Duration of use
　　From the human physiological structure, due to the human nasal mucosa blood circulation is very strong, nasal passages and very tortuous, nasal hair from a filter of the "barrier". When the air inhaled nostrils, the air flow in the twists and turns in the channel to form a vortex, so that the nasal inhalation of the air flow is heated. Some tests show that the cold air at minus 7 ℃ through the nasal cavity into the lungs, the air has been heated to 28.8 ℃, which is very close to the body's temperature. If long-term wear masks, nasal mucosa will become fragile, lost the original physiological function of the nasal cavity, it can not be long-term wear masks. Masks can only be worn in special circumstances, such as in many people, the air does not flow. Of course, walking in the wild, in order to resist sand and cold, or in the air pollution of the environment, it is necessary to wear masks, but the time should not be too long. In addition, in the influenza epidemic season, to the existence of a large number of pathogens in public places, but also wear masks. Wear masks is only one way to prevent respiratory infectious diseases, the most important thing is to maintain good habits.
Cleaning and maintenance
　　The outer layer of the mask often accumulate a lot of dust in the outside air, bacteria and other dirt, while the inner layer to block the exhaled bacteria, saliva, so the two sides can not be used alternately, otherwise will contaminate the dirt directly in the outer Facial inhalation of the human body, and become a source of infection. Do not wear masks, should be folded into a clean envelope, and close to the side of the nose and mouth folded, should not be casually stuffed into the pocket or hanging in the neck.
　　If the mask is exhaled by hot air or saliva wet, the role of its barrier bacteria will be greatly reduced. Therefore, usually best to prepare a few more masks, in order to replace the use, should be replaced once a day. Wash with hot water for 5 minutes.
　　Masks should adhere to a daily cleaning and disinfection, whether gauze masks or air filter masks can be used to disinfect the heating method. The specific approach is:
　　1.Cleaning. First with warm water and soap gently rubbed gauze masks, bowl-shaped mask can be soft brush dipped in detergent gently brush the net, and then washed with water. Please note, do not rub hard, because if the gauze is too large gap between the latitude and longitude to prevent the role of loss of droplets.
　　2.Disinfection. Wash the mask in a 2% peracetic acid solution for 30 minutes or in boiling water for 20 minutes or on the steamer for 15 minutes, and then dry standby. This method is suitable for gauze masks and bowl masks.
　　3.Examination. Before use again, you should carefully check the masks and masks are still intact, for the gauze masks and masks can take light inspection method, that is, to take care of the lamp to see if there is no obvious spot, the middle part and the edge of light Rate is not the same, if there is doubt to replace the new. In any case, the face mask and mask 3 to 7 times after cleaning in general should be updated, especially good quality masks can be cleaned 10 times. Activated carbon adsorption mask should pay attention to regular replacement of activated carbon sandwich, if the activated carbon sandwich is not replaceable, used 7 to 14 days to be replaced, this mask can not be cleaned and then re-use.