Ultraviolet, or UV, radiation is, basically, sunlight. There are three types of ultraviolet light: ultraviolet A (UVA), ultraviolet B (UVB), and ultraviolet C (UVC). UVC light is absorbed by the ozone layer, but UVA and UVB rays reach the earth, and are absorbed by our skin. UV radiation from sunlight provides some health benefits, but excessive UV radiation can also be dangerous. Sunscreen can help protect against some of these dangerous effects.
Vitamin D
Most people get the majority of their vitamin D through UV radiation from sun exposure. The synthesis of vitamin D --- crucial for healthy bones --- begins when sunlight reaches the skin, according to the National Institutes of Health. A person's ability to convert sunlight into vitamin D depends on many factors, including geography, melanin content, and use of sunscreen. People with rickets --- a condition caused by vitamin D deficiency --- are often treated with UV radiation.
Skin Benefits
Chronic skin conditions such as eczema and psoriasis can be successfully treated with UV radiation, the World Health Organization reports. People who undergo UV radiation under the supervision of a medical practitioner often see a noticeable improvement in the bothersome symptoms these conditions cause. However, because of the potential dangers, UV radiation therapy should only be administered by a knowledgeable health-care professional.
Cancer
UV radiation on unprotected skin is a significant risk factor for skin cancer, according to the American Cancer Society. Both melanoma, the most serious form of skin cancer, and non-melanoma skin cancers are directly linked to too much UV radiation from exposure. With more than 2 million cases of non-melanoma skin cancers diagnosed in the United States each year, skin cancer is the most common form of cancer, and the majority of cases are linked to sun exposure, the American Cancer Society reported in 2009. continues to be one of the most common forms of cancer.
Sunburn
The most immediate effect of UV radiation is sunburn. The skin burns when the amount of ultraviolet radiation exposure is in excess of the melanin content in the skin, according to Oklahoma State University. Fair-skinned individuals have less melanin, and thus become sunburned more easily.
Premature Skin Aging
Chronic, excessive exposure to UV radiation can also cause the skin to age prematurely, resulting in wrinkles and creases, according to the Environmental Protection Agency. As the skin ages, it also gets thick and leathery.
Eye Damage
Excessive UV radiation increases a person's chance of certain eye conditions, the Environmental Protection Agency warns. Macular degeneration, skin cancer around the eyes, the growth of tissue in the eye that affects vision, and certain types of cataracts can all result from too much sun exposure.
References
- U.S. Environmental Protection Agency: Health Effects of UV Overexposure
- World Health Organization: Health Effects of UV Radiation
- American Cancer Society: Skin Cancer Facts
- Oklahoma State University: What Is Ultraviolet Radiation?
- National Institutes of Health Office of Dietary Supplements: Vitamin D
