Disposable masks are recommended to be worn for 4-6 hours, preferably not more than 8 hours. Disposable masks can not be reused, can not be cleaned, even if cleaned, can not be used again, because the arrangement of the fibers contained in the disposable mask is a certain direction, after cleaning, it is easy to change its fiber direction, the protection ability is weakened. If worn for a long time, the surface of the mask bacteria and other pathogens attached more, too many pathogens may enter the mouth through the mask, causing disease. However, if you go to a place with less crowd and less pollution, and the mask is not deformed, broken, etc., and you do not carry extra masks, you can extend the wearing time appropriately, but not more than 72 hours. In addition, the mask should also be worn correctly to prevent the polluted side from facing you. At the same time, it is not recommended to wear or reuse for a long time, pay attention to the date when buying, prevent the purchase of three or no masks, and do not discard them at will after use.