The direct effects include reddening of the skin ( sunburn ), pigmentation development (suntan), aging, and carcinogenic changes. This vitamin not only assists in growth and maintenance of the bone, but it also aids in regulation of electrolyte metabolism, protein synthesis, gene expression, and immune function which is why it is largely important to athletes, ranging from hikers, to tennis players and runners. Our editors will review what you’ve submitted and determine whether to revise the article. This decreases our atmosphere’s natural protection from the sun’s harmful ultraviolet (UV) radiation. When these cells die, the pigmentation disappears. Please log in using one of these methods to post your comment: You are commenting using your account. According to scientists, exposure to X-rays can easily damage our delicate cells and tissues. We use cookies to ensure that we give you the best experience on our website. electromagnetic radiation: Ultraviolet radiation. It’s not possible to avoid sunlight completely, but there are ways to help ensure that people don’t get too exposure to UV rays: In doing so, people can enjoy the sun and ensure that they don’t develop any life threatening conditions. ( Log Out /  The German physicist Johann Wilhelm Ritter, having learned of Herschel’s discovery of infrared waves, looked beyond the violet end of the... One of the first images taken by the Solar and Heliospheric Observatory's Extreme-Ultraviolet Imaging Telescope. The three basic skin cancers, basal- and squamous-cell carcinoma and melanoma, have been linked to long-term exposure to ultraviolet radiation and probably result from changes generated in the DNA of skin cells by ultraviolet rays. Change ), You are commenting using your Facebook account. Articles from Britannica Encyclopedias for elementary and high school students. Based on the interaction of wavelengths of ultraviolet radiation with biological materials, three divisions have been designated: UVA (400–315 nm), also called black light; UVB (315–280 nm), responsible for the radiation’s best-known effects on organisms; and UVC (280–100 nm), which does not reach Earth’s surface. Ultraviolet radiation lies between wavelengths of about 400 nanometres (1 nanometre [nm] is 10−9 metre) on the visible-light side and about 10 nm on the X-ray side, though some authorities extend the short-wavelength limit to 4 nm. UVC rays- These have more energy than the other types of UV rays with the shortest wavelengths (200-290nm). Persons of light complexion have less melanin pigment and so experience the harmful effects of ultraviolet radiation to a greater degree. Several major health problems, such as skin cancer(melanoma and nonmelanoma), premature aging, cataracts and other eye damage, and immune system suppression, all result from overexposure to these harmful rays. Ultraviolet (UV) radiation is undetectable by the human eye, although, when it falls on certain materials, it may cause them to fluoresce—i.e., emit electromagnetic radiation of lower energy, such as visible light. However, the level at which the rays influence vitamin D synthesis is largely unknown as it is dependent on other factors such as age, darkness of skin, and intensity of sunlight and can vary across several groups of people. Ultraviolet radiation is produced by high-temperature surfaces, such as the Sun, in a continuous spectrum and by atomic excitation in a gaseous discharge tube as a discrete spectrum of wavelengths. Ultraviolet radiation, that portion of the electromagnetic spectrum extending from the violet, or short-wavelength, end of the visible light range to the X-ray region. Long exposure or high intensities of UV hurts the eyes tissues and causes a ‘burning’ of the eye, called ‘snow blindness’. Let us know if you have suggestions to improve this article (requires login). Our latest podcast episode features popular TED speaker Mara Mintzer. For malignant skin cancer, those in the 90th percentile for physical activity have an increased risk of cancer than those in the 10th percentile. As a rule, after regeneration of the epithelium, vision is fully restored. Unlike X-rays, ultraviolet radiation has a low power of penetration; hence, its direct effects on the human body are limited to the surface skin. Our current concerns with UV radiation are the rays that come from the sun. Uv light can be used to disinfect surfaces. Change ), You are commenting using your Twitter account. Fortunately, because of this, they react with ozone at the atmosphere and don’t usually reach the ground, so they are not normally a risk factor for any diseases. Get exclusive access to content from our 1768 First Edition with your subscription. UV radiation is present in sunlight, and constitutes about 10% of the total electromagnetic radiation output from the Sun. Our Sun puts off light at all the different wavelengths in electromagnetic spectrum, but it is ultraviolet waves that are responsible for causing our sunburns. These are the classifications most often used in Earth sciences. UV rays damage the DNA of skin cells and cancers start developing when the damage affects the DNA of genes controlling skin cell growth. Omissions? Hospitals use them