Application of an Air Purification System to Control Air-borne Bacterial Contamination in a University Clinic

摘要

Indoor air purification has become a popular issue since the outbreak of severe acute respiratory syndromes (SARS) in 2003. Bacterial and viral contamination in indoor air has become a serious concern in healthcare facilities. In addition, there was a market boom in air purification products during the outbreak. This paper reviews the major techniques available for bacteria removal, including ultraviolet (UV) germicidal irradiation, photo-catalytic oxidation, filtration using HEPA filters and ozone disinfection; and describes the testing results of an air purification system in a university clinic. The system is installed with UV lamps and titanium dioxide honeycomb section for photo-catalytic oxidation. Total bacteria count was measured to test the effectiveness of the system. Without the use of purifier, the bacteria count could reach 500-600 cfu/m{sup}3 when there were 18 persons or more in the clinic waiting area. The air purifier can reduce the bacteria count to 400-450 cfu/m{sup}3 under similar occupancy condition. In addition, two bacteria decay profiles were measured after clinic service hour. The one with the use of air purifier could achieve a decay rate of 4.72 hour, comparing with the natural decay rate of 0.95 hour.