1. The standard of the mask:
（1）. N95 mask: it is produced and certified according to the American standard NOISH, the manufacturer is 3M and Honeywell; the filtration efficiency of non-oily particulate matter is ≥95 %%
（2）. KN95 mask: It is a compulsory standard of Chinese standard GB2626-2006, the filtration efficiency of non-oily particulate matter is ≥95 %% u3002
（3）. FFP2 is the European standard EN149;
All the three types of masks printed on the masks are qualified masks.
The test methods for the filtration efficiency of the above three grade masks are exactly the same! Therefore, the filtration efficiency levels are consistent.
Medical protective mask: filtration efficiency ≥95 %% uFF08 using non-oily particulate matter test). It is required to pass the synthetic blood penetration test (to prevent splashing of body fluids) and to meet the microbiological indicators.
Medical n95 masks need to be protected against high-pressure liquid splashes, so they have a higher standard than ordinary n95; taking 3M as an example, models 1860 and 9132 are the most commonly used medical protective masks.
In addition, there are 1860s for children. Ordinary people or medical personnel who are not exposed to high-pressure liquid splashes can choose ordinary n95 masks that meet the NOISH standard
At present, there are three types of hospital masks, namely medical masks, medical surgical masks and medical protective masks (the most common N95 masks)
（1）. Medical masks are the easiest masks to buy. They are useful for blocking the respiratory transmission of the new coronavirus, but they are not as effective as medical surgical masks and N95 masks.
This kind of mask is called "disposable medical mask". The implementation standard is YY / T0969-2013. It is relatively breathable and easy to buy. It can be bought by general pharmacies and can filter most bacteria. It is effective for this new coronavirus. The disadvantage is that it has no anti-permeation effect, and the effect is not as good as medical surgical masks and N95 masks. It is suitable for daily outgoing use in non-epidemic areas, but it is not suitable for close contact with new coronaviruses, and it is not suitable for use in hospitals and other crowded places.
（2）. Medical surgical masks. It is effective for blocking new coronaviruses and is highly recommended.
Medical surgical masks are the most commonly used masks for medical staff. General surgical masks can be selected for contact with common infected patients, such as colds, pneumonia, treatment of wounds with common bacterial infections, and surgical operations. Compared with ordinary masks, this kind of mask has better sealing performance. The biggest difference with ordinary masks is that it is impermeable. The particle filtration must be ≥30 %% uFF0C, which is very effective for blocking new coronaviruses. It is suitable for crowded places in epidemic areas, hospitals and other places, and used for medical treatment. It is the most practical mask. In the hospital, except for high-risk positions, staff in other positions can wear this mask for protection.
（3）. Protective mask: such as N95 mask, the protective effect is the strongest, but it is generally unnecessary and expensive.
Protective mask implementation standard GB19038-2010
, N95 masks are commonly used in hospitals. N95 mask is one of 9 anti-particulate masks certified by NlOSH (National Institute of Occupational Safety and Health). "95" means that under the testing conditions specified in the NI0SH standard, the non-oily 0.3um particles have a filtering effect of 95 %%. The maximum holding point of the u3002N95 mask is to prevent the transmission of droplets caused by patients' body fluids or blood splashes. The size is 1 to 5 microns in diameter. Try not to choose a breathing valve when choosing N95.
N95 masks must be worn when contacting patients with special infections, such as H1N1 flu, SARS and other highly infectious patients, or new coronavirus pneumonia. For the general population, it is generally not necessary.