EnglishViews: 235 Author: Grand Packing Publish Time: 2020-04-15 Origin: Grand Packing
The mask whose non-oily particle prevention efficiency is no less than 95% is authenticated as N95 by National Institute for Occupational Safety and Health (NIOSH), while the same mask of is authenticated as KN 95 in accordance with Respiratory Protective Equipment -- Non-powered Air-purifying Particle Respirator.
N95 or KN95, they stand the respirators’ prevention grade rather than specific brands or products. “N” or “KN” represents prevention to non-oily particles (such as virus, bacteria, dust...) . the number “95” indicates that the masks’ prevention efficiency is no less than 95% under the regulated testing conditions. Regardless of the authentication standard, N95 and KN95 are of the same classification and efficiency.
Besides, FFP2 respirators authenticated by EN149 standard has equivalent prevention efficiency with N95 and KN95 masks. FFP2 masks’ filtering efficiency is no less than 94% under the testing conditions regulated by EN. The certified mask are all marked with ‘EN149: 2001 + A1: 2009 FFP2”.
COVID-19 can only spread by hosts. Once they leaves hosts (animals, humans...), the virus will die soon. However, COVID-19 can be spread through contact or droplets. Among them, the droplets after cough, speaking or sneeze are the main spreading medium. If a virus carrier sneezes in an enclosed space (such as train or plane), the droplets will be inhaled by another person possibly and that person might be affected. Therefore, a face mask is needed for prevention.
Virus and their spreading medium all exist in the form of particle and particles are all of narrow diameter. N95 and KN95 can exactly filter these fine particles with their filtering materials of good performance. During the efficiency testing method, particles whose diameter is 0.3μm is applied. Among particles of variable diameters distributed normally, particles of 0.3μm diameter is the most difficult to be filtered. Besides, strict requirements are raised to tightness of KN95 or N95 mask. Therefore, wearing N95 or KN95 correctly can effectively prevent the wearer from being exposed to pathogenic microorganisms and prevent virus from entering human body through respiratory tract. However, the wearer should also pay attention to their hands and eyes in case that they are affected by other means.
Common gauze, cotton or sponge masks cannot play the same role with N95/KN95. They can’t filter effectively, so they are not suggested.
For medical surgical mask, products in accordance with relative standards in medical industry can be used. Although they can filter non-oily particles and bacteria in certain efficiency, no standard is formed on their tightness. Therefore, their application is limited.
KN95 or N95 respirators can effectively prevent particles suspending in air and have good tightness. However, medical workers are not suggested to wear them in high-load body fluid splashing places.
Since N95/KN95 respirators are of high prevention efficiency and good tightness, certain resistance will be generated during breathing. A mask with exhalation valve can effectively decrease expiration resistance and avoid heat accumulation. Therefore, a respirator with exhalation valve can make wearer more comfortable without feeling suffocated. The valve opens during expiration for quick exhaust of hot and humid air but closes automatically during inhale to prevent dust, bacteria and virus from entering. Therefore, it is also called single valve. Worn correctly, the qualified and certified KN95/N95 can achieve expected prevention, no matter whether they have exhalation valve or not.
However, if they have been infected with COVID-19 or are suspected to be infected, the wearers should wear N95/KN95 respirators without exhalation valve. The reason is that the air is exhausted through the valve directly without filtering and virus might attach to droplets and be spread to people around.
The answer is “No”. KN95 masks filter particles in the way of electrostatic adsorption. Washing and disinfection will both cause static dissipation and so that mask effect is weakened. Besides, the second contamination will also result unpredictable risk and harm to users.
GB2626 standard also defines KN95 respirator as disposable mask. Generally speaking, users should change masks in the following four cases: 1) masks are polluted; 2) parts are damaged; 3) masks are wetted; 4) the breathing resistance is increased.
