This work investigates O3 production in a planar atmospheric pressure air dielectric barrier discharge reactor numerically and experimentally. The surface temperature of the reactor is measured by an infrared (IR) thermal imager, and the O3 densities of cases in the reactive zone are measured by ultraviolet absorption spectroscopy. The 1.5D plasma fluid model (PFM) with transverse convection is employed to capture the average properties of a single microdischarge (MD) generated in the reactor and is integrated with the 3D gas flow model for modeling species densities in the reactor. The simulated temperature distribution of the reactor surface is validated by that measured and the simulated O3 densities agree with those measured at different locations and flow rates. In the 1.5D PFM, the simulated results show that the O3 molecules produced in the case of 4 SLM are much more than those produced in the case of 1 SLM though the O atoms produced in the case of 1 SLM are around 20 % more than those produced in the case of 4 SLM. In the case of 1 SLM, more than 48% of O3 molecular generated are destructed, while only around 14% of O3 molecules are destructed in the case of 4 SLM. The analysis shows that around 73% of O atoms generated in the 1.5D PFM are consumed in the formation of O3 molecules in the case of 4 SLM, while only 18% of O atoms generated in the case of 1 SLM are consumed in the formation of O3 molecules. The overall O3 yield efficiency reaches 97 g/kWh with the O3 concentration increasing to 2700 ppm in the case of 4 SLM, while the O3 yield efficiency decreases to 10 g/kWh and O3 concentration drops to 1400 ppm in the case of 1 SLM.