Face masks: What works, what doesn’t


Pushpa Girimaji

Following the Covid-19 pandemic, we had been all instructed that we should always put on masks to comprise the unfold of the illness and we don’t must spend cash on costly masks, however could make our personal easy cotton masks from any outdated material or simply tie a shawl or a big handkerchief to cowl our mouth and nostril. However, with a number of of my buddies catching the virus regardless of the masks, I’m questioning whether or not the masks that we’re carrying are protected sufficient. Can you throw some mild on this?

Well, N-95 masks provide the most effective safety — the quantity 95 representing the share of filtration effectivity of the masks. Besides, they’re so designed as to suit snugly across the nostril and the mouth in order that there is no such thing as a hole between the masks and the face, thus providing most safety. However, due to their scarcity, these have been reserved for these working within the well being sector or these caring for Covid-19 constructive sufferers at residence.

Studies have proven that do-it-yourself single layered material masks don’t, in any method, match as much as the filtration effectivity of the N-95. And if these masks are free becoming, then the safety is even much less. However, one needn’t despair. The material masks will be pretty much as good as the most effective, with using the correct materials, design and match.

Several current research evaluating the effectivity of fabric masks in filtering viruses have given us glorious perception into the filtering properties of assorted materials and find out how to design them in such a method as to make sure most safety from the lethal virus. I wish to quote on this context, a examine printed in April within the American Chemical Society Journal (ACS Nano) this 12 months. Titled ‘Aerosol Filtration Efficiency of Common Fabrics used in Respiratory Cloth Masks’, it checked out 15 totally different varieties of materials, together with cotton, cotton quilt, pure silk, flannel (65 per cent cotton and 35 per cent polyester) , artificial silk or polyester, chiffon (90 per cent polyester and 10 per cent spandex), totally different polyester cotton blends, to say some. The examine’s conclusions information us in making the most effective masks for our safety.

The examine factors out that the filtration effectivity of a cloth varies on the idea of its thread depend. Cotton, for instance, performs a lot better as a cloth for masks, at increased weave densities or thread depend; 600 TPI (threads per inch) cotton was discovered to be far simpler than 80 TPI cotton. It recommends that porous materials must be prevented and people with tight weaves and low porosity, resembling these present in cotton sheets with excessive thread depend must be used for making the masks.

The examine emphasises that extra layers of material present higher safety than a single layer. For instance, whereas two layers of pure silk provided 65 per cent filtration effectivity, 4 layers gave 86 per cent. The effectivity of 1 layer of 600 TPI cotton was 79 per cent, whereas that of two layers was 82 per cent. Similarly, a layer of chiffon gave 67 per cent filtration effectivity, whereas two layers, 83 per cent.

It discovered that by combining totally different varieties of materials and leveraging their mechanical and electrostatic filtering properties, the masks may very well be made much more efficient. For instance, a hybrid material masks made of 1 layer of excessive thread depend cotton and two layers of pure silk or chiffon was much more superior. While such hybrids of cotton and chiffon confirmed a filtration effectivity of as a lot as 97 per cent, that with cotton and silk confirmed 94 per cent.

The examine discovered that an ill-fitting or free masks that didn’t maintain onto the face tightly and left gaps lowered the filtration effectivity by as a lot as 50-60 per cent. While a correct becoming cotton and silk hybrid masks offered a filtration effectivity of 94 per cent, an ill-fitting one gave a filtration effectivity of simply 37 per cent.

Are such masks out there in market?

I’m certain they’re. These days, so many firms are making masks. You may make them at residence or get one tailor-made for you. Just make sure that they match effectively.



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