"N95" is a standard set by the Occupational Safety and Health Institute (NIOSH) of the United States CDC, and is not a specific product name. As long as the product meets the N95 standard and passes the NIOSH review, it can be called a "N95 mask".

The biggest feature of the N95 mask is that it can prevent droplet infection caused by a patient's body fluid or blood splash. The size of the droplets is 1 to 5 microns in diameter. The U.S. Occupational Safety and Health Administration (OSHA) requires medical institutions that medical workers exposed to tuberculosis bacteria must wear masks higher than N95.

safety standard
The N95 mask is one of nine standards established by NIOSH in 1995. "N" means "not resistant to oil". "95" indicates that the particle concentration in the mask is 95% lower than that of the particles outside the mask when exposed to the specified number of special test particles. The value of 95% is not the average value, but the minimum value, so the average value of actual products is mostly set above 99%.

NIOSH certified other anti-particulate mask levels also include: N99, N100, R95, R99, R100, P95, P99, P100, these protection levels can cover the protection range of N95, where "R" means suitable for oil or non-oil Particulate matter, if used for the protection of oily particulate matter, the use time does not exceed 8 hours; "P" means suitable for oily or non-oily particulate matter, if used for oily particulate matter, the use time should follow the manufacturer's recommendations. And "99" and "100" refer to the filtration efficiency levels, respectively.

Divided into "N", "R" and "P" according to oil resistance, and divided into "95", "99" and "100" according to the capture rate. "R" means "resistant to oil", "P" means "oil proof", "99" in the capture rate means more than 99%, and "100" means more than 99.7%.

In addition, when the N100, P100, and R100 three-type masks are tested with 0.3 micron particles, the barrier efficiency must be above 99.7%. The N99, P99, and R99 are all filtration rates above 99%, while the N95, P95, and R95 are all filtration rates Above 95%.

Therefore, N95 masks are tested with 0.3 micron sodium chloride particles, and the blocking rate must be more than 95%. When the wearer's face is tightly tested, ensure that the air can pass in and out through the mask when it is close to the edge of the face. Only those who meet this test will be issued the N95 certification number. In general, protective masks that have passed the domestic existing standards certification have not yet reached the N95 level standard.

Medical protection
During the SARS outbreak in 2003, the World Health Organization (WHO) and the United States Centers for Disease Control and Prevention (CDC) issued relevant precautionary measures for the care of SARS patients, suggesting that the time of exposure to air should be reduced to reduce the probability of droplets in the air. Among them, it is particularly recommended to use protective masks that meet the National Institute of Occupational Safety and Health (NIOSH) N95 certification.

In the prevention and treatment of HIN1 influenza A, N95 masks have also become a must-have for medical staff and a protective article recommended to the public.

On May 19, 2009, Chinese disease control expert Zhong Nanshan said in an interview with the media that ordinary masks have little effect on the prevention of influenza A. Zhong Nanshan said: "If you have a cold and have a mask, you can use it to prevent spreading when you sneeze with a mask. It may be useful. Generally speaking, ordinary masks are useless. If you want to prevent them, wear N92 masks."

The N95 mask is a mask with a breathing valve. The function of the breathing valve is to work in a hot and humid environment with poor ventilation or heavy workload. Using a mask with a breathing valve can help you feel more comfortable when exhaling. Use time: It depends on the personal use situation and environment, but when it is found that breathing is difficult or uncomfortable, the mask is contaminated with foreign matter such as blood stains or droplets, the user feels that breathing resistance has increased, and the mask is damaged, etc., it should be replaced immediately.

Yu Hangying, director of the Department of Infection Management of the Zhejiang Provincial Hospital of Traditional Chinese Medicine, suggested that ordinary citizens do not blindly wear professional protective masks. "Like wearing such professional protective masks, you must be trained. If you do not understand this knowledge, it is best not to Wear it casually. "

Chief Yu reminded: "Patients with cardiovascular disease, do not wear 3M masks, especially N95 models, because this mask is professional anti-virus, thick texture, patients can easily cause breathing difficulties after wearing, due to hypoxia And feel dizzy. "Only patients with a clear diagnosis need to wear professional masks. If ordinary people wear masks, it is better to choose a better breathability.

Mask selection
1.Choose the right type of mask

(1) Medical protective masks should be the first choice for medical workers, and ordinary degreasing gauze masks should be the first choice for ordinary citizens to use in daily life. In special occasions, such as visiting doctors and visiting patients, it is better for ordinary citizens to choose medical masks.

(2) The materials used for masks should be free of odors and harmless to the human body, especially the materials in contact with the human face should be non-irritating and allergic.

2.Select qualified masks

When choosing a mask, it depends on whether there is a trade name on the packaging, whether there is information about the manufacturer or supplier, whether there is a mask certificate or instructions for use. Disposable masks must have a one-time indication, and reusable medical protective masks must be marked with a method of sterilization. In general, ordinary gauze masks must be marked as normal or disinfected.

3. Choose a regular manufacturer

For the prevention of influenza, we usually choose ordinary non-fat gauze masks or medical protective masks, which need to be purchased from various outlets of legally operated medical stores or from manufacturers with health licenses or medical device registration certificates.

4. Don't forget to check the appearance when choosing a mask

This is a problem that we tend to ignore when choosing a mask. First of all, we must check whether the packaging of the mask is complete and whether it is damaged. There must be no holes or stains on the surface of the mask. Medical protective masks should not have exhalation valves. For tight arch masks, the lateral diameter is not less than 14cm, and the longitudinal diameter is not less than 14cm. The length of the medical protective rectangular mask is not less than 17cm, and the width is not less than 17cm. The number should not be less than 12 layers. In addition, we must remind everyone that if you choose a medical mask, remember to have a nose clip. The nose clip is made of bendable plastic material and the length is not less than 8.5cm.

Performance limitations
Respiratory tract infections do not spread through the respiratory tract;

Preventive measures should precede exposure;

The tight structure and efficient filtering of the mask will increase breathing resistance and reduce comfort;

Suitability-if the mask design is not suitable for the user's face shape, it will cause leakage;

Meeting the requirements of suitability and correct use, protective masks can reduce the concentration of harmful substances by 10 times.

The government has not established safe exposure limits for pathogenic microorganisms, and respiratory protection only reduces the risk of disease, but does not eliminate the risk.

Widely used
Respiratory protection for certain particulate matter, such as dust generated during grinding, cleaning and processing of minerals, flour and certain other materials. It is also suitable for liquid or non-oily non-toxic volatile gases produced by spraying. particulates. Can effectively filter and purify the inhaled abnormal odor (except for toxic gases). This product can help reduce the level of exposure to certain inhalable microbial particulates (such as mold, anthrax, tuberculosis, etc.), but it does not eliminate the risk of exposure to infection, illness, or death.

Expert advice
The hot-selling N95 masks on the Internet can reach 95% after testing and filtering, and the effect of protecting PM2.5 should be the best. However, for N95 masks, doctors do not recommend ordinary people to wear them: "In theory, the more tightly the mask's protective material is, the better the effect of blocking particulate matter. On the other hand, the more tightly the mask is, the more difficult it is to breathe, and the better it is Dizziness may be caused by hypoxia. Wearing professional protective masks such as N95 can easily cause breathing difficulties, especially for patients with cardiovascular disease and more. "

It is understood that, compared to N95 masks, KN90 masks are more suitable for ordinary people. Of course, whether it feels comfortable to wear varies from person to person. "If it's only used to block inhalable particles from entering the body, disposable medical masks are also fine."

Post time: Mar-16-2020
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