Overview of Sun Rays and Skin Damage
Sunscreen is needed to protect the skin form two types of damaging rays from sunlight. They are called ultra violet or UV rays for short. The two types of ultra violet rays that can damage skin are UV-A and UV-B. Being exposed to these types of sun rays over a period of time can cause the short-term condition of sunburn. The amount of time it takes to get sunburn varies from person to person. Anyone can be sunburned, but the fairer the skin, the more easily it will burn.
Being exposed over a longer period of time can lead to skin cancer known as melanoma. In addition to skin health problems, overexposure to UV rays can affect immune system and eye health.
UV-A rays have a long wavelength and penetrate deeply into human skin. UV-A rays are not absorbed by the ozone layer of Earth's atmosphere.
UV-B rays are shorter than UV-A and do not penetrate as deeply into our skin. UV-B rays are the ones that cause sunburn. These rays are somewhat absorbed by the ozone layer.
UV-C rays are absorbed by Earth's ozone layer before they can cause damage to skin.
Sunscreen works by scattering or absorbing these UV-A and UV-B sun rays.
How Sunscreen Protects from UV Rays
Sunscreen protects skin from UV rays in two ways: 1) absorbing radiation and 2) reflecting radiation. In the first case, some specific ingredients in sunscreen work to absorb the damaging radiation in UV rays. These ingredients are the organic chemical compounds OMC (octyl methoxycinnamate) or oxybenzone. These organic compounds absorb the radiation from UV rays before they can penetrate the skin and then give off the energy in the form of heat. The inorganic chemical compounds in sunscreen work in the opposite way by reflecting harmful radiation off the skin before it can be absorbed and cause damage. Titanium oxide and zinc oxide are two of these types of active ingredients in sunscreen.
All Sunscreen Is Not Created Equal: Know About SPF
All sunscreens do not protect skin against both types of damaging UV rays. They do not all offer the same strength of protection either. This strength of protection from the sun is measured as SPF or sun protection factor. The higher the SPF, the more protection the sunscreen will provide from UV-B rays only. SPF doesn't refer to protection from UV-A rays. To protect yourself from UV-A rays, buy a broad spectrum protection product. An SPF of 15 will protect the skin from most of the harmful UV rays.
Things That Can Affect How Well Sunscreen Works
Even the effectiveness of the best sunscreen decreases when it's not used according to manufacturer's instructions so follow the guidelines on product labels. Here are some things that can diminish the effectiveness of sunscreen:
1. Not applying enough sunscreen.
2. Not reapplying sunscreen as often as recommended on the label.
3. Drying off with a towel after sweating or swimming, which can wipe away even waterproof sunscreen from the skin.
4. Being outdoors when the UV rays are strongest, during the hours of 10a.m. and 4 p.m.
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