When it comes to protecting yourself from the sun's harmful UV rays, the best way to ensure you're safe is to buy clothing that has been designed to provide protection. Although covering up can help block some of the UV radiation, it's important to remember that if you can see light through a fabric, UV rays can also pass through. Ultraviolet (UV) light is a form of energy that has wavelengths between 100 nanometers (nm) and 400 nm. To make sure you're getting the best protection, look for clothing labels that indicate the UV Protection Factor (UPF) value.
This value is a scale from 15 to more than 50 and indicates how much protection the garment provides against UV rays from the sun. Additionally, labels that say “Absorb UV rays up to 400 nm” or “Meet ANSI UV requirements” mean that the glasses block at least 99% of UV rays. It's important to note that UV rays reach the ground all year round, even on cloudy or foggy days. The intensity of these rays can vary depending on many factors, such as time of day, season, and location.
To get an idea of the intensity of UV light in your area on a given day, check out the United States National Weather Service and Environmental Protection Agency's (EPA) UV Index, which is a scale from 1 to 11+. Finally, it's important to limit your exposure to direct sunlight outdoors for too long. Additionally, because the ability of UV light to penetrate acrylic plastic depends on its chemical formulation, you may find plastic sheets that allow UV-C rays to penetrate.