Chemical composition of air and its hygienic importance. Did you know that air is a mixture of gases? Gas composition of air

LECTURE No. 3. Atmospheric air.

Topic: Atmospheric air, its chemical composition and physiological

the meaning of the components.

Atmospheric pollution; their impact on public health.

Lecture outline:

Chemical composition atmospheric air.

Biological role and physiological significance its components: nitrogen, oxygen, carbon dioxide, ozone, inert gases.

The concept of atmospheric pollution and its sources.

Impact of atmospheric pollution on health (direct impact).

The influence of atmospheric pollution on the living conditions of the population (indirect impact on health).

Issues of protecting atmospheric air from pollution.

The gaseous envelope of the earth is called the atmosphere. The total weight of the earth's atmosphere is 5.13  10 15 tons.

The air that forms the atmosphere is a mixture of various gases. The composition of dry air at sea level will be as follows:

Table No. 1

Composition of dry air at a temperature of 0 0 C and

pressure 760 mm Hg. Art.

The composition of the earth's atmosphere remains constant over land, over sea, in cities and in rural areas. It also does not change with height. It should be remembered that we are talking about the percentage of air components at different altitudes. However, the same cannot be said about the weight concentration of gases. As you rise upward, the density of the air decreases and the number of molecules contained in a unit of space also decreases. As a result, the weight concentration of the gas and its partial pressure decrease.

Let us dwell on the characteristics of the individual components of air.

The main component of the atmosphere is nitrogen. Nitrogen is an inert gas. It does not support breathing or combustion. Life is impossible in a nitrogen atmosphere.

Nitrogen plays an important role biological role. Nitrogen in the air is absorbed by certain types of bacteria and algae, which form organic compounds from it.

Under the influence of atmospheric electricity, a small amount of nitrogen ions are formed, which are washed out of the atmosphere by precipitation and enrich the soil with nitrogen and nitrogen salts. nitric acid. Salts of nitrous acid are converted into nitrites under the influence of soil bacteria. Nitrites and ammonia salts are absorbed by plants and serve for the synthesis of proteins.

Thus, the transformation of inert atmospheric nitrogen into living matter of the organic world is carried out.

Due to the lack of nitrogenous fertilizers of natural origin, humanity has learned to obtain them artificially. A nitrogen fertilizer industry has been created and is developing, which processes atmospheric nitrogen into ammonia and nitrogen fertilizers.

The biological significance of nitrogen is not limited to its participation in the cycle of nitrogenous substances. He plays important role as a thinner of atmospheric oxygen, since life is impossible in pure oxygen.

An increase in nitrogen content in the air causes hypoxia and asphyxia due to a decrease in the partial pressure of oxygen.

As the partial pressure increases, nitrogen exhibits narcotic properties. However, in open atmosphere conditions the narcotic effect of nitrogen does not manifest itself, since fluctuations in its concentration are insignificant.

The most important component of the atmosphere is gaseous oxygen (O 2 ) .

Oxygen in our solar system is found in a free state only on Earth.

Many assumptions have been made regarding the evolution (development) of terrestrial oxygen. The most accepted explanation is that the vast majority of oxygen in the modern atmosphere was produced by photosynthesis in the biosphere; and only an initial, small amount of oxygen was formed as a result of photosynthesis of water.

The biological role of oxygen is extremely great. Without oxygen, life is impossible. The Earth's atmosphere contains 1.18  10 15 tons of oxygen.

In nature, processes of oxygen consumption continuously occur: the respiration of humans and animals, the processes of combustion, oxidation. At the same time, processes of restoration of the oxygen content in the air (photosynthesis) are continuously taking place. Plants absorb carbon dioxide, break it down, absorb carbon, and release oxygen into the atmosphere. Plants emit 0.5  10 5 million tons of oxygen into the atmosphere. This is enough to cover the natural loss of oxygen. Therefore, its content in the air is constant and amounts to 20.95%.

The continuous flow of air masses mixes the troposphere, which is why there is no difference in oxygen content in cities and rural areas. The oxygen concentration fluctuates within a few tenths of a percent. It does not matter. However, in deep holes, wells, and caves, the oxygen content may drop, so descending into them is dangerous.

When the partial pressure of oxygen drops in humans and animals, phenomena of oxygen starvation are observed. Significant changes in the partial pressure of oxygen occur as you rise above sea level. Phenomena of oxygen deficiency can be observed during mountain climbing (mountain climbing, tourism), and during air travel. Climbing to an altitude of 3000m can cause altitude or mountain sickness.

