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Since the outbreak of the new crown, the Internet has been joking: "I used to wear a mask to grab money, but now I take money to grab a mask, but I can't buy it!" There is no doubt that this paragraph portrays the importance of masks. To do three things well, masks are so important, how much do you know?

Wearing a mask can not only protect yourself, but also ensure that you will not spread viruses that you don't know.

1. The past and present of masks Before the Qing Dynasty, once China encountered a major plague, it often suffered heavy casualties! Although people know that the plague is contagious, they dare not come into contact with infected people naturally, but because they don’t know the source of the disease or how to prevent it, superstition, random medical treatment, etc. make the epidemic worse; besides escaping from their homes, survivors almost It is a matter of fate. At the end of Ming Dynasty, Wu Youke conducted in-depth research and wrote the

"Plague Theory"

He realized that this epidemic came from qi, and the unhealthy qi in the world must first cover his nose and even mouth with a cloth towel. In the Qing Dynasty, Cao Tingdong's "Healthy Essay" wrote: I often go in and out, but I rarely feel the wind, that is, cover my mouth and nose with sleeves to avoid fashion. "plague" The earliest record of masks should be the ancient Roman Empire. In the first century AD, scientist Pliny wrote Natural History. He recorded that the animal’s bladder skin covered his mouth and nose, avoiding toxic dust. By the 1440s, the "Black Death" had become popular in Europe, and some doctors would wear bird beak masks, which contained various aromatic substances and filtering substances in their mouths, which can be said to be the earliest gas masks.

Doctor Beak

At the end of the 18th century, a bag or textile covering the entire head appeared in Europe. Some of these respiratory protection devices are equipped with valves, while others are equipped with slightly pressurized cylinders. In 1848, Lewis P. Haslett of the United States invented the "Hasley lung protector", which was the first patented air purification mask. The mask uses a one-way air valve and a filter element made of wet wool, which can greatly filter dust in the air. Subsequently, inventors in various European countries began to conduct in-depth research on this mask. Among them, the Scottish chemist John Stenhouse (John Stenhouse) used activated carbon for the first time.

The picture on the right is the Scottish chemist John Stenhouse (John Stenhouse) In 1895, the German pathologist Ledersch discovered that germs can infect wounds through the air. Therefore, it is recommended that medical staff cover their mouth and nose with gauze. Although there is only one layer of this gauze, the effect cannot be ignored. It takes the form of modern surgical masks. In 1897, French surgeon Paul Berg used surgical masks with more modern medical significance for the first time. The gauze is 6 layers thick. Since then, countries have successively improved surgical masks, such as adding iron bars on the bridge of the nose and ring ears.

Original surgical mask

Nowadays, there are many types of masks, especially the most important surgical masks. Different countries have different standards, and different manufacturers have different styles.

English respirator or face mask means mask, but respirator is more suitable for professional use, such as respirator, gas mask, etc., and face mask is widely used, whether it is a beauty mask or a gas mask, you can use it.

2. Types of masks

The main function of the mask is to prevent the lungs from inhaling harmful gases, and by filtering harmful gases, odors, particles in droplets, etc., so that humans can breathe normal air. Since its development, in addition to respiratory protection, masks also have the functions of dustproof, warmth and covering. The specific types are as follows:

Paper mask, cotton mask, surgical mask, N95 mask

Paper mask/paper mask: It can block more than 70% of particles with a diameter of 5 microns. It is suitable for regular cleaning, but not for epidemic prevention; it can be used on both sides and is basically disposable. Cotton gauze mask: This mask can only filter large particles such as dust and pollen, and is suitable for daily cleaning work; if in a hospital, it must be used without surgery to reduce the number of water droplets coughing by the wearer. Reusability is its biggest advantage.

Activated carbon mask/activated carbon mask: This type of mask can absorb organic gas or toxic dust, but cannot prevent the penetration of bacteria. It is suitable for painting work, spraying pesticides and even preventing road dust. It is not suitable as a virus protection mask. Activated carbon mask Surgical mask/surgical mask: Originally designed to prevent water droplets on the nose and mouth of the wearer, the Centers for Disease Control and Prevention of the United States is skeptical about whether it can prevent the wearer from suffering from respiratory diseases. However, it is generally considered to be airtight. The better the effect, it can prevent 90% of the submicron droplets from spreading and is suitable for outpatients and flu patients. Generally speaking, the filter layer is electrostatically charged, and the use time is about 4 hours. N95 protective mask/N95Mask: This mask can block more than 95% of sub-micron particles, but the respiratory impedance is very high. For example, the inhalation resistance and expiration resistance have increased by 26% and 22%, respectively, so they are not suitable for long-term use. In addition, an American medical journal reported that there is no significant difference between it and surgical masks in preventing influenza.

N95 mask and breathing valve As for whether the mask has a breathing valve, there is actually not much difference. The most important function of virus prevention is the same. However, using the valve to breathe is more comfortable, but if you are infected with a virus, do not use it. N95 has a breathing valve because the valve will release the patient's virus.

