Lim, Mariana K.Fadaka, Esther A.Germicidal ultraviolet (GUV) radiation, particularly shortwave UV-C (200-280 nm) is a promising technique used for disinfection of several microbiological targets. In the wake of the COVID-19 pandemic, its use for disinfecting eukaryotic viruses has garnered attention as an intervention to prevent transmission of airborne respiratory viruses. This study examines 222 nm GUV, primarily in liquid, and uses various bacteriophages (MS2, Phi6, T1, and T4) as surrogates to model eukaryotic viruses, aiming to broaden current understanding of GUV disinfection efficacy and virus models. Usage of bacteriophages (RG1 organisms) as virus surrogates serves as a low risk alternative to handling pathogenic viruses (RG2 organisms), allowing for safer infectious disease transmission mitigation research. UV exposures of bacteriophages were conducted in a collimated beam chamber designed according to Bolton and Linden (2003) [1], which was validated using iodide/iodate actinometry. For MS2 phage experiments, approximately 0.75, 1.1, 4.5, and 6.4 log reductions in PFU/mL were observed following UV exposures of 2.5, 5, 15, and 30 minutes (fluence of 7.60, 15.22, 45.65, 91.29 mJ/cm2), respectively. Liquid experiments with other phages are still ongoing. Continued efforts will also explore 222 nm disinfection in an aerosol state via a single pass flow chamber, using the same virus models as in liquid. Future work will also repeat all experiments with eukaryotic viruses such as influenza to compare virus behavior to that of the phages. [1] Bolton, J. R., & Linden, K. G. (2003). Standardization of methods for fluence (UV dose) determination in bench-scale UV experiments. Journal of environmental engineering, 129(3), 209-215.en-USGermicidal UVUV disinfectionBacteriophagesInfluenzaSARS-CoV-2Viral transmission222 nmPresentation