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Multiscale Models for Aerosol Transmission of Highly Infectious SARS-CoV-2 Novel Coronavirus
SUKRANT DHAWAN, Huang Zhang, Renhui Ruan, Pratim Biswas, Washington University in St Louis
Abstract Number: 320
Working Group: The Role of Aerosol Science in the Understanding of the Spread and Control of COVID-19 and Other Infectious Diseases
Abstract
The highly infectious SARS-CoV-2 novel coronavirus has resulted in a global pandemic. More than ten million people are already impacted, with infected numbers expected to go up. There is a lot of discussion underway with conflicting opinions examining the airborne nature of the SARS-CoV2 virus. Coughing, sneezing and even breathing emit respiratory droplets which can carry infectious particles. It is important to understand how exhaled particles move through air to susceptible person to get answers regarding airborne transmission of SARS-CoV-2. Surprisingly, important phenomena prevalent with respect to aerosols (suspended droplets) have not been considered in recent SARS-CoV-2 studies. There are many studies conducted on the airborne spread of viruses causing diseases such as SARS and measles, however there are very limited studies that couple the transport characteristics with the aerosol dynamics of the droplet.
In this study, a comprehensive model for simultaneous droplet evaporation and transport, due to diffusion, gravitational settling, and ambient air flow, is developed. The considerations for viral load in droplets and virus decay are accounted for in the model to determine the spatial and temporal concentration of viable virus exhaled by the infected individual. The exposure to viable virus and risk of infection is determined using respiratory deposition curves. The effect of the different parameters such as ambient air velocity, relative humidity, viral load is determined on the risk of exposure as the function of separation distance from the infected person.
The model is further evolved to study the risk of virus exposure in a ventilated classroom. The droplet dispersion in a ventilated classroom is simulated by CFD with a validated Eulerian-Eulerian method. The effect of humidity, room temperature, droplet size, separation, and layout of ventilation system on the droplet transportation and subsequent risk of exposure is studied.