to disinfect rooms. Some of the many dangers of ultraviolet Radiation or UV rays would be that you can develop skin cancer and possibly die. Reducing the risk of skin-related conditions. They have longer wavelength (320-400nm) and cause skin cells to age and can cause some indirect damage to cells’ DNA. The direct effects include reddening of the skin (sunburn), pigmentation development (suntan), aging, and carcinogenic changes. ( Log Out /  Your email address will not be published. If you continue to use this site we will assume that you are happy with it. The blood capillaries (minute vessels) in the skin dilate with aggregations of red and white blood cells to produce the red coloration. In physics, ultraviolet radiation is traditionally divided into four regions: near (400–300 nm), middle (300–200 nm), far (200–100 nm), and extreme (below 100 nm). This site uses Akismet to reduce spam. Some of the many dangers of ultraviolet Radiation or UV rays would be that you can develop skin cancer and possibly die. Plants utilize the energy of the Sun’s rays in the process of photosynthesis to produce carbohydrates and proteins, which serve as basic organic sources of food and energy for animals. Sources:, Labs in schools use them to disinfect the goggles. UV rays can positively impact athletes, but only on a small scale. Researches show that 90% of skin cancers are caused by UV rays. ALL RIGHTS RESERVED. 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. Enter your email address to follow this blog and receive notifications of new posts by email. Ultraviolet radiation also has positive effects on the human body, however. Constant exposure to the Sun’s ultraviolet radiation induces most of the skin changes commonly associated with aging, such as wrinkling, thickening, and changes in pigmentation. Change ), You are commenting using your Google account. Ultraviolet waves can cause damage to skin cells and eyes, and increase the risk of skin cancer ; X-rays and gamma rays can cause the mutation of genes, which can lead to cancer Most of the ultraviolet radiation in sunlight is absorbed by oxygen in Earth’s atmosphere, which forms the ozone layer of the lower stratosphere. The main symptoms are increased tearing, photophobia, swelling of the corneal epithelium, blepharospasm. UV-B rays are the harmful rays that cause sunburn. The application of sunscreen to the skin can help to block absorption of ultraviolet radiation in such persons. Ultraviolet (UV) Radiation is a form of electromagnetic radiation that comes from the sun and man-made sources like tanning beds. Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox. It is also produced by electric arcs and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights. In addition, marine scientists have suggested that a rise in UVB levels in the Southern Ocean between 1970 and 2003 was strongly linked to a simultaneous decline in fish, krill, and other marine life. 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. Because of its bactericidal capabilities at wavelengths of 260–280 nm, ultraviolet radiation is useful as both a research tool and a sterilizing technique. ( Log Out /  Updates? Several major health problems, such as skin cancer (melanoma and nonmelanoma), premature aging, cataracts and other eye damage, and immune system suppression, all result from overexposure to these harmful rays. Corrections? This article was most recently revised and updated by,, Health Physics Society - Ultraviolet Radiation, ultraviolet radiation - Student Encyclopedia (Ages 11 and up). Many insects, however, are able to see ultraviolet radiation. Light has…. Recent studies show that athletes, ranging from hikers, to tennis players and runners exceed the recommended ultraviolet exposure limit by up to eight-fold during the summer and autumn months, putting them at a high risk for UV ray related conditions. Is All Leather Vegan? Although long-wavelength ultraviolet is not considered an i… They can damage the DNA in skin cells directly, and are the main rays that cause sunburns. The Sun is a source of the full spectrum of ultraviolet radiation, which is commonly subdivided into UV-A, UV-B, and UV-C. A suntan occurs when melanin pigments in cells in the deeper tissue portion of the skin are activated by ultraviolet radiation, and the cells migrate to the surface of the skin. By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica. Melanin is a chemical pigment in the skin that absorbs ultraviolet radiation and limits its penetration into tissues. Tanning is a natural body defense relying on melanin to help protect the skin from further injury. ( Log Out /  Learn how sunscreen protects human skin from ultraviolet radiation. When the ozone layer becomes thin, however, more UVB radiation reaches Earth’s surface and may have hazardous effects on organisms. It stimulates the production of vitamin D in the skin and can be used as a therapeutic agent for such diseases as psoriasis. Fluorescent lamps exploit the ability of ultraviolet radiation to interact with materials known as phosphors that emit visible light; compared with incandescent lamps, fluorescent lamps are a more energy-efficient form of artificial lighting.