On Safe Placement of Closed-Type Ultraviolet Germicidal Units (Recirculators) in Residential and Public Buildings

Introduction: Recirculators used for indoor air disinfection in residential and public buildings in the presence of humans must ensure the required level of germicidal efficiency and exclude the possibility of adverse health effects of non-ionizing physical factors. Objective information about the levels of physical factors created by these units is therefore of current interest. Objective: To substantiate safe placement of recirculators within residential and public buildings. Materials and methods: We measured UV light energy levels, sound levels, and 50 Hz electromagnetic fields at different distances from the housing of five recirculators, four of which were medical devices and one was a household appliance. All measurements were taken in an anechoic shielded chamber. Results: We established that UV waves were emitted beyond the housing of two out of five recirculators. When the devices were wall-mounted in accordance with the instructions for use, levels of UV irradiation complied with the requirements of sanitary rules and regulations at the measurement point located at a height of 1.5 m from the support surface at a distance of 1 m from the recirculator. Levels of 50 Hz electromagnetic fields at a distance of 30 cm from the recirculator did not exceed hygienic standards. Measured noise levels at a distance of 1 m from the devices corresponded to those declared in the specifications. Conclusion: Application of recirculators sets the task of minimizing potential detrimental effects of UV radiation and noise on humans, one of the ways to solve which is to establish a safe distance for placing the devices in rooms serving different functional purposes and to select operating modes ensuring adequate disinfection efficiency at minimum levels of human exposure to hazardous factors.