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What does the air around us consist of? Report on the topic of air. What is the air we breathe made of?

Air is a mixture of gases, consisting of 78% nitrogen, 21% oxygen, relatively little carbon dioxide, and also water vapor.

Air is necessary for breathing for all living organisms: humans, animals, plants.

The ocean of air surrounds our planet, fills all the voids on earth, and is found in water in dissolved form.

The uneven heating of air above the Earth's surface moves air masses and causes wind. Warm, lighter air rises above land or sea, cold, heavier air sinks down from the upper layers. This affects the climate of many areas.

meaning of air on earth
properties of air
air composition
air protection
amazing winds

The meaning of air on earth

Air is necessary for breathing for all living organisms.
The movement of air masses associated with uneven heating at the Earth's surface determines climatic features in different regions. It is the winds that bring from the oceans all the masses of water that feed the rivers and give life to living nature.
Many properties of air are used in Everyday life people and animals.
Sound transmission over a distance occurs through air. Sound is vibrations in the air that are picked up by the ear. The most enormous cosmic disasters, such as the explosion of a star, take place completely silently, in perfect silence. We can experience the pleasure of hearing sound only on Earth, where there is atmospheric air.

Properties air

The flight of airplanes, hot air balloons, the movement of a sailboat and a wind power plant, the soaring of birds, the operation of a vacuum cleaner - all this occurs due to the properties of air.

Air elasticity, that is, the ability of air to restore its previous volume after the pressure on it ceases - car tires, ball, air gun. Compressibility characterizes the property of air to change its volume and density with changes in pressure and temperature.

Low thermal conductivity of air and used, for example, in double window frames. Glass by itself does not protect against cold; it only retains air, which is a poor conductor of heat. And the apartment maintains the desired temperature.

Air is transparent and invisible, odorless, has no definite volume, has a mass lighter than water, warm air is lighter than cold air, and rises upward. Man has learned to use many properties in science and technology.

Compound air

Air consists of 1/5 oxygen, 4/5 nitrogen, and no more than 1% is made up of other gases, including carbon dioxide. Contains air and water vapor.

It is oxygen that animals and humans need. Carbon dioxide CO 2 is consumed by plants and produces oxygen. Therefore, the composition of the air is different in a forest or in a city. In the city there is less oxygen, more carbon dioxide, in the forest - vice versa. Forests are called the “lungs” of our planet.

Air protection

Human industrial activity leads to environmental pollution. Humanity burns oil, gas, gasoline, coal and other types of fuel in the furnaces of power plants, various factories, and in car engines. Incomplete combustion of fuel releases particles into the air harmful substances. They are carried with air masses by winds all over the world and, together with precipitation, return to the earth, polluting water, soil and all the nature around us.

Air pollution leads to the greenhouse effect. The surface of the globe is gradually warming up. Glaciers at the poles are melting, the level of the world's oceans is rising. More and more disasters are befalling humanity. In order to live comfortably in the future, a person must take care of protecting the cleanliness of the air by reducing emissions from industrial enterprises and cars. This is a question of the existence of a bright future.

Amazing winds

Wind is one of the most common natural phenomena. Familiar and understandable to everyone. Sometimes pleasant, sometimes unpleasant.

What is wind? Where the air is heated more, it rises, colder and heavier air sinks down. We say: the wind blows.

It also happens: sand dunes sing mysterious songs. The poisonous breath of a sandstorm poisons all living things.

The wind is blowing, and a huge whirlwind is rushing over the earth - a tornado. A tropical storm leaves behind a heavy picture of destruction.

Tornado is the name given to a tornado of gigantic destructive power in North America. These whirlwinds destroy everything in their path.

“During the lesson,” says the teacher! one of the American schools - I heard a deafening roar. The wind blew suddenly with monstrous force. Before I had time to take the children to safety, all the glass in the school blew out. The children rushed to me. But then, as if invisible wings, they were picked up by various objects that were in the classroom. We all rose into the air. Children and the wreckage of the school were swirling around me.”

When a tornado moves along the ground, it resembles a huge vacuum cleaner - everything that comes along the way is sucked into the funnel. When wind passes through bodies of water, the bottom is often exposed.

There are such tornadoes in our country, it’s true, but they are so fierce, but also strong. Several years ago, at a crossing near Moscow railway the wind lifted the railway box high into the air. She was thrown to the ground forty meters from the old place. The lineman who was in it remained alive. And all this happened in a matter of minutes. Roofs torn off houses flew in the air, as if they had suddenly miraculously become weightless. Where the tornado crossed the Moscow River, its bottom was exposed. A formidable whirlwind passed about forty kilometers, destroying several villages near Moscow along the way.

Why do tornadoes form?

There is still a lot hidden by nature. It is known that they are formed in a thundercloud, where powerful flows of moist warm and cold air collide and move. A heavy downpour falls from the cloud, and the whirlwind captures and spins more and more new streams, forming a huge funnel.

A hurricane at sea is very dangerous. Several years ago, American scientists on a cruiser tried to get into the center of the hurricane to see for themselves what was happening there. This attempt ended tragically. The last report from researchers was that the waves in the center of the typhoon reached a height of 40 meters and raged with monstrous force. Currently, many useful discoveries have been made by typhoon hunter pilots. Their main task is to notify about the danger, where the typhoon is, what its strength is, where it is moving.

Download a report on the topic air for grades 2 - 3 in the subject the world

Chemical composition air is of great hygienic importance, since it plays a decisive role in the respiratory function of the body. Atmospheric air is a mixture of oxygen, carbon dioxide, argon and other gases in the ratios given in table. 1.

Oxygen(O2) is the most important component of air for humans. At rest, a person usually absorbs an average of 0.3 liters of oxygen per minute.

During physical activity, oxygen consumption increases sharply and can reach 4.5/5 liters or more per minute. Fluctuations in the oxygen content in atmospheric air are small and, as a rule, do not exceed 0.5%.

