What are UVA and UVB?
They are simply different wavelength bands of ultraviolet light with different ranges of wavelengths. UVB has shorter wavelengths and higher energy and does not penetrate the surface of the skin. It causes sunburn. UVA has longer wavelengths and penetrates below the surface of the skin where over time it causes permanent sun damage consisting of wrinkling, “aging,” and pigment changes. A sunblock that protects against both UVA and UVB is called “broad spectrum.”