The sun sends us light, heat and ultraviolet (UV) radiation. We are all exposed to ultraviolet radiation from the sun and artificial sources used in industry, trade and other sectors of the economy.
The ultraviolet radiation region includes waves in the range of 100 – 400 nm and is conventionally divided into three groups:
- UV-A (UVA) (315–400 nm)
- UVB (280–315 nm)
- UV-C (UVC) (100–280 nm)
The influence of natural factors on the level of ultraviolet radiation:
Height of the Sun
The higher the sun is in the sky, the higher the level of ultraviolet radiation. Consequently, the level of ultraviolet radiation varies depending on the time of day and season. Outside the tropics, the highest degree of radiation is observed in the summer months when the sun is at its zenith around noon.Latitude
As you approach the equatorial regions, the degree of radiation increases.Cloudiness
The degree of ultraviolet radiation is higher in clear skies, but even in the presence of clouds the degree of ultraviolet radiation can be high. In this case, ultraviolet radiation, scattered, is reflected by various surfaces, and therefore the overall level of ultraviolet radiation can be quite high.Height
As altitude increases, the decreasing layer of the atmosphere absorbs ultraviolet radiation to a lesser extent. With an increase in altitude for every 1000 m, the level of ultraviolet radiation increases by 10% - 12%.Ozone
The ozone layer absorbs part of the ultraviolet radiation aimed at earth's surface. The thickness of the ozone layer varies throughout the year and even throughout the day.Reflection from the Earth's surface
Ultraviolet radiation reflected or scattered in varying degrees different surfaces, for example, pure snow can reflect up to 80% of ultraviolet radiation, dry coastal sand about 15%, sea foam about 25%.- More than 90% of UV radiation can penetrate through light cloud cover.
- Clean snow reflects up to 80% of UV radiation.
- UV radiation increases by 4% for every 300 m rise.
- People who work indoors are exposed to 5-10 times less UV radiation per year than people who work outdoors.
- In water at a depth of 0.5 m, the level of UV radiation is 40% of the level of UV radiation at the surface.
- We receive 60% of the total amount of UV radiation in the time period from 10-00 to 14-00 hours.
- Shade reduces UV radiation levels by 50% or more.
- White sand reflects up to 15% of UV radiation.
Effects of ultraviolet radiation on health
Small amounts of ultraviolet radiation are beneficial and necessary for the production of vitamin D. Ultraviolet radiation is also used to treat several diseases, including rickets, psoriasis and eczema. Treatment is carried out under medical supervision, taking into account the benefits of treatment and the risks of exposure to ultraviolet radiation.
However, long-term exposure to ultraviolet radiation in humans can lead to acute and chronic damage to the skin, eyes and immune system.
A popular misconception is that only fair-skinned people should be concerned about excessive "sun exposure." Darker skin has higher levels of the protective pigment melanin. People with such skin have a lower incidence of skin cancer. However, skin cancer is also diagnosed in this population, but often at a later and more dangerous stage.
The risk of damage to the eyes and immune system from ultraviolet radiation does not depend on skin type.
The most commonly known acute lesions resulting from excessive exposure to ultraviolet radiation are sunburn and tanning, with prolonged exposure to ultraviolet radiation causes degenerative changes in cells and blood vessels, which leads to premature aging of the skin. Ultraviolet radiation can also cause acute eye damage.
Chronic lesions include skin cancer and cataracts.
Every year there are 2-3 million cases of non-malignant skin cancer and 132,000 cases of skin melanoma. Non-cancerous skin cancer can be removed surgically and rarely fatal, malignant melanoma is one of the leading causes of death in the fair-skinned population.
Each year, approximately 12 to 15 million people go blind due to cataracts. Studies have shown that up to 20% of blindness may be caused or worsened by sun exposure, especially in India, Pakistan and other countries close to the equator.
There is also speculation that ultraviolet radiation may increase the risk of infectious diseases and limit the effectiveness of vaccinations.
However, despite all of the above, many consider intense tanning to be normal. Children, teenagers and their parents perceive tanning as an indicator of attractiveness and good health.
Risk group
- Prolonged sun exposure during childhood increases the risk of developing skin cancer later and can cause serious damage to the eyes.
