What is ultraviolet (UV) light?
Ultraviolet light (UV) is a form of electromagnetic radiation with a wavelength from 100nm to 400nm. The UV spectrum is further broken down into 3 bands known as UVC, UVB, and UVA. UVC wavelengths are from 100-280nm, UVB wavelengths are from 280- 315nm, and UVA wavelengths are from 315-400nm. UV is present naturally in solar radiation. Radiation is the emission energy in the form of waves or particles through space or through a material medium, and includes, among other forms, ultraviolet, visible light, and infrared emission. Above the Earth’s atmosphere, solar radiation is 10% UV (UVC, UVB & UVA), 40% visible, and 50% infrared. After passing through the Earth’s atmosphere, radiation is 5% UV (UVB & UVA only), 43% visible, and 52% infrared. All UVC is absorbed by the Earth’s atmosphere, which notable as it relates to UV light disinfection technology because most UV light disinfection technology is based on UVC wavelengths and must be electrically generated. See other FAQs for more information on specific UVC sources.
