a critical aspect of a high performance”
The report recommends that designers working on cloth mask for mass production should be informed that finishing is critical to its performance.
Edges and contours should fit as tightly as possible, as failure can result in air proliferation, and over 50% reduction in filter efficiency, and an increased probability of inhaling the virus.
“In summary, we find that the use of cloth masks can potentially provide significant protection against the transmission of particles in the aerosol size range.”
It is, however, important to state that cloth masks do not absolutely protect the user from the novel coronavirus.
