Important to pay attention to quality of masks that you wear

With Covid-19 showing no signs of abating, our cloth masks are here to stay. These masks have in fact now become part of our daily wear and we are constrained to

With Covid-19 showing no signs of abating, our cloth masks are here to stay. These masks have in fact now become part of our daily wear and we are constrained to purchase more of them or make them at home in order to protect ourselves.

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That’s not all. Given the rapid spread of the disease, we also need to pay much more attention to the quality of these cloth masks and their design and fit, so as to ensure maximum protection from the deadly virus. Fortunately , several recent studies have measured the filtration efficiencies of different kinds of fabrics for use in masks and we need to take note of them to wear what is in our best interest.

I would like to quote in this context, a study published in April this year in the American Chemical Society Journal (ACS Nano), that gives good advice on how to improve the filtration efficiency of your cloth mask.

Titled “Aerosol filtration efficiency of common fabrics used in respiratory cloth masks” the study has looked at 15 different kinds of fabrics and made some extremely important recommendations for improving the effectiveness of cloth face masks.

For example, the study points out that the filtration efficiency of a fabric varies on the basis of its thread count. Cotton, for example, performs much better as a material for mask, at higher weave densities or thread count. A 600 TPI (threads per inch) cotton, for example, was found to be far more effective than 80 TPI cotton. So the study recommends that fabrics that are porous should be avoided and those with tight weaves and low porosity, such as those found in cotton sheets with high thread count, should be used for making the mask.

Secondly, the study points out that more layers of fabric provide better protection than a single layer. For example, while two layers of natural silk offered 65 per cent filtration efficiency, four layers gave 86 per cent efficiency. Similarly one layer of chiffon gave 67 per cent filtration efficiency, while two layers gave, 83 per cent. The efficiency of one layer of 600 TPI cotton was 79 per cent, while that of two layers , 82 per cent.

Third, the study found that by combining different kinds of fabrics and leveraging their mechanical and electrostatic filtering properties, the mask could be made even more effective. For example, a hybrid cloth mask made of one layer of high thread count cotton and two layers of natural silk or chiffon , could be very effective. While such hybrids of cotton and chiffon showed a filtration efficiency of as much as 97 per cent, that with cotton and silk, 94 per cent.

The study also emphasized the importance of ensuring that the mask is so designed as to fit the consumer snugly, particularly around the nose and the mouth. In fact the study showed that improper fit and leakages could well reduce the filtration efficiency of masks by over 50- 60 per cent. So consumers would do well to keep these things in mind when they purchase or make their own mask and wear them..

We are all aware that N-99 and N-95 masks offer the best protection (the numbers 95 and 99 represent the percentage of filtration efficiency of the mask) and most of them are also so designed as to fit snugly around the nose and the mouth, but they are reserved for those in the health sector.

On the other hand, several studies evaluating different kinds of masks have ranked the home-made single layer mask that most of us wear, as the poor cousin. And if the fit is not good, then the protection that they offer is even lower. But that need not be so. With the use of right material and design, the fabric masks can be as good as the best, and consumers must make the effort to ensure that.

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