PEGI: Peroxide Enhanced Germicidal Irradiation for Rapid Bioaerosol Disinfection
EMMALEE BIESIADA, Mark Hernandez,
University of Colorado at Boulder Abstract Number: 568
Working Group: Control and Mitigation Technology
AbstractConventional aerosol disinfection systems rely either on chemical disinfectants or ultraviolet irradiation (UVGI) to inactivate airborne microorganisms. Here we present here, the engineered combination of trace hydrogen peroxide vapors with low-doses of ultraviolet light to achieve the accelerated disinfection of viral and bacterial bioaerosols. The purposeful activation of hydrogen peroxide with germicidal UV is introduced as PEGI: Peroxide Enhanced Ultraviolet Disinfection. Below its NIOSH personal exposure limit (1 ppm) vaporized hydrogen peroxide (H
2O
2) was activated using different doses of conventional and far UV light. Using separate UVGI sources (222 nm and 254 nm), we present the PEGI disinfection response of bioaerosols commonly use model the disinfection response of airborne bacteria and viruses. In both pilot (1m
3) and full-scale chambers (10m
3), the inactivation of airborne Bacillus subtilis, its spores and MS2 virus was observed at higher (60% RH) and lower (25% RH) humidity level, in the presence and absence of UV irradiation and peroxide vapor alone, and in combinations. Under all conditions tested, the inactivation rates associated with PEGI exposures were significantly greater than with either UV or H
2O
2 exposures alone, under otherwise identical conditions. These results suggest that PEGI induces a synergist biological inactivation response in the atmospheric environment at low and mid-range relative humidity. Under PEGI exposure, peroxide activation with 222 nm light enabled a more potent airborne disinfection scenario than its 254 nm counterpart, when normalized by the spherical irradiance (UV dose) received by the respective bioaerosols in the presence of trace amounts of hydrogen peroxide vapor. While the purposeful application of UV and hydrogen peroxide has been leveraged in aquatic environments for advanced oxidation of potable water, this approach has not been used for aerosol disinfection. Results from this study demonstrate PEGI feasibility and provide basic design parameters for the rapid inactivation of bioaerosols in contained environments.