Mask study: N95 respirator best, neck fleece worst at preventing COVID-19 infection

A new study has confirmed that proper mask use can prevent the spread of COVID-19, however not all masks are equally effective. Due to shortages of medical-grade face masks, many people have turned to household items such as bandanas and neck fleeces for protection. A new Duke University study compared 14 different commonly-used mask designs, and measured the volume of respiratory droplets transmitted during regular speech. The aim of the study was to test homemade mask materials that have not been tested in practice, and compare them to medical-grade equipment. With mask use becoming mandatory in more indoor locations across Canada, the study provides valuable information for Canadians wanting to protect themselves - and the community - from COVID-19.

Researchers tested a fitted N95 respirator, a valved N95 respirator, surgical masks, several types of cotton mask, a poly/cotton blended mask, a knitted mask, a bandana and a neck fleece. Using a black box, an infrared light, and a cellphone to measure the droplets that pass through each mask design, the researchers were able to determine that the medical-grade masks were significantly better at reducing droplet transmission. The fitted N95 respirator mask received a perfect score, with zero droplets passing through, followed by the surgical mask. Among the cotton masks tested, the valved N95 mask was the most efficient. Among homemade masks, knitted masks were not particularly effective at reducing droplet spread, however bandanas were shown to be worse. The study found that the neck fleece was the poorest choice among mask options, and was actually worse than wearing no mask at all. Researchers noted that the material of the neck fleece dispersed the largest droplets into a multitude of smaller droplets, which could then spread further, explaining the increase in droplet count compared to wearing no mask.

The best option for Canadians to keep themselves safe would be to acquire medical-grade fitted N95 respirator masks, but with shortages in equipment across the country, the next best option would be regular surgical masks or cotton masks with an N95 valve, which can be purchased at pharmacies across the country.

Source: Vancouver Sun