Sunscreen, also known as sunblock, sun cream or suntan lotion, is a lotion, spray, gel or other topical product that absorbs or reflects some of the sun 's ultraviolet (UV) radiation and thus helps protect against sunburn. Diligent use of sunscreen can also slow or temporarily prevent the development of wrinkles, moles and sagging skin.
Depending on the mode of action, sunscreens can be classified into physical sunscreens (i.e., those that reflect the sunlight ) or chemical sunscreens (i.e., those that absorb the UV light ).
Medical organizations such as the American Cancer Society recommend the use of sunscreen because it aids in the prevention of squamous cell carcinomas. Many sunscreens do not block UVA radiation, which does not primarily cause sunburn but can increase the rate of melanoma and photodermatitis. The use of broad- spectrum (UVA/UVB) sunscreens can address this concern.
Sunscreens are commonly rated and labeled with a sun protection factor (SPF) that measures the fraction of sunburn-producing UV rays that reach the skin. For example, "SPF 15" means that 1/15th of the burning radiation reaches the skin through the recommended thickness of sunscreen. Other rating systems indicate the degree of protection from non-burning UVA radiation.
Copyright 2024 puzzlefactory.com All rights reserved.
