Ultraviolettvalgus

Ultraviolet radiation, often abbreviated as UV, is a form of electromagnetic radiation with wavelengths shorter than visible light but longer than X-rays. It is invisible to the human eye but can be detected by special instruments. UV radiation is typically divided into three categories based on its wavelength: UV-A, UV-B, and UV-C.

UV-A radiation has the longest wavelengths, ranging from 315 to 400 nanometers (nm). It is the most abundant type of UV radiation reaching the Earth's surface and is responsible for the tanning effect on human skin. UV-A can also penetrate deep into the skin and cause damage to the DNA, leading to skin aging and wrinkles.

UV-B radiation has wavelengths between 280 and 315 nm. It is the primary cause of sunburn and is also responsible for the development of skin cancer. UV-B radiation is absorbed by the ozone layer in the Earth's stratosphere, which helps protect life on Earth from its harmful effects.

UV-C radiation has the shortest wavelengths, ranging from 100 to 280 nm. It is the most energetic type of UV radiation and is almost entirely absorbed by the Earth's atmosphere, making it harmless at the surface. However, it is used in various applications such as sterilization and water purification.

UV radiation is produced by the Sun and by artificial sources such as tanning beds, black lights, and mercury-vapor lamps. Exposure to UV radiation can have both beneficial and harmful effects on human health. While UV-B radiation is known to cause skin cancer and other health issues, UV-A radiation can also contribute to skin aging and other skin problems. Therefore, it is important to protect the skin from excessive UV exposure by using sunscreen, wearing protective clothing, and seeking shade when possible.