Ultraviolet (UV) radiation is a form of electromagnetic radiation with a wavelength shorter than that of visible light but longer than X-rays, ranging from about 10 nm to 400 nm. It is categorized into three types based on wavelength: UVA (320-400 nm), UVB (280-320 nm), and UVC (100-280 nm). UV radiation is primarily emitted by the sun, but artificial sources like tanning beds and mercury vapor lamps also produce it. While UVC is mostly absorbed by the Earth’s atmosphere and does not reach the surface, UVA and UVB penetrate the atmosphere and have significant biological effects.

UV radiation plays a crucial role in the synthesis of vitamin D in the skin, which is vital for bone health. However, excessive exposure can lead to harmful effects such as skin aging, sunburn, and an increased risk of skin cancer. It can also cause eye damage, including cataracts. In environmental contexts, UV radiation is a factor in the degradation of materials and contributes to the formation of ozone in the stratosphere, which protects life by absorbing most of the sun’s harmful UV radiation. Understanding UV radiation is essential for public health, environmental protection, and various technological applications, such as sterilization and fluorescence.