In residential, public and sports premises, no significant changes in oxygen content are observed, since outside air penetrates into them. Under the most unfavorable hygienic conditions in the room, a decrease in oxygen content of 1% was noted. Such fluctuations do not have a noticeable effect on the body.

Typically, physiological changes are observed when the oxygen content decreases to 16-17%. If its content decreases to 11-13% (when rising to a height), pronounced oxygen deficiency appears, a sharp deterioration in well-being and a decrease in performance. Oxygen content up to 7-8% can be fatal.

In sports practice, oxygen inhalation is used to increase performance and intensity of recovery processes.

Carbon dioxide(CO2), or carbon dioxide, is a colorless, odorless gas formed during the breathing of people and animals, rotting and decomposition of organic substances, combustion of fuel, etc. In atmospheric air outside settlements The carbon dioxide content averages 0.04%, and in industrial centers its concentration rises to 0.05-0.06%. In residential and public buildings, when there are a large number of people in them, the carbon dioxide content can increase to 0.6-0.8%. Under the worst hygienic conditions in a room (large crowds of people, poor ventilation, etc.), its concentration usually does not exceed 1% due to the penetration of outside air. Such concentrations do not cause negative effects in the body.

With prolonged inhalation of air containing 1-1.5% carbon dioxide, a deterioration in health is noted, and at 2-2.5% pathological changes are detected. Significant disruption of body functions and decreased performance occur when the carbon dioxide content is 4-5%. At levels of 8-10%, loss of consciousness and death occur. Significant increases in carbon dioxide levels in the air can occur when emergency situations in confined spaces (mines, mines, submarines, bomb shelters, etc.) or in places where intensive decomposition of organic substances occurs.

Determining the carbon dioxide content in residential, public and sports facilities can serve as an indirect indicator of air pollution from human waste products. As already noted, carbon dioxide itself in these cases does not cause harm to the body, however, along with an increase in its content, a deterioration in the physical and chemical properties of the air is observed (temperature and humidity increase, the ionic composition is disrupted, foul-smelling gases appear). Indoor air is considered to be of poor quality if the carbon dioxide content in it exceeds 0.1%. This value is accepted as a calculated value when designing and installing ventilation in rooms.

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Chemical composition of air is important in the implementation of respiratory function. Atmospheric air is a mixture of gases: oxygen, carbon dioxide, argon, nitrogen, neon, krypton, xenon, hydrogen, ozone, etc. Oxygen is the most important. At rest, a person absorbs 0.3 l/min. During physical activity, oxygen consumption increases and can reach 4.5–8 l/min. Fluctuations in the oxygen content in the atmosphere are small and do not exceed 0.5%. If the oxygen content decreases to 11-13%, symptoms of oxygen deficiency appear.

Oxygen content of 7-8% can lead to death. Carbon dioxide is colorless and odorless, formed during respiration and decay, combustion of fuel. In the atmosphere it is 0.04%, and in industrial zones – 0.05-0.06%. With a large crowd of people it can increase to 0.6 - 0.8%. With prolonged inhalation of air containing 1-1.5% carbon dioxide, a deterioration in health is noted, and with 2-2.5% - pathological changes. At 8-10% loss of consciousness and death, the air has a pressure called atmospheric or barometric. It is measured in millimeters of mercury (mmHg), hectopascals (hPa), millibars (mb). Normal atmospheric pressure is considered to be at sea level at a latitude of 45˚ at an air temperature of 0˚C. It is equal to 760 mmHg. (The air in a room is considered to be of poor quality if it contains 1% carbon dioxide. This value is accepted as a calculated value when designing and installing ventilation in rooms.

Air pollution. Carbon monoxide is a colorless and odorless gas that is formed during incomplete combustion of fuel and enters the atmosphere with industrial emissions and engine exhaust gases. internal combustion. In megacities, its concentration can reach 50-200 mg/m3. When smoking tobacco, carbon monoxide enters the body. Carbon monoxide is a blood and general toxic poison. It blocks hemoglobin, it loses its ability to carry oxygen to tissues. Acute poisoning occurs when the concentration of carbon monoxide in the air is 200-500 mg/m3. At the same time, it is observed headache, general weakness, nausea, vomiting. The maximum permissible average daily concentration is 0 1 mg/m3, one-time – 6 mg/m3. The air can be polluted by sulfur dioxide, soot, tarry substances, nitrogen oxides, and carbon disulfide.

Microorganisms. IN small quantities are always in the air, where they are carried with soil dust. Microbes released into the atmosphere infectious diseases die quickly. The air in residential premises and sports facilities poses a particular danger in terms of epidemiology. For example, in wrestling halls there is a microbial content of up to 26,000 per 1m3 of air. Aerogenic infections spread very quickly in such air.

Dust It is light dense particles of mineral or organic origin; when dust gets into the lungs, it lingers there and causes various diseases. Industrial dust (lead, chrome) can cause poisoning. In cities, dust should not exceed 0.15 mg/m3. Sports grounds must be regularly watered, have a green area, and carry out wet cleaning. Sanitary protection zones have been established for all enterprises that pollute the atmosphere. In accordance with the hazard class they have different sizes: for enterprises of class 1 - 1000 m, 2 - 500 m, 3 - 300 m, 4 -100 m, 5 - 50 m. When locating sports facilities near enterprises, it is necessary to take into account the wind rose, sanitary protection zones, the degree of air pollution, etc.

One of important events for the protection of the air environment are preventive and ongoing sanitary supervision and systematic monitoring of the state of atmospheric air. It is carried out using an automated monitoring system.

Clean atmospheric air at the surface of the Earth has the following chemical composition: oxygen - 20.93%, carbon dioxide - 0.03-0.04%, nitrogen - 78.1%, argon, helium, krypton 1%.

The exhaled air contains 25% less oxygen and 100 times more carbon dioxide.
Oxygen. The most important component of air. It ensures the flow of redox processes in the body. An adult consumes 12 liters of oxygen at rest, and 10 times more during physical work. In the blood, oxygen is bound to hemoglobin.

