Air purifiers do not necessarily filter viruses. The air purifier commonly used today is composed of a fan and a filtration device. The fan draws in the air from the home, the filtration device filters out various pollutants, and then the filtered air is discharged. Air purifiers are mainly suitable for removing one or more pollutants from the air, but there is no requirement for viruses or other pathogenic microorganisms to be killed in the product standards. It is recommended to ventilate daily, either through natural ventilation or mechanical ventilation, and it should be noted that in the current low temperature, attention should be paid to keeping warm or paying attention to ventilation time to prevent colds caused by the large temperature difference between indoor and outdoor.