Medical masks, dust hazards, long-term inhalation of higher concentrations of dust can cause lung diffuse, progressive fibrosis based systemic disease (pneumoconiosis); for example, inhalation of toxic dust such as lead, copper, zinc and manganese can dissolve on the bronchial wall and be absorbed, and be carried to all parts of the body by blood, causing systemic poisoning. Lead poisoning is chronic, but if the poisoned person has a fever, or takes some drugs and drinks excessive alcohol, it will also cause acute attack of poisoning; excessive inhalation of copper dust may lead to hemolytic anemia; zinc oxide fume will be produced when zinc is burned, and a kind of "metal smoke fever" disease like malaria will be produced after inhalation; Long term inhalation of manganese and its oxide dust or smoke has adverse effects on central nervous system, respiratory system and digestive system. 1. Medical protective mask 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 infections 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 aerodynamic median diameter is (0.24 ± 0.06)