When living in high mountains for a long time, people become accustomed to the lack of oxygen and acclimatization occurs.

High partial pressure of oxygen is unfavorable for humans. At a partial pressure of more than 600 mm, the vital capacity of the lungs decreases. Inhalation of pure oxygen (partial pressure 760 mm) causes pulmonary edema, pneumonia, and convulsions.

Under natural conditions, there is no increased oxygen content in the air.

Ozone is an integral part of the atmosphere. Its mass is 3.5 billion tons. The ozone content in the atmosphere varies with the seasons: it is high in spring and low in autumn. The ozone content depends on the latitude of the area: the closer to the equator, the lower it is. Ozone concentration has a diurnal variation: it reaches its maximum at noon.

Ozone concentration is unevenly distributed over altitude. Its highest content is observed at an altitude of 20-30 km.

Ozone is continuously produced in the stratosphere. Under the influence of ultraviolet radiation from the sun, oxygen molecules dissociate (break apart) to form atomic oxygen. Oxygen atoms recombine (combine) with oxygen molecules and form ozone (O3). At altitudes above and below 20-30 km, the processes of photosynthesis (formation) of ozone slow down.

The presence of an ozone layer in the atmosphere is of great importance for the existence of life on Earth.

Ozone blocks the short-wavelength part of the solar radiation spectrum and does not transmit waves shorter than 290 nm (nanometers). In the absence of ozone, life on earth would be impossible due to the destructive effect of short-term ultraviolet radiation on all living things.

Ozone also absorbs infrared radiation with a wavelength of 9.5 microns (microns). Thanks to this, ozone retains about 20 percent of the earth's thermal radiation, reducing its heat loss. In the absence of ozone, the absolute temperature of the Earth would be 7 0 lower.

Ozone is brought into the lower layer of the atmosphere - the troposphere - from the stratosphere as a result of mixing air masses. With weak mixing, the ozone concentration at the earth's surface drops. An increase in ozone in the air is observed during a thunderstorm as a result of discharges of atmospheric electricity and an increase in turbulence (mixing) of the atmosphere.

At the same time, a significant increase in ozone concentration in the air is the result of photochemical oxidation of organic substances that enter the atmosphere with vehicle exhaust gases and industrial emissions. Ozone is a toxic substance. Ozone has irritant effect on the mucous membranes of the eyes, nose, throat at a concentration of 0.2-1 mg/m3.

Carbon dioxide (CO 2 ) is present in the atmosphere at a concentration of 0.03%. Its total quantity is 2330 billion tons. A large number of Carbon dioxide is found dissolved in the water of seas and oceans. In bound form, it is part of dolomites and limestones.

The atmosphere is constantly replenished with carbon dioxide as a result of the vital processes of living organisms, the processes of combustion, rotting, and fermentation. A person emits 580 liters of carbon dioxide per day. Large amounts of carbon dioxide are released during the decomposition of limestone.

Despite the presence of numerous sources of formation, there is no significant accumulation of carbon dioxide in the air. Carbon dioxide is constantly assimilated (absorbed) by plants during the process of photosynthesis.

In addition to plants, the seas and oceans regulate the carbon dioxide content in the atmosphere. When the partial pressure of carbon dioxide in the air increases, it dissolves in water, and when it decreases, it is released into the atmosphere.

In the surface atmosphere there are slight fluctuations in the concentration of carbon dioxide: over the ocean it is lower than over land; higher in the forest than in the field; higher in cities than outside the city.

Carbon dioxide plays a big role in the life of animals and humans. It stimulates the respiratory center.

There is a certain amount in atmospheric air inert gases: argon, neon, helium, krypton and xenon. These gases belong to the zero group of the periodic table, do not react with other elements, and are inert in the chemical sense.

Inert gases are narcotic. Their narcotic properties manifest themselves at high barometric pressure. In an open atmosphere, the narcotic properties of inert gases cannot manifest themselves.

In addition to the components of the atmosphere, it contains various impurities of natural origin and pollution introduced as a result of human activity.

Impurities that are present in the air other than its natural chemical composition are called atmospheric pollution.

Atmospheric pollution is divided into natural and artificial.

Natural pollution includes impurities entering the air as a result of spontaneous natural processes (plant and soil dust, volcanic eruptions, cosmic dust).

Artificial atmospheric pollution is formed as a result of human production activities.

