Which type of ultraviolet radiation is primarily responsible for tanning the skin?

Ultraviolet radiation is categorized into three types: UV-A, UV-B, and UV-C, each with different effects on the skin. UV-A is the type of ultraviolet radiation that penetrates the skin more deeply and is primarily responsible for tanning. It stimulates the production of melanin, which leads to a darker skin tone as a response to sun exposure. This response is a natural protective mechanism against DNA damage caused by ultraviolet radiation.

UV-B, while it contributes to tanning, is more associated with sunburn and is primarily responsible for inducing skin damage and the production of Vitamin D. UV-C is mostly absorbed by the Earth's atmosphere and does not reach the skin, making it negligible in terms of tanning effects. X-rays are a form of ionizing radiation and are not a type of ultraviolet light, having a completely different effect on biological tissues.

Understanding this distinction is crucial for grasping how different types of UV radiation interact with the skin and the processes leading to tanning.