Effect of Ozone Gas on Removal of Airborne Particles

Airborne particles are one of the most important factors in the spread of infectious pathogens and must be monitored in healthcare facilities. Viable particles are living microorganisms, whereas non-viable particles do not contain microorganisms but act as transport for viable particles. The effectiveness of ozone in reducing these particles in a non-controlled room and a controlled cleanroom using high-efficiency particles air (HEPA) filter was analyzed in this study.

Viable particles and non-viable particles sized 0.5 and 5 μm were quantified before and after ozonation in two different health environments: non-controlled (group 1) and controlled area, which was associated with a HEPA filtering system (group 2). Active air sampling using a MAS 100 was used to count the number of viable particles, while the number of non-viable particles/m³ was obtained following the manufacturer's recommendations of the Lasair III 310C system.

Our results of the viable particles counting were not quantifiable and analyzed using statistical tests. Both groups showed a slight tendency to reduce the number of viable particles after ozonation of the environmental air. A statistically significant reduction of non-viable 5 μm particles after ozonation was observed in both groups (G1: p = 0,009; G2: p = 0,002). Reduction in the non-viable 0.5 μm particles after ozonation was observed only in group 2, associated with the HEPA filter. In group 1, after ozonation, a significant increase in 0.5 μm particles was observed, probably due to the breaking of 5 μm particles by ozone gas. Our results suggest that ozone gas can break 5 μm particles and, when associated with a HEPA filter, increases its effectiveness in removing 0.5 μm particles.

Considering that 5 μm particles are important in the air transport of microorganisms, their reduction in the environment can be a relevant parameter in controlling the dissemination of infections.