A nucleic acid sampling worker in Beijing was diagnosed! Experts urgently remind that masks should be worn like this →

According to the Beijing Municipal Health Commission's report on May 4, from 15:00 on May 3 to 15:00 on May 4, Beijing had 52 new local cases of COVID-19 infection. Among them, infected person 617 had visited the home of infected person 328 for sampling.

Why is it important to wear N95/KN95 masks? What are the precautions for wearing N95/KN95 masks? What are the details that ordinary people should not ignore when wearing masks? The reporter interviewed Professor Jin Xiangyu, deputy director of the Industrial Textile Engineering Center of the Ministry of Education and director of the Department of Nonwoven Materials and Engineering of Donghua University, and Cui Can, deputy director of the Infection Management and Disease Prevention and Control Department of Beijing You'an Hospital Affiliated to Capital Medical University.

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Pay attention to these details to avoid "ineffective mask wearing"

The first is to distinguish the inside and outside, and the top and bottom of the mask.

Generally, the inside and outside of the mask can be judged by the color depth of the mask, the front and back of the printed fonts, and the direction of the fold. Generally, the dark color and printed fonts are the front, the side with the fold downward is the outside, and the end of the metal strip/sponge strip is the top of the mask. N95/KN95 masks are generally folded or arched, and it is easy to distinguish the front and back.

The second is to adjust the nose clip of the mask.

Many people use the thumb and index finger of one hand to adjust the nose clip. The problem with this approach is that the thumb and index finger have different strengths, and using these two fingers to press the nose clip may cause the nose clip to be asymmetrical. The correct approach is to use the index and middle fingers of both hands to shape the nose clip along the bridge of the nose.

The third is to do a tightness test.

Make sure the mask fits the face as closely as possible. A simple way to test the fit is to put on the mask, gently cover the outside of the mask with both hands, and exhale forcefully. If air leaks from the bridge of the nose, adjust the nose clip of the mask in time; if air leaks from the chin or cheeks, adjust the position of the mask; if air leakage cannot be avoided after adjusting the position of the mask, it is likely that the mask is not suitable for the wearer's face shape, and you can replace it with a mask of another brand or model.

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"We must pay attention to the way we wear masks. Because everyone's face shape is different, it is difficult to ensure the personalization of masks. People with small faces should pay special attention to the close fit." Jin Xiangyu emphasized that wearing a mask correctly can greatly reduce the level of exposure to pathogenic microorganisms in the air and effectively prevent virus-carrying microparticles from entering the human body through the respiratory tract.

Jin Xiangyu also reminded that N95/KN95 masks include both medical and non-medical types. Among them, masks with the "medical" mark are suitable for front-line hospital personnel because they meet the performance requirements of resistance to synthetic blood penetration and water resistance. "To prevent cross-infection, in addition to wearing a mask, you must also wear protective clothing and a mask correctly."

N95/KN95 masks have higher filtration efficiency

Pang Xinghuo, deputy director of the Beijing Center for Disease Control and Prevention, reminded that key personnel such as front-line epidemic prevention personnel, takeout express delivery personnel, etc. should wear N95/KN95 masks while working.

On May 6, the Taipei City Department of Commerce issued a new version of the "Guidelines for Prevention and Control of Takeaway Delivery Personnel during the COVID-19 Epidemic," which also stipulates that takeaway delivery personnel must wear N95/KN95 masks and disposable gloves during the delivery process.

“The N95 mask can filter out more than 95% of non-oily particles (aerosols) under specified air flow conditions (85L/min), hence the name N95.

KN95 masks and N95 masks have the same level of protection, but KN95 masks follow Chinese standards, while N95 masks follow American standards. "Jin Xiangyu introduced.

The filtration efficiency of mask filter materials directly affects the level of protection. If masks are ranked from high to low according to their filtration efficiency for particulate matter, the ranking results are: N95/KN95 masks, medical surgical masks, ordinary medical masks, and ordinary cotton masks.

In addition, the sealing of the mask also affects its protective power. N95/KN95 masks are more airtight and more water-repellent, oil-repellent, and alcohol-repellent than flat masks.

Cui Can emphasized that given that N95/KN95 masks have a higher virus filtering efficiency, under the current epidemic situation, key groups such as front-line epidemic prevention personnel and food delivery personnel should insist on wearing N95/KN95 masks, which can provide stronger protection for themselves, others and the environment.

The general public should choose these masks carefully

"We do not emphasize that everyone in the general public should wear N95/KN95 masks. Compared with N95/KN95 masks, flat masks are more breathable and more comfortable. If the general public does not go to dangerous areas, wearing this type of mask is enough." Jin Xiangyu said.

"If conditions permit, you should try to choose masks that meet the relevant standards." Cui Can emphasized that a very important point in choosing masks is to see whether the masks meet the relevant national standards and industry standards.

Regarding some printed masks and black cotton masks that have become popular recently, experts said that they do not recommend their use during the epidemic.

With the arrival of summer, some businesses are still selling anti-stuffy masks or cooling masks. In this regard, Jin Xiangyu said: "Summer cooling masks are more of a commercial gimmick. This type of mask mainly uses a cooling slow-release method, adding cooling burst beads (such as mint and wild chrysanthemum aromatherapy substances) to the mask. The cooling feeling lasts for a short time and the effect is not obvious. If some unknown chemicals are added, it may also destroy the protective effect of the mask. At present, there is no unified product standard for cooling masks at home and abroad, and each manufacturer can only make some explanations. During the epidemic, the so-called cooling masks must also have a protective effect."

Cui Can said: "Many people excessively pursue the beauty and comfort of masks, but the purpose of wearing a mask is to prevent the virus from entering the respiratory tract. Compared with good protection and protecting yourself and others, the beauty and comfort of the mask are secondary."

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Comprehensive sources: Science and Technology Daily, Hangzhou CDC, Metropolitan Express, etc.