Masks can be divided into air filter masks and air supply masks.
Plane masks are divided into: cotton masks, non-woven masks, polymer masks, active carbon powder filter masks, active carbon fiber felt pad masks.
Masks are divided into medical masks and non-medical masks.
N series: no time limit for protection of non oil suspended particles
R Series: eight hours for protection of non oil and sweat oil suspended particles
P Series: no time limit for the protection of non oil suspension particles and sweat oil suspension particles
Some of the carriers of the particles are oily, and these substances attached to the electrostatic non-woven fabric will reduce the electrical property and make the fine dust penetrate. Therefore, the filter material to prevent the oil-bearing aerosol should be subject to special electrostatic treatment to achieve the purpose of preventing the fine dust. Therefore, each series is divided into three levels: 95%, 99%, 99.97% (referred to as 95, 99, 100), so there are nine categories of filter materials.
Medical protective mask (N95)
"Medical protective mask" has a good fit with the wearer's face. It can filter the particles in the air, and block the pollutants such as droplets, blood, body fluids and secretions. The filtration efficiency of non oil particles can reach more than 95% (which means that it can reach N95 grade). It is a common personal protective equipment for dealing with air borne diseases. The common medical protective masks are arched, butterfly and so on.
Disposable medical mask
Generally, it is suitable for general health care, with the lowest level of protection, which is limited to the mechanical barrier of dust particles or aerosols.
(1) The appearance of the mask shall be clean and in good shape, and there shall be no damage or stain on the surface;
(2) The size of the expanded mask shall not be less than 17cm (length) × 17cm (width);
(3) The filtration efficiency of non oil particles of respirator shall not be less than 10%;
(4) The number of bacteria in the mask should be no more than 100 CFU / g;
(5) Air flow resistance: the suction resistance of the mask shall not exceed 343.2pa.
Received a lot of consultation from friends, at present, N95, N90 and medical surgical masks are basically out of stock. There are also disposable medical masks and medical nursing masks. According to the query of a series of information, the protection level of medical nursing masks is slightly lower, but in the current situation, only these two protection levels are used. Pay special attention to the correctness of wearing.