Pollutant dispersion in a natural ventilated dental clinic

Mechanical ventilation poses some challenges for control of pollutants in a fully enclosed dental clinic. Natural ventilation is used in some clinics because of its high exhausting efficiency and low non-renewable energy consumption. In this study, a dental clinic model was built using a computational fluid dynamics platform. The objective was to study the effect of natural ventilation on pollutant dispersion in this setting. The evaluations were conducted using the advanced turbulence model, large eddy simulation for the flow field and the discrete phase modelling for pollutant tracks. Three basic ventilation paths were identified, the 'single narrow path', 'narrow path' and 'dispersive path'. The results show that the first of these had the highest efficiency, with an escape time of about 1/30 and 1/100 of the narrow and dispersive paths, respectively. Despite the position of the pollutant source and facilities such as bulkheads, escape time was significantly reduced when the ventilation flow rate was increased under the single narrow and dispersive paths. However, for the narrow path, these factors played a more dominant role in the escape time than the ventilation flow rate. Practical application: This study is expected to provide information and guidance in understanding the pollutant spread in a naturally ventilated room such as a dental clinic.