Toilets dominate environmental detection of SARS-CoV-2 virus in a hospital

Zhen Ding; Hua Qian; Bin Xu; Ying Huang; Te Miao; Hui-Ling Yen; Shenglan Xiao; Lunbiao Cui; Xiaosong Wu; Wei Shao; Yan Song; Li Sha; Lian Zhou; Yan Xu; Baoli Zhu; Yuguo Li

The 5 th floor has a fan coil air-conditioning system with an outdoor-air supply. Two fans deliver 1000 m 3 /h and 8500 m 3 /h (2300 L/s) outdoor air to the non-patient and patient rooms, respectively. No ventilation is provided to the corridor, and a positive pressure is maintained at the nursing station, with no exhaust. According to the original design, each of the 19 isolation rooms is provided with an average of 47 L/s of outdoor air (2.0 ACH). The exhaustair fan in the bathroom of each isolation room operates continuously, creating a negative pressure in the ward. Based on the CO2 data, the outdoor air-supply rate was calculated to be 64 L/s (2.5 ACH). The airflow pattern was found to lead from the corridor to each isolation room, and to subsequently exhaust via the bathroom.