Enhancing Biosafety in Emergency Medical Vehicles: An Efficacy Evaluation of Nano-Catalyzed Photocatalytic Oxidation for Proactive Microbial Disinfection

This study investigates the efficacy of a nano-catalyzed Photocatalytic Oxidation (PCO) system for the proactive inactivation of resilient microbial spores within the confined environments of emergency medical vehicles. Addressing the limitations of conventional decontamination methods against persistent airborne pathogens, this research evaluated four PCO configurations in a 9 m3 simulated ambulance chamber. The system's performance was quantified using two recalcitrant biological indicators Bacillus subtilis and Aspergillus niger. Experimental results demonstrated that while natural decay accounted for minimal spore reduction (<11%), the PCO system consistently achieved an inactivation efficiency exceeding 3.0-log (99.9%). Specifically, the UVA+TiO2 configuration exhibited the most stable and reproducible inactivation kinetics. These microbiological data were subsequently integrated into an empirical foundation for an EMS-based decision-support system. By formalizing the determined Total Kill Time (TKT) parameters-60 minutes for A. niger and 90 minutes for B. subtilis-this study proposes a data-driven Safe-to-Enter informatics framework. This framework transitions ambulance biosafety from subjective manual estimation to verifiable digital protocols, enhancing occupant safety through evidence-based informatics within the digital health ecosystem.