Full-scale experimental and numerical study of bioaerosol characteristics against cross-infection in a two-bed hospital ward

Liu, Zhijian; Wang, Liangqi; Rong, Rui; Fu, Shifeng; Cao, Guoqing; Hao, Cuicai

The transmission and deposition of pathogenic bioaerosols and the subsequent contamination of the air and surfaces is well recognized as a potential route of hospital cross-infection. A full-scale experiment using Bacillus subtilis and computational fluid dynamics were utilized to model the bioaerosol characteristics in a two-bed hospital ward with a constant air change rate (12 ACH). The results indicated that the bioaerosol removal efficiency of unilateral downward ventilation was 50% higher than that of bilateral downward ventilation. Additionally, health care workers (HCWs) and nearby patients had lower breathing zone concentrations in the ward with unilateral downward ventilation. Furthermore, a partition played a positive role in protecting patients by reducing the amount of bioaerosol exposure. However, no obvious protective effect was observed with respect to the HCWs. Only 10% of the bioaerosol was deposited on the surfaces in the ward with unilateral downward ventilation, while up to 35% of the bioaerosol was deposited on the surfaces in the ward with bilateral downward ventilation during the 900 s. The main deposition locations of the bioaerosols were near the wall on the same side of the room as the patient's head in all cases. This study could provide scientific evidence for controlling cross-infection in hospital wards, as well as several guidelines for the disinfection of hospital wards.