Though N95 and surgical face masks are the best options when it comes to reducing the spread of droplets, homemade face masks are also effective…assuming they’re made correctly, according to researchers with the India Institute of Science. Homemade face masks may be used because they’re more economical than buying boxes of surgical masks, or they may be used when commercial masks are in short supply.
The researchers performed an in-depth analysis of homemade face masks and their ability to filter droplets when a person talks, sneezes, or coughs. The scientists simulated the droplets produced by coughing using a piezoelectric-based droplet dispenser; the results found that homemade face masks should have three or more cotton layers to ‘significantly’ reduce droplet aerosolization.
The study found that towel-based cotton fabrics were ideal for homemade face masks, though they also tested other cotton materials like handkerchiefs, summer stole, and surgical masks. If possible, the researchers note that it is better to use N95 masks (the kind without a vent) or surgical masks — the disposable paper masks that are typically greenish-blue in color.
The findings are in line with previous studies on face masks, the range of which includes everything from confirmation that any mask is better than no mask at all up through the use of multiple layers to filter more particles. Researchers have noted multiple times that a mask’s effectiveness is based partly on how well it fits — a loose-fitting mask with large gaps, for example, isn’t as effective as masks that fit tightly on the user’s face.
Of note, the researchers behind this latest study found that homemade fabric face masks remained effective at up to 70 wash cycles. This is similar to a recent study that found fabric face masks remain effective for around a year, assuming their stitching doesn’t come apart or the fabric doesn’t loosen, reducing the fit.