The impact of airflow and air purification on the resuspension and removal of deposited particulate matter

Air purifiers are a popular tool to manage indoor particulate matter; however, their effectiveness with respect to resuspending and removing particles that have been deposited on surfaces is limited. This study proposed and evaluated a method of removing both suspended and deposited particulate matter using an air purifier in conjunction with an airflow source. First, the effectiveness of the air purifier with respect to removing deposited particulate matter was determined in a static environment and under forced airflow. Then, the removal efficiency of the purification system was evaluated under varying airflow orientations and velocities. Results showed that the air purifier contributed to particulate matter resuspension and removal, and the efficiency was significantly improved under forced resuspension due to airflow generation. The orientation of the airflow was found to have an impact on the resuspension and removal efficiency of particulates, and four-way airflow was more effective compared to one-way airflow. This was attributed to four-way flow increasing the airflow diffusion radius compared to one-way flow. A flow velocity of 5 m/s or greater was necessary to resuspend deposited particulate matter. These findings illustrate that forced resuspension is an effective means of reducing deposited particulate matter in indoor environments, and four-way airflow with a wide diffusion radius and a velocity of 5 m/s or higher are the optimum conditions for this purpose.