Wearing a mask is an important measure to prevent infection of new crown , but it is not the only measure. In addition, the effectiveness of wearing a mask to prevent the new coronavirus is also related to the type of mask and whether it is worn correctly. Below we will introduce in detail some of the common masks we currently have to see how protective the mask you are wearing is against the new coronavirus?
1. How many types of masks do we currently wear?
The masks that people often wear now can be mainly divided into the following types: N95 masks, KN95 masks, surgical masks and ordinary medical protective masks. These types of masks have different anti-coronavirus effects. Let me give you a detailed introduction so that you can choose different masks for different occasions.
1, N95 masks
N95 is a protection standard, which is formulated by the National Institute of Occupational Safety and Health (NIOSH). It refers to the filtration effect of non-oily particles (dust, acid mist, paint mist and microorganisms ) with a diameter of 0.075μm (micron) ±20μm, which is greater than 95%. If it is a doctor-specific N95 mask, its outer layer can also prevent blood spatter.
There are 9 types of NIOSH-certified masks, including N95, N99, N100, R95, R99, R100, P95, P99, and P100. The larger the value, the stronger the protective capability.
2, KN95 masks
KN95 masks are designed and produced in accordance with China's national standard GB 2626-2019 "Respiratory Protective Equipment Self-priming Filtering Anti-Particulate Respirators", proposed by the China State Administration of Work Safety. In terms of the effect of filtering particulate matter, is the same as N95 masks. All have achieved a 95% filtration effect on non-oil particles of 0.075μm ±20μm.
There are two series of the above standards, including KN series and KP series. The former is the more common KN95 mask we have now, which mainly protects against non-oily particles. The latter increases the protection against oily particles.
3, surgical masks
Surgical masks are the masks most commonly worn by surgeons in hospitals. The main material is non-woven fabric. When used, the sealing is relatively good, and it has good protection ability against the splash of blood and body fluids during surgery. Surgeons usually use it more, and it can also be used in patient care, dental operations and other occasions. In the process of communicating with patients, it can prevent the infection of respiratory diseases such as saliva droplets. In daily life, medical workers will not be infected and will not infect others.
In addition to preventing blood and body fluid splashes and saliva droplet infections, surgical masks have a filtration effect of 30% for 0.3μm non-oily particles.
4, medical protective mask
The requirements of this kind of mask are slightly lower than medical surgical mask . It is a self-priming medical filter protective equipment, which has a good filtering effect on nasal secretions and oral secretions. It is suitable for patients with respiratory diseases who have been exposed to , airborne or close droplet transmission during diagnosis and treatment.
Medical protective masks can also filter more than 30% of 0.3μm non-oily particles.
2. Can the above masks filter the new coronavirus?
This is also an issue that people are very concerned about. From the above introduction, N95 masks and KN95 masks have the highest filtration ability. They both have the ability to filter more than 95% of non-oily particles of 0.075μm±20μm. Surgical masks and medical protective masks only have a filtration capacity of 30% for non-oily particles of 0.3 μm.
But do you know what the diameter of the new coronavirus is?
The diameter of the new coronavirus is 60nm (nanometer)-140nm, 1nm=1/1000μm, converted to μm, it is also 0.06μm--0.14μm, and the average size is 0.1μm. According to this value, whether it is an N95 mask or a KN95 mask, it can effectively filter the new coronavirus in the air. Unless the new coronavirus is extremely small in the air, with a diameter of less than 0.075 μm, the protective ability is a little poor.
As for hospital surgical masks and medical protective masks, their filtration ability is 30% protective against 0.3μm non-oily particles. Obviously, they are powerless against the new coronavirus with only 60nm-140nm in the air.
However, the main mode of transmission of the new coronavirus is through saliva droplets such as talking and coughing, or it is spread in aerosol . Generally speaking, the aerosols produced by healthy people when they talk or sneeze are between 1 and 2000 μm, and most of them are between 1 and 2 μm. However, the aerosols produced by COVID-19 patients are slightly larger than those of normal people. Looking at it this way, a medical mask that can filter 0.3μm is more than enough to filter aerosols. Of course, it is difficult for medical protective masks to filter the new coronavirus flying in the air.
3. How to wear a mask correctly?
As we said above, whether masks can effectively filter the new coronavirus, in addition to the production standards of the masks, correct wearing is also very important. No matter how good a mask is, if it is not worn correctly, its protective capabilities will be greatly reduced.
1. Wash your hands first
When wearing a mask, your hands must be clean, so before wearing a mask, it is best to wash your hands according to the " seven-step hand washing method ".
2. Distinguish between up and down, inside and outside
When wearing a mask, you must distinguish between up and down, inside and outside, otherwise the mask will lose its protective ability. Both N95 masks and KN95 masks have a metal strip on the upper part, while medical masks can touch a metal line, which is the upper part. The outside of medical masks and are usually blue, so don’t wear them backwards.
3. Sealing
After putting on the mask, pinch the metal strip or wire on the upper part of the mask according to the shape of the nose, leaving no gaps as much as possible. The lower part should also cover the chin.
4. Replace it in time
Generally, ordinary people should not use medical masks for more than 8 hours. Of course, the time required by medical staff is shorter. If the mask gets wet, it must be replaced in time.
5. To remove the mask
, use one hand to take it off from behind the ear, pinch it twice and fold it in half, put it in a plastic bag, tie it and throw it into the trash, and then wash your hands.
