A mask is a physical barrier between the wearer's mouth and nose and creates potential contaminants in the immediate environment, which can help block large particles of droplets, splashes, sprays or splashes that may contain bacteria (viruses and bacteria), preventing When it enters the nose and mouth, the mask can also help reduce the exposure of saliva and respiratory secretions to others. As a protective mask for humans, the mask requires FDA certification when it is exported to the United States
Disposable masks, both civil and medical, must be FDA-compliant. The civilian and medical parameters are as follows,
Respiratory protective masks-American standard NOISH:
N90: PFE> = 90%
N95: PFE> = 95%
Surgical Mask-American Standard ASTM F2100:
LEVEL1: BFE> = 95%, PFE> = 95%
LEVEL2: BFE> = 98%, PFE> = 98%
LEVEL3: Same as LEVEL2, other indicators are better
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