The sun, in addition to providing heat and light essential for life, is responsible for emitting different types of radiation; exposure to some of them can cause from wrinkles, redness and inflammation, until alteration in the cells. That's why you need to protect yourself from the sun even if it's cloudy.
Thanks to the terrestrial atmosphere, the radiations that are more energetic like gamma rays, x and UV can not reach us directly.
According to Dr. Mauro Valdés Barrón, coordinator of the Solar Radiation Section of the Institute of Geophysics of the UNAM , UV rays that are classified according to their wavelength in UVA, UVB and UVC, interact differently with the atmosphere.
"The ozone layer stops 100 percent of the UVC, ninety percent of the UVB type and totally lets the ultraviolet UV rays pass".
Once UV rays pass through the ozone layer they continue to interact with other elements, such as the clouds that are responsible for slowing from five to ten percent of said radiation.
"Particles that are suspended in the atmosphere whether they are of natural or human origin, such as soot, dust, sea breeze or ash from a volcano, also deflect or modify UV rays, but they can only be attenuated by less than two percent."
When this type of radiation reaches Earth, the skin, the organ of greater extension in the human being, is the one in charge of protecting us. This is thanks to the fact that the epidermis is formed mainly of keratinocytes, cells that produce keratin that prevents solar radiation from damaging internal tissues.
In the epidermis is also melanin, the pigment in charge of the color of our skin, hair and iris, which when interacting with the UV rays it turns them into harmless heat.
Melanin is also responsible for tan of our skin. When UV rays come in contact with it there is an increase in its production in order to offer protection against burns.
But when there is an excess of radiation these protective cells can break. That's why Dr. Valdés Barrón recommends protecting yourself from the sun even on cloudy days with 3 easy steps:
These simple methods of protection are essential to avoid damage such as burns, cataracts or skin cancer. Always use them in the most sunny hours, it does not matter if the day is cloudy.
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