Sun Protection Factor, more popularly known as SPF, is a measure of how well a sunscreen can protect the skin from harmful UVB radiations. Experimentally, it is the ratio of amount of light that induces redness in sunscreen-protected skin, to the amount of light that induces redness in unprotected skin.
Harmful Effects of UV Rays
Sunscreens should not be perceived as a cosmetic but as an essential to protect one’s skin. Thus, any individual exposing their skin to UV radiations through direct sunlight, especially in a tropical country such as India, requires a sunscreen. The numerous toxic effects of UV from natural sunlight and therapeutic artificial lamps are a major concern for human health. Some of the acute effects of UV irradiation on normal human skin comprise sunburn inflammation (erythema), tanning and local or systemic immunosuppression.
Decoding Percentage of SPF Factor in Your Sunscreen
SPF is not directly related to time of solar exposure but to amount of solar exposure. Also, SPF and percentage of UV ray protection does not follow a linear curve. A compilation of the same is as given below:
It has been evaluated that SPF 30 blocks 97% UVB rays which is ideal for protection from harmful rays when exposing skin to the sun on a normal sunny day. A higher SPF value renders better skin protection.
How to Apply Sunscreen
The amount of sunscreen applied is directly proportional to the amount of solar radiation absorbed. In other words, more sunscreen results in less solar energy absorption. Since sunscreens may wear off and become less effective with time.Read More..
Also Read: Homemade Honey Face Mask Recipes for Beautiful Skin
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