- All children under 15 years of age have sensitive skin and eyes - protect them and set a good example for them yourself!
- Children under one year old should not be exposed to direct sunlight!
- Parents, protect your children from the sun! Teach them about sunscreen use and sun exposure!
Health effects of ozone depletion
Depletion of the ozone layer is likely to increase the adverse effects of ultraviolet radiation, since stratospheric ozone is an effective absorber of ultraviolet radiation.
As the ozone layer decreases, the protective filter provided by the atmosphere decreases. Accordingly, the population and the environment are exposed to higher levels of ultraviolet radiation, especially UVB radiation, which has a major impact on the health of humans, animals, marine organisms and plant life.
Computational models predict that a 10% decrease in stratospheric ozone could cause an additional 300,000 non-cancerous skin cancers, 4,500 malignant skin cancers, and 1.6 to 1.75 million cases of cataracts annually.
GLOBAL SOLAR ULTRAVIOLET (UV) INDEX
Introduction
Since the 1970s, there has been an increase in the incidence of skin cancer among fair-skinned people. This increase is associated with the population's habits of being “in the sun” under its ultraviolet component and the generally accepted opinion about the attractiveness and benefits of tanning.
Thus, there is an urgent need to increase public awareness about harmful effects ultraviolet radiation, with the goal of changing the habits of the population to prevent the trend of increasing cases of skin cancer.
The Global Ultraviolet Index is a simplified measure of the level of ultraviolet radiation on the Earth's surface and an indicator of potential skin hazards. It serves as a means of raising public awareness and warning of the need to take protective measures against exposure to ultraviolet radiation.
The UVI was developed by the World Health Organization with the assistance of the United Nations Human Rights Program environment, World Meteorological Organization, International Commission on Non-Ionizing Radiation Protection, German Federal Office for Radiation Protection.
Since the first announcement in 1995, several international expert meetings have been held (Les Diablerets; Baltimore, 1996; Les Diablerets, 1997; Munich, 2000) to streamline public education about UVR and promote the use of UVR as a means of sun protection.
What is the Global Solar Ultraviolet Index?
The global solar UV index (UVI) characterizes the level of solar ultraviolet radiation at the Earth's surface. The UV index takes values from zero and above. Moreover, the higher the UV index value, the greater the potential danger to human skin and eyes and the shorter the time required to cause harm to health.
UV index values correspond to levels of exposure to ultraviolet radiation from the sun in the following categories:
Why do you need an ultraviolet index?
The UV Index is an important means of raising public awareness of the risks of excessive exposure to ultraviolet radiation and warning of the need for sunscreen use. The level of ultraviolet radiation and, therefore, the UV index values vary throughout the day. Usually the maximum value of ultraviolet radiation observed in a 4-hour period around solar noon is shown. Sunny noon lasts from 12 noon to 2 pm.
When people make plans for the day and decide “what to wear”, they are usually guided by the weather forecast (or the view from the window) and especially the air temperature forecast.
Similar to the temperature scale, the UV index shows the level of ultraviolet radiation and possible danger influence of the Sun.
Knowing the UV index forecast can help everyone make healthy choices.
| Required protective measures depending on the UV index value | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| No protection required | Protection required | Increased protection required | ||||||||||
| Stay out premises doesn't represent dangers |
At noon stay in the shadows! Wear clothes with long sleeves and a hat! Use sunscreen! |
Wait out the midday hours indoors! Stay in the shade outdoors! Be sure to wear clothes long sleeves, hat, use sunscreen! |
||||||||||
Even for people with very sensitive fair skin, the risk of harm to health is minimal at UV index values below 3 and under normal circumstances the use of protective products is not required.
Protection is required for UV index values above 3, increased protective measures are required for UV index values of 8 and above. In this case, you need to use all protective equipment:
- Limit exposure to the sun during midday hours.
- Stay in the shadows.
- Wear long sleeves.
- Wear a wide-brimmed hat to protect your eyes, face and neck.
- Protect your eyes with fitted glasses.
- Use sunscreen with a sun protection factor (SPF) of 15+. Do not use sunscreen to extend your sun exposure.
