Mixing and Dispersion of Aerosols in Multi-Zone Residences

MENGJIA TANG, Daniel Rush, Sangeetha Kumar, Atila Novoselac, The University of Texas at Austin

     Abstract Number: 482
     Working Group: Indoor Aerosols

Abstract
Exposure to particulate matter (PM) in homes typically accounts for a large proportion of a person's total daily exposure. Various indoor activities including cooking, cleaning, and walking can substantially increase the PM level and overall exposure. To accurately estimate, and subsequently reduce PM exposure due to PM releasing events, it is essential to understand the transport of aerosols across different zones in a common multi-zone residential environment. Depending on the longevity of the PM source, PM size, and ventilation and mixing mechanisms in the residence, there can be a high variation in PM exposure across different rooms. This study used controlled experiments in the full-scale three-bedroom two-bath home that is used as a testing facility at the University of Texas at Austin. Concentrations of ultrafine (<0.1 μm), fine (0.3 – 2.5 μm), and coarse particles (2.5 – 10 μm) were measured in multiple rooms during and following different types of PM generation. Together with the particles, tracer gas was released, and the temporal concentration was measured in each room. The PM generating event mimicked instantaneous (less than 1 minute), short-term (15 minutes), and long-term (2 hours) PM sources released in a kitchen; the fate of particles of different sizes as well as the tracer gas was determined for different levels of air mixing in the home (the air conditioning fan ON and OFF). Preliminary results suggest that ultrafine particles follow the same pattern regardless of the level of air mixing while air mixing has a large impact on the dispersion of fine particles. The dispersion of coarse particles throughout the house is relatively small.