What percentage of sunlight that reaches Earth is UV light?

The correct answer highlights that approximately 5% of sunlight that reaches Earth consists of ultraviolet (UV) light. Understanding the composition of sunlight is essential for recognizing the significance of UV rays and their effects on both human health and the environment.

UV light is categorized into three types: UVA, UVB, and UVC. While the vast majority of sunlight is made up of visible light (around 46% of the sunlight that reaches the Earth) and infrared radiation (roughly 49%), the smaller percentage that falls into the UV range is critical for various biological processes, including vitamin D synthesis in the skin.

Appreciating that UV light constitutes about 5% of the solar spectrum helps in developing effective sun protection strategies and managing exposure to minimize health risks like skin cancer. This knowledge is particularly relevant in contexts such as tanning, where understanding UV exposure is key to promoting safe practices.