- Protect your little ones: This is especially important.
Myths and reality
| MYTH | REALITY |
|---|---|
| Sun tanning is beneficial. | Tanning is the body's defense against further damage from ultraviolet radiation. |
| A tan protects you from the sun. | A dark tan on fair skin provides limited protection, equivalent to an SPF (sun protection factor) of approximately 4. |
| You won't tan on a cloudy day. | Up to 80% of the sun's ultraviolet radiation penetrates cloud cover. Fog can increase ultraviolet radiation levels. |
| You won't get tanned while in the water. | Water provides minimal protection from ultraviolet radiation, and reflection from water can increase the level of ultraviolet radiation. |
| Ultraviolet radiation is not dangerous in winter. | UV radiation levels are generally lower during the winter months, but reflection from snow can double them, especially at altitudes. Be especially careful in early spring when the air temperature is low but solar UV radiation is strong. |
| Sunscreen is a means of protection, I can increase the tanning time. | Sunscreen should not be used to prolong the time spent in the sun, but to enhance protection from ultraviolet radiation. |
| You won't get burned if you take breaks while tanning. | Exposure to ultraviolet radiation tends to accumulate throughout the day. |
| You won't tan if the sun's heat is imperceptible. | Sun tanning is caused by ultraviolet radiation, which cannot be felt. When we feel the heat of the Sun, we feel its infrared, not ultraviolet, radiation. |
REMEMBER!
- Tanning does not stop ultraviolet radiation! Even if your skin is tanned, limit sun exposure to midday hours and use sun protection measures.
- Limit your sunbathing time! A tan is an indication that your skin has received an overdose of ultraviolet radiation! Protect your skin!
- Wear Sunglasses, wide-brimmed hat and protective clothing, use SPF 15+ sunscreen.
- Using sunscreen is not a means of extending your time in the sun, but of reducing the health risks of being in the sun.
- Taking certain medications, as well as using perfumes and deodorants, make the skin more sensitive, causing severe sunburn.
- Exposure to the sun increases the risk of developing skin cancer, accelerates skin aging and damages the eyes. Protect yourself!
- Shadow is one of the best means protection from solar radiation. Try to stay in the shade during the midday hours, when UV radiation is highest.
- Cloudy skies do not prevent sunburn. Ultraviolet radiation penetrates clouds.
- Remember that damage to the skin and eyes is caused by ultraviolet radiation, which cannot be seen or felt - DO NOT BE FOOLED BY MODERATE TEMPERATURES!
- If you expect to be outdoors during the day, be sure to wear sunscreen, a hat, and long sleeves.
- When on the ski slopes, don't forget that altitude and clear snow can double your UV exposure, and don't forget your sunglasses and sunscreen! In the mountains, the level of ultraviolet radiation increases by approximately 10% every 1000 m.
- Information sources:
1. Materials from the website of the World Health Organization (WHO).
http://www.who.int/uv/intersunprogramme/activities/uv_index/en/index.html
2."Global Solar UV Index. A Practical Guide". "Global Solar UV Index. A Practical Guide.", WHO 2002
http://www.who.int/uv/publications/globalindex/en/index.html
The guidelines are recommended by the World Health Organization, the World Meteorological Organization, the United Nations Environment Programme, and the International Commission on Non-Ionizing Radiation Protection.Forecast of UV index and ozone layer thickness provided.
Ultraviolet radiation in medicine is used in the optical range of 180-380 nm (integral spectrum), which is divided into short-wave region (C or AF) - 180-280 nm, medium-wave (B) - 280-315 nm and long-wave (A) - 315- 380 nm (DUV).
Physical and physiological effect ultraviolet radiation
Penetrates into biological tissues to a depth of 0.1-1 mm, is absorbed by molecules of nucleic acids, proteins and lipids, has photon energy sufficient to break covalent bonds, electronic excitation, dissociation and ionization of molecules (photoelectric effect), which leads to the formation of free radicals, ions, peroxides (photochemical effect), i.e. there is a consistent conversion of the energy of electromagnetic waves into chemical energy.
