Ultraviolet radiation from the sun. Sources of ultraviolet radiation. What are ultraviolet rays

General characteristics of ultraviolet radiation

Note 1

Ultraviolet radiation discovered I.V. Ritter in $1842$. Subsequently, the properties of this radiation and its application were subjected to the most careful analysis and study. Scientists such as A. Becquerel, Warshawer, Danzig, Frank, Parfenov, Galanin and many others made a great contribution to this study.

Currently ultraviolet radiation widely used in various fields of activity. Ultraviolet activity reaches its peak in the high temperature range. This type of spectrum appears when the temperature reaches from $1500$ to $20000$ degrees.

Conventionally, the radiation range is divided into 2 areas:

1. Near spectrum, which reaches the Earth from the Sun through the atmosphere and has a wavelength of $380$-$200$ nm;
2. Distant Spectrum absorbed by ozone, air oxygen and other atmospheric components. This spectrum can be studied using special vacuum devices, which is why it is also called vacuum. Its wavelength is $200$-$2$ nm.

Ultraviolet radiation can be short-range, long-range, extreme, medium, vacuum, and each type has its own properties and finds its own application. Each type of ultraviolet radiation has its own wavelength, but within the limits indicated above.

Spectrum of ultraviolet sunlight, reaching the Earth's surface, is narrow - $400$...$290$ nm. It turns out that the Sun does not emit light with a wavelength shorter than $290$ nm. Is this true or not? The answer to this question was found by a Frenchman A. Cornu, who established that ultraviolet rays shorter than $295$ nm are absorbed by ozone. Based on this, A. Cornu suggested that the Sun emits short-wave ultraviolet radiation. Oxygen molecules under its influence disintegrate into individual atoms and form ozone molecules. Ozone in the upper atmosphere covers the planet protective screen.

Scientist's guess confirmed when man managed to rise to the upper layers of the atmosphere. The height of the Sun above the horizon and the amount of ultraviolet rays reaching the earth's surface are directly related. When the illumination changes by $20$%, the amount of ultraviolet rays reaching the surface will decrease by $20$ times. Experiments have shown that for every $100$ m of ascent, the intensity of ultraviolet radiation increases by $3$-$4$%. In the equatorial region of the planet, when the Sun is at its zenith, rays with a length of $290$...$289$ nm reach the earth's surface. The earth's surface above the Arctic Circle receives rays with a wavelength of $350$...$380$ nm.

Ultraviolet radiation sources

Ultraviolet radiation has its sources:

1. Natural springs;
2. Man-made sources;
3. Laser sources.

Natural source ultraviolet rays is their only concentrator and emitter - this is our Sun. The star closest to us emits a powerful charge of waves that can pass through the ozone layer and reach the earth's surface. Numerous studies have allowed scientists to put forward the theory that only with the advent of the ozone layer on the planet could life arise. It is this layer that protects all living things from harmful excess penetration of ultraviolet radiation. The ability for the existence of protein molecules, nucleic acids and ATP became possible precisely during this period. Ozone layer performs a very important function, interacting with the bulk UV-A, UV-B, UV-C, it neutralizes them and does not allow them to reach the surface of the Earth. Ultraviolet radiation arriving at the earth's surface has a range that ranges from $200$ to $400$ nm.

The concentration of ultraviolet radiation on Earth depends on a number of factors:

1. The presence of ozone holes;
2. Position of the territory (height) above sea level;
3. The height of the Sun itself;
4. The ability of the atmosphere to scatter rays;
5. Reflectivity of the underlying surface;
6. States of cloud vapors.

Artificial sources Ultraviolet radiation is usually created by humans. These can be instruments, devices, and technical means designed by people. They are created to obtain the desired spectrum of light with specified wavelength parameters. The purpose of their creation is so that the resulting ultraviolet radiation can be usefully used in various fields of activity.

Sources of artificial origin include:

1. Having the ability to activate the synthesis of vitamin D in human skin erythema lamps. They not only protect against rickets, but also treat this disease;
2. Special apparatus for solariums, preventing winter depression and giving a beautiful natural tan;
3. Used indoors to control insects attractant lamps. They pose no danger to humans;
4. Mercury-quartz devices;
5. Excilamps;
6. Luminescent devices;
7. Xenon lamps;
8. Gas discharge devices;
9. High temperature plasma;
10. Synchrotron radiation in accelerators.

Artificial sources of ultraviolet radiation include lasers, whose operation is based on the generation of inert and non-inert gases. This can be nitrogen, argon, neon, xenon, organic scintillators, crystals. Currently exists laser working for free electrons. It produces a length of ultraviolet radiation equal to that observed under vacuum conditions. Laser ultraviolet is used in biotechnological, microbiological research, mass spectrometry, etc.

