On The Modeling and Simulation of COVID-19 Spreading In a Classroom

A clear understanding of aerosol transport in different environments is crucial to find physics-informed measures for COVID-19 spreading mitigation. In this study, we investigated aerosol transport and surface deposition in a realistic classroom environment using Computational Fluid Dynamics (CFD) simulations. An instructor and nine students were placed in a 9 m by 9 m classroom, 2.4 m apart, following the social distance recommendations. A real situation of the room ventilation was applied by considering the classroom air conditioning according to ASHRAE 62.1 ventilation standards. Four different parameters including the particle size, aerosol source location, presence of sneeze guards in front of students, and the window state open vs. closed were studied. It is found that a significant fraction (24 – 50%) of particles smaller than 15 μm exit the classroom through the return diffusers of the air conditioning system within 15 minutes. This highlights the importance of effective filtration and sterilization systems within air conditioners. Sneeze guards are found to reduce the aerosol transmission of the 1 μm particles from the source to others by ~92%. By opening windows, the particle exit fraction can be increased by ~38% and aerosol deposition on people in the room is reduced.