The mechanism of action of UV radiation is biophysical, humoral and neuro-reflex:
Changes in the electronic structure of atoms and molecules, ionic configuration, electrical properties cells;
- inactivation, denaturation and coagulation of protein;
- photolysis - breakdown of complex protein structures - release of histamine, acetylcholine, biogenic amines;
- photooxidation - increased oxidative reactions in tissues;
- photosynthesis - reparative synthesis in nucleic acids, elimination of damage in DNA;
- photoisomerization - internal rearrangement of atoms in a molecule, substances acquire new chemical and biological properties (provitamin - D2, D3),
- photosensitivity;
- erythema, with CUF it develops within 1.5-2 hours, with DUF - 4-24 hours;
- pigmentation;
- thermoregulation.
Ultraviolet radiation has an effect on functional state various organs and human systems:
Leather;
- central and peripheral nervous system;
- autonomic nervous system;
- the cardiovascular system;
- blood system;
- hypothalamus-pituitary-adrenal glands;
- endocrine system;
- all types of metabolism, mineral metabolism;
- respiratory organs, respiratory center.
The healing effect of ultraviolet radiation
The reaction from organs and systems depends on the wavelength, dose and method of exposure to UV radiation.
Local irradiation:
Anti-inflammatory (A, B, C);
- bactericidal (C);
- painkiller (A, B, C);
- epithelializing, regenerating (A, B)
General exposure:
Stimulating immune reactions (A, B, C);
- desensitizing (A, B, C);
- regulation of vitamin balance “D”, “C” and metabolic processes(A, B).
Indications for UV therapy:
Acute, subacute and chronic inflammatory process;
- trauma to soft tissues and bones;
- wound;
- skin diseases;
- burns and frostbite;
- trophic ulcer;
- rickets;
- diseases of the musculoskeletal system, joints, rheumatism;
- infectious diseases- flu, whooping cough, erysipelas;
- pain syndrome, neuralgia, neuritis;
- bronchial asthma;
- ENT diseases - tonsillitis, otitis media, allergic rhinitis, pharyngitis, laryngitis;
- compensation for solar deficiency, increasing the stamina and endurance of the body.
Indications for ultraviolet irradiation in dentistry
Diseases of the oral mucosa;
- periodontal diseases;
- dental diseases - non-carious diseases, caries, pulpitis, periodontitis;
- inflammatory diseases maxillofacial region;
- TMJ diseases;
- facial pain.
Contraindications to UV therapy:
Malignant neoplasms,
- predisposition to bleeding,
- active tuberculosis,
- functional kidney failure,
- stage III hypertension,
- severe forms atherosclerosis.
- thyrotoxicosis.
Ultraviolet radiation devices:
Integrated sources using DRT (mercury arc tube) lamps of various powers:
ORK-21M (DRT-375) - local and general irradiation
- OKN-11M (DRT-230) - local irradiation
- Mayachnye OKB-ZO (DRT-1000) and OKM-9 (DRT-375) - group and general irradiation
- ON-7 and UGN-1 (DRT-230). OUN-250 and OUN-500 (DRT-400) - local irradiation
- OUP-2 (DRT-120) - otolaryngology, ophthalmology, dentistry.
Selective short-wave (180-280 nm) use bactericidal arc lamps (BA) in the glow electric discharge mode in a mixture of mercury vapor and argon. Lamps of three types: DB-15, DB-30-1, DB-60.
Irradiators are produced:
Wall mounted (OBN)
- ceiling (OBP)
- on a tripod (OBSh) and mobile (OBP)
- local (BOD) with lamp DRB-8, BOP-4, OKUF-5M
- for blood irradiation (AUFOK) - MD-73M "Isolda" (with lamp low pressure LB-8).
Selective long-wave (310-320 nm) use fluorescent erythema lamps (LE), 15-30 W, made of uveolian glass with an internal phosphor coating:
Wall-mounted irradiators (OE)
- suspended reflected distribution (OED)
- mobile (OEP).
Beacon-type irradiators (EOKS-2000) with a xenon arc lamp (DKS TB-2000).
An ultraviolet irradiator on a tripod (OUSH1) with a fluorescent lamp (LE153), a large beacon ultraviolet irradiator (OMU), a tabletop ultraviolet irradiator (OUN-2).
