Effect of Ventilation on Aerosol Transmission in an Indoor Seminar Room in Lincoln, UK

The advent of the coronavirus pandemic has increased global awareness of indoor air quality especially, as it pertains to the design of workspaces with adequate ventilation. This study aims to quantify the effect of various ventilation configurations on aerosol dispersion in an existing seminar room using computational fluid dynamics (CFD). The aerosol transport is achieved by carrying out Eulerian-Lagrangian simulations using the Discrete Phase Model in Ansys Fluent. The seminar room studied has a closed glass observation window. The fact that the window cannot be opened may present a high risk of infection transmission, especially in cases where the air conditioning system is not switched on or is broken. To assess the impact of this on the spread of possibly infected bio-aerosol emitted from a coughing person, three cases were investigated. The baseline case consists of the room with the observation window closed and no air conditioning (AC). Minimal air change per hour (ACH) is achieved by the gaps underneath and above the door as well as the outlet air ventilation port. Two other cases were benchmarked against this base case. The first consists of having the observation window half open while the other considers the observation window closed with the AC on having the recommended 8 ACH of ventilation for seminar rooms. The simulations showed that while AC with natural ventilation help in transporting droplets out of the room by increased air circulation, aerosol propagation is also dampened at source by forcing the trapping of droplets on clothing and immediate nearby surfaces. In summary, this study contributes to the design, retrofitting and reconfiguration of new or similar existing design of university and educational facilities seminar rooms. The findings can also contribute to the design of similar spaces within other building typologies like hotels and other public indoor workplaces.