Application of ultraviolet radiation

Ultraviolet radiation has characteristics that allow it to be used in various fields.

UV characteristics:

1. High level of chemical activity;
2. Bactericidal effect;
3. The ability to cause luminescence, i.e. glow of different substances in different shades.

Based on this, ultraviolet radiation can be widely used, for example, in spectrometric analyses, astronomy, medicine, in the disinfection of drinking water, in the analytical study of minerals, for the destruction of insects, bacteria and viruses. Each area uses a different type of UV with its own spectrum and wavelength.

Spectrometry specializes in identifying compounds and their composition based on their ability to absorb UV light of a specific wavelength. Based on the results of spectrometry, the spectra for each substance can be classified, because they are unique. The destruction of insects is based on the fact that their eyes detect short-wave spectra that are invisible to humans. Insects fly to this source and are destroyed. Special installations in solariums expose the human body to UV-A. As a result, melanin production is activated in the skin, which gives it a darker and more even color. Here, of course, it is important to protect sensitive areas and eyes.

Medicine. The use of ultraviolet radiation in this area is also associated with the destruction of living organisms - bacteria and viruses.

Medical indications for ultraviolet treatment:

1. Trauma to tissues, bones;
2. Inflammatory processes;
3. Burns, frostbite, skin diseases;
4. Acute respiratory diseases, tuberculosis, asthma;
5. Infectious diseases, neuralgia;
6. Diseases of the ear, nose and throat;
7. Rickets and trophic gastric ulcers;
8. Atherosclerosis, renal failure, etc.

This is not the entire list of diseases for which ultraviolet radiation is used.

Note 2

Thus, ultraviolet helps doctors save millions of human lives and restore their health. Ultraviolet light is also used to disinfect premises and sterilize medical instruments and work surfaces.

Analytical work with minerals. Ultraviolet light causes luminescence in substances, and this makes it possible to use it to analyze the qualitative composition of minerals and valuable rocks. Precious, semi-precious and ornamental stones produce very interesting results. When irradiated with cathode waves, they give amazing and unique shades. The blue color of topaz, for example, when irradiated turns out to be bright green, emerald - red, pearls shimmer with multicolors. The spectacle is amazing, fantastic.

Ultraviolet was discovered more than 200 years ago, but only with the invention of artificial sources of ultraviolet radiation was man able to use the amazing properties of this invisible light. Today, an ultraviolet lamp helps fight many diseases and disinfects, allows the creation of new materials and is used by criminologists. But in order for UV spectrum devices to bring benefits and not harm, it is necessary to clearly understand what they are and what they serve.

What is ultraviolet radiation and how does it happen?

You probably know that light is electromagnetic radiation. Depending on the frequency, the color of such radiation changes. The low-frequency spectrum appears red to us, the high-frequency spectrum appears blue. If you raise the frequency even higher, the light will turn purple and then disappear completely. More precisely, it will disappear for your eyes. In fact, the radiation will go into the ultraviolet spectrum, which we are not able to see due to the characteristics of the eye.

But if we do not see ultraviolet light, this does not mean that it does not affect us in any way. You won't deny that radiation is safe because we can't see it. And radiation is nothing more than the same electromagnetic radiation as light and ultraviolet, only at a higher frequency.

But let's return to the ultraviolet spectrum. It is located, as we found out, between visible light and radiation:

Dependence of the type of electromagnetic radiation on its frequency

Let's put light and radiation aside and take a closer look at ultraviolet radiation:

Division of the ultraviolet range into subranges

The figure clearly shows that the entire UV range is conventionally divided into two subranges: near and far. But in the same figure above we see the division into UVA, UVB and UVC. In the future, we will use exactly this division - ultraviolet A, B and C, since it clearly delineates the degree of impact of radiation on biological objects.

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The final section of the far range is not marked in any way, since it has no particular practical significance. Air for ultraviolet radiation with a wavelength shorter than 100 nm (also called hard ultraviolet) is practically opaque, so its sources can only be used in a vacuum.

Properties of ultraviolet radiation and its effect on living organisms

So, we have three ultraviolet ranges at our disposal: A, B and C. Let's consider the properties of each of them.

Ultraviolet A

The radiation lies in the range of 400 - 320 nm and is called soft or long-wave ultraviolet. Its penetration into the deep layers of living tissue is minimal. When used in moderation, UVA not only does not harm the body, but is also beneficial. It strengthens the immune system, promotes the production of vitamin D, and improves skin condition. It is under this ultraviolet light that we sunbathe on the beach.

