Radiation which occupies the segment of the electromagnetic wavelength spectrum between 10 to 400 nanometers, invisible to the human eye. That’s why UV lights are often referred to as “black” lights. Ultraviolet radiation is widely used in industrial processes and research practices. Ultraviolet radiation emitted by the sun or man-made sources (e.g. tanning beds or lamps, lasers, arc welding etc.) is considered as a cancer-causing agent.
UVA is a type of ultraviolet (UV) radiation. UVA radiation penetrates deep into the skin and is responsible for premature aging of the skin and skin cancer.