What percentage of natural sunlight is comprised of invisible ultraviolet light?

Natural sunlight is composed of various wavelengths, and a small portion of that spectrum includes ultraviolet (UV) light, which is not visible to the human eye. Approximately 5% of natural sunlight consists of ultraviolet light. This percentage highlights the significant yet relatively small portion of the solar spectrum that carries energy we cannot see but is crucial for various biological processes, such as vitamin D synthesis in the skin and the potential for skin damage and other health effects from excessive exposure.

Knowing this percentage is important in fields such as cosmetology and skincare, as it underscores the importance of protecting the skin from UV exposure, even on cloudy days or indoors, where UV light can still penetrate. Understanding these aspects of sunlight can significantly impact how treatments and products are formulated in the beauty industry.