What does the UV index measure?

The UV index specifically measures the strength of ultraviolet (UV) radiation from the sun. This index is a valuable tool used to inform the public about the potential for skin damage due to UV exposure, helping individuals make informed decisions about sun protection. A higher UV index indicates a greater risk of harm from unprotected sun exposure, which is particularly relevant for activities such as tanning.

In contrast, the other options focus on factors unrelated to the measurement of UV radiation. For instance, the amount of tanning lotion used does not indicate the level of UV radiation present, and the intensity of tanning bed lights varies by device and does not correspond directly to the natural UV exposure from the sun. Similarly, the duration of tanning sessions relates to exposure time rather than the measurement of UV radiation itself. Thus, understanding the UV index is crucial for promoting safe tanning practices and minimizing the risk of skin damage.