What does Broad Spectrum mean on a sunscreen label?
The sun emits two types of harmful rays: ultraviolet A (UVA) and ultraviolet B (UVB). UVA rays are the dominant tanning rays and are a major cause of skin aging and even skin cancer. UVB rays are predominantly the cause of sunburn and skin cancers, but can also contribute to the development of fine lines, dark spots and wrinkles. UVA rays penetrate through glass windows, UVB rays do not.