Ozone. A chemically unstable gas, it is capable of absorbing solar short-wave ultraviolet radiation, which has a detrimental effect on all living things. Ozone absorbs long-wave infrared radiation emanating from the Earth, and thereby prevents its excessive cooling (the Earth's ozone layer). Under the influence of ultraviolet radiation, ozone decomposes into an oxygen molecule and an atom. Ozone is a bactericidal agent for water disinfection. In nature, it is formed during electrical discharges, during the evaporation of water, during ultraviolet radiation, during a thunderstorm, in the mountains and in coniferous forests.

Carbon dioxide. It is formed as a result of redox processes occurring in the body of people and animals, combustion of fuel, and decay of organic substances. In the air of cities, the concentration of carbon dioxide is increased due to industrial emissions - up to 0.045%, in residential premises - up to 0.6-0.85. An adult at rest emits 22 liters of carbon dioxide per hour, and during physical work - 2-3 times more. Signs of deterioration in a person’s health appear only with prolonged inhalation of air containing 1-1.5% carbon dioxide, pronounced functional changes - at a concentration of 2-2.5% and pronounced symptoms (headache, general weakness, shortness of breath, palpitations, decreased performance) – at 3-4%. The hygienic importance of carbon dioxide lies in the fact that it serves as an indirect indicator of general air pollution. The carbon dioxide standard in gyms is 0.1%.

Nitrogen. An indifferent gas serves as a diluent for other gases. Increased inhalation of nitrogen can have a narcotic effect.

Carbon monoxide. Formed during incomplete combustion of organic substances. It has neither color nor smell. The concentration in the atmosphere depends on the intensity of vehicle traffic. Penetrating through the pulmonary alveoli into the blood, it forms carboxyhemoglobin, as a result of which hemoglobin loses its ability to carry oxygen. The maximum permissible average daily concentration of carbon monoxide is 1 mg/m3. Toxic doses of carbon monoxide in the air are 0.25-0.5 mg/l. With prolonged exposure, headache, fainting, palpitations.

Sulphur dioxide. It enters the atmosphere as a result of burning fuel rich in sulfur (coal). It is formed during the roasting and smelting of sulfur ores and during the dyeing of fabrics. It irritates the mucous membranes of the eyes and upper respiratory tract. The sensation threshold is 0.002-0.003 mg/l. The gas has a harmful effect on vegetation, especially coniferous trees.
Mechanical air impurities come in the form of smoke, soot, soot, crushed soil particles and other solids. Air dust content depends on the nature of the soil (sand, clay, asphalt), its sanitary condition (watering, cleaning), air pollution from industrial emissions, and the sanitary condition of the premises.

Dust mechanically irritates the mucous membranes of the upper respiratory tract and eyes. Systematic inhalation of dust causes respiratory diseases. When breathing through the nose, up to 40-50% of dust is retained. Microscopic dust that remains suspended for a long time is the most unfavorable from a hygienic point of view. The electrical charge of dust enhances its ability to penetrate and linger in the lungs. Dust. containing lead, arsenic, chromium and other toxic substances, causes typical poisoning phenomena, and when penetrated not only by inhalation, but also through the skin and gastrointestinal tract. In dusty air, the intensity of solar radiation and air ionization are significantly reduced. To prevent the adverse effects of dust on the body, residential buildings are located on the windward side of air pollutants. Sanitary protection zones with a width of 50-1000 m or more are arranged between them. In residential premises, systematic wet cleaning, ventilation of rooms, change of shoes and outerwear, in open areas the use of dust-free soils and watering.

Air microorganisms. Bacterial pollution of air, as well as other objects external environment(water, soil), poses an epidemiological danger. There are various microorganisms in the air: bacteria, viruses, molds, yeast cells. The most common is airborne transmission of infections: airborne a large number of microbes that enter the Airways healthy people. For example, during a loud conversation, and even more so when coughing and sneezing, tiny droplets are sprayed over a distance of 1-1.5 m and spread with air over 8-9 m. These droplets can be suspended for 4-5 hours, but in most cases settle in 40-60 minutes. In dust, the influenza virus and diphtheria bacilli remain viable for 120-150 days. There is a well-known relationship: the more dust there is in indoor air, the more abundant the microflora content in it.

Chemical composition of air

Air is a mixture of gases that form a protective layer around the Earth - the atmosphere. Air is necessary for all living organisms: animals for breathing, and plants for nutrition. In addition, air protects the Earth from the harmful ultraviolet radiation of the Sun. The main components of air are nitrogen and oxygen. The air also contains small admixtures of noble gases, carbon dioxide and a certain amount of solid particles - soot and dust. All animals need air to breathe. About 21% of air is oxygen. An oxygen molecule (O2) consists of two bonded oxygen atoms.

Air composition

The percentage of various gases in the air varies slightly depending on location, time of year and day. Nitrogen and oxygen are the main components of air. One percent of the air consists of noble gases, carbon dioxide, water vapor and pollutants such as nitrogen dioxide. Gases contained in air can be separated by fractional distillation. The air is cooled until the gases become liquid (see the article “Solids, Liquids and Gases”). After this, the liquid mixture is heated. Each liquid has its own boiling point, and the gases formed during boiling can be collected separately. Oxygen, nitrogen and carbon dioxide constantly enter living organisms from the air and return to the air, i.e. a cycle occurs. Animals inhale oxygen from the air and exhale carbon dioxide.

Oxygen

Oxygen is essential for life. Animals breathe it, use it to digest food and get energy. During the day, a process occurs in plants photosynthesis, and plants release oxygen. Oxygen is also necessary for combustion; Without oxygen, nothing can burn. Almost 50% of the compounds in the earth's crust and oceans contain oxygen. Ordinary sand is a compound of silicon and oxygen. Oxygen is used in breathing apparatus for divers and in hospitals. Oxygen is also used in steel production (see article "Iron, steel and other materials") and rocketry (see article "Rockets and spacecraft").

