How Particle Resuspension from Inner Surfaces of Ventilation Ducts Affects Indoor Air Quality—A Modeling Analysis

Dust particles deposited on the inner surfaces of the ventilation ducts can be resuspended by passing airflow. A physical-science-based model is developed to understand how particle resuspension affects the indoor air quality. This integrated model takes into consideration particle mass balance models for straight ventilation duct, duct bend, ventilation room, and air filter. The straight duct and room models have been validated using experimental data. With the integrated model, we find that in-duct resuspension of particles could lead to significant increase in exposure to airborne particles for indoor occupants. It is also found that indoor particle exposure is a linear function of dust mass loading. Greater ventilation rate, which means higher air speed above the dust particles, would lead to greater exposure ratio, while fresh air ratio has little influence. Possible control methods are discussed as well.