Assessing impact of intermittent window opening strategies on pathogen-laden droplet dispersion in a coach bus

Opening windows in coach buses is a practical approach to improving natural ventilation and mitigating infection risk (IR). Due to human behavior and weather conditions, the intermittent window opening strategy (IWOS) is a more common practice than keeping windows constantly open. Despite its prevalence, there are no studies exploring IWOS specifically in vehicles. We employed indoor-outdoor coupled CFD simulations to assess the effects of various IWOS on pathogen-laden droplet (PLD) dispersion and IR in a coach bus that occurred a COVID-19 outbreak in Hunan, China. Results reveal that after ventilating through two skylights for 600–1800 s, opening front and rear windows (FW+RW) or FW with a wind catcher (FW+WCH) for just 40 s can reduce PLD concentration (Cave) to 5