Skip to main content.
Enviropaedia Sponsors and Supporters

Ultraviolet Light

( Article Type: Explanation )

Ultraviolet (UV) radiation is between visible light and X-rays on the spectrum (4 x 10-7 to 5 x 10-9). The UV spectrum is further divided by wavelengths into A, B and C bands. Most UV radiation is absorbed in the ozone layer before it reaches the lower reaches of the atmosphere. In people, it acts on ergo sterol in the skin to produce vitamin D and is absorbed by melanin in the skin causing it to darken. Within cells, it causes damage through chromosome breakage. Excessive exposure to ultraviolet radiation results in skin cancer. Research studies are beginning to suggest that the weakening of the ozone layer by industrial activities may be affecting the southern hemisphere and that the incidence of skin cancer, particularly in South Africa, is rising. Health specialists now agree that it is dangerous to spend time exposed to the sun without some form of protective layers to reduce the effects of ultraviolet radiation. There is no consensus on the value and success of using sun-block lotions to minimise the effects of ultraviolet light on the skin.

Associated Organisations: