Comply with YY/T0969-2013 "Technical Requirements for Medical Surgical Masks" in China, important technical indicators include filtration efficiency, bacterial filtration efficiency and respiratory resistance: (1) Filtration efficiency: Under the condition of air flow (30 ± 2) L / min, the filtration efficiency of aerodynamic median diameter (0.24 ± 0.06)m sodium chloride aerosol is not less than 30%; (2) Bacterial filtration efficiency: Under the specified conditions, the filtration efficiency of Staphylococcus aureus aerosol with an average particle diameter of (3 ± 0.3) m is not less than 95%; (3) Breathing resistance: Under the condition of filtration efficiency flow, the inhalation resistance does not exceed 49Pa, and the exhalation resistance does not exceed 29.4Pa.