Artificial sources of atmospheric pollution are divided into 4 groups:

transport;

industry;

thermal power engineering;

burning of garbage.

Let's look at their brief characteristics.

The current situation is characterized by the fact that the volume of emissions from road transport exceeds the volume of emissions from industrial enterprises.

One car emits more than 200 chemical compounds into the air. Each car consumes an average of 2 tons of fuel and 30 tons of air per year, and emits 700 kg of carbon monoxide (CO), 230 kg of unburned hydrocarbons, 40 kg of nitrogen oxides (NO 2) and 2-5 kg ​​of solids into the atmosphere.

The modern city is saturated with other modes of transport: railway, water and air. The total amount of emissions into the environment from all types of transport tends to continuously increase.

Industrial enterprises rank second after transport in terms of the degree of damage to the environment.

The most intensive pollutants of atmospheric air are enterprises of ferrous and non-ferrous metallurgy, petrochemical and coke-chemical industries, as well as enterprises producing building materials. They emit tens of tons of soot, dust, metals and their compounds (copper, zinc, lead, nickel, tin, etc.) into the atmosphere.

Entering the atmosphere, metals pollute the soil, accumulate in it, and penetrate into the water of reservoirs.

In areas where industrial enterprises are located, the population is exposed to the risk of adverse effects of atmospheric pollution.

In addition to solid particles, industry emits various gases into the air: sulfuric anhydride, carbon monoxide, nitrogen oxides, hydrogen sulfide, hydrocarbons, radioactive gases.

Pollutants can remain in the environment for a long time and have a harmful effect on the human body.

For example, hydrocarbons remain in the environment for up to 16 years and take an active part in photochemical processes in the atmospheric air with the formation of toxic mists.

Massive air pollution is observed when solid and liquid fuels are burned at thermal power plants. They are the main sources of atmospheric pollution with sulfur and nitrogen oxides, carbon monoxide, soot and dust. These sources are characterized by massive air pollution.

Currently, many facts are known about the adverse effects of atmospheric pollution on human health.

Atmospheric pollution has both acute and chronic effects on the human body.

Examples of the acute impact of atmospheric pollution on public health are toxic fogs. Concentrations of toxic substances in the air increased under unfavorable meteorological conditions.

The first toxic fog was recorded in Belgium in 1930. Several hundred people were injured and 60 people died. Subsequently, similar cases were repeated: in 1948 in the American city of Donora. 6,000 people were affected. In 1952, 4,000 people died from the Great London Fog. In 1962, 750 Londoners died for the same reason. In 1970, 10 thousand people suffered from smog over the Japanese capital (Tokyo), and in 1971 – 28 thousand.

In addition to the listed disasters, analysis of research materials by domestic and foreign authors draws attention to an increase in the general morbidity of the population due to air pollution.

The studies carried out in this regard allow us to conclude that as a result of exposure to atmospheric pollution in industrial centers there is an increase in:

overall mortality rate from cardiovascular and respiratory diseases;

acute nonspecific morbidity of the upper respiratory tract;

chronic bronchitis;

bronchial asthma;

emphysema;

lung cancer;

decreased life expectancy and creative activity.

In addition, at present, mathematical analysis has revealed a statistically significant correlation between the level of incidence of the population with diseases of the blood, digestive organs, skin diseases and levels of air pollution.

Respiratory system, digestive system and skin are the “entry gate” for toxic substances and serve as targets for their direct and indirect action.

The influence of atmospheric pollution on living conditions is regarded as an indirect (indirect) impact of atmospheric pollution on public health.

It includes:

reduction of general illumination;

reduction of ultraviolet radiation from the sun;

changes in climatic conditions;

deterioration of living conditions;

negative impact on green spaces;

negative impact on animals.

Air pollutants cause great damage to buildings, structures, and construction materials.

The total economic cost to the United States from air pollutants, including their impact on human health, building materials, metals, fabrics, leather, paper, paint, rubber and other materials, is $15-20 billion annually.

All of the above indicates that the protection of atmospheric air from pollution is a problem of extreme importance and the object of close attention of specialists in all countries of the world.

All measures to protect atmospheric air must be carried out comprehensively in several areas:

Legislative measures. These are laws adopted by the government of the country aimed at protecting the air environment;

Rational placement of industrial and residential areas;

Technological measures aimed at reducing emissions into the atmosphere;

Sanitary measures;

Development of hygienic standards for atmospheric air;

Monitoring the purity of atmospheric air;

Control over the work of industrial enterprises;

Improvement of populated areas, landscaping, watering, creation of protective gaps between industrial enterprises and residential complexes.