Low pressure gas discharge lamp LUF-153 in the UUD-1, UDD-2L units for Puva and therapy, in the UV irradiator for the limbs OUK-1, for the head OUG-1 and in the irradiators EOD-10, EGD-5. Units for general and local irradiation are produced abroad: Puva, Psolylux, Psorymox, Valdman.
Technique and methodology of ultraviolet therapy
General exposure
Carry out according to one of the following schemes:
Main (from 1/4 to 3 biodoses, adding 1/4 each)
- slow (from 1/8 to 2 biodoses, adding 1/8 each)
- accelerated (from 1/2 to 4 biodoses, adding 1/2 at a time).
Local irradiation
Irradiation of the affected area, fields, reflexogenic zones, staged or by zone, extrafocal. factional.
Features of irradiation with erythemal doses:
One area of skin can be irradiated no more than 5 times, and the mucous membrane - no more than 6-8 times. Repeated irradiation of the same area of skin is possible only after the erythema has subsided. The subsequent radiation dose is increased by 1/2-1 biodose. When treating with UV rays, light-protective glasses are used for the patient and medical staff.
Dosing
Dosing of UV irradiation is carried out by determining the biodose, the biodose is the minimum amount of UV radiation sufficient to obtain the weakest threshold erythema on the skin within least time, with a fixed distance from the irradiator (20 - 100 cm). The biodose is determined using a BD-2 biodosimeter.
There are different doses ultraviolet irradiation:
Suberythemal (less than 1 biodose)
- erythema small (1-2 biodoses)
- medium (3-4 biodoses)
- large (5-6 biodoses)
- hypererythemal (7-8 biodoses)
- massive (over 8 biodoses).
For air disinfection purposes:
Indirect radiation for 20-60 minutes, in the presence of people,
- direct radiation for 30-40 minutes, in the absence of people.
Ultraviolet radiation Prepared by 11th grade student Yumaev Vyacheslav
Ultraviolet radiation - invisible to the eye electromagnetic radiation, occupying the region between the lower limit of the visible spectrum and upper limit X-ray radiation. The wavelength of UV radiation ranges from 100 to 400 nm (1 nm = 10 m). According to the classification of the International Commission on Illumination (CIE), the UV radiation spectrum is divided into three ranges: UV-A - long wavelength (315 - 400 nm) UV-B - medium wavelength (280 - 315 nm) UV-C - short wavelength (100 - 280 nm.) The entire UVR region is conventionally divided into: - near (400-200 nm); - distant or vacuum (200-10 nm).
Properties: High chemical activity, invisible, high penetrating ability, kills microorganisms, in small doses has a beneficial effect on the human body: tanning, UV rays initiate the process of formation of vitamin D, which is necessary for the body to absorb calcium and ensure normal development of the bone skeleton, ultraviolet radiation is active influences the synthesis of hormones responsible for daily biological rhythm; but in large doses it has negative biological effects: changes in cell development and metabolism, effects on the eyes.
UV radiation spectrum: line (atoms, ions and light molecules); consists of stripes (heavy molecules); Continuous spectrum (occurs during inhibition and recombination of electrons).
Discovery of UV radiation: Near UV radiation was discovered in 1801 by the German scientist N. Ritter and the English scientist W. Wollaston based on the photochemical effect of this radiation on silver chloride. Vacuum UV radiation was discovered by the German scientist W. Schumann using a vacuum spectrograph with a fluorite prism and gelatin-free photographic plates that he built. He was able to detect short-wave radiation up to 130 nm. N. Ritter W. Wollaston
Features of UV radiation Up to 90% of this radiation is absorbed by atmospheric ozone. For every 1000m increase in altitude, UV levels increase by 12%
Application: Medicine: the use of UV radiation in medicine is due to the fact that it has bactericidal, mutagenic, therapeutic (medicinal), antimitotic, preventive effects, disinfection; laser biomedicine Show business: Lighting, lighting effects
Cosmetology: In cosmetology, ultraviolet irradiation is widely used in solariums to obtain an even, beautiful tan. A deficiency of UV rays leads to vitamin deficiency, decreased immunity, and poor performance nervous system, the appearance of mental instability. Ultraviolet radiation has a significant effect on phosphorus-calcium metabolism, stimulates the formation of vitamin D and improves all metabolic processes in the body.
