Efficiency of Workplace Air Disinfection Using a Photocatalytic Recirculator

Introduction: Photocatalytic recirculators located along the natural movement of air disinfect and neutralize indoor air, promote its circulation, and fill the interior volume with purified air according to the “general” or “dispersing” scheme, thus reducing the levels of air pollutants. Yet, they are unable to provide adequate protection against severe pollution close to its source. 
Objective: To study the efficiency of disinfection of the workplace air using a specially developed forced and exhaust photocatalytic recirculator. 
Methods: Testing was carried out in the breathing zone of a laboratory assistant at the workplace without natural and artificial ventilation in the box of the Department of Clinical Microbiology. The efficiency of air disinfection was judged by a decrease in the total microbial count after ultraviolet and photocatalytic treatment using the recirculator. 
Results: In the chamber of the developed forced and exhaust photocatalytic recirculator, high energy illumination and exposure to ultraviolet radiation of the C spectrum are created, as well as high surface and volume density of bactericidal flux and bactericidal energy, corresponding to the experimental values of antimicrobial surface and volume doses at 95 % bacterial efficiency for Staphylococcus aureus. We established that the recirculator provided a 90.19 % air disinfection per cycle and supplied the air with 94.99 % and 95.53 % of microbes killed to the breathing zone of the laboratory assistant at distances of 1 m and 2 m at an acceptable velocity. It also disinfected the contaminated air by 96.55 % and 95.97 % at the workplace at distances of 1 m and 2 m by exhausting the air at an acceptable velocity compared to a serial photocatalytic recirculator. 
Conclusion: For effective air purification in the working space, it is advisable to use the developed photocatalytic recirculator equipped with additional air ducts, which ensures the exhaust of 96 % of contaminated air and the disinfection rate of 95 % at an acceptable speed.