Abstract

Many contaminants such as carbon monoxide, benzene, toluene and ethyl benzene in the living area of a house originate from attached garages. As houses are designed and constructed more airtight and energy efficient, these contaminants are retained in indoor air, jeopardizing the occupants' health. In this study a multi-zone model for indoor air quality and contaminant transport analysis, CONTAM, was employed to analyze the impact of garage-house interface on the contaminant transport from attached garages to living area. Parametric studies of two buildings have been carried out based on the experimental data of five normalized Effective Leakage Area (ELA) of the garage-house interface. The parametric study indicates that both natural ventilation (wind direction and speed) and mechanical ventilation system influence the pressure difference in the house and consequently affect the contaminant transport from the garage to the house. For the simulations of wind directions for one of the modeled house, the highest and lowest concentration in the living room occurs with the wind directions of 135˚ and 270˚ respectively, regardless of garage-house ELA. Furthermore, the simulation results of wind speeds demonstrate that as the wind speed increases, the peak contaminant concentration indoors increases. However, as the wind speed increases, the infiltration increases. As a result, the exposure to the contaminant actually decreases. Moreover, seven different exhaust ventilation flow rates in different locations were evaluated. The result shows that the worst case scenario is when implementing 52 L/s exhaust ventilation (master bath (10 L/s), hall bath (10 L/s), bedroom2 (22 L/s), living room (10 L/s)).