Gaseous emissions, a side effect of livestock and poultry production, need to be mitigated to improve sustainability. Emissions of odorous gases like ammonia (NH₃) have a detrimental effect on the environment. We are building on previous research to bring advanced oxidation technologies from the lab to the farm. To date, we have shown that ultraviolet A (UV-A) has the potential to mitigate selected odorous gases in the swine production. Much less research on emissions mitigation has been conducted in the poultry production. Thus, the study objective was to investigate whether the UV-A can mitigate NH₃ that is a surrogate gas for the odor in the simulated poultry barn environment. The effects of several variables were tested on a lab-scale: the presence of photocatalyst, relative humidity, treatment time, and dust accumulation under two different light intensities (fluorescent and light-emitting diode, LED). The results provide evidence that photocatalysis with TiO₂ coating and UV-A light can reduce NH₃ concentration. The particular % reduction depends on the presence of photocatalysts, relative humidity (RH), light type (intensity), treatment time, and dust accumulation on the photocatalyst surface. The mitigation of NH₃ varied from 2.6–18.7% and was affected by RH and light intensity. The % reduction of NH₃ was the highest at 12% RH and increased with treatment time and light intensity. The % reduction of NH₃ decreased with the accumulation of poultry dust. The results warrant scaling up to a pilot-scale where the technology could be evaluated with economic analyses. This conference paper is a shorter version of the peer-reviewed journal paper.