In addition to the listed measures of the internal state plan, interstate programs for the protection of atmospheric air are currently being developed and widely implemented.

The problem of air protection is being solved in a number of international organizations - WHO, UN, UNESCO and others.

On the blog pages we talk a lot about a variety of chemicals and mixtures, but we have not yet had a story about one of the most important complex substances - air. Let's fix this and talk about air. In the first article: a little history of the study of air, its chemical composition and basic facts about it.

A little history of air exploration

Currently, air is understood as a mixture of gases that form the atmosphere of our planet. But it was not always so: for a long time scientists thought that air was a simple substance, an integral substance. And although many scientists expressed hypotheses about the complex composition of air, things did not go further than guesses until the 18th century. In addition, air was given philosophical significance. IN Ancient Greece air was considered one of the fundamental cosmic elements, along with earth, fire, earth and water, forming all things. Aristotle attributed air to the sublunar light elements, personifying humidity and heat. Nietzsche in his works wrote about air as a symbol of freedom, as the highest and most subtle form of matter, for which there are no barriers.

In the 17th century, it was proven that air is a material entity, a substance whose properties, such as density and weight, can be measured.

In the 18th century, scientists carried out reactions of air with various substances in sealed chemical vessels. Thus, it was found that approximately a fifth of the air volume is absorbed, and the remaining part of combustion and respiration is not supported. As a result, it was concluded that air is a complex substance, consisting of two components, one of which, oxygen, supports combustion, and the second, nitrogen, “spoiled air,” does not support combustion and respiration. This is how oxygen was discovered. A little later, pure nitrogen was obtained. And only at the very end of the 19th century, argon, helium, krypton, xenon, radon and neon, also found in air, were discovered.

Chemical composition

Air is made up of a mixture of about twenty-seven different gases. About 99% is a mixture of oxygen and nitrogen. The remaining percentage includes: water vapor, carbon dioxide, methane, hydrogen, ozone, inert gases (argon, xenon, neon, helium, krypton) and others. For example, hydrogen sulfide can often be found in the air, carbon monoxide, iodine, nitrogen oxides, ammonia.

It is believed that in clean air with normal conditions contains 78.1% nitrogen and 20.93% oxygen. However, depending on geographical location and altitude above sea level, the air composition may vary.

There is also such a thing as polluted air, that is, air whose composition differs from natural atmospheric air due to the presence of pollutants. These substances are:
. of natural origin (volcanic gases and dust, sea salt, smoke and gases from natural fires, plant pollen, dust from soil erosion, etc.).
. anthropogenic origin - resulting from industrial and domestic human activities (emissions of carbon, sulfur, nitrogen compounds; coal and other dust from mining and industrial enterprises; agricultural waste, industrial and household landfills, emergency spills of oil and other environmentally hazardous substances; gas exhausts Vehicle and so on.).

Properties

Clean atmospheric air is colorless and odorless; it is invisible, although it can be felt. The physical parameters of air are determined by the following characteristics:

Mass;
. temperature;
. density;
. atmospheric pressure;
. humidity;
. heat capacity;
. thermal conductivity;
. viscosity.

Most air parameters depend on its temperature, so there are many tables of air parameters for different temperatures. Air temperature is measured using a meteorological thermometer, and humidity is measured using a hygrometer.

Air exhibits oxidizing properties (due to its high oxygen content), supports combustion and respiration; conducts heat poorly and dissolves well in water. Its density decreases as temperature increases, and its viscosity increases.

In the following article you will learn about several interesting facts about air and its use.

We all know very well that without air, not a single living creature can live on earth. Air is vital for all of us. Everyone, from children to adults, knows that it is impossible to survive without air, but not everyone knows what air is and what it consists of. So, air is a mixture of gases that cannot be seen or touched, but we all know very well that it is around us, although we practically do not notice it. To conduct research various nature, including, is possible in our laboratory.

We can feel the air only when we feel a strong wind or we are near a fan. What does air consist of? It consists of nitrogen and oxygen, and only a small part of argon, water, hydrogen and carbon dioxide. If we consider the composition of air in percentage, then nitrogen is 78.08 percent, oxygen 20.94%, argon 0.93 percent, carbon dioxide 0.04 percent, neon 1.82 * 10-3 percent, helium 4.6 * 10-4 percent, methane 1.7 * 10-4 percent, krypton 1.14*10-4 percent, hydrogen 5*10-5 percent, xenon 8.7*10-6 percent, nitrous oxide 5*10-5 percent.

