Selected methods for effective inactivation of microorganisms in experimental chambers intended for indoor air bioaerosol studies

The frequent occurrence of threats from various airborne biological factors has led to a significant increase in experimental research on bioaerosols in recent years. One of the key areas of interest for researchers in this field are microorganisms present in enclosed spaces, both suspended in indoor air and settled on surfaces. A common feature of all these experiments in the initial stage of the investigation is the simulation of basic phenomena related to bioaerosols based on closed experimental systems. During this type of research, a crucial preliminary step that significantly impacts the quality of biological research results is the process of ensuring the appropriate microbiological purity of the experimental cells. The filtration methods currently used for indoor air purification in chambers do not effectively remove microorganisms from surfaces, especially in difficult to reach areas. Microorganisms settled on surfaces are detached because of air movement in the chamber and can reform bioaerosol. Therefore, for many years, research has been aimed at developing an effective technique for decontaminating air and surfaces in enclosed spaces. In recent years, there has been a development of chemical disinfection techniques based on the generation of fog from biocidal agents. The paper presents selected results of original research, demonstrating that the decontamination of experimental chambers for bioaerosol studies using dry fog generated from hypochlorous acid (HOCl) at a concentration of 300 ppm allows a high degree of microbiological purity before biological experiments and does not pose a threat to human health. Furthermore, the use of HOCl-generated dry fog as a method to decontaminate experimental chambers and laboratory spaces can also reduce the threat posed by biological agents to research personnel and protect against the contamination of the surrounding environment.