Ozone was generated using dielectric barrier discharges at atmospheric pressure to treat sugarcane bagasse for bioethanol production. It was shown that interaction of ozone molecules with the pretreatment reactor wall (stainless steel) needs to be considered during bagasse oxidation in order to evaluate the pretreatment efficiency. The decomposition coefficients for ozone on both materials were determined to be (3.3 ± 0.2) × 10−8 for stainless steel and (2.0 ± 0.3) × 10−7 for bagasse. The results have indicated that ozone decomposition has occurred more efficiently on the biomass material.