UV air disinfection respiratory viral aerosols

다국어 초록 (Multilingual Abstract)

Ultraviolet (UV) air disinfection is one of the engineering control methods utilized to control airborne transmission of pathogenic microorganisms in high risk settings. However, despite the recent emergence of respiratory viral pathogens such as SARS coronavirus and avian influenza viruses, UV air disinfection of viral aerosols is poorly studied. Hence, we characterized UV disinfection of viral aerosols using MS2, adenovirus, and coronavirus. The objectives of this study are (1) characterize the effect of nebulization and air sampling on the survival of tested viruses; (2) quantitatively estimate UV susceptibilities of these viral aerosols; (3) evaluate the effect of relative humidity (RH) on the susceptibility of viral aerosols to UV irradiation. A bench-size experimental chamber was built and evaluated for this study. MS2, adenovirus, or coronavirus was aerosolized into the experimental chamber, exposed to different UV doses, at either 50% or 75-80% RHs, and then sampled by AGI-30 liquid impinger at 12.5 LPM. The collected samples were analyzed by plaque assays to measure the UV susceptibilities of tested viral aerosols. Our data indicated that neither nebulization nor air sampling using liquid impinger caused significant inactivation of non-enveloped viruses such as MS2 or adenovirus. However, coronavirus was significantly inactivated by both nebulization and air sampling. Both MS2 and adenoviruses were very resistant to UV air disinfection. Less than 1 log reduction in viable virus was observed at the 2.6 mJ/㎠ UV dose for both viruses. However, coronavirus was more susceptible to UV air disinfection, which suggests that UV air disinfection could be an efficient environmental control method to prevent airborne transmission of novel SARS coronavirus. There was no significant protective effect of high RH on UV susceptibilities of the tested viral aerosols. Finally, our study also confirmed that UV disinfection rates of viral aerosols are much different from those of viruses suspended in water.