But in case of an overdose, even the mild ultraviolet range can pose a certain danger to humans. A good example: I got to the beach, lay down for a couple of hours and “burned out.” Sound familiar? Undoubtedly. But it could have been even worse if you had been lying there for five hours or with your eyes open and without quality sunglasses. With prolonged exposure to the eyes, UVA can cause a burn to the cornea and literally burn the skin to blisters.

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All of the above is also true for other biological objects: plants, animals, bacteria. It is moderate UVA that largely provokes “blooming” of water in reservoirs and spoilage of food, spurring the growth of algae and bacteria. An overdose of it is extremely harmful.

Ultraviolet B

Medium wave ultraviolet, occupying the range 320 - 280 nm. Ultraviolet radiation with this wavelength is capable of penetrating the upper layers of living tissues and causing serious changes in their structure, including partial destruction of DNA. Even a minimal dose of UVB can cause serious and quite deep radiation burns to the skin, cornea and lens. Such radiation also poses a serious danger to plants, and for many types of viruses and bacteria, due to their small size, UVB is generally fatal.

Ultraviolet C

The shortest wavelength and most dangerous range for all living things, which includes ultraviolet radiation with a wavelength from 280 to 100 nm. UVC, even in small doses, can destroy DNA chains, causing mutations. In humans, exposure typically causes skin cancer and melanoma. Due to its ability to penetrate deep enough into tissue, UVC can cause irreversible radiation burns to the retina and deep damage to the skin.

An additional danger is the ability of ultraviolet C radiation to ionize oxygen molecules in the atmosphere. As a result of such exposure, ozone is formed in the air - triatomic oxygen, which is the strongest oxidizing agent, and in terms of the degree of danger for biological objects, it belongs to the first, most dangerous category of poisons.

Ultraviolet lamp device

Man has learned to create artificial sources of ultraviolet radiation, and they can emit in any given range. Structurally, ultraviolet lamps are made in the form of a flask filled with an inert gas with an admixture of metallic mercury. Refractory electrodes are soldered onto the sides of the flask, to which the power supply voltage of the device is supplied. Under the influence of this voltage, a glow discharge begins in the flask, which causes mercury molecules to emit ultraviolet light in all spectra of the UV range.

Ultraviolet lamp design

By making a flask from one material or another, designers can cut off radiation of a certain wavelength. Thus, an erythema glass lamp transmits only type A ultraviolet radiation; a UVB bulb is already transparent to UVB, but does not transmit hard UVC radiation. If the flask is made of quartz glass, then the device will emit all three types of ultraviolet spectrum - A, B, C.

All ultraviolet light lamps are gas-discharge and must be connected to the network through a special ballast. Otherwise, the glow discharge in the flask will instantly turn into an uncontrolled arc.

Electromagnetic (left) and electronic ballasts for ultraviolet discharge lamps

Important! Incandescent lamps with a blue balloon, which we often use for warming up for ENT diseases, are not ultraviolet. These are ordinary incandescent light bulbs, and the blue bulb serves only to ensure that you do not get a thermal burn and do not damage your eyes with bright light, holding a rather powerful lamp close to your face.

The Minin reflector has nothing to do with ultraviolet radiation and is equipped with a regular incandescent blue glass lamp

Application of UV lamps

So, ultraviolet lamps exist, and we even know what's inside them. But what are they for? Today, ultraviolet light devices are widely used both in everyday life and in production. Here are the main areas of application of UV lamps:

1. Change in the physical properties of materials. Under the influence of ultraviolet radiation, some synthetic materials (paints, varnishes, plastics, etc.) can change their properties: harden, soften, change color and other physical characteristics. A living example is dentistry. A special photopolymer filling is flexible until the doctor, after installing it, illuminates the oral cavity with soft ultraviolet light. After this treatment, the polymer becomes stronger than stone. Beauty salons also use a special gel that hardens under a UV lamp. With its help, for example, cosmetologists extend nails.

After treatment with an ultraviolet lamp, the filling, soft as plasticine, acquires exceptional strength

2. Forensics and criminal law. Polymers that glow in ultraviolet light are widely used to protect against counterfeiting. For fun, try illuminating the bill with an ultraviolet lamp. In the same way, you can check banknotes of almost all countries, the authenticity of especially important documents or stamps on them (the so-called “Cerberus” protection). Forensic scientists use ultraviolet lamps to detect traces of blood. It, of course, does not glow, but it completely absorbs ultraviolet radiation and will appear completely black against the general background.

