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 the 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 the study of air
Currently, air is understood as a mixture of gases that form the atmosphere of our planet. But this was not always the case: for a long time, scientists thought that air is a simple substance, an integral substance. And although many scientists expressed hypotheses about the complex composition of the air, things did not go beyond conjectures until the 18th century. In addition, air was given a philosophical meaning. In ancient Greece, air was considered one of the fundamental cosmic elements, along with earth, fire, earth and water, which form everything that exists. Aristotle attributed air to the sublunar light elements, personifying moisture and heat. Nietzsche in his writings 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 proved 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. So it was found that about a fifth of the volume of air is absorbed, and the remaining part of combustion and breathing 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 were discovered argon, helium, krypton, xenon, radon and neon, which are also present in the air.
Chemical composition
Air is made up of a mixture of about twenty-seven different gases. Approximately 99% is a mixture of oxygen and nitrogen. As part of the remaining percentage: water vapor, carbon dioxide, methane, hydrogen, ozone, inert gases (argon, xenon, neon, helium, krypton) and others. For example, hydrogen sulfide, carbon monoxide, iodine, nitrogen oxides, ammonia can often be found in the air.
It is believed that clean air under normal conditions contains 78.1% nitrogen and 20.93% oxygen. However, depending on the geographical location and altitude above sea level, the composition of the air may vary.
There is also such a thing as polluted air, that is, air whose composition differs from the natural atmospheric one due to the presence of pollutants. These substances are:
. natural origin (volcanic gases and dust, sea salt, fumes 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 domestic dumps, accidental spills of oil and other environmentally hazardous substances; vehicle exhaust gases, etc.).
Properties
Pure atmospheric air has no color and smell, 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 of the air parameters depend on its temperature, so there are many tables of air parameters for various temperatures. Air temperature is measured with a meteorological thermometer, and humidity is measured with a hygrometer.
Air exhibits oxidizing properties (due to the high oxygen content), supports combustion and respiration; poorly conducts heat, dissolves well in water. Its density decreases as the temperature increases and its viscosity increases.
In the following article, you will learn about some interesting facts about air and its applications.
Air is a mixture of gases necessary for the existence and maintenance of life on the planet. What are its features, and what substances are included in the air?
Air is essential for breathing for all living organisms. It consists of nitrogen, oxygen, argon, carbon dioxide and a number of impurities. The composition of atmospheric air can vary depending on conditions and terrain. So in the urban environment, the level of carbon dioxide in the air, compared with the forest belt, increases due to the abundance of vehicles. At high altitudes, the oxygen concentration decreases because nitrogen molecules are lighter than oxygen molecules. Therefore, the oxygen concentration decreases faster.
Scottish physicist and chemist Joseph Black in 1754 experimentally proved that air is not just a substance, but a mixture of gases.
Rice. 1. Joseph Black.
If we talk about the composition of air as a percentage, then its main component is nitrogen. Nitrogen occupies 78% of the total volume of air. The percentage of oxygen in the air molecule is 20.9%. Nitrogen and oxygen are the 2 main elements of air. The content of other substances is much less and does not exceed 1%. Thus, argon occupies a volume of 0.9%, and carbon dioxide - 0.03%. Air also contains impurities such as neon, krypton, methane, helium, hydrogen and xenon.
Rice. 2. The composition of the air.
In industrial premises, the aeroionic composition of the air is of great importance. The negatively charged ions present in the air have a positive effect on the human body, energize it, and improve mood.
Nitrogen
Nitrogen is the main constituent of air. The translation of the name of the element - "lifeless" - may refer to nitrogen as a simple substance, but nitrogen in a bound state is one of the main elements of life, is part of proteins, nucleic acids, vitamins, etc.
Nitrogen - an element of the second period, does not have excited states, since the atom does not have free orbitals. However, nitrogen is able to exhibit in the ground state valency not only III, but also IV due to the formation of a covalent bond by the donor-acceptor mechanism with the participation of the unshared electron pair of nitrogen. The oxidation state that nitrogen can exhibit varies widely: from -3 to +5.