In the upper layers of the atmosphere, oxygen atoms combine in threes to form the ozone molecule (O3). Ozone is an allotropic modification of oxygen. Ozone is a poisonous gas, but in the atmosphere the ozone layer protects our planet by absorbing most of the sun's harmful ultraviolet radiation (more in the article "The Sun's Impact on Earth").

Nitrogen

More than 78% of air is nitrogen. Proteins, from which living organisms are built, also contain nitrogen. The main industrial application of nitrogen is ammonia production needed for fertilizers. To do this, nitrogen is combined with hydrogen. Nitrogen is pumped into packaging for meat or fish, because... upon contact with ordinary air, products oxidize and deteriorate. Human organs intended for transplantation are stored in liquid nitrogen because it is cold and chemically inert. A nitrogen (N2) molecule consists of two bonded nitrogen atoms.

Plants obtain nitrogen from the soil in the form of nitrates and use it to synthesize proteins. Animals eat plants, and nitrogen compounds are returned to the soil through animal excretions and when their dead bodies decompose. In the soil, nitrogen compounds are decomposed by bacteria, releasing ammonia and then free nitrogen. Other bacteria absorb nitrogen from the air and convert it into nitrates for use by plants.

Carbon dioxide

Carbon dioxide is a compound of carbon and oxygen. The air contains about 0.003% carbon dioxide. A carbon dioxide (CO2) molecule consists of two oxygen atoms and one carbon atom. Carbon dioxide is one of the elements of the carbon cycle. Plants absorb it during photosynthesis, and animals exhale it. Carbon dioxide is also produced by the combustion of substances containing carbon, such as wood or gasoline. Because our cars and factories burn so much fuel, the proportion of carbon dioxide in the atmosphere is growing. Most substances cannot burn in carbonic acid gas, which is why it is used in fire extinguishers. Carbon dioxide is denser than air. It “smothers” the flame, cutting off the access of oxygen. Carbon dioxide dissolves slightly in water, forming a weak solution of carbonic acid. Solid carbon dioxide is called dry ice. When dry ice melts, it turns into gas; it is used to create artificial clouds in the theater.

Air pollution

Soot and poisonous gases - carbon monoxide, nitrogen dioxide, sulfur dioxide - pollute the atmosphere. Carbon monoxide is formed during combustion. Many substances burn so quickly that they do not have time to add enough oxygen and instead of carbon dioxide (CO2), carbon monoxide (CO) is formed. Carbon monoxide is very poisonous; it prevents the animals' blood from carrying oxygen. There is only one oxygen atom in a carbon monoxide molecule. Car exhaust contains carbon monoxide as well as nitrogen dioxide, which causes acid rain. Sulfur dioxide is released when fossil fuels, especially coal, are burned. It is poisonous and makes breathing difficult. In addition, it dissolves in water and causes acid rain. Dust and soot particles emitted into the atmosphere by enterprises also pollute the air; we inhale them, they settle on plants. Lead is added to gasoline for better combustion (however, many cars now run on lead-free gasoline). Lead compounds accumulate in the body and have a detrimental effect on the nervous system. In children they can cause brain damage.

Acid rain

Rainwater always contains a little acid due to dissolved carbon dioxide, but pollutants (sulfur and nitrogen dioxides) increase the acidity of the rain. Acid rain causes corrosion of metals, corrodes stone structures and increases the acidity of fresh water.

Noble gases

Noble gases are 6 elements of group 8 of the periodic table. They are extremely chemically inert. Only they exist in the form of individual atoms that do not form molecules. Because of their passivity, some of them are used to fill lamps. Xenon is practically not used by humans, but argon is pumped into light bulbs and filled with creep tone fluorescent lamps. Neon flashes red-orange when electrically charged. It is used in sodium street lamps and neon lamps. Radon is radioactive. It is formed by the decay of the metal radium. No helium compounds are known to science, and helium is considered completely inert. Its density is 7 times less than the density of air, which is why airships are filled with it. Helium filled Balloons equipped with scientific equipment and launched into the upper atmosphere.

Greenhouse effect

This is the name for the currently observed increase in carbon dioxide content in the atmosphere and the resulting global warming, i.e. increase in average annual temperatures around the world. Carbon dioxide prevents heat from leaving the Earth, just as glass maintains high temperatures inside a greenhouse. As there is more carbon dioxide in the air, more heat is trapped in the atmosphere. Even slight warming causes sea levels to rise, winds to change and some of the ice at the poles to melt. Scientists believe that if the carbon dioxide content increases as quickly, then in 50 years the average temperature could increase by 1.5°C to 4°C.

air is a mixture of gases, and therefore elements. . Nitrogen, oxygen, carbon dioxide. There are other gases in cities...

Percentage of gases.

do you need a graphical representation of an air molecule?

Air in chemistry - NO2

zit hain. Allah Akbar. takbir foreign words that are forbidden to be spoken. what is this for - HZ

If you think that air has its own separate formula, you are mistaken; in chemistry it is not designated in any way.

Air is the natural mixture of gases, mainly nitrogen and oxygen, that makes up the earth's atmosphere. Air composition: Nitrogen N2 Oxygen O2 Argon Ar Carbon dioxide CO2 Neon Ne Methane CH4 Helium He Krypton Kr Hydrogen H2 Xenon Xe Water H2O In addition, air always contains water vapor. So, at a temperature of 0 °C, 1 m³ of air can hold a maximum of 5 grams of water, and at a temperature of +10 °C - already 10 grams. In alchemy, air is symbolized as a triangle with a horizontal line.

nitrogen

we inhale the main component. air

Alternative descriptions

Gas that makes metal brittle

A gas that makes up 78% air

Main "air filler"

The main component of the air you breathe, which is pure form you can't breathe

Air Component

Fertilizer in the air

Chemical element - the basis of a number of fertilizers

Chemical element, one of the main plant nutrients

Chemical element, component of air

Nitrogenium

Liquid refrigerant

Chemical element, gas

Magic sword of Paracelsus

In Latin, this gas is called “nitrogenium”, that is, “giving birth to saltpeter”

The name of this gas comes from the Latin word for lifeless.