Security elements for banknotes, stamps and passports (Belarus), visible only in ultraviolet light

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If you have watched films about criminologists, you have probably noticed that in them, blood under a UV lamp, contrary to what I said above, glows blue-white. To achieve this effect, specialists treat suspected blood stains with a special compound that interacts with hemoglobin, after which it begins to fluoresce (glow in ultraviolet radiation). This method is not only more visual for the viewer, but also more effective.

3. With a deficiency of natural ultraviolet radiation. The benefits of ultraviolet A lamp for biological objects were discovered almost simultaneously with its invention. With a lack of natural ultraviolet radiation, the human immune system suffers, and the skin acquires an unhealthy pale tint. If plants and indoor flowers are grown behind a glass window or under ordinary incandescent lamps, then they do not feel the best - they grow poorly and often get sick. It's all about the lack of ultraviolet radiation of spectrum A, the deficiency of which is especially harmful for children. Today, UVA lamps are used to strengthen the immune system and improve skin condition everywhere where there is not enough natural light.

Using ultraviolet lamps of spectrum A to compensate for the deficiency of natural ultraviolet radiation

In fact, devices used to replenish the deficiency of natural ultraviolet light emit not only ultraviolet A, but also B, although the share of the latter in the total radiation is extremely small - from 0.1 to 2-3%.

4. For disinfection. All viruses and bacteria are also living organisms, and they are so small that it is not difficult to “overload” them with ultraviolet light. Hard ultraviolet (C) light can literally pass right through some microorganisms, destroying their structure. Thus, spectrum B and C lamps, called antibacterial or bactericidal, can be used to disinfect apartments, public institutions, air, water, objects, and even to treat viral infections. When using UVC lamps, an additional disinfecting factor is ozone, which I wrote about above.

Using ultraviolet lamps for disinfection and antibacterial treatment

You've probably heard the medical term quartzization. This procedure is nothing more than the treatment of objects or the human body with strictly dosed hard ultraviolet radiation.

Main characteristics of ultraviolet radiation sources

What characteristics of a UV lamp should you be guided by in order to get the maximum effect when using it and not cause harm to the health of yourself and others? Here are the main ones:

1. Radiation range.
2. Power.
3. Purpose.
4. Service life.

Emitted range

This is the main parameter. Depending on the wavelength, ultraviolet radiation acts differently. If UVA is dangerous only for the eyes, and when used correctly does not pose a serious threat to the body, then UVB can not only damage the eyes, but also cause deep, sometimes irreversible burns on the skin. UVC is an excellent disinfectant, but can be fatal to humans because radiation at this wavelength destroys DNA and creates the poisonous gas ozone.

On the other hand, the UVA spectrum is absolutely useless as an antibacterial agent. There will be practically no benefit from such a lamp, for example, when cleaning the air from microbes. Moreover, some types of bacteria and microflora will become even more active. Thus, when choosing a UV lamp, you need to clearly understand what it will be used for and what emission spectrum it should have.

Power

This refers to the strength of the UV flux created by the lamp. It is proportional to the power consumption, so when choosing a device, they usually focus on this indicator. Household ultraviolet lamps usually do not exceed a power of 40-60, professional devices can have a power of up to 200-500 W or more. The former usually have low pressure in the flask, the latter – high. When choosing a radiator for certain purposes, you need to clearly understand that in terms of power, more does not always mean better. To obtain maximum effect, the radiation of the device must be strictly dosed. Therefore, when purchasing a lamp, pay attention not only to its purpose, but also to the recommended area of ​​the room or the performance of the device if it is used to purify air or water.

Purpose and design

According to their purpose, ultraviolet lamps are divided into household and professional. The latter usually have higher power, a wider and harder radiation spectrum and are complex in design. That is why they require a qualified specialist and relevant knowledge for their service. If you are going to buy an ultraviolet lamp for home use, then it is better to refuse professional devices. In this case, there is a high probability that the lamp will do more harm than good. This is especially true for devices operating in the UVC range, the radiation of which is ionizing.

By type of design, ultraviolet lamps are divided into:

1. Open. These devices emit ultraviolet light directly into the environment. If used incorrectly, they pose the greatest danger to the human body, but they allow for high-quality disinfection of the room, including the air and all objects in it. Lamps of an open or semi-open (narrowly directed radiation) design are also used for medical purposes: treatment of infectious diseases and replenishment of ultraviolet deficiency (phytolamps, solariums).

The use of bactericidal lamps for antibacterial treatment of premises

2. Recirculators or closed type devices. The lamp in them is located behind a completely opaque casing, and UV study affects only the working medium - gas or liquid, driven by a special pump through the irradiated chamber. In everyday life, recirculators are usually used for bactericidal treatment of water or air. Since the devices do not emit ultraviolet light, when used correctly, they are completely safe for humans and can be used in their presence. Recyclers can be for both domestic and industrial purposes.