In nature, nitrogen occurs in the form of a simple substance - N2 gas and in a bound state. In the nitrogen molecule, the atoms are bound by a strong triple bond (bond energy 940 kJ/mol). At ordinary temperatures, nitrogen can only interact with lithium. After preliminary activation of the molecules by heating, irradiation or the action of catalysts, nitrogen reacts with metals and non-metals.
Oxygen
Oxygen is the most common element on Earth: the mass fraction in the earth's crust is 47.3%, and the volume fraction in the atmosphere is 20.95%, the mass fraction in living organisms is about 65%.
In almost all compounds (except compounds with fluorine and peroxides), oxygen exhibits a constant valency II and an oxidation state of 2. The oxygen atom does not have excited states, since there are no free orbitals on the second outer level. As a simple substance, oxygen exists in the form of two allotropic modifications - oxygen gases O2 and ozone O3. The most important oxygen compound is water. About 71% of the earth's surface is occupied by a water shell; life is impossible without water.
Ozone in nature is formed from atmospheric oxygen during lightning discharges, and in the laboratory - by passing an electrical discharge through oxygen.
Rice. 3. Ozone.
Ozone is an even stronger oxidizing agent than oxygen. In particular? it oxidizes gold and platinum
Oxygen in industry is usually obtained by liquefying air, followed by separation of nitrogen due to its evaporation (there is a difference in boiling points: -183 degrees for liquid oxygen and -196 degrees for liquid nitrogen.). Total ratings received: 249.
Let's make a reservation right away, nitrogen in the air occupies a large part, however, the chemical composition of the remaining share 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 content of nitrogen in the air is 78% by volume and 75% by mass, that is, this element dominates 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, how much nitrogen is in the air, we have already figured out, 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 is just 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, used for cooling and for other purposes.
2. Oxygen
The oxygen content in the air is one of the most popular questions. Keeping the intrigue, let's digress to one funny fact: oxygen was discovered twice - in 1771 and 1774, however, due to the difference in the publications of the discovery, the credit for the discovery of 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 the 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 a poison, leads to difficulties in the functioning of the nervous system, respiratory failure 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, so much is needed for healthy full breathing.
3. Argon
Argon in the air takes the third place, it has no smell, color and taste. A significant biological role of this gas has not been identified, but it has a narcotic effect and is even considered doping. Argon extracted from the atmosphere is used in industry, medicine, for creating an artificial atmosphere, chemical synthesis, fire fighting, 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 emitted due to the work of industry. In human life, carbon dioxide is used in fire fighting, the food industry as a gas and as a food additive E290 - a preservative and baking powder. In solid form, carbon dioxide is one of the most well-known dry ice refrigerants.
5. Neon
The same mysterious light of disco lanterns, bright signs and modern headlights use the fifth most common chemical element, which is also inhaled by a person - neon. Like many inert gases, neon has a narcotic effect on a person at a certain pressure, but it is this gas that is used in the preparation of divers and other people working at elevated 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 give lamps with other gases.
6. Methane
Methane and air have a very ancient history: in the primary atmosphere, even before the appearance of man, methane was in much greater quantities. Now this gas, extracted and used as a fuel and raw material in production, is not so widely distributed in the atmosphere, but is still emitted from the Earth. Modern research establishes the role of methane in the respiration and life of the human body, but there are no authoritative data on this subject yet.
7. Helium
Looking at how much helium is in the air, anyone will understand that this gas is not one of the most important in importance. Indeed, it is difficult to determine the biological significance of this gas. Not counting the funny voice distortion when inhaling helium from a balloon 🙂 However, helium is widely used in industry: in metallurgy, food industry, for filling balloons and meteorological probes, in lasers, nuclear reactors, etc.
