Use of a portable HEPA air cleaner in a hospital ward for reducing disease infection

Abstract

Use of a portable HEPA filter cleaner in a room is believed to be capable of reducing the risk of transmission of infectious diseases through removing the particles or large droplets to which pathogens are attached. It is hoped that the portable HEPA filter(s) can increase the effective air change rate (for particle removal only) in a general ward to the ventilation standard of an isolation ward for emerging infection diseases when there are insufficient number of isolation wards. An experiment was conducted in a full scale experimental ward with a dimension of 6m x 6.7m x 2.7m and 6 beds to test the performance of a portable HEPA filter cleaner. The removal efficiency for different size particles was measured at different locations. The influence of the portable HEPA air cleaner on the airflow pattern was also studied through smoke visualization and CFD simulations. The results show that the HEPA filter can decrease effectively the particle concentration level, and the effective air change rate achieved by HEPA filter (for particle removal only) is ranged 2.7-5.6 ACH in the ward. The strong supply air jet from the portable HEPA filter cleaner interacted with the room airflow pattern and became dominated, introducing a global airflow mixing in the room.