Portable air cleaners with HEPA filtration and UV-C irradiation to reduce air contamination in a multi-patient dental environment.

BACKGROUND

Aerosols and droplets generated by dental procedures can carry infectious agents such as bacteria, fungi, and viruses (i.e., bioaerosols), contaminating the air before settling on to surfaces.

METHODS

This in situ study evaluated the air decontamination achieved using two commercial portable devices equipped both with high-efficiency particulate air filters (HEPA) and ultraviolet germicidal irradiation (UV-C) in a shared dental environment located in Recife, Pernambuco, Brazil. The environment was assessed through physical, chemical, and microbiological assays. Data were analysed using analysis of covariance (ANCOVA) or a Wilcoxon test.

FINDINGS: Compared with control, both air cleaners significantly reduced bioaerosol counts and improved indoor-to-outdoor (I/O) ratio values, particularly after 6 h of continuous operations near an aerosol source. These results suggest that portable air-cleaning devices positioned close to aerosol sources can effectively reduce microbiological contamination in shared dental environments, complementing personal protective equipment (PPE) and manual cleaning routines. In this setting, both portable air-cleaning devices (Model 1 and Model 2) significantly decreased bioaerosol levels, with Model 1 showing greater efficacy for particles ≤5 μm after adjusting for confounders. Significant reductions were observed after 6 h of continuous use. Although both devices met the recommended air quality limits, air changes per hour remained below clinical standards, highlighting the need for multiple units.

CONCLUSION

Portable air cleaners can support infection control; however, ventilation system upgrades, consistent PPE use, and administrative controls remain essential, even in the post-COVID-19 era.