Breathing valve principle In addition, various masks produced by different manufacturers, such as three-dimensional masks. The three-dimensional structure can reduce the pressure on the ears and greatly reduce the trouble of fogging of the glasses. Suitable for long-term wear; another example is the anti-smog mask, which can block particles less than or equal to 2.5 microns in the air. PM2.5 refers to suspended particles less than 2.5 microns in diameter. There are also nanofiber masks and so on. Not to mention the famous 3M mask.

Among many 3M masks, surgical masks and N95 masks are currently the most urgent. General surgical masks are standard masks for medical staff. The general public is usually advised to use these masks to avoid seasonal flu. Masks are usually made of non-woven fabrics (or non-woven fabrics) and are divided into three layers. Some manufacturers design four layers. , Such as Japan's Moistmake moisturizing mask, the three layers from the outside to the inside are: waterproof layer, can prevent the droplets from being contaminated. The filter layer is equipped with an electrostatic filter to filter bacterial drops. The moisture-absorbing layer absorbs the breath exhaled by the wearer.

Surgical mask structure N95 mask is the mask recommended by the US Centers for Disease Control and Prevention in most air pollution situations. It can prevent the spread of droplets caused by the patient's body fluid or blood splashing. What is N95? The National Institute of Occupational Safety and Health (NIOSH) has established three rating standards based on the ability of masks to resist non-oily particles with a diameter of 0.3 microns and above (such as dust, microorganisms, sodium chloride, etc.). They are N, R, P, where "N" means not suitable for oily particles, "R" has certain resistance to oily particles, and "P" has strong resistance to oily particles; the following numbers are the ability to filter particles Percentage, such as 95 can block 95% of particles, so N95 is the standard. N95 mask is a mask that can block 95% of non-oily particles (including PM2.5).

The non-oily particle size comparison is similar to that of N95 mask. There is also the European Union (EN149:2001) FFP (FilteringFacePieces). Its FFP1 filtering effect is at least 80%, while FFP2 can filter 94% of particles. Compared with N95, in non-oily particle filtration, FFP3 with a higher standard can filter 99%; in addition, Japanese DS2 refers to disposable masks, RS2 can be reused, while KF95 or higher Korean masks can filter more than 95% Of suspended particles.

Japan's RS2 mask and KN95 are standards formulated by China (GB2626-2006), and there are also KP standards for filtering oily particles. The Chinese KN standard is basically the same as the American NIOSH standard in terms of technical requirements and test methods, so there is no difference in their functions. Since KN95 is a standard, there will naturally be many manufacturers producing valves of different styles without valves.

However, the most popular KN95 mask sold in Guangzhou, if the mask does not specify the size of the particles to be tested, it may be the same as an ordinary mask, and the ability to filter particles is not strong. If you buy a foreign mask, you can determine whether it has an antivirus function by checking whether the following 3 capital letters are printed on the package. BFE (bacterial filtration efficiency) The filtration efficiency of bacteria is mainly tested with particles of about 3 microns and a specific flow rate. PFE (ParticleFiltrationEfficiency) particle filtration efficiency is tested with an average of 0.1 micron particles. VFE (VirusFiltrationEfficiency) virus filtration efficiency is tested with an average of 1.7 micron particles.

The smallest droplet size is 0.6 microns. 3. Use masks correctly. Regarding the correct use of masks, especially surgical masks, television and the Internet are almost overwhelming introductions. For example, do not touch the surface of the mask, do not use alcohol or high temperature disinfection, do not completely cover the mouth, nose, chin, etc., so I will not repeat them here; but there are two aspects that need special attention: 1. Wearing a mask! The most common way to wear a surgical mask in reverse is with the white side facing out. In fact, the blue side should be facing outward. However, if there are two sides with the same color, you can observe the direction of the metal strip or crease. The bumps or creases are usually on the outside.

Why should we pay attention to wearing the crease face down? If worn in the wrong direction, it will strengthen the absorbent layer, thereby reducing the ability of the filter and waterproof layer, which is likely to increase the risk of infection. 2. Fogging of the glasses means that you are wearing them incorrectly! Generally speaking, if you wear a mask correctly, the glasses will not fog. If mist appears, it is usually because the top of the mask does not fit the face and the airflow will flow to the gap when breathing. This will reduce the filter of the mask. influences.

A mask with a gap is not absolutely capable of isolating the virus. Virus prevention should pay more attention to hygiene, such as frequent hand washing and disinfection. 4. What if there is no mask. Although the masks on the market are not as tight as before, in order to prevent emergencies, I will edit the mask manufacturing methods suggested by experts such as the Hong Kong University Shenzhen Hospital, the Hong Kong Consumer Council and the Hong Kong Consumer Association. Science Park. concise. This kind of homemade mask can only be DIY with transparent plastic cover, kitchen absorbent paper or boxed three-layer paper. At the same time, it has been tested to meet the standards of safety, low cost, breathability and comfort, simple production and easy-to-find materials.