This gas, a component of air, was practically absent from the primary atmosphere of the Earth 4.5 billion years ago.

A gas whose liquid is used to cool ultra-precision instruments

What liquid gas is stored in a Dewar flask?

The gas that froze Terminator II

Gas cooler

What gas extinguishes fire?

Most abundant element in the atmosphere

Base of all nitrates

Chemical element, N

Freezing Gas

Three quarters air

Contains ammonia

Gas from air

Gas number 7

Element from saltpeter

The main gas in the air

The most popular gas

Element from nitrates

Liquid gas from a vessel

No. 1 gas in the atmosphere

Fertilizer in the air

78% air

Gas for cryostat

Almost 80% air

Natural chemical composition of atmospheric air

In terms of chemical composition, pure atmospheric air is a mixture of gases: oxygen, carbon dioxide, nitrogen, as well as a number of inert gases (argon, helium, krypton, etc.). Since air is a physical mixture, and not a chemical compound of its constituent gases, when rising even tens of kilometers, the percentage of these gases practically does not change.

However, with height, as a result of a decrease in atmospheric density, the concentrations and partial pressure of all gases in the air decrease.

At the Earth's surface the atmospheric air contains:

oxygen – 20.93%;

nitrogen – 78.1%;

carbon dioxide – 0.03-0.04%;

inert gases – from 10-3 to 10-6%.

Oxygen (O2)- the most important part of air for life. It is necessary for oxidative processes and is found in the blood, mainly in a bound state - in the form of oxyhemoglobin, which is transported by red blood cells to the cells of the body.

The transition of oxygen from alveolar air to blood occurs due to the difference in partial pressure in alveolar air and venous blood. For the same reason, oxygen flows from arterial blood into the interstitial fluid, and then into the cells.

In nature, oxygen is spent mainly on the oxidation of organic substances contained in air, water, soil and combustion processes. The loss of oxygen is replenished due to its large reserves in the atmosphere, as well as as a result of the activity of phytoplankton in the oceans and land plants. Continuous turbulent flows of air masses equalize the oxygen content in the surface layer of the atmosphere. Therefore, the oxygen level at the Earth's surface fluctuates slightly: from 20.7 to 20.95%. In residential premises and public buildings, the oxygen content also remains virtually unchanged due to its easy diffusion through the pores building materials, cracks in windows, etc.

In sealed rooms (shelters, submarines, etc.), the oxygen content can decrease significantly. However, a pronounced deterioration in well-being and a decrease in performance in people are observed with a very significant drop in oxygen content - up to 15-17% (at normal - almost 21%). It should be emphasized that in this case we are talking about a reduced oxygen content at normal atmospheric pressure.

When the air temperature increases to 35-40°C and high humidity, the partial pressure of oxygen decreases, which can have an impact on Negative influence on patients with symptoms of hypoxia.

In healthy people, oxygen starvation due to a decrease in the partial pressure of oxygen can be observed when flying (altitude sickness) and when climbing mountains (mountain sickness, which begins at an altitude of about 3 km).

Altitudes of 7-8 km correspond to 8.5-7.5% oxygen in the air at sea level and for untrained people are considered incompatible with life without the use of oxygen devices.

A dosed increase in the partial pressure of oxygen in the air in pressure chambers is used in surgery, therapy and emergency care.

Oxygen in its pure form has a toxic effect. Thus, in experiments on animals it was shown that when breathing pure oxygen, animals exhibit atelectasis in the lungs after 1-2 hours, impaired capillary permeability in the lungs after 3-6 hours, and pulmonary edema after 24 hours.

Hyperoxia develops even faster in an oxygen environment with high pressure - both damage to the lung tissue and damage to the central tissue is observed. nervous system.

Carbon dioxide or carbon dioxide, in nature exists in free and bound states. Up to 70% of carbon dioxide is dissolved in the water of the seas and oceans; the composition of some mineral compounds (limestones and dolomites) includes about 22% of the total amount of carbon dioxide. The rest comes from animals and vegetable world. In nature, continuous processes of release and absorption of carbon dioxide occur. It is released into the atmosphere as a result of human and animal respiration, as well as combustion, rotting, and fermentation. In addition, carbon dioxide is formed during the industrial roasting of limestones and dolomites, and it can be released with volcanic gases. Along with the processes of formation in nature, there are processes of assimilation of carbon dioxide - active absorption by plants during the process of photosynthesis. Carbon dioxide is washed out of the air by precipitation.

An important role in maintaining a constant concentration of carbon dioxide in the atmospheric air is played by its release from the surface of the seas and oceans. Carbon dioxide dissolved in the water of the seas and oceans is in dynamic equilibrium with carbon dioxide in the air and, when the partial pressure in the air increases, dissolves in water, and when the partial pressure decreases, it is released into the atmosphere. The processes of formation and assimilation are interconnected, due to this the content of carbon dioxide in the atmospheric air is relatively constant and amounts to 0.03-0.04%. Recently, the concentration of carbon dioxide in the air of industrial cities has been increasing as a result of intense air pollution by fuel combustion products. The carbon dioxide content in urban air can be higher than in a clean atmosphere, up to 0.05% or more. The role of carbon dioxide in creating the “greenhouse effect”, leading to an increase in the temperature of the surface layer of air, is known.

