Cao Jingui, director of the infection control department of the Air Force General Hospital, suggests that if you have to go out in these two days, you should clean up the haze attached to our body in time to prevent the harm of PM2.5 to the human body after entering indoors. The way to clean up is very simple, do three things: wash your face, rinse your mouth, and clean your nasal cavity. The best way to wash the face is to use warm water, which can effectively clean the haze particles attached to the skin; the purpose of gargling is to remove the dirt attached to the mouth; the most critical is to clean the nasal cavity. Director Cao taught everyone a simple and easy to learn method of cleaning the nasal cavity: wash your hands, hold warm water, gently absorb water with your nose and quickly blow your nose, repeat several times, the nasal cavity is clean of all the dirty things. It is worth noting that when cleaning the nasal cavity, be sure to gently suck water to avoid choking and coughing. Parents can use clean cotton swabs dipped in water to clean the nasal cavity of their children repeatedly.