One of the most important systems for ensuring the required air quality in Orthodox churches is the ventilation system. Mechanical ventilation is getting contaminated during operation. The air, passing through the air ducts, contains dust particles, including pathogenic bacteria. To prevent bacteria from multiplying in the ventilation system, bactericidal filters must be used. Halls of Orthodox churches belong to public buildings with a large crowd of people with a long stay. Such premises require a bactericidal efficiency of at least 90%. For the ventilation systems of the church of St. Theophan the Recluse, the authors proposed and implemented a device for bactericidal air treatment using ultraviolet radiation. The bactericidal effectiveness of this device was 92%, which is higher than required. The authors recommend using the proposed device for public buildings.

Keywords: Orthodox church, church buildings, ventilation of religious buildings, bactericidal treatment of air, ultraviolet radiation, air disinfection, bactericidal effectiveness