Considering virus contagion, experts suggest that masks be changed every four hours during epidemic. However, frequency mask change will also lead to great material consumption. Current guides of Centers for Disease Control and Prevention (CDC) suggest that we can take some measures to save material. The masks can be left for people more in need, such as medical staff and patients. If acceptable, healthy people can lengthen the usage time of KN95 or repeat usage, provided that masks are not polluted while wearing and taking off. And after taking off, the mask should be put into a sealed sachet and stored at a clean, dry and non-polluted place. But mask reuse will also be certainly risky. Once being polluted, the mask should be reasonably classified and dealt with according to relative medical regulations or pollutant and waste disposal regulations.
We should also pay attention to fitness of masks, except filtering efficiency and breathing resistance. The fitness is the premise of that wearing mask can achieve expected prevention goal. If the mask cannot completely fit to user’s face, breathed air will be exhausted firstly through the gap due to differential pressure. In addition, beard and hear will influence tightness. All in all, users should wear masks in correct manner.
Due to different face features, people might get different wearing effect for the same mask.
A. Some adult masks are sized L, M and S. Users can choose according to different face features;
B. Children have small face so children-specific mask of smaller size should be chosen for them.
Parents should be able to identify some risks when choosing and wearing masks for their kids. For example, children is unable to wear masks correctly or take off masks while feeling uncomfortable. In this case, it’s better for children to wear masks under parent’s guide and help.
No. If worn correctly, a N95 or KN95 can achieve the desired effect. Wearing more masks cannot cause poor tightness, but also increase breathing resistance.
Actually, we are suggested to wear masks when we catch cold symptomized by cough and sniff, in flu season or in the smog weather.
1) Wash hands before and after wearing masks; don’t touch mask outside so as not to pollute hands or masks;
2) After usage, classify and process masks contacting virus or bacteria in accordance with related regulations and wash hands.
During epidemic, used masks might be full of virus and bacteria. The policy of waste sorting have been implemented in many cities and countries. For these two reasons, masks after usage cannot be thrown casually. Some netizens give some tips, such as scalding masks in boiling water, burning them or shredding them... However, all of them is not scientific. Some suitable suggestions are list as following:
1) Medical institutions: throwing masks into garbage bag for medical waste;
2) Healthy people: throwing masks into harmful garbage can;
3) People who are suspected to be affected: handing masks to related staff during treatment or isolation and dealing with them as medical waste;
4) Patients fevering, coughing or sniffing and people contacting these patients: disinfecting masks with 75% alcohol, putting them into sealed sachets and throwing them into garbage can; or throwing masks into garbage can first and then disinfecting with 84 disinfectant.
Currently, on internet appear some videos on used recycle or inferior mask production. There inferior products cannot protect us as expected, but some remained materials might even harm us. The risk of used masks cannot be imagined, either. Anyway, what we can do is to buy N95/KN95 from regular channels.
Although wearing KN95 respirators can greatly reduce the risk, we are still possible to be affected. Therefore, please prevent and isolate ourselves according to national regulation during epidemic. We must wear masks correctly and keep hands and eyes sanitary.
No. Some tutorial videos on Internet show us how to produce masks with cotton, yarn or canvas... These materials cannot prevent virus or other particles well. Their tightness is either good. Masks made of them cannot protect us effectively. Therefore, it’s better to not use them.
Half-mask respirators can replace KN95 when the latter is not available. The changeable filter cotton also meet the requirements on KN95 regulated in Respiratory protective equipment -- non-powered air-purifying particle respirator. In addition, compared with disposable KN95 respirator, silicone applied for half-mask respirators are softer. Headband and neckband can also be adjusted according to head or neck size. Therefore, the half-mask respirators can fit face and prevent virus better. Besides, its exhalation valve makes user more comfortable during usage.
However, they are also not suggested for infected or possibly infected people. Face mask and some parts such as headband can be recycled after disinfection with 75% alcohol.
Especially for medical staff, KN95 respirators can be used, matching with goggles. Experts also points out that goggles are more helpful to prevent COVID-19.
