UV rays: how do they work?
Sole, instructions for use
The solar spectrum it is composed of electromagnetic rays which in turn consist of waves of variable length and energy. The rays penetrate the skin more or less deeply, and can have both beneficial and harmful consequences.
UV and IR rays: what's the difference?
See also
THE ultraviolet rays (UV) are electromagnetic rays whose wavelength lies between that of visible light and that of X rays. Infrared rays (IR), on the other hand, have a wavelength greater than that of visible light.
There are various types of rays ultraviolet: UV-A (400-315 nm), UV-B (315-280 nm), UV-C (280-10 nm).
The most harmful are the UVC, which however do not reach the earth's surface because they are absorbed by the atmosphere, rejected by the ozone layer. This is the reason why the ozone hole is potentially dangerous.
The UVB, which have a medium wavelength, do not exceed the superficial layers of the skin, are absorbed by the stratum corneum.
95% of the UV rays that reach the earth's surface are made up of GRAPE, whose wavelength is quite wide and which can penetrate into the deep layers of the epidermis.
Features
The sensation of heat that the sun gives us is due to infrared rays, while ultraviolet rays pass through the atmosphere even when it is cold or cloudy.
It must be borne in mind that ultraviolet rays are more numerous between 12 and 16, and increase progressively as you go up in altitude. Furthermore, some elements reflect part of the UV received; this is the case of water (5% reflects), sand (20%), grass (5%) and especially snow (85%).
What are the consequences on the skin?
The UVB they act on the epidermis: they stimulate melanin, a reddish-brown pigment that colors the skin and protects it from the sun's rays. After 48 hours of UVB exposure, a lasting tan is obtained.
The GRAPE they penetrate deeper into the dermis and are responsible for skin aging as they damage the elastin and collagen fibers, two skin proteins whose lesions are irreversible. A sunburned area will remain delicate for life and must always be carefully protected.
The IR penetrate into the deep layers of the epidermis. They don't tan a lot but cause blood vessels to dilate which can be a source of small circulation problems.
Peculiarities
UVB, the pros: essential for the synthesis of vitamin D, which fixes the calcium in the bones and plays a fundamental role in the epidemic structure. In addition, they help us tan.
the cons: responsible for sunstrokes, they can cause mutations in the cell structure.
UVA, the pros: they tan quickly, but the tan is temporary.
the cons: produce free radicals, which alter the cells and supporting fibers, causing skin aging. Thus we witness the appearance of wrinkles and brown spots and even the development of some dermatoses (skin diseases), from the most benign to the most severe (melanoma: skin cancer).
IR, the pros: give a pleasant sensation of warmth.
the cons: dehydrate and dry the skin.
The solution?
Choose a good sunscreen: only in this way can you preserve the health of your skin!
