Deposition of Particles on Supply Air Duct in Mechanically Ventilated Residential Buildings

Abstract

Particles deposited on the surfaces of ducts could be a second source of indoor air pollution. From a previous field study, it was found that 78% of occupants don’t use mechanical ventilation fans, and the occupants frequently open windows to ventilate indoor air, instead of the mechanical fans. In this study, a model to predict the deposition in ducts was developed through theoretical analysis, and the model was estimated with the measured data of 15 sample apartments. The deposition was also calculated using particle resuspension equations. The results of this study showed that the amount of particles deposited on the supply air ducts was significantly influenced by the mechanical fan operation conditions. Intermittent fan operation might increase the particle deposition on the supply air ducts. The results indicate that the mechanical ventilation system in houses is carefully designed to prevent deposition and resuspension in the supply air ducts of mechanical ventilation.