Poultry farmers are producing eggs, meat, and feathers with increased efficiency and lower carbon footprint. Technologies to address concerns about the indoor air quality inside barns and the gaseous emissions from farms to the atmosphere continue to be among industry priorities. We have been developing and scaling up a UV treatment that has the potential to reduce odor and other gases on the farm-scale. In our recent laboratory-scale study, the use of UV-A and a special TiO₂-based photocatalyst reduced concentrations of several important air pollutants (NH₃, CO₂, N₂O, O₃) without impact on H₂S & CH₄. Therefore, this research's objectives were to (1) scale-up of the UV treatment to pilot-scale, (2) evaluate the mitigation of odor and odorous VOCs. The effects of a photocatalyst's presence (photocatalysis & photolysis), UV intensity (LED & fluorescent), and treatment time we studied in the pilot-scale experiments inside a poultry barn. The results of pilot-scale experiments were consistent with the lab-scale: the % reduction under photocatalysis was generally higher than photolysis. In addition, the % reduction of target gases at a high light intensity and long treatment time was higher. The % reduction of NH₃ was 5~9%. There was no impact on H₂S, CH₄, and CO₂ under any experimental conditions. N₂O & O₃ concentrations were reduced at 6~12% & 87~100% by both photolysis & photocatalysis. In addition, concentrations of several VOCs responsible for livestock odor were reduced from 26~62% and increased with treatment time & light intensity. The odor was reduced by 18%. Photolysis treatment reduced concentrations of N₂O, VOCs, and O₃, only. Further scale-up and research at the farm-scale are warranted.