Ultraviolet Radiation

Ultraviolet (UV) radiation is defined as that portion of the electromagnetic spectrum between X-rays and visible light, with wavelengths that range between 40 and 400 nanometers (nm). This wavelength interval falls in the energy range of 3 to 30 electron volts (eV). The UV spectrum is divided into the following five categories:

• Vacuum UV with wavelength of 40 to 190 nm
• Far UV with wavelength of 190 to 220 nm
• UVC with wavelength of 220 to 290 nm
• UVB with wavelength of 290 to 320 nm
• UVA with wavelength of 320 to 400 nm

The sun is our primary natural source of UV radiation. Artificial sources include germicidal lamps, mercury vapor lamps, tanning booths, black lights, curing lamps, halogen lights, high-intensity discharge lamps, fluorescent and incandescent sources, and some types of ...