Have you heard about the UVA and UVB? Let me first introduce the meaning of both words. UV refers to ultraviolet light and it's devided into three types; UVA, UVB and UVC. It is named Ultraviolet means its spectrum has electromagnetic waves with frequencies higher than those that the human eye can identify as the color violet. UVA and UVB. Among UV subtypes, UV subtype A or UVA has the longest wavelength measuring between 320 and 400 nanometers (nm) and has two other wave ranges within at 340 to 400nm and 320 to 400nm. Another subtype is the UV subtype B also known as UVB which has a range of 290 to 320nm. While, UVC radiation, does not penetrate the atmosphere's ozone layer and does not reach Earth makes it less known. For the purpose of skin health, UVC rays are of little or no concern. Nearly 100% of the UVC rays emitted by the sun are absorbed by the ozone layer before the sun's rays ever reach the Earth.
How does this electromagnetic waves can cause aging? As you know, UVA and UVB types are harmful to our skin, damaging its surface and inner structure when taking prolonged sunbaths. UVA damages collagen fibers of the skin there by contributing to the speedy aging of the skin.The UVA damage is deeper, as the UVA rays are longer than the UVB and it reach the inner strata of the skin. They are responsible for causing the skin to lose its elasticity and wrinkling, leading to premature aging of the skin. They also can burn the skin, but at a deeper level. The UVA rays are not at all absorbed by the atmosphere and completely reach Earth.
Mean while, the UVB rays are mostly responsible for most cases of sunburn, as they are shorter than UVA rays and only reach the surface of the skin that is made up of the epidermis layer. The UVB radiation is absorbed by the stratum corneum on the epidermis surface. This stratum corneum is the dead cells layer - the visible layer of the skin. The UVA radiation is partly absorbed and blocked by the ozone layer before reaching Earth.
Futhermore, UV rays can also cause other disorders of the skin besides cancer, such as photoaging, actinic keratoses, lupus vulgaris (tuberculosis of the skin), psoriasis or vitiligo (a discontinuous depigmentation of the skin.) So, protect yourself from exposing to harmful UV rays of the sun with sunscreen or UV protection for a healthier skin and slow the aging! To read more on how to slow aging, read HERE.