UV light, formally known as ultraviolet light, is a form of electromagnetic energy that falls between visible light and X-ray energy. At low levels, UV light triggers the natural production of vitamin D and provides benefits in the treatment of psoriasis and other skin diseases. Overexposure to UV light, however, can trigger a range of harmful side effects.
Sources
Most of our natural exposure to UV light, or UV radiation, comes from sunlight, according to the Health Physics Society. Significant sources of artificial UV exposure include black lights, tanning beds or lamps, mercury vapor lamps and certain types of lasers. UV light comes in a range, or spectrum, that includes the subtypes of light called UVA, UVB and UVC. The dangers of UV exposure vary according to each UV light subtype.
UVA Overexposure
The most common form of UV light is UVA, or black light, the Health Physics Society reports. At tolerable levels, UVA causes tanning of your skin and triggers the formation of beneficial vitamin D. Overexposure to UVA, however, can suppress your immune function, cause abnormal skin toughening and lead to cataracts. In addition to natural sunlight, common sources of UVA include tanning beds and lamps designed for the treatment of skin disorders.
UVB Overexposure
UVB is typically the most dangerous form of UV light and has the power to alter to normal function of your cellular DNA. Potential consequences of UVB overexposure include sunburn, the formation of cataracts and the onset of skin cancer. Normally, the ozone layer in the atmosphere prevents substantial amounts of UVB from reaching the planet's surface. But depletion of atmospheric ozone may increase the effects of UVB and in turn increase your risk of skin cancer.
UVC Overexposure
UVC is theoretically the most cancerous form of UV light, according to Ohio State University. Although atmospheric ozone absorbs the vast majority of this form of light and thereby significantly diminishes UVC-related dangers, ozone depletion may increase your UVC risks. If you use a welding machine, overexposure to the UVC content of a welder's light may cause burns on the corneas in your eyes, according to the Health Physics Society. Exposure to UVC light reflected off snow can produce snow blindness.
Considerations
Melanoma and other forms of skin cancer cause roughly 66,000 deaths globally each year, according to the World Health Organization. Although these cancers most commonly occur in light-skinned populations, they also occur regularly in dark-skinned populations. In fact, if you are dark-skinned, delays in detection may lead to the development of more serious cancer symptoms. In addition, roughly 2.5 million people go blind across the globe each year as a result of cataracts caused by or worsened by sunlight and UV exposure.
