As long as the air conditioner is on, it smells good. How?

First, the running time of the system is not long, and the fins of the heat exchanger are blocked. Secondly, some inefficient filtration systems at the end of air supply, such as computer rooms and hotel rooms, are well decorated, and fresh air and air conditioning supply are filtered, but dust can still be found near some indoor air supply outlets and on the surface of window sills, and a layer of dust is also attached to the surface of internal components. ...