A kindergarten teacher apologizes to parents for using ultraviolet lamps, or UV lamps, on her students in Hangzhou, East China's Zhejiang province, May 22, 2012. The teacher, surnamed Dai, used the UV lamps to intimidate and punish children who misbehaved. She has been suspended from her post, and the local government launched an investigation. The 42 kids in the class received medical exams following the incident.

Ultraviolet rays are used to kill bacteria, viruses and mold spores. Exposure to UV light causes human skin to create Vitamin D, which helps bones absorb calcium. But excessive exposure can damage the DNA in skin cells and increase a person's risk for both melanoma and non-melanoma skin cancer. [Photo/CFP]