Ultraviolet (UV) light emitting diodes (LEDs) are an emerging technology for surface disinfection. UV LEDs emitting UV-C irradiation have proven effective in inactivating bacterial, viral and protozoan pathogen surrogates and have been demonstrated for point-of-use disinfection (Chatterley and Linden, 2010, Bowker et al., 2011, Lui et al., 2016).
UV-C LEDs have enormous potential since they are smaller, lighter, and less fragile than traditional mercury vapor lamps (Vilhunen, 2010). Additionally, they are mercury-free and provide the capability to be turned on and off instantaneously.
Considerable research has evaluated UV-C LEDs at various wavelengths for pathogen inactivation. Several studies have evaluated the efficacy of germicidal UV LED irradiation, emitted in relatively narrow bandwidths (nominal full width at half maximum, FWHM, of 10–12 nm) at or near 255 nm, 265 nm, 269 nm, 275 nm, 280 nm, and 285 nm for inactivating Escherichia coli (Chatterley and Linden, 2010, Vilhunen, 2010, Bowker et al., 2011, Oguma et al., 2013, Oguma et al., 2016, Lui et al., 2016). At least two studies evaluated UV LEDs emitting at or near 250 nm, 270 nm, and 282 for inactivating Bacillus subtilis spores (Wurtele et al., 2011, Morris, 2012). Other research evaluated UV LEDs emitting at 255 nm and 275 nm for inactivating coliphage MS2 and T7 (Bowker et al., 2011). A recent study evaluated UV LEDs emitting at 285 nm for inactivating adenovirus 5, MS2, and QB (Oguma et al., 2016).
