In recent years, the need for effective indoor air disinfection procedures and devices has become increasingly important. Numerous studies have highlighted the varying degrees of efficiency with which essential oils control biological aerosols. This project focuses on the antimicrobial activity of tea tree oil, a natural product from Australia, delivered using the “Unitor™ Duct Air Treatment” and “Unitor™ A/C Unit Air Treatment” solutions from Wilhelmsen Ships Service. The study explored multiple scenarios, focusing on the inactivation of bacterial and fungal aerosols in various indoor environments. The findings demonstrated that all tested products efficiently eliminated bacterial and fungal strains, with significant reductions observed even within the first 24 h of treatment. Continued operation over the subsequent six days brought airborne microbial concentrations down to just a few strains per cubic metre. These promising results highlight the potential for the further development of bioaerosol inactivation technologies that employ essential oil vapour discharge over extended periods. The tested products, leveraging the antimicrobial properties of essential oils, present a strong solution for air quality control, particularly in environments prone to high bioaerosol concentrations.