Integrated numerical approach of computational fluid dynamics and epidemiological model for multi-scale transmission analysis in indoor spaces

The indoor environment can play a significant role in the airborne transmission of diseases, such as those caused by influenza virus and tuberculosis virus. The airborne route of transmission is considered to be critically important for evaluating the risk to occupants' health due to exposure to these contaminants. In this paper, an analytical procedure coupling with the computational fluid dynamics (CFD)-based prediction has been proposed for the determination of the unsteady and non-uniform contaminant concentration distribution within an indoor environment. A basic epidemiological model (here, SIR model) is used to evaluate the health risk. This numerical procedure can be used to predict exposure risk of residents, i.e. airborne transmission in two-dimensional horizontal space in a hospital. Furthermore, an integrated simulation procedure is also proposed for prediction of the concentration of an infectious contaminant using a multi-nesting method connecting to a building space, a micro-climate around a human body, and respiratory air tract in a human body, in order to provide quantitative and qualitative information for estimating contaminant dose that could have been taken up by the residents due to indoor exposure. On the basis of this numerical simulation, detailed information on the unsteady spatial distribution of contaminant concentration, the breathing concentration of infectious contaminant, and the non-uniform distribution of contaminant adsorption/deposition in respiratory air tract could be provided to enable suitable design of a heating, ventilation and air-conditioning (HVAC) system for an acceptable indoor environment fit for a particular medical provision such as in a hospital.