Carbon dioxide is a physiological stimulant of the respiratory center. Its partial pressure in the blood is ensured by the regulation of acid-base balance. In the body, it is in a bound state in the form of sodium carbonate salts in plasma and red blood cells. When large concentrations of carbon dioxide are inhaled, redox processes are disrupted. The more carbon dioxide in the air we breathe, the less of it the body can release. The accumulation of carbon dioxide in the blood and tissues leads to the development of tissue anoxia. When the carbon dioxide content in the inhaled air increases to 3-4%, symptoms of intoxication are observed; at 8%, severe poisoning occurs and death occurs. The carbon dioxide content is used to judge the cleanliness of air in residential and public buildings. Significant accumulation of this compound in the air closed premises indicates a sanitary problem in the premises (overcrowding, poor ventilation). The maximum permissible concentration of carbon dioxide in the air of medical institutions is 0.07%, in the air of residential and public buildings - 0.1%. The last value is accepted as a calculation value when determining the ventilation efficiency of residential and public buildings.

Nitrogen. Along with oxygen and carbon dioxide, the composition of atmospheric air includes nitrogen, which in terms of quantitative content is the most significant part of atmospheric air.

Nitrogen belongs to the inert gases; it does not support respiration and combustion. Life is impossible in a nitrogen atmosphere. Its cycle occurs in nature. Nitrogen in the air is absorbed by certain types of soil bacteria, as well as blue-green algae. Under the influence of electrical discharges, nitrogen in the air turns into oxides, which, washed out of the atmosphere by precipitation, enrich the soil with salts of nitrous and nitric acids. Under the influence of soil bacteria, nitrous acid salts are converted into nitric acid salts, which in turn are absorbed by plants and serve for protein synthesis. It has been established that 95% of atmospheric air is assimilated by living organisms and only 5% is bound as a result of physical processes in nature. Consequently, the bulk of fixed nitrogen is of biogenic origin. Along with the absorption of nitrogen, it is released into the atmosphere. Free nitrogen is formed during the combustion of wood, coal, and oil; a small amount of free nitrogen is released during the decomposition of organic compounds by denitrifying microorganisms. Thus, in nature there is a continuous nitrogen cycle, as a result of which atmospheric nitrogen is converted into organic compounds. When these compounds decompose, nitrogen is restored and released into the atmosphere, and then it is again bound by biological objects.

Nitrogen is an oxygen diluent, and therefore performs a vital function, since breathing pure oxygen leads to irreversible changes in the body. When studying the effect of various nitrogen concentrations on the body, it was noted that its increased content in the inhaled air contributes to the onset of hypoxia and asphyxia due to a decrease in the partial pressure of oxygen. When the nitrogen content increases to 93%, death occurs. Nitrogen exhibits the most pronounced adverse properties under conditions of high pressure, which is associated with its narcotic effect. The role of nitrogen in the origin of decompression sickness is also known.

Noble gases. Inert gases include argon, neon, helium, krypton, xenon, etc. Chemically, these gases are inert; they dissolve in body fluids depending on the partial pressure. The absolute amount of these gases in the blood and tissues of the body is negligible. Among the inert gases, a special place is occupied by radon, actinon and thoron - decay products of the natural radioactive elements radium, thorium, actinium.

Chemically, these gases are inert, as noted above, and their dangerous effect on the body is associated with their radioactivity. IN natural conditions they determine the natural radioactivity of the atmosphere.

Air temperature

Atmospheric air is heated mainly from the earth's surface due to the heat it receives from the Sun. About 47% solar energy, reaching the ground, is absorbed by the earth's surface and converted into heat. Approximately 34% of the sun's energy is reflected back into space from cloud tops and the Earth's surface, and only a fifth (19%) of the sun's energy directly heats the atmosphere. In this regard, the maximum air temperature occurs between 13 and 14 hours, when the earth's surface is heated to the greatest extent. The heated ground layers of air rise upward, gradually cooling. Therefore, with an increase in altitude above sea level, the air temperature decreases by an average of 0.6 ° C for every 100 meters of rise.

Heating of the atmosphere occurs unevenly and depends primarily on geographic latitude: the greater the distance from the equator to the pole, the greater the angle of inclination sun rays to the plane of the earth's surface, the less energy is supplied per unit area and heats it less.

The difference in air temperatures depending on the latitude of the area can be very significant and amount to more than 100°C. Thus, the highest air temperatures (up to +60°C) were recorded in equatorial Africa, the minimum (up to –90°C) – in Antarctica.

Daily fluctuations in air temperature are also very significant in a number of equatorial countries, constantly decreasing towards the poles.

Daily and annual fluctuations in air temperature are influenced by whole line natural factors: intensity of solar radiation, nature and topography of the area, altitude above sea level, proximity of seas, nature of sea currents, vegetation cover, etc.

The influence of unfavorable air temperature on the body is most pronounced when people stay or work outdoors, as well as in some production premises where very high or very low air temperatures are possible. This applies to agricultural workers, builders, oil workers, fishermen, etc., as well as those working in hot shops, in ultra-deep mines (1-2 km), service specialists refrigeration units and etc.

In residential and public premises there are opportunities to ensure the most favorable air temperature (through heating, ventilation, use of air conditioners, etc.).

Atmosphere pressure

On the surface of the globe, fluctuations in atmospheric pressure are associated with weather conditions and during the day, as a rule, do not exceed 4-5 mm Hg.

However, there are special conditions of human life and work in which there are significant deviations from normal atmospheric pressure that can have a pathological effect.

Our planet is enveloped in a shell of air - the atmosphere. Thanks to it, life became possible on the globe, because all living beings - people, plants, animals - need air. It contains not only oxygen, but also many other elements that are also of great importance.

What is air?

Air is a mixture of various gases: oxygen, nitrogen, carbon dioxide, argon and water vapor. However, the most important component of air, without which life on the planet would be impossible, is oxygen.

The composition of air is influenced by two main factors:

Height above sea level. As you climb the mountain, the amount of oxygen in the air will decrease more and more.
Features of the area. In large cities, the amount of carbon dioxide is much higher than in a clean forest.

Rice. 1. The air in the forest is the cleanest.

Clean air is colorless and odorless.