Food industry: Disinfection of water, air, premises, containers and packaging with UV radiation. It should be emphasized that the use of UVI as physical factor impact on microorganisms can ensure disinfection of the environment to a very high degree, for example up to 99.9%.
Forensics: Scientists have developed technology that can detect the slightest doses explosives. The device for detecting traces of explosives uses a very thin thread (it is two thousand times thinner than a human hair), which glows under the influence of ultraviolet radiation, but any contact with explosives: trinitrotoluene or other explosives used in bombs stops its glow. The device detects the presence of explosives in the air, in water, on fabric and on the skin of crime suspects. Using invisible UV inks for protection bank cards and banknotes from counterfeiting. Images and design elements invisible in normal light are applied to the card, or the entire card is made to glow in UV rays.
Sources of UV radiation: emitted by all solids whose temperature is >1000 C, as well as luminous mercury vapor; stars (including the Sun); laser installations; gas-discharge lamps with quartz tubes (quartz lamps), mercury; mercury rectifiers
Protection from UV radiation: Application of sun screens: - chemical ( chemical substances and covering creams); - physical (various barriers that reflect, absorb or scatter rays). Special clothing (for example, made from poplin). To protect eyes in industrial conditions, light filters (glasses, helmets) made of dark green glass are used. Full protection from UV of all wavelengths is provided by flint glass (glass containing lead oxide) 2 mm thick.
Thank you for your attention!
UV radiation is electromagnetic waves, which are invisible to the human eye. It occupies a spectral position between visible and x-ray radiation. The ultraviolet radiation interval is usually divided into near, middle and far (vacuum).
Biologists made such a division of UV rays so that they could better see the difference in the effect of rays of different lengths on a person.
- Near ultraviolet is commonly called UV-A.
- medium - UV-B,
- far - UV-C.
Ultraviolet radiation comes from the sun and the atmosphere of our planet Earth protects us from the powerful effects of ultraviolet rays. The sun is one of the few natural UV emitters. At the same time, far-ultraviolet UV-C is blocked almost completely by the Earth's atmosphere. Those 10% of long-wave ultraviolet rays reach us in the form of the sun. Accordingly, the ultraviolet that reaches the planet is mainly UV-A, and in small quantities UV-B.
One of the main properties of ultraviolet radiation is its chemical activity, due to which UV radiation has great influence on the human body. Short-wave ultraviolet radiation is considered the most dangerous for our body. Despite the fact that our planet protects us as much as possible from exposure to ultraviolet rays, if you do not take certain precautions, you can still suffer from them. Sources of short-wave radiation are welding machines and ultraviolet lamps.
Positive properties of ultraviolet light
Only in the 20th century did research begin to prove positive effects of UV radiation on the human body. The result of these studies was the identification of the following beneficial properties: strengthening human immunity, activation defense mechanisms, improving blood circulation, dilating blood vessels, increasing vascular permeability, increasing the secretion of a number of hormones.
Another property of ultraviolet light is its ability change carbohydrate and protein metabolism
human substances. UV rays can also affect ventilation of the lungs - the frequency and rhythm of breathing, increasing gas exchange, and the level of oxygen consumption. Functioning also improves endocrine system, the body produces vitamin D, which strengthens musculoskeletal system person.
Application of ultraviolet radiation in medicine
Quite often, ultraviolet light is used in medicine. Despite the fact that in some cases ultraviolet rays can have a bad effect on the human body, when correct use they may be useful.
Medical institutions have long ago invented useful application artificial ultraviolet light. There are various emitters that can help a person using ultraviolet rays cope with various diseases
. They are also divided into those that emit long, medium and short waves. Each of them is used in a specific case. Thus, long-wave radiation is suitable for treating the respiratory tract, for damage to the osteoarticular apparatus, as well as in the case of various skin injuries. We can also see long-wave radiation in solariums.
