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The copyright holder for this preprint (which was not peer-reviewed) is .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 Both fine and large droplets are exhaled during respiration, and the infection risk from respiration is known to be highest when two people are in close contact. Liu et al. (2017) proposed that in addition to the traditional large-droplet mechanism, a short-range aerosol mechanism may also be important. An examination of the spatial concentration profile starting from the mouth of the infected person shows a continually reduced concentration profile in the exhaled jet, which weakens at some distance and merges into and becomes indistinguishable from the background room air. The average room concentration of aerosols is thus a function of source strength and ventilation rate. When the ventilation rate of the room is sufficiently low, the room average condition can become as concentrated as within the exhaled air. Hence, in theory, even if an infectious agent is not typically (i.e., under adequate ventilation) transmitted by a long-range aerosol mechanism, the spatial extent of transmission increases if the ventilation rate is very low. We refer to such transmission as an extended short-range aerosol mechanism.