Comparison of airflow and particulate matter transport in multi-room buildings for different natural ventilation patterns

This study numerically investigates airflow characteristics and particulate matter (PM) transport in multi-room buildings for different natural ventilation patterns with the same air change rate. Four typical natural ventilation patterns (full-open, pass-through, right short-circuit and left short-circuit), representing the ratios of the outlet-to-inlet opening size ranging from 1.67 to 0.17, are considered to study multi-room airflow characteristics. A measured indoor PM10 profile in Taipei Metropolis is input into the above four ventilation patterns as the initial condition of the PM size distribution. The time variation of indoor PM10/PM2.5/PM1 concentrations in each room for various ventilation patterns is next investigated. The effect of ventilation pattern on particle removal mechanism is emphasized. The results show that although the air change rate of the building is the same, airflow characteristics and PM transport behaviors are quite different for various ventilation patterns. The removal efficiencies of PM10 for the four ventilation patterns are all found to be much better than those of PM2.5 and PM1. Particle escape is the major mechanism to remove PM for rooms with double-sided ventilation, whereas particle deposition is important for single-sided ventilation rooms.