This research evaluated the effectiveness of local supply ventilation in controlling air quality at or near workers’ breathing zones in livestock confinement buildings. Commercially available ceiling (box-type) diffusers and local supply ventilation systems were evaluated in a pilot-scale experimental facility and compared in terms of their ventilation effectiveness for airborne dust and spatial variability in dust concentration. Commercial ceiling diffusers were either one-way (i.e., box1) or two-way ceiling diffusers (i.e., box2). The local supply ventilation systems involved introducing supplemental air at the central alley in combination with either the one-way (i.e., local1) or the two-way (i.e., local2) commercial ceiling diffusers. Both local1 and local2 improved the ventilation effectiveness at the alley compared to box1 and box2 diffusers. Additionally, local2 had the highest overall relative ventilation effectiveness (E₀= 1.36) and most uniform dust concentration distribution (CV = 0.17), indicating the potential of this system in improving the air quality within livestock buildings. Further, the wall exhaust (i.e., exhaust located at the center of one wall) was generally better than the floor exhaust (i.e., exhaust located at the center of the floor), especially for the local ventilation system, in terms of ventilation effectiveness and spatial variability in dust concentration.

Units: Dual