UV dissociation and calculation for O3 gas generated from non-thermal atmospheric-pressure biocompatible plasma sterilizer

Nonthermal atmospheric–pressure biocompatible plasma (NBP) sterilizers effectively deactivate microorganisms, such as viruses, bacteria, and fungi, using eco-friendly treatment methods without generating any waste or toxic by-products. The ozone density generated from the plasma source of surface microdischarge (SMD) in plasma sterilizers has been decreased by 70%, resulting in a density of less than 0.05 ppm, whereas the densities of OH and H2O2 have significantly increased due to UV-C dissociation with a high absorption cross section for ozone gas. The ozone density was calculated by estimating the oxygen atoms using the major reaction equations for ozone formation and dissociation, and measurement of the time constant of diffusion decrease (τdif). The ratio of the O density for the O3 density generated from the plasma source decreased as the distance between the ozone measurement locations and the plasma source increased. In particular, the excited state density of atomic oxygen O(1D) could be estimated at the downstream region of the air outlet in this study.