INFRARED RADIATION (IR radiation, IR rays), electromagnetic radiation with wavelengths $λ$ from approx. 0.74 µm to approx. 1–2 mm, i.e. radiation occupying the spectral region between the red end of visible radiation and short-wave (submillimeter) radio emission. I. and. refers to optical radiation, but unlike visible radiation, it is not perceived by the human eye. Interacting with the surface of bodies, it heats them, which is why it is often called thermal radiation. Conventionally, the area of I. and. divided into near ($λ$=0.74–2.5 µm), middle (2.5–50 µm) and far (50–2000 µm). I. and. discovered by W. Herschel (1800) and independently by W. Wollaston (1802).
Spectra I. and. can be lined (atomic spectra), continuous (condensed matter spectra) or striped (molecular spectra). Optical The properties (transmittance, reflection, refraction, etc.) of substances in radiation, as a rule, differ significantly from the corresponding properties in visible or ultraviolet radiation. Mn. substances that are transparent to visible light are opaque to And. and. certain wavelengths, and vice versa. So, a layer of water several thick. centimeters is opaque to I. and. with $λ>$ 1 µm, so water is often used as a heat-protective filter. Plates made of $\ce{Ge}$ and $\ce{Si}$, opaque to visible radiation, are transparent to radiation. certain wavelengths, black paper is transparent in the far infrared region (such substances are used as light filters for isolating radiation).
The reflectivity of most metals in I. and. significantly higher than in visible radiation, and increases with increasing wavelength (see Metal optics). Thus, the reflection of surfaces $\ce{Al,\, Au,\, Ag,\, Cu}$ I. and. with $λ$=10 µm reaches 98%. Liquid and solid non-metallic. substances have a selective (wavelength-dependent) reflection of radiation, the position of the maxima of which depends on their chemical properties. composition.
Passing through the earth's atmosphere, I. and. weakened due to scattering and absorption by air atoms and molecules. Nitrogen and oxygen do not absorb I. and. and weaken it only as a result of scattering, which for I. and. significantly less than for visible light. Molecules $\ce{H_2O,\, CO_2,\, O_3}$, etc., present in the atmosphere, selectively (selectively) absorb radiation, and absorb radiation especially strongly. water vapor. The $\ce{H_2O}$ absorption bands are observed in the entire IR region of the spectrum, and the $\ce{CO_2}$ bands are observed in its middle part. In the surface layers of the atmosphere there are only a small number of “transparency windows” for radiation. The presence of smoke particles, dust, and small drops of water in the atmosphere leads to an additional weakening of I. and. as a result of its scattering on these particles. At small particle sizes I. and. Scatters less than visible radiation, which is used in IR photography.
What is infrared radiation
Radiation adjacent to the red part of the visible spectrum, not perceived by our organs of vision, but having the ability to heat illuminated surfaces, was called infrared. The prefix "infra" means "more". In our case, these are electromagnetic rays with a wavelength greater than that of visible red light.
What is the source of infrared radiation
Its natural source is the Sun. The range of infrared rays is quite wide. These are waves with a length from 7 to 14 micrometers (µm). Partial absorption and scattering of infrared rays occurs in the Earth's atmosphere.
The scale of infrared solar radiation is evidenced by the fact that it accounts for 58% of the entire spectrum of electromagnetic waves emanating from our star.
This fairly wide range of IR rays is divided into three parts:
- long waves emitted by a heater with temperatures up to 300 °C;
- medium - up to 600 °C;
- short - more than 800 °C.
All of them are emitted by excited atoms (i.e., those with excess energy), as well as ions of the substance. All bodies are a source of IR radiation if their temperature is above absolute zero (minus 273 °C).
So, depending on the temperature of the emitter, IR rays of different wavelengths, intensities and penetrating abilities are formed. And this determines how infrared radiation affects a living organism.
Sky Reviews
Sky in the near-infrared range 1–4 µm and in the mid-infrared range 25 µm (COBE/DIRBE)
In the near-infrared range, the Galaxy is visible even more clearly than in the visible.
But in the mid-IR range the Galaxy is barely visible. Observations are greatly hampered by dust in the solar system. It is located along the ecliptic plane, which is inclined to the galactic plane at an angle of about 50 degrees.
Both surveys were obtained by the DIRBE (Diffuse Infrared Background Experiment) instrument on board the COBE (Cosmic Background Explorer) satellite. This experiment, begun in 1989, produced complete maps of infrared sky brightness from 1.25 to 240 μm
.
