Modeling aerosol behavior in multizone indoor environments

A publicly available aerosol dynamics model, MIAQ4, is coupled to a widely used multizone air flow and transport model, COMIS, to better understand and quantify the behavior of particles in indoor environments. MIAQ4 simulates the evolution of a size and chemically resolved particle distribution, including the effects of direct indoor emission, ventilation, filtration, deposition, and coagulation. COMIS predicts interzonal air-exchange rates based on pressure gradients (due to wind, buoyancy, and HVAC operation) and leaks between the zones and with the outside. The capabilities of the coupled system are demonstrated by predicting the transport of particles from two sources in a residence: environmental tobacco smoke (ETS) and particles generated from cooking. For ETS, MIAQ4 predicts particle size distributions that are similar to the emission source profile because ETS particles, concentrated in the size range 0.1–1 μm, are transformed by coagulation and deposition slowly compared with the rates of transport. For cooking, MIAQ4 predicts that the larger-sized particles will settle rapidly, causing a shift in size distribution as emissions are transported to other rooms.