Disposable masks have an expiration date. The shelf life of a disposable mask is generally two years, it is recommended to use within the shelf life. One-time masks that exceed the expiration date are not recommended for use and should be disinfected as far as possible.

In daily life, the commonly used mask is a disposable mask. Disposable mask is made of three layers of non-woven fabric, filter paper, carbon cloth containing lead and so on. It is mainly divided into one-time two-layer mask, one-time non-woven fabric mask, one-time three-layer mask and one-time activated carbon mask, which can be used in hospitals, beauty, pharmaceutical, factories, schools, public places.

Disposable masks can prevent respiratory tract infection, bacteria, anti-virus and so on to some extent, especially in the period of the occurrence of new coronavirus. Disposable masks have become essential protective equipment for people.

It should be noted that the disposable mask has shelf-life. And its shelf life is generally two years. Before the outbreak people rarely wear masks, so when buying disposable masks must pay attention to the production date.

At the same time, also pay attention to disposable mask packaging on whether there is "medical surgical mask" the words of the label. Disposable masks not only have an expiration date, but also have an expiration date for use.

Under normal circumstances if the use of outdoor, such as the subway, bus, supermarkets, shopping malls and other public places, disposable masks need 4-6 hours to change. But if it is in the new type of pneumonia virus epidemic area, the suggestion is to change it every two hours.