Aerodynamic Characteristics and RNA Concentration of SARS-CoV-2 Aerosol in Wuhan Hospitals during COVID-19 Outbreak

Yuan Liu; Zhi Ning; Yu Chen; Ming Guo; Yingle Liu; Nirmal Kumar Gali; Li Sun; Yusen Duan; Jing Cai; Dane Westerdahl; Xinjin Liu; Kin-fai Ho; Haidong Kan; Qingyan Fu; Ke Lan

Generally undetectable or very low concentrations of airborne SARS-CoV-2 were found in most PAA inside the two hospitals in Wuhan. The negative pressure ventilation and high air exchange rate inside ICU, CCU and ward room of Renmin Hospital are effective in minimizing airborne SARS-CoV-2. Fangcang Hospital hosted over 200 mild symptom patients in each zone during the peak of the COVID-19 outbreak. However, the SARS-CoV-2 aerosol concentrations inside the patient hall were very low during the two batches of sampling periods, showing the protective and preventive measures taken in Fangcang Hospital are effective in hindering the aerosol transmission and reducing the potential infection risks of the medical staff. Inside the Renmin Hospital ICU rooms, the two aerosol deposition samples tested positive with an estimated deposition rate of 31 and 113 copies m -2 hr -1 . The deposited virus may come from respiratory droplet or virus-laden aerosol transmission. Our findings add support to a hypothesis that virus-laden aerosol deposition may play a role in surface contamination and subsequent contact by susceptible people resulting in human infection.