Recirculator – sterilizer for water (left) and air

3. Universal. Devices of this type can operate in both air recirculation and direct radiation modes. Structurally designed as a recirculator with a folding casing. When assembled, it is a regular recirculator; with the curtains open, it is an open-type bactericidal lamp.

Universal bactericidal lamp in recirculator mode (left)

Service life

Since the operating principle and design of an ultraviolet lamp are similar to the principle and design of a fluorescent lighting device, it is logical to assume that their service life is the same and can reach 8,000–10,000 hours. In practice, this is not entirely true. During operation, the lamp “ages”: its luminous flux decreases. But if in a conventional lighting lamp this effect is noticeable visually, then it is impossible to check it “by eye” with a UV lamp. Therefore, the manufacturer limits itself to a much shorter operating life: from 1,000 to 9,000 hours, depending on the power of the lamp, its purpose and, of course, the quality of materials, components and brand.

Surely many people know that ultraviolet radiation can create a double situation for your skin. It can cause what we call a tan (in other words, it affects the melanin under our skin) on the body, or it can cause a serious burn.

Ultraviolet light- the most powerful radiation from our main and only system - the Solar, now every schoolchild knows this. What we see as the sun's rays is actually just light from a star reaching us through an incredible distance.

Ultraviolet waves, invisible to us, simply remain outside the spectrum that is accessible to the human eye.

These are just the remnants of energy that reaches us from the Sun through the distance to the Earth (which is 149,600,000 km) and overcomes the main protection of the planet - the ozone layer.

What we can feel on our skin are tiny particles of the incredible amount of heat that the star releases every second. You may have heard about the ozone layer from environmental television programs and other similar material, and for good reason.

If the ozone layer did not exist, all life on Earth would die almost instantly from a powerful flow of radiation. Yes, ultraviolet radiation is radioactive and in large doses can cause harm, even death.

The ultraviolet range of radiation is between the rays visible to us (namely the violet border of our light vision) and x-rays.

That is why this type of electromagnetic rays got its name - ultraviolet, from lat. ultra (above something, beyond something) and violet (purple from English).

Ultraviolet light also has different wavelengths - from 400 to 100 nm. The wavelength is important - it affects living organisms with a force directly proportional to the range.

The USF wavelength of 280-200 nm has the strongest effect on living organisms, for example, organ tissue. It acts as a bactericidal radiation on microorganisms, completely destroying them.

Who discovered ultraviolet?

Suspicions that invisible spectra of light exist have been circulating among the greatest minds of mankind for a very long time. Scientists of that time could not explain the phenomenon, but they made very promising guesses, which led modern scientists to the discovery in its pure form.

The discovery occurred shortly after humanity discovered infrared radiation. Around this time, German physicist Johann Wilhelm Ritter began to conduct research in the region at the opposite end of the spectrum, with rays beyond the violet limit.

The nineteenth century had just begun, people still did not know a lot about light and what it was, not to mention what ultraviolet radiation was.

Everything was learned through experimentation, rare contacts with colleagues from other countries and a long process of trial and error. Ritter followed the same path.

He conceived an interesting experiment, which he carried out in his research using silver chloride. By irradiating it with different parts of the spectrum, he noticed that the oxidation of the substance occurs at different rates.

Each part of the spectrum had a different effect, but one indicator stood out very clearly from the others - silver darkened fastest outside the violet part, or rather in front of it.

Despite the fact that even knowledge about the wavelength range was quite blurred at that time, scientists drew a conclusion from this that changed physics forever.

After much discussion and discussion, the conclusion was given to the public quite clearly.

Scientists have agreed that light can be divided into three conditional, strictly separate parts:

1. visible light (visible to the human eye);
2. infrared radiation (invisible rays that give the effect of heat and are responsible for oxidation);
3. ultraviolet rays (restorative).

Of course, then no one could know the effect of ultraviolet radiation on human skin, as well as all the areas in which people will use this radiation in the future.

Nevertheless, research continued and continues today, and ultraviolet constantly surprises scientists with some new properties and possibilities for its use.

The benefits of ultraviolet radiation for humans

Every year, humanity discovered more and more new ways to use this amazing radiation.

One of the most famous and familiar to anyone who has had the misfortune of staying in a hospital for a long time is quartzing - irradiating a hospital room with ultraviolet light in order to completely sterilize the room from microorganisms.

Although the method is old, it is still used - many hospital wards are still equipped with special lamps that emit ultraviolet rays.

