[noun] The sun emits a spectrum of light rays that reach the surface of the earth, including ultraviolet (UV) rays. Although helpful in the body’s manufacture of vitamin D, UV rays can also be responsible for burns and even skin cancer. There are three key types of ultraviolet radiation.

• UVC rays, which have the shortest wavelength, are the most charged with energy. They are completely filtered out when they enter the atmosphere.
• UVB rays have a medium wavelength and shallowly penetrate the skin. They stimulate melanin production and allow lasting tanning, but can cause sunburn if the skin is not properly protected.
• UVA rays are the least energetic and have the longest wavelength. More than 95% of the UV rays that come into contact with our skin are UVAs. They are responsible for immediate tanning, but also for the appearance of dark spots with prolonged exposure. UVA rays also intensify skin ageing, as they impact the skin cells and support fibres of the dermis.