The sun transmits electromagnetic radiation in waves or particles at different wavelengths and frequencies. This range of wavelengths is called the electromagnetic (EM) spectrum. Ultraviolet light (UV) is one of the regions of the electromagnetic spectrum.There are two types of Ultraviolet (UV) light that can harm your skin — UVA and UVB.  Broad-spectrum ultraviolet radiation (UVA and UVB) is the strongest and most damaging to living things, according to the National Toxicology Program.UVA rays can prematurely age your skin, causing wrinkling and age spots. UVB rays can burn your skin. Too much exposure to UVA or UVB rays can cause skin cancer. A broad-spectrum sunscreen can protect you from both UVA and UVB radiation.