The reddening, swelling and pain sunburn are the symptoms of toxic reaction to the sun's ultraviolet(UV) rays.
UV rays penetrate into our skin and damage the molecules on the skin's surface.
UV rays are respondsible for photoaging and skin cancer. Therefore to prevent over exposure under the sun, sunscreen is recommanded.
Sunscreen combine organic and inorganic chemicals to filter the the UV rays from the sun so it does not reach the deeper layer of our skin.
Sunscreens include sunblocks as one of their active ingredients.
Sunblock able to reflect the light away from skin. It contain reflective particles such as zinc oxide.
Zinc oxide is the metal zinc that has been oxidized. The chemical formula is ZnO, held together by an ionic bond.
Zinc oxide is a broad spectrum blocker.The particles sit on the outermost layer of our skin and absorb the ultraviolet radiation, protecting the living skin below.
Other than zinc oxide, there are some organic molecules in sunscreen can absorb the ultraviolet radiation and release it as heat:
- PABA(para-aminobenzoic acid) absorb UVB
- Cinnamates absorb UVB
- Benzophenones absorb UVA
- Anthranilates absorb UVA and UVB
- Ecamsules absorb UVA
