The application of ozone removing air cleaning systems can reduce the exposure to indoor ozone and ozone reaction products. Previous studies have demonstrated the potential of ultraviolet photocatalytic oxidation (UV-PCO) in ozone removal. However, there is still lack of information on the ozone removal performance of commercial UV-PCO systems. Experimental study was conducted to investigate ozone removal performance of three different commercial PCO and one in-house PCO under the same UVC light conditions. The dynamic single-pass tests were carried out. All three commercial PCO showed low ozone removal efficiencies. Increasing the number of PCO layers can improve the ozone removal performance; however, increasing from 2-layer to 3-layer showed minor increase. The effects of UV-PCO operation conditions like ozone concentration, air velocity and relative humidity were studied. No clear trend was observed when the challenge concentration is varied between 85 ppb and 200 ppb. Ozone removal efficiency was lower at higher air velocity, and its trend follows the power law. When the relative humidity was higher than 50%, lower ozone removal performance was observed.