Ozone as an alternative decontamination process for N95 facemask and biosafety gowns

COVID-19 pandemic created a global shortage of medical protective equipment. Here, we considered ozone (O₃) a disinfectant alternative due to its potent oxidative activity against biological macromolecules. The O₃ decontamination assays were done using SARS-CoV-2 obtained from patients to produce artificial contamination of N95 masks and biosecurity gowns. The quantification of SARS-CoV-2 was performed before and after exposing the samples to different ozone gas concentrations for times between 5 and 30 min. Viral loads as a function of the O₃ exposure time were estimated from the data obtained by the RT-PCR technique. The genetic material of the virus was no longer detected for any tested concentrations after 15 min of O₃ exposure, which means a disinfection Concentration-Time above 144 ppm min. Vibrational spectroscopies were used to follow the modifications of the polymeric fibers after the O₃ treatment. The results indicate that the N95 masks could be safely reused after decontamination with treatments of 15 min at the established O₃ doses for a maximum of 6 cycles.