The benefits and harms of IR radiation for human health
You can answer the question - is infrared radiation harmful to humans, armed with some information.
Long-wave infrared rays hitting the skin affect nerve receptors, causing a feeling of warmth. Therefore, infrared radiation is also called thermal radiation.
More than 90% of this radiation is absorbed by moisture contained in the upper layers of the skin. It only causes an increase in the temperature of the skin. Medical research has shown that long-wave radiation is not only safe for humans, but also improves immunity and triggers the mechanism of regeneration and healing of many organs and systems. IR rays with a wavelength of 9.6 microns are especially effective in this regard. These circumstances determine the use of infrared radiation in medicine.
A completely different mechanism of action of infrared rays on the human body, which belongs to the short-wave part of the spectrum. They are able to penetrate to a depth of several centimeters, causing heating of internal organs.
At the site of irradiation, due to dilation of the capillaries, redness of the skin may appear, including the formation of blisters. Short IR rays are especially dangerous for the organs of vision. They can provoke the formation of cataracts, disturbances in water-salt balance, and the appearance of seizures.
The cause of the well-known thermal shock effect is short-wave infrared radiation. An increase in brain temperature of 1 °C already causes its symptoms:
- dizziness;
- nausea;
- increased heart rate;
- darkening of the eyes.
Overheating by 2 °C can trigger the development of meningitis.
Now let's understand the concept of intensity of electromagnetic radiation. This factor depends on the distance to the heat source and its temperature. Low-intensity long-wave thermal radiation plays an important role for the development of life on the planet. The human body needs constant replenishment of these wavelengths.
Thus, the harm and benefits of infrared radiation are determined by the wavelength and exposure time.
Sources
In the infrared, the Hubble telescope can see more galaxies than stars
A fragment of one of the so-called Hubble Deep Fields. In 1995, a space telescope collected light coming from one part of the sky for 10 days. This made it possible to see extremely faint galaxies up to 13 billion light years away (less than one billion years from the Big Bang). Visible light from such distant objects undergoes a significant red shift and becomes infrared.
The observations were carried out in a region far from the galactic plane, where relatively few stars are visible. Therefore, most of the registered objects are galaxies at different stages of evolution.
Sombrero Galaxy in Infrared
The giant spiral galaxy, also designated M104, is located in a cluster of galaxies in the constellation Virgo and is visible to us almost edge-on. It has a huge central bulge (a spherical thickening at the center of the galaxy) and contains about 800 billion stars - 2-3 times more than the Milky Way.
At the center of the galaxy is a supermassive black hole with a mass of about a billion solar masses. This is determined by the speed of movement of stars near the center of the galaxy. In the infrared, a ring of gas and dust is clearly visible in the galaxy, in which stars are actively being born.
Nebulae and dust clouds near the center of the Galaxy in the IR range
How to avoid harmful effects of IR rays
Since we have determined that short-wave infrared radiation has a negative effect on the human body, let’s find out where this danger may lie in wait for us.
First of all, these are bodies with a temperature exceeding 100 °C. These may include the following.
- Industrial sources of radiant energy (steel melting, electric arc furnaces, etc.) Reducing the risk of their exposure is achieved by special protective clothing, heat shields, the use of newer technologies, as well as therapeutic and preventive measures for operating personnel;
- Heaters. The most reliable and proven of them is the Russian stove. The warmth it emits is not only extremely pleasant, but also healing. Unfortunately, this detail of everyday life has almost completely sunk into oblivion. It was replaced by all possible electric heaters. Those of them whose heat-generating coil is protected by heat-insulating material emit soft long-wave radiation. It has a beneficial effect on the body. Heaters with an open heating element emit hard, short-wave radiation, which can lead to the negative consequences described above. In the technical data sheet of the heater, the manufacturer is obliged to indicate the nature of the radiation of this device.
If you become the owner of a short-wave heater, follow the rule - the closer the heater is, the shorter its exposure time should be.
Harm of an infrared heater
Every year, heaters whose operating principle is based on infrared radiation are becoming more and more popular.
Manufacturers assure that using them is safe, economical, and very convenient. They are capable of generating much more heat than fan heaters or oil heaters and do not burn oxygen at all. The unique features of this device are widely advertised on television and on the Internet. But is everything as carefree and reliable as they say? What are the benefits of an infrared heater and is there any harm? Conclusions about the benefits and harms of an infrared (IR) heater can be drawn if you understand what IR radiation is, what its strength and features are.
