Dispersion of exhalation pollutants in a two-bed hospital ward with downward ventilation system

A downward ventilation system has been proposed as a standard ventilation design by Centers for Diseases Control and Prevention (CDC) in Hong Kong for isolation rooms. This paper deals with the effect of a downward ventilation system in a general ward to test whether it could reduce the risk of cross infection. The dispersion of exhalation pollutants and exposure of receiving patients in a general ward was studied. A full scale experimental room was used to simulate two-bed hospital ward, appropriate to test contaminant transmission between two patients.Two life-sized breathing thermal manikins (both were equipped with breathing mechanisms) were used to simulate a source patient and a receiving patient.But the results showed that the expected unidirectional airflow appeared impossible to be obtained.