19 10, a plague that shocked the world spread from Lake Baikal to the northeast of China. Lian Dewu was appointed as "the chief medical officer with full authority for epidemic prevention in the three northeastern provinces". In order to prevent the epidemic, he designed a mask made of double gauze to stop the spread of bacteria, thus quickly stopping the spread of the plague.

This mask, which was widely used at that time, was named "Wu Mask". With a mask and a series of other measures, it took him only 67 days to control the plague, and even Dewu became famous all over the world.

Matters needing attention

Duration of use

From the physiological structure of human body, because the blood circulation of nasal mucosa is very strong, the passage in nasal cavity is very tortuous, and nasal hair constitutes a "barrier" for filtration.

When air is inhaled into the nostrils, the airflow forms a vortex in the tortuous channel, which warms the airflow inhaled into the nasal cavity. Experiments show that when cold air at minus 7℃ is inhaled into the lungs through the nasal cavity, its airflow has been heated to 28.8℃, which is very close to the temperature of the human body. If you wear a mask for a long time, it will make the nasal mucosa fragile and lose the original physiological function of the nasal cavity, so you can't wear a mask for a long time.

Masks can only be worn in special circumstances, such as crowded places with poor ventilation. Of course, you need to wear a mask when walking in the wild, in order to resist wind and cold, or to move in an environment with air pollution, but the time should not be too long. In addition, in the flu season, you should wear a mask when you go to public places where there may be a lot of pathogenic bacteria. Wearing a mask is only one of the ways to prevent respiratory infectious diseases, and the most important thing is to maintain good living habits.