Fine particulate matter can be inhaled into and accumulate deep in human respiratory systems because of their small sizes and long air-suspending time, causing serious health concerns. It is crucial to understand fine particle indoor dispersion behavior and their relationship with outdoor particle conditions. However, sophisticated building configurations such as atrium, stairwell, and elevator space, and complicated heating, ventilating, and air-conditioning (HVAC) systems add to the complexities of identifying the indoor-outdoor correlations. Along with a field particle concentration measurement in a three-story institutional building, this paper reports a study of the feasibility and effectiveness of using a multizone simulation program to predict the penetration of outdoor fine particles into large nonresidential buildings. The study used measured indoor and outdoor fine particle concentrations and HVAC supply conditions to calibrate the simulation model. The calibrated model was then used to predict the indoor fine particle dispersions with the real outdoor weather and particle conditions. Good agreement is obtained between the simulation and experimental results. The study found that accurate specification of actual fan-driven ventilation rates is most important for achieving good simulation results when the mechanical system is on, while properly defining exterior envelope leakages is more critical when the system is off. The paper demonstrates a practical approach to conducting a multizone airflow and contaminant simulation for large buildings for which both blower door and tracer gas tests are difficult.

Units: Dual