The oxygen content in the air is very high because oxygen is necessary for life. human body. Oxygen, which is observed in the air during breathing, enters the cells of the human body and participates in the oxidation process, as a result of which the energy needed for life is released. Also, oxygen, which is present in the air, is required for the combustion of fuel, which produces heat, as well as for the production of mechanical energy in internal combustion engines.

Inert gases are also extracted from air during liquefaction. How much oxygen is in the air, if you look at it as a percentage, then oxygen and nitrogen in the air are 98 percent. Knowing the answer to this question, another question arises, what gaseous substances are included in the air.

So, in 1754, a scientist named Joseph Black confirmed that air consists of a mixture of gases, and not a homogeneous substance as previously thought. The composition of the air on earth includes methane, argon, carbon dioxide, helium, krypton, hydrogen, neon, and xenon. It is worth noting that the percentage of air may vary slightly depending on where people live.

Unfortunately, in major cities the proportion of carbon dioxide as a percentage will be higher than, for example, in villages or forests. The question arises what percentage of oxygen is in the air in the mountains. The answer is simple, oxygen is much heavier than nitrogen, so there will be much less of it in the air in the mountains, this is because the density of oxygen decreases with altitude.

Level of oxygen in the air

So, regarding the ratio of oxygen in the air, there are certain standards, for example, for the work area. In order for a person to be able to fully work, the oxygen level in the air is from 19 to 23 percent. When operating equipment in enterprises, it is necessary to ensure the tightness of the devices, as well as various machines. If, when testing the air in the room where people work, the oxygen level is below 19 percent, then it is imperative to leave the room and turn on emergency ventilation. You can control the level of oxygen in the air at the workplace by inviting the EcoTestExpress laboratory and research.

Let's now define what oxygen is

There is oxygen chemical element In Mendeleev's periodic table of elements, oxygen has no smell, no taste, no color. Oxygen in the air is extremely necessary for human breathing, as well as for combustion, because it’s no secret that if there is no air, then no materials will burn. Oxygen contains a mixture of three stable nuclides, the mass numbers of which are 16, 17 and 18.

So, oxygen is the most common element on earth, as for the percentage, the largest percentage of oxygen is found in silicates, which is about 47.4 percent of the mass of the solid earth’s crust. Also in maritime and fresh waters The entire earth contains a huge amount of oxygen, namely 88.8 percent; as for the amount of oxygen in the air, it is only 20.95 percent. It should also be noted that oxygen is part of more than 1,500 compounds in the earth's crust.

As for the production of oxygen, it is obtained by separating air at low temperatures. This process happens like this: first, air is compressed using a compressor; when compressed, the air begins to heat up. The compressed air is allowed to cool to room temperature, and after cooling it is allowed to expand freely.

When expansion occurs, the temperature of the gas begins to drop sharply; after the air has cooled, its temperature can be several tens of degrees below room temperature, such air is again subjected to compression and the released heat is removed. After several stages of air compression and cooling, a number of other procedures are performed as a result of which the pure oxygen without any impurities.

And here another question arises: what is heavier: oxygen or carbon dioxide. The answer is simply of course carbon dioxide will be heavier than oxygen. The density of carbon dioxide is 1.97 kg/m3, but the density of oxygen, in turn, is 1.43 kg/m3. As for carbon dioxide, it turns out that it plays one of the main roles in the life of all life on earth, and also has an impact on the carbon cycle in nature. It has been proven that carbon dioxide is involved in the regulation of respiration, as well as blood circulation.

What is carbon dioxide?

Now let’s define in more detail what carbon dioxide is, and also designate the composition of carbon dioxide. So, carbon dioxide in other words is carbon dioxide, it is a colorless gas with a slightly sour odor and taste. As for air, the concentration of carbon dioxide in it is 0.038 percent. Physical properties carbon dioxide is that it does not exist in a liquid state under normal conditions atmospheric pressure, but passes directly from the solid state to the gaseous state.

Carbon dioxide in solid form is also called dry ice. Today, carbon dioxide is a participant global warming. Producing carbon dioxide through combustion various substances. It is worth noting that during the industrial production of carbon dioxide it is pumped into cylinders. Carbon dioxide pumped into cylinders is used as fire extinguishers, as well as in the production of carbonated water, and is also used in pneumatic weapons. And also in the food industry as a preservative.

