Numerical modelling of ventilation strategies for mitigating cough particles transmission and infection risk in hospital isolation rooms

Abstract

This study used numerical modelling to analyze air velocity, cough particle distribution and infection risks in an isolation room. It investigated air change rates, inlet/outlet vent positioning and assessed various ventilation rates and outlet configurations for reducing infection risks. Quantitative assessments revealed different particle escape timings. In Case 1, smaller particles (2–4 μm) took 8.2 s to escape, while in Case 2, this time extended to 22.7 s. At 48 ACH, there were significant improvements in removing particles of various sizes, particularly those sized 2–4 μm, 16–24 μm and 40–50 μm, reducing the infection risk. The use of the Wells-Riley model highlighted considerable reductions in infection probabilities with higher ACH. Specifically, infection risks were reduced to 5% in Case 1 and 17% in Case 2, underscoring the marked advantage of Case 1 in reducing infection probabilities, particularly for smaller particles. Furthermore, escalated ACH values consistently correlated with decreased infection probabilities across all particle sizes, highlighting the pivotal role of ventilation rates in mitigating infection risks. The study comprehensively investigated the distribution of air velocity, dynamics of cough particles and infection risk associated with different ventilation strategies in isolation rooms.