On the Problem of Optimal Microbiological Decontamination of Air Environment and Surfaces

Abstract

Modern civilization, providing economic and social progress, at the same time objectively creates—sometimes close to ideal—conditions for the spread of various infections. The catastrophic consequences of the SARS-CoV-2 pandemic clearly indicate that homo sapiens appeared to be unable to effectively resist the onslaught of the coronavirus. The purpose of this publication is an attempt to fill the gap in the development of effective methods and means for microbiological decontamination that are optimal in terms of critical parameters. The observational data indicate that a significant number of SARS-CoV-2 coronavirus infections occur by air without a direct contact with the source, including over a long time interval. Precipitation helps to cleanse the air from pollutants and viruses, reducing noncontact contamination, which additionally brings up to date the problem of optimal microbiological decontamination of the air environment and surfaces. A thermodynamic approach has been used to optimize microbiological sterilization. It is shown that irreversible chemical oxidation reactions are the shortest way to achieve sterility, and they are capable of providing high reliability of decontamination. It has been established that oxygen is an optimal oxidant, including from the point of view of ecology, since its reactive forms harmoniously fit into natural exchange cycles. The optimal method for obtaining reactive oxygen species for disinfection is the use of low-temperature (“cold”) plasma, which provides the energy-efficient generation of oxidative reactive forms: atomic oxygen (O), ozone (O₃), hydroxyl radical (^•OH), hydrogen peroxide (H₂O₂), superoxide (\({\text{O}}_{2}^{ - }\)), and singlet oxygen O₂(a¹Δ_g). Due to a short lifetime for most of the above forms outside the plasma applicator, objects remote from the plasma generator should be sterilized with ozone (O₃), the minimum lifetime of which is quite long. It has been substantiated that the microwave method of generating oxygen plasma is optimal for energy-efficient ozone production. A modular principle of generation is proposed for varying the productivity of ozone-generating units over a wide range. The module has been developed on the basis of an adapted serial microwave oven, in which a non-self-sustaining microwave discharge is maintained thanks to ionizers (igniters), including those based on radiating radionuclides-emitters. In case of massive contamination of surfaces, it is advisable—in addition to ozone (O₃) air disinfecting—to use aqueous solutions of hydrogen peroxide (H₂O₂). It is essential that these reactive oxygen species for disinfecting objects remote from the plasma generator are highly efficient and, at the same time, environmentally neutral. Reliable and affordable personal protective equipment is proposed for activities in zones of increased ozone concentration. The considered optimal means of disinfection can be applicable not only in medicine but also adapted for numerous practices in agriculture, industry, and everyday life.