Sunscreen Continued
How Sunscreen Works
Sunscreens work by physically blocking ultraviolet light. Sunscreens may provide protection with various chemicals which act to either reflect the UV rays or absorb the radiation. White zinc oxide is a commonly used substance which, applied thickly, reflects UV rays. Para-aminobenzoic acid is a common substance that absorbs UVB rays, although it may cause an allergic reaction. Cinnamates also absorb UVB, while benzophenones absorb UVA and anthranilates absorb both.
The Effectiveness of Sunscreens
All sunscreens are graded according to SPF, or Sun Protection Factor. One easy way to calculate the efficiency of a sunscreen is to multiply the time that the skin can be exposed to the sunlight without burning by the SPF factor. For example, someone who can stay in the sun for 20 minutes safely would technically be safe for 200 minutes when using an SPF 10 sunscreen. However, studies show that most people do not apply sunscreen properly in amounts adequate to provide the graded level of protection, and doctors recommend a minimum of SPF 15 for general purpose use.
What Happens without Sunscreen
Skin that is repeatedly subjected to UV radiation over time may develop sun damage in the form of premature wrinkling, premature aging and even skin cancer. Special risk factors for UV ray susceptibility include fair skin, red or blond hair, light-colored eyes, easy burning of the skin, being prone to moles and freckles, high levels of sun exposure as a child or a familial history of skin cancer.
Using Sunscreen
Sunscreen should be applied at least twenty minutes before intended exposure to strong sunlight and be re-applied regularly to receive the benefits of its protection. Many cosmetic products today have built-in sunscreen, but people are encouraged to still use separate sun protection products, as the level of protection offered by such products is not generally adequate to prevent sun damage. However, such cosmetic products can give an extra level of protection to additional products.
By Kira Lee
|
|
