Ultraviolet radiation is an electromagnetic radiation emitted by the sun that hits the earth in waves that can range from 200 to 400 nanometers in length. This radiation is responsible for 9% of all energy emitted by the sun reaching the planet’s surface.
The name of ultraviolet radiation is related to the frequency with which this radiation reaches the earth, because it is larger than visible light, with violet being the most frequent color that can be seen by human eyes.
Also called simply UV, ultraviolet radiation can present a number of risks to humans and other life forms on the planet, which can cause various injuries and burns. However, the Earth has natural protection against the sun’s ultraviolet rays, the ozone layer, which filters out most of this radiation, thus acting as a kind of natural shield on planet Earth, preventing radiation from letting it hit it lethally.
However, not all effects of ultraviolet radiation are negative for life, and ultraviolet rays are also responsible for the main source of vitamin D, essential for the body. That is, it is healthy for human skin when exposure to these rays is done in a moderate manner, avoiding periods when sunlight is strongest and most intense.
Types of Ultraviolet Radiation
Ultraviolet radiation can be divided into three different types of radiation according to their wavelengths, these being UVA rivers, UVB rays and UVC rays.
UVA rays are the most common type of ultraviolet radiation, as they have waves that extend from 320 to 400 nanometers, which makes them the rays with the highest incidence on the surface of planet Earth.
Another factor that makes these the most frequent rays is linked to the fact that these rays are not filtered by the ozone layer, which means that without this filter, UVA rays reach Earth equally throughout the earth. even when the days are cloudy or cloudy. In addition, its incidence is equal in all seasons of the year.
Although not at high risk for health, UVA rays can cause a lot of damage to the skin when absorbed in a disorderly manner and can lead to some lesions on deeper layers of the skin, destroying elastin and collagen fibers, for example. thus causing premature aging, among other problems.
Therefore, the use of sunscreens is essential to prevent exposure to UVA rays from allowing this type of ultraviolet radiation to cause serious health problems, and to avoid exposure to the sun in periods of greater intensity.
UVB rays, unlike UVA, have a shorter length, ranging from 280 to 320 nanometers, which allows them to be partially filtered by the ozone layer. This way, only a small part of the UVB rays reach the earth’s surface.
The fact that it is filtered makes UVB rays present different levels of incidence during the year, and summer is the time with the highest incidence of this type of ultraviolet radiation on Earth. This difference is also felt during the day, with the period from 10h to 16h being the most intense UVB rays, and exposure to this radiation should be avoided.
Because it is a type of radiation that can cause the most damage to the skin and general health, UVB rays are the ones that attract the most studies, as measuring its incidence allows problems to be identified as holes in the layer. ozone, for example, so that such problems can be known by the incidence of UVB rays on the earth’s surface.
Exposure to UVB rays is even more harmful than exposure to UVA rays, as this type of radiation can cause reddening of the skin in a short time and severe skin burns. In addition, UVB rays can cause skin cancer and eye problems such as cataracts or even permanent blindness.
Thus, as with UVA rays, the use of sunscreens during any exposure to UVB rays is critical, as well as avoiding long exposure to these rays.
UVC rays have the shortest waves among the three types of ultraviolet radiation, with waves smaller than 280 nanometers. These waves are completely filtered through the ozone layer so that UVC rays do not reach the earth’s surface.
This filter is essential for life on Earth since UVC rays are completely harmful to the biosphere so the ozone layer filter is essential for life.
However, through artificial sources, UVC rays are reproduced in some situations so that they can be used in sterilization procedures, especially in surgical materials, or in water treatment plants, since this type of ultraviolet radiation has great bactericidal properties, contributing positively to such procedures.