What is IR radiation
Infrared radiation: harmful
The impact of infrared radiation on the human body has been studied for a long time; large-scale research has been carried out in this area by physiotherapists, scientists and physicians. In the course of a detailed analysis of the devices, their actions, and the intensity of the waves produced, we can talk about the harm that IR heaters can cause.
The most noticeable harm of an infrared heater is drying out the skin. Heating of its surface occurs instantly, with the evaporation of moisture, and the body does not have time to produce it in the required volume. Staying near an IR heater for a long time is harmful, as it can lead to burns, especially if you are near a device that emits short and medium-length waves.
Particularly dangerous to human health is the radiation of waves from an infrared heater of short and medium length, since when they are systematically exposed to human skin, this can cause burns on his body
People involved in production, where such radiation is constantly present, are especially at risk. When skin that is not protected by clothing is systematically exposed to infrared radiation, an internal change occurs in its structure. The irreversible process of protein melting begins, cell membranes lose their permeability, and blood cells begin to change.
The irreparable harm of an infrared heater is the irradiation of the retina and lens of the eye. With regular exposure to rays on its sensitive membranes, vision may decrease, and in the future a dangerous disease - cataracts - may arise.
Heaters emitting short and long waves are designed for outdoor heating: in a cafe, on a summer terrace, in a gazebo. When installing such a device in a room, a person can get severe burns, including redness and blisters.
Benefits of IR heater
IR rays have nothing to do with solar radiation or microwave waves and do not contain harmful ultraviolet radiation. These are completely different radiations. Research in this area has proven that IR heaters do not harm the human body if properly selected and installed.
The principle of operation of IR waves is very similar to the dissipation of solar heat. A device installed in a room heats the walls, interior items, and floors, which then release heat, creating a comfortable temperature in the room.
An infrared heater heats the surrounding objects in the room, not the air, which prevents oxygen from burning out. Important!
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The benefits of an infrared heater are significant - it is the best device for heating a living space, as it instantly heats but does not dry out the air, destroys germs and dampness, and does not burn oxygen.
The direction of IR rays is pointwise, so it is successfully used for outdoor heating of people, which is impossible when using convector devices.
Long-wave radiation has found wide application in medicine: it is used in dentistry and surgery. IR devices are ideal for warming up certain areas of the body, and some patients are prescribed to visit special infrared saunas for therapeutic purposes.
The benefit of an infrared heater lies in its positive effect on human immunity. IR radiation has a beneficial effect on the manifestations of inflammatory and cold diseases, contributing to the fastest healing of a person. People who have a long-wave infrared heater in their home have a high resistance to acute respiratory infections, as well as good health.
Thanks to the effects of long waves, visiting an infrared sauna helps to heal faster from inflammatory and cold diseases
The rational use of infrared rays is used in the treatment of psoriasis, various allergic manifestations and severe skin diseases. For illnesses such as diabetes or hypertension, doctors recommend using devices with long-wave infrared radiation in apartments.
Recommendations
Before purchasing an infrared heater, you should carefully read the instructions and find out what waves are produced when it is heated, as well as the material of the heating element.
Unscrupulous manufacturers may use cheap, low-quality material in the manufacture of the device, which will release hazardous substances into the air during operation. The damage to the infrared heater in this case will be significant. The safest and most efficient incandescent elements are tubular, carbon and ceramic.
The usefulness of an IR heater is questionable if a halogen lamp is installed as a heating element. It tends to emit dangerous short waves that have a negative effect on humans. Therefore, it is better to avoid using such heating devices in everyday life.
When installing the device in a room, you must take into account its area and the height of the walls, especially if you plan to mount it to the ceiling. If placed low, it will heat and dry out the scalp, which can cause migraines. It is not recommended to use an infrared heater during sleep, and it is better not to use it at all in a children's room.
It is highly undesirable to use IR in a child’s room or during sleep, especially near the heads of household members
An IR heater will be beneficial if it is placed correctly in the apartment. The device is installed so that the waves are distributed evenly over the entire area of the room and are directed not at the person, but at the surface of the interior items.
It is imperative to choose only a high-quality IR heater, namely, so that it exactly matches the declared characteristics. When choosing a good IR heater, it is desirable that it be equipped with a sensor for protection against overheating, tipping over, a remote control, and a built-in thermostat that helps maintain a constant temperature.
