A popular face coverage style may not do much to limit the spread of coronavirus, according to a study by Duke University.
The researchers found that while most cotton, cloth, or style-of-surgery masks tested were effective in limiting the number of expelled points of an expelled person while talking, “neck shell” or neck shearing actually resulted in more minor evictions.
“We attribute this to the sheet, the textile, shattering those large particles into very small particles,”; Martin Fischer, an associate professor of research at Duke, said in a news release.
The novel coronavirus that causes COVID-19 is spread from person to person mainly through the breathing points that we all expel from our mouths when we talk, sneeze, cough or breathe heavily, according to most experts.
Fischer said it is possible that dropping more small dots through a thin mask is worse than expelling larger dots without shields at all.
“[The smaller particles] tend to stay longer in the air, they can be more easily transported in the air, so it can be productively effective to wear such a mask, “said Fischer.” It is not the case that every mask is better that nothing. There are some masks that actually do more harm than good. “
However, some have said that termination is premature and we do not have enough information to state that those masks do more harm than good. Slate news director Susan Matthews points out that the researchers tested only one subject with the gaiter-style mask, increasing the chances that the mask simply did not fit, or that there was some other issue with either the mask or the subject of the test.
The subject also repeated the short phrase “stay healthy, people”, 10 times for each mask. The subject did not speak at different levels of volume, cough, sneeze, or simulate other conditions such as heavy breathing during exercise. Gaiter masks are very popular among runners because of their lightweight construction and looser fit.
A study conducted by the University of Wisconsin-Madison in July found that guters were more effective than other types of masks at capturing drops from a simulated cough, but that the study used “convenient” home guitars made from tightly woven with a nose-piece metal and elastic to ensure a good fit.
Matthews also notes that we do not know if a person who exposes a larger number of small spots is more likely to spread the disease than a person who produces fewer, larger spittle spots loaded with the virus.
The Duke team’s findings were published online last week in Science Advances, a peer-reviewed journal.
Fisher and the Duke team tested 14 different types of masks using cardboard, laser lights and a cell phone camera, as you can see in the short video below.
The subject repeats the same phrase in confection, first without the mask, then with different styles of masks to see which were more effective. The laser makes the points coming out of a person’s mouth visible and the camera records those points to be calculated.
The team found that surgical masks as well as cotton, cloth, and polypropylene masks were effective in blocking spots from spreading when the subject spoke in a normal voice. The best performing masks were the N95 medical grade masks – without valves – used by medical professionals.
Neck shearing (Mask # 11 in the photo above) actually resulted in more points being counted. Bandana reduced the number of dots by half, others reduced the number of dots to 20 percent or less of the number of masks.
One of the researchers told The Washington Post that the guitar he poorly tested was made of a lightweight, elastic polyester material that was marketed as a breathing item for outdoor sports activities.
“If you can see it through it when you bring it to light and you can easily inflate it, it ‘s certainly not protecting anyone,” Postren told Warren S. Warren, a co-author of the paper.
Medical masks N95 with valves carried around as well as cotton masks, with researchers noting that the valves were created to prevent dots from entering the mask from the outside, to prevent the person wearing the mask from expelling the dots that others could breathe inside.
The overall reception of the letter is clear, however. While some masks perform better than others, most masks are effective in reducing the spots that spread the coronavirus.
“Wearing a mask is a simple and straightforward way to reduce the spread of COVID-19,” said Dr. Eric Westman, a Duke doctor who collaborated with Fischer to design the experiment, in a news release. “About half of the infections are from people who show no symptoms and often do not know they are infected. They can spread the virus unknowingly when they cough, sneeze and just talk.
“If everyone wore a mask, we could stop up to 99% of these points before they reach someone else. In the absence of a vaccine or antiviral drug, it is the proven way to protect others as well as yourself. “
This study was designed as a test of the concept of researchers’ technique for measuring point propagation. Researchers say further research is needed to test different masks under different conditions, such as speaking in different volumes, or coughing and sneezing.
“We certainly encourage everyone to wear a mask, but we want to make sure that when you wear a mask and go to the trouble of making a mask, you make one or wear one that actually helps not only you, but helps all, “said Fischer.