Non-woven masks, as the name suggests, are made of non-woven fibers, which are bonded or inlaid together by heating, chemical or mechanical processes to create thin cloth sheets.
On January 7, the board of education in Tokyo's Suginami Ward (Board of Education in Tokyo's Suginami Ward) required all elementary and junior high school teachers to wear non-woven masks. Even in physical education classes, this was a written appeal for thorough anti-infection measures. a part of. The board of directors also announced that, if possible, it is recommended that children also wear masks.
The Board of Education explained that this recommendation is [based on the opinion of the ward public health center and does not mean that we will force children to wear non-woven masks."
At the same time, from gynecological clinics, dentists, and clothing stores in the Tokyo area to hairdressers in Hokkaido and fitness centers in Kyushu, the websites of medical institutions across Japan show that more and more medical institutions began to require patients and customers to wear this this month. Kind of non-woven masks. Some places provide masks to customers, while a barber shop sells them for 30 yen (about 29 cents) per person.
Nevertheless, polyurethane masks are still very popular, especially among young people. A 32-year-old woman from Ishikawa City, Chiba Prefecture has been a believer in polyurethane masks since last spring. She told the "Daily Shimbun" reporter, "I like them because you can wash and reuse them, and you can choose Different colors to match your outfit. Moreover, the white non-woven fabric is easy to get makeup stains."
She added, [If I go to the hospital, I will wear a non-woven fabric, but as long as the society treats me less harshly, I plan to continue using polyurethane masks most of the time."
The sudden increase in the recommended amount of non-woven face masks stems from research by a team that includes the Riken Institute of Japan`s Toyohashi Institute of Technology, which is supported by the Japanese government. Through simulations on the Fuqua supercomputer, the research team investigated the effectiveness of different types of masks-non-woven fabrics, ordinary cloths, and polyurethane masks-to stop water droplets. The spread of droplets in the mouth and nose of infected persons is one of the main ways for the spread of coronavirus.
The simulation results published last year showed that many types of non-woven masks can filter out more than 90% of water droplets, but their air permeability is not high. Depending on the type of fabric, the number of layers, and other factors, the results of conventional cloth masks are also very different. Some masks perform as well as their non-woven fabrics.
On the other hand, polyurethane masks can only filter out 20-40% of droplets.
Based on these results, the research team tested the effectiveness of the mask when actually worn. As predicted, very few droplets pass through nonwoven masks, and polyurethane masks perform relatively poorly.
However, this does not mean that the research team is issuing an endorsement for non-woven masks. Simply put, not all masks are equally effective. There are also some masks on the market that have a worse filtering effect than ordinary cloth masks.
"Basically, those that make breathing difficult are more effective. That's what I want people to remember," said Makoto Tsubokura, a professor at Kobe University in Japan and leader of the research team. He added, [If you are in an ordinary office environment, a cloth mask is fine. When you are going to a place where you may encounter people, wear a non-woven mask. In other words, according to Your physical condition and the risk of infection where you are going to choose your mask."