A Novel Methodology for Risk Assessment of Airborne Transmission due to Covid-19 in University Classrooms

The Covid-19 pandemic revolutionized the way of designing buildings, which should be created to improve health conditions and limit the spread of contagion. Among these, schools certainly need special attention. To improve indoor conditions, the first step of this study was conducted by simulating three classrooms having different ventilation strategies, using a CFD analysis. Then the infection probability was calculated using the Gammaitoni-Nucci model to analyse the risk in the classrooms according to different ventilation and building characteristics. The study showed the need for providing adequate ventilation to ensure healthy conditions for the students. Furthermore, the infection probability was calculated considering non-uniform environments, which can result from various air distributions in the classroom due to local non-uniformities. The configuration obtained from the CFD analysis was then compared to the standard condition. which considers the classrooms as uniform environments. This allows an understanding of the effective conditions to which students are exposed and to comprehend whether the classical models do not risk underestimating the infection probability. This study provides a new methodology for airborne transmission risk assessment in non-homogeneous environments and supports designers with a new tool to evaluate HVAC systems layout and classroom operation.