Standardization of Gaseous Ozone Disinfectant Efficacy, Recommendations of Methods and Conditions for Future Comparative Studies

Following the UK’s transition from the EU, the introduction of new or novel biocidal products must comply with the Biocidal Products Regulation (BPR). The unique characteristics of ozone, including its generation, intrinsic properties, and safety considerations, do not fully conform to the preferred methodologies for testing surface biocidal efficacy, such as BS EN 17,272:2020. The lack of standardized testing suited for ozone and resources available for efficacy and safety data may inadvertently lead to the production of inefficient disinfection equipment. The absence of a robust protocol underlies disparities in published test conditions, making comparisons and conclusions difficult to interpret, leading to delays in research, industry production, and regulatory approval. This review examines and evaluates both the intrinsic and extrinsic factors affecting gaseous ozone disinfection. This evaluation serves as a base for recommendations aimed at guiding the development of a standardized protocol, from ozone concentration to chamber parameters. These include factors applied throughout all ozone testing and factors that should be addressed per application. It is anticipated that implementing these recommendations and establishing a validated methodology will facilitate robust comparison of ozone disinfection studies, fostering standardization of microbial surface decontamination, particularly for BPR approval.