Sunlight contains three divisions of ultraviolet radiation; UVA, UVB, and UVC (which does not reach the Earth’s surface). The lower stratosphere of the Earth contains oxygen that absorbs the majority of the harmful UVB radiation. The overwhelming majority, 99 percent of the ultraviolet rays that reach the Earth’s surface, are UVA.
“When the ozone layer becomes thin, however, more UVB radiation reaches Earth’s surface and may have hazardous effects on organisms. For example, studies have shown that UVB radiation penetrates the ocean’s surface and may be lethal to marine plankton to a depth of 30 metres (about 100 feet) in clear water” (Ultraviolet Radiation, 2013).
In humans, ultraviolet radiation can cause several harmful effects. Some of these include
“reddening of the skin (sunburn), pigmentation development (suntan), aging, and carcinogenic changes. Ultraviolet sunburns can be mild, causing only redness and tenderness, or they can be so severe as to produce blisters, swelling, seepage of fluid, and sloughing of the outer skin. The blood capillaries (minute vessels) in the skin dilate with aggregations of red and white blood cells to