Composition of inhaled and exhaled air

Now let's look at the composition of inhaled and exhaled air. First, let's define what breathing is. Breathing is a complex, continuous process through which the gas composition of the blood is constantly renewed. The composition of inhaled air is 20.94 percent oxygen, 0.03 percent carbon dioxide and 79.03 percent nitrogen. But the composition of exhaled air is only 16.3 percent oxygen, as much as 4 percent carbon dioxide and 79.7 percent nitrogen.

You can notice that the inhaled air differs from the exhaled air in the oxygen content, as well as in the amount of carbon dioxide. These are the substances that make up the air we breathe and exhale. Thus, our body is saturated with oxygen and releases all unnecessary carbon dioxide outside.

Dry oxygen improves the electrical and protective properties of films due to the absence of water, as well as their compaction and reduction of volume charge. Also, dry oxygen under normal conditions cannot react with gold, copper or silver. To spend chemical analysis air or other laboratory test, including, can be done in our EcoTestExpress laboratory.

Air is the atmosphere of the planet on which we live. And we always have the question of what is included in the air, the answer is simply a set of gases, as it was already described above which gases are in the air and in what proportion. As for the content of gases in the air, everything is easy and simple; the percentage ratio for almost all areas of our planet is the same.

Composition and properties of air

Air consists not only of a mixture of gases, but also of various aerosols and vapors. Percentage composition air is the ratio of nitrogen, oxygen and other gases in the air. So, how much oxygen is in the air, the simple answer is just 20 percent. Component composition gas, as for nitrogen, it contains the lion's share of all air, and it is worth noting that when high blood pressure nitrogen begins to have narcotic properties.

This is of no small importance, because when divers work, they often have to work at depths under enormous pressure. Much has been said about oxygen because it is of great importance for human life on our planet. It is worth noting that a person’s inhalation of air with increased oxygen is not a long period does not have a detrimental effect on the person himself.

But if a person inhales air from increased level oxygen for a long time, this will lead to the occurrence pathological changes in organism. Another main component of air, about which much has already been said, is carbon dioxide, as it turns out that a person cannot live without it as well as without oxygen.

If there was no air on earth, then not a single living organism would be able to live on our planet, much less function somehow. Unfortunately, in modern world a huge number of industrial facilities that pollute our air, in Lately they are increasingly calling for what needs to be protected environment and also monitor the cleanliness of the air. Therefore, you should take frequent measurements of the air to determine how clean it is. If it seems to you that the air in your room is not clean enough and this is to blame external factors you can always contact the EcoTestExpress laboratory, which will carry out everything necessary tests(, research) and will give a conclusion about the purity of the air you inhale.

The composition of the air on earth is one of the reasons for our life. Without air, a person will live only three minutes, and after 10 clinical death will occur.

As long as we breathe, we live. Not on any planet solar system there is no such close connection between chemistry and biology. Our world is unique.

Depending on the territory, the volume of the main component of the vital gas ranges from 16 to 20 percent - this is oxygen, the formula of which is O 2. Its variation is felt in space as “freshness” after a thunderstorm - this is ozone O 3.

From this article you will learn all the secrets of the earth's air envelope. What will happen to the world without one component? What harm can it cause? How will a slight deterioration of the atmosphere affect life?

What is air

The ancient Greeks used two words to define air: calamus, which meant the lower layers of the atmosphere (Dim), and aether meaning the bright upper layers of the atmosphere (the space above the clouds).

In alchemy, the symbol for air is a triangle divided in two by a horizontal line.

In the modern world, this definition would suit it - a gas mixture surrounding the planet, which protects against the penetration of solar radiation and large doses of ultraviolet radiation.

Over a multimillion-year period of development, the planet transformed gaseous substances and created a unique protective shield, which is almost impossible to see. Their mass fraction is disproportionately small for space.

Nothing else has an impact on the formation of the world. If we remember that part of the air masses is oxygen, then what will happen on earth without it? Buildings and structures will collapse.

Metal bridges and other structures that fascinate millions of tourists will turn into a single lump due to the small number of oxygen molecules (in this situation, close to zero). The life of all living organisms on the planet will worsen, and some will lead to death.

