The survival time of M. tuberculosis in the air is affected by the environment, such as light and disinfectants, and can survive for hours to months. Mycobacterium tuberculosis has a high lipid content and is more resistant to certain physical and chemical factors (e.g., acidic and alkaline environments), and can survive in dry sputum for 6 to 8 months, and can remain infectious for 8 to 10 days if it adheres to dust. However, Mycobacterium tuberculosis is less resistant to moist heat, ultraviolet light, and ethanol; for example, Mycobacterium tuberculosis can die in 2~3 hours in direct sunlight. In order to reduce the risk of Mycobacterium tuberculosis infection, you should wear a mask in an environment where bacteria are excreted, open windows for daily ventilation, and try to ensure a sunny environment. In addition, if you have symptoms of coughing and sputum, go to your local hospital as soon as possible.