Although novel coronavirus can be transmitted by respiratory droplets, the distance of respiratory droplet transmission is very short and does not float in the air for a long period of time. The outdoor space is very large and respiratory droplets or aerosols are not able to reach the effective concentration of infection, so even if the windows are opened and ventilated, it does not cause infection and there is generally no new coronavirus in the air. Therefore, it is recommended to keep windows open at least 2 times a day in the home to effectively reduce the risk of novel coronavirus pneumonia infection and to promote the physical and mental health of the family. While opening the windows, you should pay attention to keep warm to avoid catching a cold.