Bioaerosol deposition in single and two-bed hospital rooms: A numerical and experimental study

Abstract Aerial dispersion of pathogenic microorganisms and subsequent contamination of surfaces is well recognised as a potential transmission route for hospital acquired infection. Simulation approaches such as computational fluid dynamics (CFD) are increasingly used to model particle behaviour in indoor air and the results interpreted to infer infection risk. However there is little validation of such methods in the open literature. This paper considers the ability of CFD simulations to accurately predict spatial distributions of bioaerosol deposition in indoor environments and explores the influence that different room layouts have on deposition patterns. Spatial deposition of aerosolised Staphylococcus aureus was measured in an aerobiology test room arranged in three different layouts: an empty room, a single-bed and a two-bed hospital room. Comparison with CFD simulations using Lagrangian particle tracking demonstrates that a realistic prediction of spatial deposition is feasible, and that a Reynolds Stress (RSM) turbulence model yields significantly better results than the k – ɛ RNG turbulence model used in most indoor air simulations. Results for all layouts demonstrate that small particle bioaerosols are deposited throughout a room with no clear correlation between relative surface concentration and distance from the source. However, a physical partition separating patients is shown to be effective at reducing cross-contamination of neighbouring patient zones.