The aim of this on-site experiment is to evaluate and compare efficiencies of currently utilized biological additives to reduce emissions of dust and bioaerosol in a confinement swine house. The mean reduction rate of total dust only after spray ranged was approximately 30% for all the treatments, compared to initial level before spraying additives which was found to reduce the initial level of total dust significantly (p<0.05). The mean reduction rate of all the treatments at 1 hr after spraying was about 24% which was 6% lower than only after spray. Since 3 hr after spraying, however, total dust level fluctuated inconstantly for all the treatments, besides application of soybean oil. The mean reduction rates of all the treatments only after spraying as compared to initial level before spraying were about 53% for total airborne bacteria (p< 0.01) and 51% for total airborne fungi (p<0.01), respectively. At 1 hr after spraying, the reduction rate of total airborne fungi averaged to about 35% for all the treatments (p<0.05), while in significant reductions of total airborne bacteria were found only in the treatments with salt water, soybean oil, artificial spice, and essential oil (p>0.05). The fluctuations of total airborne bacteria and fungi, which were similar to total dust, were observed for all the treatments 3 hr after spray.