Once dust is on a surface will tend to cling to that surface unless it is wiped off or blown off by a significant airflow. A low speed airflow like a fan intak

Once dust is on a surface will tend to cling to that surface unless it is wiped off or blown off by a significant airflow. A low speed airflow like a fan intake will probably not pickup much of that dust. Most of the dust will come in from the air in the room.