UVA is a long, ultraviolet wavelength emitted by the sun and grow lights. UVA rays are the “aging” rays in the UV spectrum. This wavelength may have a greater potential to cause damage, as these rays penetrate the skin deeper. UVB, on the other hand, are the “burning” rays in the UV spectrum responsible for the skins color change. Both types of rays are capable of causing significant damage to the human body.