All people, including staff, leave the room during quartzing, since ultraviolet rays of sufficient power for a bactericidal effect will certainly harm a person.

A person who finds himself even briefly under the effect of such a lamp will feel a buzzing in his ears, increased blood pressure, and will be haunted by a specific smell and headache.

Ultraviolet (UVS) radiation is also used in water disinfection. Along with chlorine, which is used more for industrial purposes, and not for water that should then get into people's homes, ultraviolet light not only helps purify water, but also eliminates the consequences of chlorination and ozonation of water - excessive hardness, chemical sediment.

It is most popular when purifying water for industrial needs, for factories and swimming pools - the spectrum of ultraviolet radiation is such that such purification will not cause harm to humans.

The same chlorine is much more dangerous - if, for example, in a swimming pool you do not calculate the proportions of the substance to the water, chlorine can easily cause weak but noticeable minor burns to your skin.

Ultraviolet has also distinguished itself in the field of environmental analysis. It, like any radiation, can be used to study substances. The effect is especially visible on minerals - when irradiated, rocks and stones begin to glow, each in a different way.

There are no consequences of such irradiation, and the special reaction of each mineral to ultraviolet rays has been very useful to geologists. Now, by shining through entire layers of rocks, one can “recognize” this or that stone with almost absolute certainty.

X-rays are also used by geologists for such analyses, but the amazing effectiveness of ultraviolet light is difficult to compete with.

Well, perhaps the most well-known area of ​​application of such rays is now. This, oddly enough, is the field of cosmetology.

Humanity has long wondered if ultraviolet in the sun's rays (namely, the Sun is the main source of cosmic ultraviolet for us) causes tanning on human skin.

Then why not create an artificial source and get this effect all year round, and not just during the beach seasons, when sunbathing is possible?

The effect of UVC on the skin is extremely simple and mechanical - the rays act on our human pigment (melanin), which simply protects itself, darkening in the process - this also explains the reason for the disappearance of the tan over time.

We managed to create an artificial source - now these are ultra-modern solariums with gentle lamps. They are almost completely safe for people with any skin type, and they use ultraviolet light easily and without any fear.

No one is safe from applying too much of a tan or spoiling the even tone, but getting burns in a solarium will not happen - safety precautions will not allow it.

The dangers of ultraviolet radiation for skin

By the way, about safety. In small amounts, ultraviolet radiation in the open air cannot cause harm more serious than sunburned skin, even if you are in water.

But we are talking about a standard dose of radiation for a person, and there are people who, voluntarily or unwittingly, receive excess ultraviolet rays much more often than several times a year.

Unfortunately, this threatens not only permanent tanning. The rays do not act on the skin in the best way, sometimes forming or intensifying an existing melanoma - in other words, skin cancer.

There are several types of melanomas, but all of them are malignant tumors. Moreover, it does not matter where you sunbathe - both cosmic solar and artificial ultraviolet, which is used in solariums, will have the same effect.

The risk of getting melanoma is small, but if you have had other cancers before, ultraviolet radiation increases the chance of recurrence, which has been proven.

Melanoma– the worst of the options and the chances of it happening are small. But if you overuse sunbathing, you will get a few more unpleasant surprises.

These are the skin burns we all know from childhood, after which the top layer of the epidermis slides off in shreds. There is a high probability of premature skin aging due to the same melanin, which simply cannot withstand such a load.

And if you get rid of the burns, since special creams are already used everywhere for the treatment and prevention of sunburn, then it is unlikely that aging will be reversed.

Another ingenious human invention, sunglasses, was also invented in an attempt to combat excess ultraviolet radiation, because these rays are also very harmful to the human eye.

The harmful effect will be of the same type - a burn, but only to the main barrier of the eye, the retina. This is a serious injury, the integrity of the retina is very difficult and expensive to restore.

Remarkably, when replacing the retina, some patients began to literally see ultraviolet radiation in the form of a faint purple glow, and in new models of rapidly developing implants this error no longer exists.

You can protect your eye from the rays only with a direct “screen”, the role of which is played by the glass of the glasses - its main function is precisely this, and not to improve your visibility on a sunny day.

Surprisingly, from our enemy we have slowly but surely turned ultraviolet into a conditional friend. We use radiation to solve everyday problems, which, with any more or less serious breach in the ozone layer, can easily cause an apocalypse.

We have learned to handle it with caution and know its main secrets, but this does not mean at all that it is no longer dangerous for us.

First of all, everything depends on the people themselves - until technology is developed enough to completely save us from the effects of cosmic radiation, we should be extremely careful and beware of burns, especially with such consequences.