To summarize, we can conclude that IR heaters will be useful for humans if they are long-wave, occupy the right place in the apartment, and only high-quality materials are used in their manufacture.
Infrared heaters are the first step towards perfect climate control technology. They are comfortable, safe, multifunctional, produce the maximum amount of heat produced and have an undeniable advantage - efficiency!
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Help for Heat Stroke
Nature has endowed humans with a very advanced thermoregulation system. But, if heat stroke does occur, a certain set of measures should be taken to minimize its consequences:
- move the victim to a cool place;
- free him from restrictive clothing;
- apply cold to the head, heart area, neck, armpits, groin areas and spine;
- wrap the victim in a cold, wet sheet - as water evaporates from its surface, the temperature will decrease;
- to enhance the effect, direct the air flow from the fan;
- give the victim cool, plenty of fluids;
- in severe cases, artificial respiration and calling an ambulance are indicated.
Humanity lives in a world of natural and man-made sources of various radiations. The impact of infrared radiation on the human body is undeniable. But there are no statistics proving its harm.
And knowledge of the patterns of its interaction with biological objects allows us to use the beneficial effects of infrared radiation on humans to prevent diseases and treat various diseases.
The benefits of infrared rays
The benefits of using infrared rays in medicine have been scientifically proven. General improvement of human health, treatment of bacterial infections, lowering blood pressure and muscle relaxation - this is an incomplete list of the positive aspects of this amazing discovery.
Man, thanks to his perseverance, managed to find useful application for this amazing phenomenon in the most diverse and sometimes even unrelated areas of his activity. Of course, behind all this there is a careful study of the properties of rays.
Infrared thermometers, pyrometers
The operating principle of these devices is as follows. The optical system of the thermometer catches the energy of the object, expressed by a certain linear sector (the so-called “measured spot”) and sends it to the detonator; there it is modified into an electrical signal and, when converted, is displayed on the display in the form of specific digital indicators.
IR thermometers and pyrometers are capable of measuring radiation from objects with surface temperatures from -50 to +2250°C, humidity from 0 to 100%. They are contact and non-contact. The latter take readings from objects at a distance of a few millimeters to a meter.
These devices are used in household, construction, industrial work, and when testing mechanical equipment and electrical systems. A prominent representative of this type of device is Almemo 8036 - a reference device for high-precision measurements of temperatures up to +850°C.
Main features
An infrared burner differs from other devices in its heating method. Heat transfer occurs due to the emission of infrared rays, which are invisible to humans. This feature allows heat to penetrate not only into the air, but also onto interior items, which subsequently also increase the temperature in the room. The infrared emitter does not dry out the air, because the rays are primarily directed at interior items and walls. In the future, heat will be transferred from walls or objects directly to the space of the room, and the process occurs in a few minutes.
Positive sides
The main advantage of such devices is quick and easy heating of the room. For example, it will take 20 minutes to heat a cold room to a temperature of +24ºС. During the process, there is no air movement, which contributes to the formation of dust and large contaminants. Therefore, an infrared emitter is installed indoors by those people who have allergies.
In addition, infrared rays, when hitting a surface with dust, do not cause it to burn, and, as a result, there is no smell of burnt dust. The quality of heating and durability of the device depends on the heating element. Such devices use a ceramic type.
Infrared gas burners
An infrared burner is used to heat various rooms.
At first it was used for greenhouses and garages (that is, non-residential premises). However, modern technologies have made it possible to use it even in apartments. Popularly, such a burner is called a solar device, since when turned on, the working surface of the equipment resembles sunlight. Over time, such devices replaced oil heaters and convectors.
Sauna
What is an infrared cabin? This is a special room that is built from natural types of wood (for example, cedar). Infrared emitters are installed in it, acting on the tree.
During heating, phytoncides are released - useful components that prevent the development or appearance of fungi and bacteria.
Such an infrared cabin is popularly called a sauna. The air temperature inside the room reaches 45ºС, so it is quite comfortable to be in it. This temperature allows the human body to be warmed evenly and deeply. Therefore, heat does not affect the cardiovascular system. During the procedure, accumulated toxins and waste are removed, metabolism in the body is accelerated (due to the rapid movement of blood), and tissues are also enriched with oxygen. However, sweating is not the main feature of an infrared sauna. It is aimed at improving well-being.
