Best homemade face masks made from cotton and chiffon combined, research suggests

Masks have become an indispensable part of our get-up these days when we step out of the house, and much debate has gone on about the effectiveness of face masks, especially ones made of cloth.

And while disposable three-ply masks may offer better filtration against viral particles, cloth masks prevent viral particles from landing on your face and getting into your bodily system.

So which material is best to use in a face mask?

A previous study by an Asian-based social enterprise found that denim, canvas and high-threadcount bedsheets provide the best filtration, but the trade-off may be on breathability.

Based on another study published by the American Chemical Society (ACS) in April, researchers 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 at least 80 per cent of aerosol particles that are smaller than 300 nm (coronavirus particles have an average diameter of 125nm).

Substituting chiffon for silk or flannel (65 per cent cotton and 35 per cent polyester) produced similar results.

2 mechanisms at work

Chiffon being an effective layer to include in your cloth masks may come as a surprise, considering the sheerness of the fabric.

However the study found that chiffon and other similar fabrics, like silk, hold an electrostatic charge, which repels particles.

As tightly-woven cotton fabric acts as a "mechanical barrier" to particles, a combination of chiffon and cotton layers leverages on both the mechanical and electrostatic filtering and "may be an effective approach", said researchers

One example ACS gave to those who want to make their own fabric mask was to have a high-thread count cotton combined with two layers of natural silk or chiffon.

A quilt-type mask where two layers of cotton sandwich a cotton-polyester batting also works as well, it said. 

One thing to note however, is that in a subsequent update, researchers acknowledged that the airflow speed used for the tests was found to be lower than the typical resting respiratory rate.

The most important thing to watch out for though, is to ensure that the mask fits well for the wearer's protection. Research says that even a one per cent gap can reduce the filtering efficiency of a face mask by 50 per cent or more, regardless of material.

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candicecai@asiaone.om