A mask with a breathing valve carries certain risks. A mask without a breathing valve has a certain degree of closure and may cause the wearer difficulty in breathing, while a mask with a breathing valve allows the wearer to breathe more easily and smoothly, and is more suitable for people who work in a poorly ventilated environment or have chronic respiratory diseases, heart disease and other breathing difficulties. However, this type of mask is less airtight, and the current epidemic of New Coronavirus is more severe, so wearing a respiratory valve mask may risk infection with New Coronavirus. For suspected and confirmed patients, wearing a respiratory valve mask will expel gas when exhaling, and there is no filter layer during the exhaust process, which may allow the virus to be expelled, so it is not advisable to wear such masks.