Feasibility of Multi-Zone Simulation for Estimating Contributions of Outdoor Particulate Pollution to Indoor Particulate Matter Concentration

As concerns about the health effects of particulate matter (PM) are growing, controlling indoor PM has become vital for ensuring occupants' health. Active strategies, such as air purification and high-performance filtering, are widely implemented to control indoor PM. However, passive strategies, including air-tightness and compartmentalization, are promising alternatives, as demonstrated by recent studies. To enhance the implementation of passive strategies, an appropriate evaluation method for passive designs must be established. The objective of this study was to investigate whether a multi-zone-based method is suitable for the evaluation of passive strategies. Multi-zone simulations were performed for four seasons, and indoor/outdoor concentration (I/O) ratios were obtained for the exterior, interior, and corridor on every floor of the reference building. The I/O ratios at different locations indicated that the outdoor particle transport in the building was accurately estimated according to the airflow rate and path. Moreover, in addition to the effects of changes in the outdoor temperature on PM transport through the building envelope, the particle size is a significant factor affecting indoor PM concentrations. The results of this study indicated that the multi-zone method can effectively estimate the number of outdoor particles that penetrate the building envelope in different seasons and the indoor particle concentration at different indoor locations.