A Duke University study of 14 different types of face masks by scientists has provided some surprising findings regarding the effectiveness of different face masks, while also undermining the assertion that any mask or face mask is better than none.
In one test, the researchers found that talking in several masks, especially a fur or neck often worn by runners, actually dispersed the largest potential virus droplets into smaller droplets. The study examined the extent to which the masks blocked air entry points, not if the mask successfully blocked the entry points into the mouth of the mask wearer.
“Given that smaller particles are air longer than large droplets (larger droplets sink faster), the use of such a mask can be counterproductive,”; the researchers wrote in the study, which was published in Friday at Science Advances.
Generally, a fitted N95 is paired with a surgical mask for best performance in terms of minimizing the number of droplets dripping into the air. In fact, the three-layer surgical mask, which may seem uncomfortable to some, was almost as good as the N95, which is considered by many to be the gold standard of face masks. Depending on the type of material, cotton masks are also well tested.
Knitted masks and bandanas performed worse. Fleece masks, as mentioned above, were rated worse than not wearing masks at all.
Overall, fitting a mask also turned out to be very important. A so-called N95 valve mask was significantly worse than a fitted N95.
The new study comes as the pandemic has spawned a new industry of washed rags and masks for stylists ’faces. Since the end of April, New York City has distributed free surgical masks to New Yorkers faces in various locations, including city parks. In line with the guidelines of the Centers for Disease Control and Prevention, Mayor Bill de Blasio has suggested that scarves or household clothing masks can be worn instead of a surgical mask, which can be easily soiled. Although some health authorities advise against reusing surgical masks, de Blasio has said masks can be washed and regenerated.
In an interview with the Boston Globe, Warren Warren, a professor of physics, chemistry and radiology who was one of the study’s co-authors, said individuals should study the material of a face mask. “If you have a mask and you can see through it in the light and you can breathe through it, it certainly is not a very good mask,” he said.
Public health experts have said that face masks can significantly reduce the spread of the virus. Members of the White House coronavirus force group have urged Americans in recent weeks to wear them, especially in parts of the country where the virus is growing. President Donald Trump, however, has not infrequently worn a mask in public.
A new model has predicted that 66,000 US lives could be saved if 95% of all Americans follow the face mask recommendation. At least 163,000 people in the country have died from the coronavirus. Scientists at the University of Washington expect the number to rise to nearly 300,000 by December.