As students return to school and staff return to the office all with new safety protocols likely including wearing a mask, a new study from Duke University examines which masks are more effective.
Spoiler alert: A fit N95 mask, mostly reserved for those in the medical community, performed best in their test. However, because many Americans do not have access to these and have used a mix of store-bought or homemade cotton and fabric coverings, Duke tested 13 other types of masks.
The study, that was published Friday, was asked when a professor at Duke’s School of Medicine was asked to help a local group buy masks in bulk for the community. According to to CNN, the professor wanted to make sure the masks they bought were effective.
Researchers collected 14 types of masks, including the professionally customized N95 mask, a bandana, homemade cotton variants, and a surgical mask. They then used a dark room, laser beam and mobile phone camera to record how many drops (reflecting the light from the laser beam) that each mask passed through.
For each mask test and the non-mask control test, the speaker was recorded and said “Stay healthy, people” five times. Each mask was tested ten times.
Duke University
The surgical mask performed the second-best, behind the fitter N95 mask. The selection of homemade cotton masks is all carried out in a similar range. There was a big difference in material, with knitted fabric allowing more particles to pass through.
Meanwhile, bandanas and neck fleeces, as well as neck gaiters, were not as effective.
‘We notice that speaking through some masks (especially the neck fleece) the largest droplets seem to disperse into a multitude of smaller droplets, which explains the apparent increase in the droplet number relative to no mask in that case. ‘Considering that smaller particles carry air longer than large droplets (larger droplets drop faster), the use of such a mask can be counterproductive,’ the researchers note.
Duke University
The CDC recommends wearing face masks to stop the spread of Covid-19, which can spread through droplets expelled from the mouth while breathing, talking, singing, and so on.
It University of Washington’s Institute for Health Metrics and Evaluation projects involving 67,000 American lives would be saved between now and December 1 by near universal wearing of masks. They released their figures just last week.
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