Medical surgical mask
Medical-surgical masks are suitable for the basic protection of medical personnel or related personnel, as well as protection against the spread of blood, body fluids and spatter during invasive operation. The degree of protection is medium and has certain respiratory protection. Mainly in the clean environment within 100,000 cleanliness, operating room, nursing patients with low immune function and wearing body cavity puncture and other operations. Medical-surgical masks can block most bacteria and some viruses, prevent medical personnel from being infected and prevent direct discharge of microorganisms carried by medical personnel to exhale, posing a threat to patients undergoing surgery. Medical-surgical masks require a filtration efficiency of more than 95% for bacteria. For suspected respiratory patients, disposable medical surgical masks should also be dispensed to prevent infectious threats to other hospital personnel and reduce the risk of cross-infection, but the infection is not as effective as medical protective masks. 
In line with YY0469-2004 "Technical Requirements for Medical-Surgical Masks", important technical indicators include filtration efficiency, bacterial filtration efficiency, and respiratory resistance. The specific indicators are as follows:
1) Filtration efficiency: The filtration efficiency of aerodynamic median diameter (0.24±0.06) μm sodium chloride aerosol is not less than 30% under air flow rate (30±2) L/min.
2) Bacterial filtration efficiency: under the specified conditions, the filtration efficiency of Staphylococcus aureus aerosol with an average particle diameter of (3 ± 0.3) μm is not less than 95%; the bacterial filtration rate should be ≥ 95%; non-oily particles The filtration rate should be ≥30%.
3) Respiratory resistance: Under the condition of filtration efficiency flow, the inspiratory resistance does not exceed 49Pa, and the expiratory resistance does not exceed 29.4Pa. When the pressure difference ΔP of gas exchange on both sides of the mask is 49 Pa/cm, the gas flow rate should be ≥264 mm/s.
4) Nasal clips and masks: The mask should be equipped with a nose clip. The nose clip is made of plastic material. The length of the nose clip should be greater than 8.0cm. The mask tape should be easy to wear, and the breaking strength at the joint of each mask tape and the mask body should be greater than 10N.
5) Synthetic blood penetration: After 2 ml of synthetic blood is sprayed to the outer side of the mask at a pressure of 16.0 kPa (120 mmHg), no penetration should occur on the inner side of the mask.
6) Flame retardant performance: The mask material should be non-flammable material, and the flame will burn less than 5s after leaving the flame.
7) Ethylene oxide residue: Ethylene oxide sterilized masks should have an ethylene oxide residue of less than 10 μg/g.
8) Skin irritation: The primary irritation index of the mask material should be ≤ 0.4, and there should be no sensitization reaction.
9) Microbial indicators: The total number of bacterial colonies is ≤20 CFU/g. No coliforms, Pseudomonas aeruginosa, Staphylococcus aureus, hemolytic streptococcus and fungi should be detected.