Evidence for probable aerosol transmission of SARS-CoV-2 in a poorly ventilated restaurant

Yuguo Li; Hua Qian; Jian Hang; Xuguang Chen; Ling Hong; Peng Liang; Jiansen Li; Shenglan Xiao; Jianjian Wei; Li Liu; Min Kang

The copyright holder for this preprint (which was not peer-reviewed) is . https://doi.org/10.1101/2020.04. 16.20067728 doi: medRxiv preprint 6 becoming infected. Table A was excluded in this analysis. The other tables were categorized according to two criteria: distance from TA (e.g., immediate vs. remote neighbors) and airconditioning zone (i.e., the ABC zone was that immediately around TA, TB and TC and serviced by one air conditioning unit, and the non-ABC zone was everywhere else, serviced by the four other air conditioning units). The tracer measurement was carried out on March 19-20 when the intensity of the direct solar radiation was similar to that on January 24, i.e., weak sunshine, with clouds and rain. We first measured the supply/return/exhaust air flow and temperature at each air-conditioning unit and at the exhaust fan in the restroom. We arranged the tables and chairs to match the arrangement used at the January 24 lunch, as determined by analyses of the video of this occasion. The air conditioning units were turned on and the exhaust fans in the vertical glass window were left off to simulate the air-flow conditions at the time of SARS-CoV-2 infection during the lunch on January 24. Volunteers were not recruited because the experiment was performed during the strict intervention (i.e., lockdown) phase of the epidemic in Guangzhou. However, nine experimental staff sat on Tables A, B, and C and simple thermal mannequins were placed at the others. The mannequins were warm and hollow, containing a 60-W electrical bulb enclosed by a stainless steel cylinder, which produced warm plumes similar to the above human subjects. All rights reserved. No reuse allowed without permission. the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.