Ultraviolet radiation: overexposure

You are probably aware of some of the damaging effects of ultraviolet radiation from the Sun if you have ever suffered from a sunburn. Overexposure to ultraviolet radiation also is harmful to plants and animals, lowering crop yields and disrupting food chains. Living things can exist on Earth because ozone, a chemical in Earth s atmosphere, absorbs most of this radiation before it reaches Earth s surface. A chemical is any substance that has a definite composition. Ozone is a substance that consists of three particles of oxygen. 

If you have ever had a sunburn, you have experienced the damaging effects of ultraviolet radiation from the Sun. Overexposure to ultraviolet radiation is harmful to both plants and animals. Increased levels of a type of ultraviolet radiation called UVB can cause cataracts and skin cancer in humans, lower crop yields in agriculture, and disrupted food chains in nature. 

The most common exposure to ultraviolet radiation is from direct sunlight, and a familiar result of overexposure—one that is known to all sunbathers—is sunburn. Most everyone is also familiar with certain compounds and lotions that reduce the effects of the sun s rays, but many are unaware that some industrial materials, such as cresols, make the skin especially sensitive to ultraviolet rays. So much so that after... 

Ultraviolet radiation—The bright hght generated by the electric arc contains ultraviolet radiation. Without a shield or helmet outfitted with the correct filter grade, exposure can produce painful conjunctivitis or photoophthalmia, known as eye flash or arc eye. Immediate medical attention must be provided because overexposure may also cause overheating and skin burn. Because of this... 

Care must be taken to protect the eyes fi om direct or reflected illumination from ultraviolet lamps. Overexposure of the eye to UV radiation (180 to 390 nanometers) can cause extreme discomfort as well as injury. Generally, unless exposure has been extreme, the injury is of a transitory nature and involves photophobia and conjunctivitis which develop about two to four hours after exposure. In general, ordinary plastic or glass eyeglass... 

A chemical is any substance that has a definite composition. Ozone is a chemical that is made up of three particles of oxygen. Ozone forms a thick blanket above the clouds in the stratosphere. This layer of ozone protects Earth from overexposure to ultraviolet radiation from the Sun. You are probably familiar with the damage that exposure to ultraviolet radiation can do to your skin in the form of sunburn. Ultraviolet radiation can also harm other animals and plants. In the 1980s, scientists documented that the ozone layer arovmd Earth was becoming measurably thinner in some spots. 

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