The seas and oceans, evaporating in the form of hydrogen, will disappear. And when the planet becomes like the Moon, a radiation fire will reign, burning out the remains of the flora, since without oxygen the temperature will increase very much, but without an atmosphere there will be no protection from the sun.

What is air made of?

Almost the entire earth's atmosphere consists of only five gases: nitrogen, oxygen, water vapor, argon and carbon dioxide.

Other mixtures are also present in it, but for the sake of purity of presentation, the chemical composition of water vapor will not be considered. It is worth mentioning that it occupies no more than five percent of the air mass.

Air composition in percentage

Ideally, the air collected in a jar consists of:

• 78 percent from nitrogen;
• 16 - 20 percent oxygen;
• 1 percent argon;
• three hundredths of a percent carbon dioxide;
• one thousandth of one percent neon;
• 0.0002 percent methane.

Smaller components are:

• helium - 0.000524%;
• krypton - 0.000114%;
• hydrogen - H2 0.00005%;
• xenon - 0.0000087%;
• ozone O 3 - 0.000007%;
• nitrogen dioxide - 0.000002%;
• iodine - 0.000001%;
• carbon monoxide;
• ammonia.

Composition of inhaled and exhaled air

Breathing takes precedence over other human needs. From school courses, everyone knows that a person inhales oxygen and exhales carbon dioxide. Although in life there are other substances in the air besides pure O2.

Inhale - exhale. This cycle repeats about 22,000 times a day, consuming oxygen to maintain vitality. human body. The problem is that delicate lung tissue is attacked by air pollution, cleaning solutions, fibers, fumes and dust.

The first half of the article talked about reducing oxygen, but what will happen with an increase. Doubling the concentration of the main gas would lead to a reduction in fuel consumption in cars.

By breathing in more oxygen, a person would become much more psychologically positive. However, a favorable climate would allow some insects to increase in size. There are a number of theories predicting this. It seems that no one would want to encounter a spider the size of a dog, and one can only fantasize about the growth of large representatives.

Inhaling less heavy metals, humanity could overcome a number of complex diseases, but such a project would require a lot of effort. There is a whole program aimed at creating a practical paradise on earth: in every home, room, city or country. Its goal is to make the atmosphere cleaner, to rid people of dangerous work in mines and metallurgy. A place where jobs would be occupied by masters of their craft.

It is important that you can breathe clean air, untouched by industry, but this requires political, or better yet, global will. And while people are busy looking for money and cheap (dirty) technologies, all that remains is to inhale city smog. How long this will last is unknown.

The map will allow you to clearly evaluate the atmospheric air of the capital of our homeland, which is inhaled by more than a dozen people.

Hygienic value of atmospheric air

Officially, air pollution can be defined as the presence of harmful substances in the air, either particles or microscopic biological molecules that pose a threat to the health of living organisms: humans, animals or plants.

The level of air pollution in a particular location depends primarily on the source or sources of the pollution. This includes:

• car exhaust gases;
• coal power plants;
• industrial plants and other sources of pollution.

All of the above spews into the air Various types hazardous substances and toxins, exceeding the norm by tens and sometimes hundreds of times. In combination with natural sources - volcanoes, geysers, etc. - a deadly cocktail of toxic air masses is created, which is usually called “smog”.

The evidence of each person's guilt is clear. Our personal choices and industry can have a detrimental effect on much-needed gas. Over the century of technological breakthrough, nature has suffered, which means revenge is inevitable.

By increasing emissions, humanity is approaching an abyss from which there is no return and cannot be. Before it's too late, at least something should be fixed. It has been proven that alternative industrial technologies can help clean the air in Moscow, St. Petersburg, Tokyo, Berlin and any other major city.

Here are some solutions:

1. Replace gasoline with electricity in cars, and the sky over the city will become a little more beautiful.
2. Remove coal plants from cities, let them go down in the history of the country, start using the energy of the sun, water, and wind. Then, after the rain, soot will not fly out of the chimney of the next plant, but only the smell of “freshness.”
3. Plant a tree in the park. If thousands do this, then asthmatics and depressed people will stop visiting hospitals in search of unique recipe from the lips of a psychologist.

The lower layers of the atmosphere consist of a mixture of gases called air , in which liquid and solid particles are suspended. The total mass of the latter is insignificant in comparison with the entire mass of the atmosphere.