The sun is a powerful source of heat and light. Without it there can be no life on the planet. The sun emits rays that are invisible to the naked eye. Let's find out what properties ultraviolet radiation has, its effect on the body and possible harm.

The solar spectrum has infrared, visible and ultraviolet parts. UV has both positive and negative effects on humans. It is used in various spheres of life. It is widely used in medicine; ultraviolet radiation has the ability to change the biological structure of cells, affecting the body.

Sources of exposure

The main source of ultraviolet rays is the sun. They are also obtained using special light bulbs:

1. High-pressure mercury-quartz.
2. Vital luminescent.
3. Ozone and quartz bactericidal.

Currently, only a few types of bacteria are known to humanity that can exist without ultraviolet radiation. For other living cells, its absence will lead to death.

What is the effect of ultraviolet radiation on the human body?

Positive Action

Today, UV is widely used in medicine. It has a sedative, analgesic, antirachitic and antispastic effect. Positive effects of ultraviolet rays on the human body:

• intake of vitamin D, it is needed for the absorption of calcium;
• improvement of metabolism, as enzymes are activated;
• reduction of nervous tension;
• increased production of endorphins;
• dilation of blood vessels and normalization of blood circulation;
• acceleration of regeneration.

Ultraviolet light is also useful for humans because it affects immunobiological activity and helps activate the body’s protective functions against various infections. At a certain concentration, radiation causes the production of antibodies that affect pathogens.

Negative influence

The harm of an ultraviolet lamp to the human body often exceeds its beneficial properties. If its use for medicinal purposes is not performed correctly and safety precautions are not followed, an overdose is possible, characterized by the following symptoms:

1. Weakness.
2. Apathy.
3. Decreased appetite.
4. Memory problems.
5. Increased heart rate.

Prolonged exposure to the sun is harmful to the skin, eyes and immunity. The consequences of excessive tanning, such as burns, dermatological and allergic rashes, disappear after a few days. Ultraviolet radiation slowly accumulates in the body and causes dangerous diseases.

UV exposure of the skin can cause erythema. The vessels dilate, which is characterized by hyperemia and edema. Histamine and vitamin D accumulate on the body and enter the bloodstream, which promotes changes in the body.

The stage of development of erythema depends on:

• range of UV rays;
• radiation doses;
• individual sensitivity.

Excessive irradiation causes a burn on the skin with the formation of a bubble and subsequent convergence of the epithelium.

But the harm of ultraviolet radiation is not limited to burns; its irrational use can provoke pathological changes in the body.

Effect of UV on skin

Most girls strive for a beautiful tanned body. However, the skin acquires a dark color under the influence of melanin, so the body protects itself from further radiation. But it will not protect against the more serious effects of radiation:

1. Photosensitivity – high sensitivity to ultraviolet radiation. Its minimal effect can cause burning, itching or burns. This is mainly due to the use of drugs, cosmetics or certain foods.
2. Aging - UV rays penetrate into the deep layers of the skin, destroy collagen fibers, elasticity is lost and wrinkles appear.
3. Melanoma is a skin cancer that forms as a result of frequent and prolonged exposure to the sun. An excessive dose of ultraviolet radiation causes the development of malignant neoplasms on the body.
4. Basal cell and squamous cell carcinoma are cancers of the body that require surgical removal of the affected areas. This disease often occurs in people whose work requires prolonged exposure to the sun.

Any skin dermatitis caused by UV rays can cause the formation of skin cancer.

Effect of UV on the eyes

Ultraviolet radiation can also be harmful to the eyes. As a result of its influence, the following diseases may develop:

• Photoophthalmia and electroophthalmia. It is characterized by redness and swelling of the eyes, lacrimation, and photophobia. Appears in those who are often in the bright sun in snowy weather without sunglasses or in welders who do not follow safety rules.
• Cataract is clouding of the lens. This disease mainly appears in old age. It develops as a result of exposure to sunlight on the eyes, which accumulates throughout life.
• Pterygium is a growth of the conjunctiva of the eye.

Some types of cancers on the eyes and eyelids are also possible.

How does UV affect the immune system?

How does radiation affect the immune system? In a certain dose, UV rays increase the body's protective functions, but their excessive effect weakens the immune system.

Radiation radiation changes the protective cells, and they lose their ability to fight various viruses, cancer cells.

Skin protection

To protect yourself from the sun's rays, you must follow certain rules:

1. Exposure to the open sun should be moderate; a slight tan has a photoprotective effect.
2. It is necessary to enrich the diet with antioxidants and vitamins C and E.
3. You should always use sunscreen. In this case, you need to choose a product with a high level of protection.
4. The use of ultraviolet radiation for medicinal purposes is permitted only under the supervision of a specialist.
5. Those who work with UV sources are advised to protect themselves with a mask. This is necessary when using a bactericidal lamp, which is dangerous to the eyes.
6. Those who like an even tan should not visit the solarium too often.