One of the most serious environmental problems modern world is air pollution. A large number of cars, factories and factories greatly pollute the atmosphere with toxic substances. People living in cities are forced to breathe this poisonous gas. To solve this problem, it is necessary to introduce powerful treatment facilities into production.

Rice. 2. Air pollution.

What is air for?

An ocean of air surrounds the Earth, filling the voids and the tiniest crevices. It is even found in water, only in dissolved form.

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Air performs very important functions:

All living organisms need air to breathe. Thanks to the respiratory processes, the body of people and animals is saturated with energy and nutrients, and all vital processes are activated. Without air, plants would not be able to breathe and form nutrients.

A person can live without food for several weeks, without water for several days, and without air for only a few minutes. If you try not to breathe for some time, then within a few seconds you will have a strong desire to take a deep breath. Without air there is no life!

Air movement, which is associated with uneven heating, determines the climate in different regions. Land areas far from the seas and oceans are saturated with moisture brought by the winds.

Rice. 3. Formation of clouds and clouds.

Huge air space is reliable protection from dangerous solar radiation and cosmic cold.
Thanks to air, we can make and hear sounds. Sound is a wave that can be transmitted over a distance only under atmospheric conditions. For example, there is no atmosphere on the Moon, and absolute silence reigns there.

The air “blanket” is held in place by the forces of gravity. If for some reason the globe was left without an atmosphere, it would very quickly turn into a lifeless desert.

What have we learned?

When studying the topic “Air” according to the 3rd grade program of the surrounding world, we learned what air is and what is included in its composition. We also found out what functions it performs and what role it plays for all life on Earth.

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It is important in the implementation of respiratory function. Atmospheric air is a mixture of gases: oxygen, carbon dioxide, argon, nitrogen, neon, krypton, xenon, hydrogen, ozone, etc. Oxygen is the most important. At rest, a person absorbs 0.3 l/min. During physical activity, oxygen consumption increases and can reach 4.5–8 l/min. Fluctuations in the oxygen content in the atmosphere are small and do not exceed 0.5%. If the oxygen content decreases to 11-13%, symptoms of oxygen deficiency appear. Oxygen content of 7-8% can lead to death. Carbon dioxide is colorless and odorless, formed during respiration and decay, combustion of fuel. In the atmosphere it is 0.04%, and in industrial areas - 0.05-0.06%. With a large crowd of people it can increase to 0.6 - 0.8%. With prolonged inhalation of air containing 1-1.5% carbon dioxide, a deterioration in health is noted, and with 2-2.5% - pathological changes. At 8-10% loss of consciousness and death, the air has a pressure called atmospheric or barometric. It is measured in millimeters of mercury (mmHg), hectopascals (hPa), millibars (mb). Normal atmospheric pressure is considered to be at sea level at a latitude of 45˚ at an air temperature of 0˚C. It is equal to 760 mmHg. (The air in a room is considered to be of poor quality if it contains 1% carbon dioxide. This value is accepted as a calculated value when designing and installing ventilation in rooms.

Air pollution. Carbon monoxide is a colorless and odorless gas that is formed during incomplete combustion of fuel and enters the atmosphere with industrial emissions and exhaust gases from internal combustion engines. In megacities, its concentration can reach 50-200 mg/m3. When smoking tobacco, carbon monoxide enters the body. Carbon monoxide is a blood and general toxic poison. It blocks hemoglobin, it loses its ability to carry oxygen to tissues. Acute poisoning occurs when the concentration of carbon monoxide in the air is 200-500 mg/m3. In this case, headache, general weakness, nausea, and vomiting are observed. The maximum permissible average daily concentration is 0 1 mg/m3, one-time – 6 mg/m3. The air can be polluted by sulfur dioxide, soot, tarry substances, nitrogen oxides, and carbon disulfide.

Microorganisms. They are always found in small quantities in the air, where they are carried with soil dust. Microbes of infectious diseases entering the atmosphere quickly die. The air in residential premises and sports facilities poses a particular danger in terms of epidemiology. For example, in wrestling halls there is a microbial content of up to 26,000 per 1m3 of air. Aerogenic infections spread very quickly in such air.

Dust It is light dense particles of mineral or organic origin; when dust gets into the lungs, it lingers there and causes various diseases. Industrial dust (lead, chrome) can cause poisoning. In cities, dust should not exceed 0.15 mg/m3. Sports grounds must be regularly watered, have a green area, and carry out wet cleaning. Sanitary protection zones have been established for all enterprises that pollute the atmosphere. In accordance with the hazard class, they have different sizes: for enterprises of class 1 - 1000 m, 2 - 500 m, 3 - 300 m, 4 -100 m, 5 - 50 m. When placing sports facilities near enterprises, it is necessary to take into account the wind rose, sanitary protective zones, degree of air pollution, etc.

One of the important measures to protect the air environment is preventive and ongoing sanitary supervision and systematic monitoring of the state of atmospheric air. It is carried out using an automated monitoring system.

Clean atmospheric air at the surface of the Earth has the following chemical composition: oxygen - 20.93%, carbon dioxide - 0.03-0.04%, nitrogen - 78.1%, argon, helium, krypton 1%.

Carbon dioxide. It is formed as a result of redox processes occurring in the body of people and animals, combustion of fuel, and decay of organic substances. In the air of cities, the concentration of carbon dioxide is increased due to industrial emissions - up to 0.045%, in residential premises - up to 0.6-0.85. An adult at rest emits 22 liters of carbon dioxide per hour, and during physical work - 2-3 times more. Signs of deterioration in a person’s well-being appear only with prolonged inhalation of air containing 1-1.5% carbon dioxide, pronounced functional changes - at a concentration of 2-2.5% and pronounced symptoms (headache, general weakness, shortness of breath, palpitations, decreased performance) – at 3-4%. The hygienic importance of carbon dioxide lies in the fact that it serves as an indirect indicator of general air pollution. The carbon dioxide standard in gyms is 0.1%.