Atmospheric air is a mixture of gases, the main of which are nitrogen N2, oxygen O2, argon Ar, carbon dioxide CO2 and water vapor. Air without water vapor is called dry air. At the earth's surface, dry air is 99% nitrogen (78% by volume or 76% by mass) and oxygen (21% by volume or 23% by mass). The remaining 1% is almost entirely argon. Only 0.08% remains for carbon dioxide CO2. Numerous other gases are part of the air in thousandths, millionths and even smaller fractions of a percent. These are krypton, xenon, neon, helium, hydrogen, ozone, iodine, radon, methane, ammonia, hydrogen peroxide, nitrous oxide, etc. The composition of dry atmospheric air near the Earth's surface is given in table. 1.

Table 1

Composition of dry atmospheric air near the Earth's surface

The percentage composition of dry air near the earth's surface is very constant and almost the same everywhere. Only the carbon dioxide content can change significantly. As a result of the processes of breathing and combustion, its volumetric content in the air of closed, poorly ventilated rooms, as well as industrial centers, can increase several times - up to 0.1-0.2%. The percentage of nitrogen and oxygen changes quite slightly.

The real atmosphere contains three important variable components - water vapor, ozone and carbon dioxide. The content of water vapor in the air varies within significant limits, unlike other components of the air: at the earth's surface it fluctuates between hundredths of a percent and several percent (from 0.2% in polar latitudes to 2.5% at the equator, and in some cases ranges from almost zero to 4%). This is explained by the fact that, under the conditions existing in the atmosphere, water vapor can transform into a liquid and solid state and, conversely, can enter the atmosphere again due to evaporation from the earth’s surface.

Water vapor continuously enters the atmosphere through evaporation from water surfaces, from moist soil and through transpiration of plants, in different places and in different time it comes in varying quantities. It spreads upward from the earth's surface, and is transported by air currents from one place on the earth to another.

A saturation state may occur in the atmosphere. In this state, water vapor is contained in the air in the amount that is maximum possible at a given temperature. Water vapor is called saturating(or saturated), and the air containing it saturated.

The saturation state is usually reached when the air temperature decreases. When this state is reached, then with a further decrease in temperature, part of the water vapor becomes excess and condenses, turns into a liquid or solid state. Water droplets and ice crystals of clouds and fogs appear in the air. Clouds may evaporate again; in other cases, cloud droplets and crystals, becoming larger, can fall onto the earth's surface in the form of precipitation. As a result of all this, the content of water vapor in each part of the atmosphere is constantly changing.

The most important weather processes and climate features are associated with water vapor in the air and its transitions from gaseous to liquid and solid states. The presence of water vapor in the atmosphere significantly affects the thermal conditions of the atmosphere and the earth's surface. Water vapor strongly absorbs long-wave infrared radiation emitted by the earth's surface. In turn, it itself emits infrared radiation, most of which goes to the earth's surface. This reduces the nighttime cooling of the earth's surface and thus also the lower air layers.

Large amounts of heat are expended on the evaporation of water from the earth's surface, and when water vapor condenses in the atmosphere, this heat is transferred to the air. Clouds resulting from condensation reflect and absorb solar radiation on its way to the earth's surface. Precipitation from clouds is an essential element of weather and climate. Finally, the presence of water vapor in the atmosphere is important for physiological processes.

Water vapor, like any gas, has elasticity (pressure). Water vapor pressure e is proportional to its density (content per unit volume) and its absolute temperature. It is expressed in the same units as air pressure, i.e. either in millimeters of mercury, either in millibars

The pressure of water vapor at saturation is called saturation elasticity. This the maximum pressure of water vapor possible at a given temperature. For example, at a temperature of 0° the saturation elasticity is 6.1 mb . For every 10° temperature increase, the saturation elasticity approximately doubles.

If the air contains less water vapor than is needed to saturate it at a given temperature, you can determine how close the air is to the saturation state. To do this, calculate relative humidity. This is the name given to the ratio of actual elasticity e water vapor in the air to saturation elasticity E at the same temperature, expressed as a percentage, i.e.

For example, at a temperature of 20° the saturation pressure is 23.4 mb. If the actual vapor pressure in the air is 11.7 mb, then the relative humidity is

The elasticity of water vapor at the earth's surface varies from hundredths of a millibar (at very low temperatures in winter in Antarctica and Yakutia) to more than 35 millibars (at the equator). The warmer the air, the more water vapor it can contain without saturation and, therefore, the greater the water vapor pressure in it.

Relative air humidity can take on all values ​​- from zero for completely dry air ( e= 0) to 100% for saturation condition (e = E).