Treatment performs a slightly different function mid-wave ultraviolet. It is prescribed mainly to people suffering from immunodeficiency and metabolic disorders. It is also used in the treatment of musculoskeletal disorders and has an analgesic effect.
Shortwave radiation It is also used in the treatment of skin diseases, diseases of the ears, nose, damage to the respiratory tract, diabetes mellitus, with damage to the heart valves.
In addition to various devices emitting artificial ultraviolet light, which are used in mass medicine, there are also ultraviolet lasers, having a more targeted effect. These lasers are used, for example, in eye microsurgery. Such lasers are also used for scientific research.
Application of ultraviolet radiation in other areas
In addition to medicine, ultraviolet radiation is used in many other areas, significantly improving our lives. So, ultraviolet is excellent disinfectant, and is used, among other things, for treating various objects, water, and indoor air. Ultraviolet light is widely used and in printing: It is with the help of ultraviolet that various seals and stamps are produced, paints and varnishes are dried, and banknotes are protected from counterfeiting. In addition to its beneficial properties, when applied correctly, ultraviolet light can create beauty: it is used for various lighting effects (most often this happens at discos and performances). UV rays also help in finding fires.
One of the negative consequences ultraviolet exposure on the human body is electroophthalmia. This term refers to damage to the human organ of vision, in which the cornea of the eye burns and swells, and a cutting pain appears in the eyes. This disease can occur if a person looks at the rays of the sun without special protective equipment ( sunglasses) or is in a snowy area in sunny weather with very bright light. Electroophthalmia can also be caused by quartzing premises.
Negative consequences can also be achieved due to long, intense exposure to ultraviolet rays on the body. There can be quite a lot of such consequences, up to the development various pathologies. The main symptoms of overexposure are
The consequences of strong radiation are the following: hypercalcemia, growth retardation, hemolysis, deterioration of immunity, various burns and skin diseases. People who constantly work outdoors, as well as those people who constantly work with devices that emit artificial ultraviolet light, are most susceptible to excessive exposure.
Unlike UV emitters used in medicine, tanning salons are more dangerous for a person. Visits to solariums are not controlled by anyone other than the person himself. People who often visit solariums in order to achieve a beautiful tan often neglect the negative effects of UV radiation, despite the fact that frequent visits to solariums can even lead to death.
The acquisition of darker skin color occurs due to the fact that our body fights the traumatic effects of UV radiation on it and produces a coloring pigment called melanin. And if redness of the skin is a temporary defect that goes away after some time, then freckles and age spots that appear on the body, which occur as a result of the proliferation of epithelial cells - permanent skin damage.
Ultraviolet light penetrating deeply into skin, can change skin cells at the genetic level and lead to ultraviolet mutagenesis. One of the complications of this mutagenesis is melanoma, a skin tumor. It is this that can lead to death.
To avoid the negative effects of exposure to UV rays, you need to provide yourself with some protection. At various enterprises working with devices that emit artificial ultraviolet radiation, it is necessary to use special clothing, helmets, shields, insulating screens, safety glasses, and a portable screen. People who are not involved in the activities of such enterprises need to limit themselves from excessive visits to solariums and prolonged exposure to the open sun, in the summer, use sunscreens, sprays or lotions, and also wear sunglasses and closed clothing made from natural fabrics.
There are also Negative consequences from lack of UV radiation. Long-term absence of UVR can lead to a disease called “light starvation.” Its main symptoms are very similar to those of excessive exposure to ultraviolet radiation. With this disease, a person’s immunity decreases, metabolism is disrupted, fatigue, irritability, etc. appear.
The concept of ultraviolet rays was first encountered by an Indian philosopher of the 13th century in his work. The atmosphere of the area he described Bhootakasha contained violet rays that cannot be seen with the naked eye.