Nitrogen. An indifferent gas serves as a diluent for other gases. Increased inhalation of nitrogen can have a narcotic effect.

Air microorganisms. Bacterial pollution of air, as well as other environmental objects (water, soil), poses an epidemiological danger. There are various microorganisms in the air: bacteria, viruses, molds, yeast cells. The most common is airborne transmission of infections: a large number of microbes enter the air and enter the respiratory tract of healthy people when they breathe. For example, during a loud conversation, and even more so when coughing and sneezing, tiny droplets are sprayed over a distance of 1-1.5 m and spread with air over 8-9 m. These droplets can be suspended for 4-5 hours, but in most cases settle in 40-60 minutes. In dust, the influenza virus and diphtheria bacilli remain viable for 120-150 days. There is a well-known relationship: the more dust there is in indoor air, the more abundant the microflora content in it.

Let’s make a reservation right away: nitrogen occupies the majority of the air, but the chemical composition of the remaining portion is very interesting and diverse. In short, the list of main elements is as follows.

However, we will also give some explanations on the functions of these chemical elements.

1. Nitrogen

The nitrogen content in the air is 78% by volume and 75% by mass, that is, this element dominates in the atmosphere, has the title of one of the most common on Earth, and, in addition, is found outside the human habitation zone - on Uranus, Neptune and in interstellar spaces. So, we have already figured out how much nitrogen is in the air, but the question remains about its function. Nitrogen is necessary for the existence of living beings, it is part of:

proteins;
amino acids;
nucleic acids;
chlorophyll;
hemoglobin, etc.

On average, about 2% of a living cell consists of nitrogen atoms, which explains why there is so much nitrogen in the air as a percentage of volume and mass.
Nitrogen is also one of the inert gases extracted from atmospheric air. Ammonia is synthesized from it and used for cooling and other purposes.

2. Oxygen

The oxygen content in the air is one of the most popular questions. Keeping the intrigue, let's distract ourselves with one fun fact: Oxygen was discovered twice - in 1771 and 1774, but due to differences in publications of the discovery, the honor of discovering the element went to the English chemist Joseph Priestley, who actually isolated oxygen second. So, the proportion of oxygen in the air fluctuates around 21% by volume and 23% by mass. Together with nitrogen, these two gases form 99% of all earth's air. However, the percentage of oxygen in the air is less than nitrogen, and yet we do not experience breathing problems. The fact is that the amount of oxygen in the air is optimally calculated specifically for normal breathing; in its pure form, this gas acts on the body like poison, leading to difficulties in the functioning of the nervous system, disruption of breathing and blood circulation. At the same time, the lack of oxygen also negatively affects health, causing oxygen starvation and all the unpleasant symptoms associated with it. Therefore, how much oxygen is contained in the air is what is needed for healthy, full breathing.

3. Argon

Argon ranks third in the air; it is odorless, colorless and tasteless. No significant biological role of this gas has been identified, but it has a narcotic effect and is even considered doping. Argon extracted from the atmosphere is used in industry, medicine, to create an artificial atmosphere, chemical synthesis, fire extinguishing, creating lasers, etc.

4. Carbon dioxide

Carbon dioxide makes up the atmosphere of Venus and Mars; its percentage in the earth's air is much lower. At the same time, a huge amount of carbon dioxide is contained in the ocean, it is regularly supplied by all breathing organisms, and is released due to the work of industry. In human life, carbon dioxide is used in fire fighting, the food industry as a gas and as food supplement E290 – preservative and leavening agent. In solid form, carbon dioxide is one of the most well-known refrigerants, “dry ice.”

5. Neon

That same mysterious light of disco lights, bright signs and modern headlights use the fifth most common chemical element, which is also inhaled by humans - neon. Like many inert gases, neon has a narcotic effect on humans at a certain pressure, but it is this gas that is used in the training of divers and other people working under high blood pressure. Also, neon-helium mixtures are used in medicine for respiratory disorders; neon itself is used for cooling, in the production of signal lights and those same neon lamps. However, contrary to the stereotype, neon light is not blue, but red. All other colors are produced by lamps with other gases.

6. Methane

Methane and air have very ancient history: in the primordial atmosphere, even before the appearance of man, methane was in more. Now extracted and used as fuel and raw material in manufacturing, this gas is not as widespread in the atmosphere, but is still released from the Earth. Modern research establishes the role of methane in the respiration and vital functions of the human body, but there is no authoritative data on this yet.

7. Helium

Having looked at how much helium is in the air, anyone will understand that this gas is not of primary importance. Indeed, it is difficult to determine biological significance this gas. Apart from the funny distortion of the voice when inhaling helium from a balloon :) However, helium is widely used in industry: in metallurgy, the food industry, for filling aircraft and weather probes, in lasers, nuclear reactors etc.

8. Krypton

We are not talking about the homeland of Superman :) Krypton is an inert gas that is three times heavier than air, chemically inert, extracted from air, used in incandescent lamps, lasers and is still being actively studied. Among the interesting properties of krypton, it is worth noting that at a pressure of 3.5 atmospheres it has a narcotic effect on humans, and at 6 atmospheres it acquires a pungent odor.

9. Hydrogen

Hydrogen in the air occupies 0.00005% by volume and 0.00008% by mass, but at the same time it is the most common element in the Universe. It is quite possible to write a separate article about its history, production and application, so now we will limit ourselves to a small list of industries: chemical, fuel, food industry, aviation, meteorology, electric power.

10. Xenon

The latter is a component of air, which was initially considered only an admixture of krypton. Its name translates as “alien”, and the percentage of content both on Earth and beyond is minimal, which led to its high cost. Nowadays they cannot do without xenon: production of powerful and pulsed light sources, diagnostics and anesthesia in medicine, engines spacecraft, rocket fuel. In addition, when inhaled, xenon significantly lowers the voice (the opposite effect of helium), and recently inhalation of this gas has been included in the list of doping agents.