Spatial and Temporal Stability of UV-C Sources Power Density in 254 nm Fluorescent Tubes Versus 260-280 nm Light-Emitting Diodes for Pathogen Eradication for Reliable UV-C Sterilization

Due to the SARS-CoV-2 pandemic and looming threat of other pandemics, stable, safe and reliable eradication of pathogen needs are at an all-time high. UV-C (100-280 nm) irradiation kills quickly pathogens compared to UV-A (315-400 nm), which is 1,000 times less effective and UVB (280-315 nm), 100 times. 254 to 265 nm UV-C optimal for sterilization, damages DNA and RNA in air and water, to a kill rate &gt; 99.99%. But different sources of UV-C vary in the stability of their power density PD. In this work, the PD of identical 253.7 nm UV-C fluorescent tubes are found to average variation of 25% if measured weekly for three short 60 s sterilization cycles. Two out of three UVC tubes lost > 90% output in 4 months. But identical sets of four 260-280 nm UVC LED with similar output average PD variation of < 12.5% and do not decrease after 4 months. 1 mL of calibrated pathogen solutions with 100 M CFU of Lacto B. A. and E. Coli. were applied on sterile slides and irradiated with both types of sources. Conventional epifluorescence microscopy and serial dilutions were used to measure kill rate along with a new technology, InnovaBug™, using epi-fluorescence macroscopy of DNA/RNA over an of 20x 50 mm 2 to detect and count pathogens in min.