To protect yourself from radiation, you can also use special clothing.

Contraindications

The following people are contraindicated from exposure to ultraviolet radiation:

• those who have too light and sensitive skin;
• with an active form of tuberculosis;
• children;
• for acute inflammatory or oncological diseases;
• albinos;
• during stages II and III of hypertension;
• with a large number of moles;
• those who suffer from systemic or gynecological ailments;
• with prolonged use of certain medications;
• with a hereditary predisposition to skin cancer.

Infrared radiation

Another part of the solar spectrum is infrared radiation, which has a thermal effect. It is used in a modern sauna.

- This is a small wooden room with built-in infrared emitters. Under the influence of their waves, the human body warms up.

The air in an infrared sauna does not rise above 60 degrees. However, the rays warm the body up to 4 cm, when in a traditional bath the heat penetrates only 5 mm.

This happens because infrared waves have the same length as heat waves coming from a person. The body accepts them as its own and does not resist penetration. The human body temperature rises to 38.5 degrees. Thanks to this, viruses and dangerous microorganisms die. An infrared sauna has a healing, rejuvenating, and preventive effect. It is indicated for any age.

Before visiting such a sauna, you must consult with a specialist, and also follow safety precautions for staying in a room with infrared emitters.

Video: ultraviolet.

UV in medicine

In medicine there is a term “ultraviolet fasting”. This happens when the body does not get enough sunlight. To prevent any pathologies from arising, artificial ultraviolet sources are used. They help fight winter vitamin D deficiency and boost immunity.

This radiation is also used in the treatment of joints, allergic and dermatological diseases.

In addition, UV has the following healing properties:

1. Normalizes the functioning of the thyroid gland.
2. Improves the function of the respiratory and endocrine systems.
3. Increases hemoglobin.
4. Disinfects the room and medical instruments.
5. Reduces sugar levels.
6. Helps in the treatment of purulent wounds.

It must be borne in mind that an ultraviolet lamp is not always beneficial; great harm is also possible.

In order for UV radiation to have a beneficial effect on the body, you must use it correctly, follow safety precautions and not exceed the time spent in the sun. Excessive excess of radiation dose is dangerous to human health and life.

Life-giving rays.

The sun emits three types of ultraviolet rays. Each of these types affects the skin differently.

Most of us feel healthier and fuller of life after spending time at the beach. Thanks to the life-giving rays, vitamin D is formed in the skin, which is necessary for the complete absorption of calcium. But only small doses of solar radiation have a beneficial effect on the body.

But heavily tanned skin is still damaged skin and, as a result, premature aging and a high risk of developing skin cancer.

Sunlight is electromagnetic radiation. In addition to the visible spectrum of radiation, it contains ultraviolet radiation, which is actually responsible for tanning. Ultraviolet light stimulates the ability of melanocyte pigment cells to produce more melanin, which performs a protective function.

Types of UV rays.

There are three types of ultraviolet rays, which differ in wavelength. Ultraviolet radiation is able to penetrate through the epidermis of the skin into deeper layers. This activates the production of new cells and keratin, resulting in tighter, rougher skin. Sun rays penetrating the dermis destroy collagen and lead to changes in the thickness and texture of the skin.

Ultraviolet rays A.

These rays have the lowest level of radiation. Previously, it was generally believed that they were harmless, however, it has now been proven that this is not the case. The level of these rays remains almost constant throughout the day and year. They even penetrate glass.

UV A rays penetrate through the layers of the skin, reaching the dermis, damaging the base and structure of the skin, destroying collagen and elastin fibers.

A-rays promote the appearance of wrinkles, reduce skin elasticity, accelerate the appearance of signs of premature aging, and weaken the skin's defense system, making it more susceptible to infections and possibly cancer.

Ultraviolet rays B.

Rays of this type are emitted by the sun only at certain times of the year and hours of the day. Depending on air temperature and latitude, they usually enter the atmosphere between 10 a.m. and 4 p.m.

UVB rays cause more serious damage to the skin because they interact with DNA molecules found in skin cells. B rays damage the epidermis, leading to sunburn. B rays damage the epidermis, leading to sunburn. This type of radiation increases the activity of free radicals, which weaken the skin's natural defense system.

Ultraviolet B rays promote tanning and cause sunburn, lead to premature aging and the appearance of dark pigment spots, make the skin rough and rough, accelerate the appearance of wrinkles, and can provoke the development of precancerous diseases and skin cancer.