A zonal model for assessing the infection risk distribution of COVID-19 in indoor environments

Abstract

Nowadays, the search for new solutions to the pandemic situation caused by the spread of SARS-CoV-2 is one of the most important issues worldwide. The difficulties encountered in finding an effective cure for the infection and the ongoing vaccination campaign place a priority on minimising the transmission of this disease. This paper deals exclusively with the airborne route of transmission for COVID-19, proposing a model for the evaluation of infection risk. It starts from the well-known Wells-Riley model and its successive modifications and tries to couple it with a zonal model which analyses the air movement in an indoor environment. The objective of this model is evaluating whether the infection risk depends considerably on the position of the infected subject and the susceptible person in the room and how different ventilation concepts affect these aspects. The model was applied to an office room with a mixing ventilation system. The results obtained concern the sub-division of the considered volume in four cells, each one perfectly mixed. The evaluation of infection risk in different positions was carried out and an analysis on the parameters affecting this value was performed.