Protective masks, because of the epidemic situation, everyone is wearing masks when they go out. Especially those workers who are struggling in the front line should protect themselves. So why wear medical protective masks? Due to the impact of the epidemic situation, everyone is now wearing masks when they go out, especially those workers struggling in the front line. It is necessary to protect themselves. The premise of health is to have medical protective masks Medical protective mask is suitable for medical staff and related staff to protect respiratory tract infectious diseases transmitted by air. It is a kind of close fitting self-priming filtering medical protective equipment with high protection level. It is especially suitable for patients with respiratory tract infection transmitted by air or near distance through droplets in diagnosis and treatment activities. It can filter the particles in the air and block the droplets, blood, body fluid, secretion droplets, etc. it belongs to disposable products. Medical protective masks can prevent most bacteria, viruses and other pathogens. Who recommends that medical personnel should use protective masks against particles to prevent virus infection in the air of hospitals. [2] Medical protective masks meet the standard of GB 19083-2003 "technical requirements for medical protective masks". The important technical indicators include filtration efficiency of non oily particles and airflow resistance. The specific indicators are as follows: [3] 1) filtration efficiency: under the condition of air flow rate of (85 ± 2) l / min, the filtration efficiency of sodium chloride aerosol with aerodynamic median diameter of (0.24 ± 0.06) μ m is not less than 95%, that is, it meets N95 (or FFP2) and above. It can block the air borne infectious factors with diameter less than 5 μ m or contact with the infectious factors transmitted by droplets in close contact. 2) Inspiratory resistance: under the above flow conditions, the inspiratory resistance does not exceed 343.2pa (35mmh2o). 3) When the sample is sprayed to the mask under the pressure of 10.9kpa (80mmHg), the inner side of the mask should not show any technical indicators such as penetration. 4) The mask must be equipped with a nose clip, which is made of bendable plastic material with a length of more than 8.5cm. 5) The synthetic blood was sprayed to the mask sample at the pressure of 10.7kpa (80mmHg), and the inner side of the mask should not be penetrated. 2. The medical surgical mask is suitable for the basic protection of medical personnel or related personnel, as well as the protection to prevent the spread of blood, body fluid and spatter in the process of invasive operation, with medium protection level and certain respiratory protection performance. It is mainly used in clean environment with cleanliness level less than 100000, operating room work, nursing patients with low immune function and body cavity puncture. Medical surgical masks can block most of the bacteria and some viruses, prevent the medical staff from being infected, and can also prevent the medical staff from directly discharging the microorganisms in their breath, which poses a threat to the patients undergoing surgery. Medical surgical masks are required to filter bacteria more than 95%. Disposable medical surgical masks should also be provided to suspected respiratory tract patients to prevent infection threat to other hospital personnel and reduce the risk of cross infection, but the effect of avoiding infection is not as effective as medical protective masks. [4] According to yy0469-2004 "technical requirements for medical surgical masks", the important technical indicators include filtration efficiency, bacterial filtration efficiency and respiratory resistance. The specific indexes are as follows: 1) filtration efficiency: under the condition of air flow rate of (30 ± 2) l / min, the filtration efficiency of sodium chloride aerosol with aerodynamic median diameter of (0.24 ± 0.06) μ m is not less than 30%. 2) The filtration efficiency of bacteria should not be lower than 3% for Staphylococcus aureus and 0.95% for Staphylococcus aureus. 3) Respiratory resistance: under the condition of filtration efficiency flow, the inspiratory resistance is not more than 49 PA, and the expiratory resistance is not more than 29.4 PA.