Soon after infrared radiation was discovered, the German physicist Johann Wilhelm Ritter began searching for radiation at the opposite end of the spectrum, with a wavelength shorter than that of violet. In 1801, he discovered that silver chloride, which decomposes faster when exposed to light decomposes under the influence of invisible radiation outside the violet region of the spectrum. Silver chloride white within a few minutes it darkens in the light. Different parts of the spectrum have different effects on the rate of darkening. This happens most quickly in front of the violet region of the spectrum. Many scientists, including Ritter, then agreed that light consists of three distinct components: an oxidative or thermal (infrared) component, an illuminant (visible light) component, and a reducing (ultraviolet) component. At that time, ultraviolet radiation was also called actinic radiation. Ideas about the unity of three various parts spectrum were first voiced only in 1842 in the works of Alexander Becquerel, Macedonio Melloni and others.
Subtypes
Degradation of polymers and dyes
Scope of application
Black light
Chemical analysis
UV spectrometry
UV spectrophotometry is based on irradiating a substance with monochromatic UV radiation, the wavelength of which changes over time. The substance absorbs UV radiation at different wavelengths to varying degrees. A graph, the ordinate axis of which shows the amount of transmitted or reflected radiation, and the abscissa axis the wavelength, forms a spectrum. The spectra are unique for each substance, which is the basis for the identification of individual substances in a mixture, as well as their quantitative measurement.
Mineral Analysis
Many minerals contain substances that, when illuminated by ultraviolet light, begin to emit visible light. Each impurity glows in its own way, which makes it possible to determine the composition of a given mineral by the nature of the glow. A. A. Malakhov in his book “Interesting about Geology” (Moscow, “Young Guard”, 1969. 240 pp) talks about it this way: “An unusual glow of minerals is caused by cathode, ultraviolet, and x-rays. In the world of dead stone, those minerals that light up and shine most brightly are those that, once in the zone of ultraviolet light, tell about the smallest impurities of uranium or manganese included in the rock. Many other minerals that do not contain any impurities also flash a strange “unearthly” color. I spent the whole day in the laboratory, where I observed the luminescent glow of minerals. Ordinary colorless calcite became miraculously colored under the influence of various light sources. Cathode rays made the crystal ruby red; in ultraviolet light it lit up with crimson-red tones. The two minerals, fluorite and zircon, were indistinguishable in X-rays. Both were green. But as soon as the cathode light was connected, the fluorite became purple, and the zircon turned lemon yellow.” (p. 11).
Qualitative chromatographic analysis
Chromatograms obtained by TLC are often viewed under ultraviolet light, which makes it possible to identify a number of organic matter by glow color and retention index.
Catching insects
Ultraviolet radiation is often used when catching insects with light (often in combination with lamps emitting in the visible part of the spectrum). This is due to the fact that for most insects the visible range is shifted compared to human vision, in the short-wave part of the spectrum: insects do not see what humans perceive as red, but they see soft ultraviolet light.
Artificial tanning and “Mountain sun”
At certain dosages, artificial tanning can improve the condition and appearance of human skin and promotes the formation of vitamin D. Fotaria are currently popular, which in everyday life are often called solariums.
Ultraviolet in restoration
One of the main tools of experts is ultraviolet, x-ray and infrared radiation. Ultra-violet rays allow you to determine the aging of the varnish film - fresher varnish looks darker in ultraviolet light. In the light of a large laboratory ultraviolet lamp, restored areas and hand-written signatures appear as darker spots. X-rays are blocked by the heaviest elements. IN human body This bone, and in the picture there is whitewash. The basis of white in most cases is lead; in the 19th century, zinc began to be used, and in the 20th century, titanium. All these are heavy metals. Ultimately, on film we get an image of the whitewash underpainting. Underpainting is the individual “handwriting” of the artist, an element of his own unique technique. To analyze the underpainting, a database of X-ray photographs of paintings by great masters is used. These photographs are also used to determine the authenticity of a painting.
Notes
- ISO 21348 Process for Determining Solar Irradiances. Archived from the original on June 23, 2012.
- Bobukh, Evgeniy On animal vision. Archived from the original on November 7, 2012. Retrieved November 6, 2012.
- Soviet encyclopedia
- V. K. Popov // UFN. - 1985. - T. 147. - P. 587-604.
- A. K. Shuaibov, V. S. Shevera Ultraviolet nitrogen laser at 337.1 nm in frequent repetition mode // Ukrainian Physical Journal. - 1977. - T. 22. - No. 1. - P. 157-158.
- A. G. Molchanov
