%0 Journal Article
%A Mark R Sippola
%A William W Nazaroff
%B Atmospheric Environment
%D 2003
%G eng
%P 5597-5610
%T Modeling particle loss in ventilation ducts
%V 37
%X <p>Empirical equations were developed and applied to predict losses of 0.01-100 µm airborne particles making  a single pass through 120 different ventilation duct runs typical of those found in mid-sized office  buildings. For all duct runs, losses were negligible for submicron particles and nearly complete for particles  larger than 50 µm. The 50th percentile cut-point diameters were 15 µm in supply runs and 25 µm in return  runs. Losses in supply duct runs were higher than in return duct runs, mostly because internal insulation  was present in portions of supply duct runs, but absent from return duct runs. Single-pass equations for  particle loss in duct runs were combined with models for predicting ventilation system filtration efficiency  and particle deposition to indoor surfaces to evaluate the fates of particles of indoor and outdoor origin in  an archetypal mechanically ventilated building. Results suggest that duct losses are a minor influence for  determining indoor concentrations for most particle sizes. Losses in ducts were of a comparable magnitude  to indoor surface losses for most particle sizes. For outdoor air drawn into an unfiltered ventilation system,  most particles smaller than 1 mm are exhausted from the building. Large particles deposit within the  building, mostly in supply ducts or on indoor surfaces. When filters are present, most particles are either  filtered or exhausted. The fates of particles generated indoors follow similar trends as outdoor particles  drawn into the building.</p>