8. Krypton
We are not talking about the birthplace 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. Of the interesting properties of krypton, it is worth noting that at a pressure of 3.5 atmospheres it has a narcotic effect on a person, 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 abundant 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 industries, aviation, meteorology, electric power industry.
10. Xenon
The latter is in the composition of air, which was originally considered to be only an admixture to krypton. Its name translates as "alien", and the percentage of content both on Earth and beyond is minimal, which led to its high cost. Now xenon is essential: the production of powerful and pulsed light sources, diagnostics and anesthesia in medicine, spacecraft engines, rocket fuel. In addition, when inhaled, xenon significantly lowers the voice (the opposite effect of helium), and more recently, inhalation of this gas has been added to the doping list.
Less than 200 years ago, the earth's atmosphere contained 40% oxygen. Today, the air contains only 21% oxygen.
In the city park 20,8%
In the forest 21,6%
By the sea 21,9%
In the apartment and office less 20%
Scientists have proven that a 1% decrease in oxygen leads to a decrease in performance by 30%.
The lack of oxygen is the result of automobiles, industrial emissions and pollution. In the city, oxygen is 1% less than in the forest.
But the biggest culprit in the lack of oxygen is ourselves. Having built warm and hermetic houses, living in apartments with plastic windows, we protected ourselves from fresh air. With each exhalation, reducing the concentration of oxygen and increasing the amount of carbon dioxide. Often the oxygen content in the office is 18%, in the apartment 19%.
The quality of the air necessary to support the life processes of all living organisms on Earth,
determined by its oxygen content.
The dependence of air quality on the percentage of oxygen in it.
The level of comfortable oxygen content in the air
Zone 3-4: limited by the legally mandated minimum indoor oxygen standard (20.5%) and the "reference" fresh air (21%). For urban air, an oxygen content of 20.8% is considered normal.
Favorable levels of oxygen in the air
Zone 1-2: this level of oxygen content is typical for ecologically clean areas, forests. The oxygen content in the air on the ocean can reach 21.9%
Insufficient level of oxygen in the air
Zano 5-6: limited by the minimum allowable level of oxygen when a person can be without a breathing apparatus (18%).
A person's stay in rooms with such air is accompanied by rapid fatigue, drowsiness, decreased mental activity, and headaches.
Prolonged stay in rooms with such an atmosphere is dangerous to health.
Dangerously low oxygen levels in the air
Zone 7 onwards: at oxygen content16% dizziness, rapid breathing,13% - loss of consciousness,12% - irreversible changes in the functioning of the body, 7% - death.
External signs of oxygen starvation (hypoxia)
- deterioration in skin color
- fatigue, decreased mental, physical and sexual activity
- depression, irritability, sleep disturbance
- headache
Prolonged exposure to a room with insufficient oxygen levels can lead to more serious health problems, because. oxygen is responsible for all metabolic processes of the body, then the consequence of its lack is:
Metabolic disease
Decreased immunity
Properly organized ventilation system of living and working premises can be the key to good health.
The role of oxygen in human health. Oxygen:
Increases mental performance;
Increases the body's resistance to stress and increased nervous stress;
Supports the level of oxygen in the blood;
Improves the coordination of the work of internal organs;
Increases immunity;
Promotes weight loss. Regular oxygen consumption, combined with physical activity, leads to active breakdown of fats;
Sleep normalizes: it becomes deeper and longer, the period of falling asleep and physical activity decreases
Conclusions:
Oxygen affects our life, and the more it is, the more colorful and diverse our life is.
You can buy an oxygen tank or drop everything and go to live in the forest. If this is not available to you, air your apartment or office every hour. Draft, dust, noise interfere, install ventilation that will supply you with fresh air, clean it from exhaust gases.
Do everything to fresh air in your home and you will see changes in your life.
We take about 20,000 breaths every day. It is enough to stop the flow of oxygen into the blood for 7–8 minutes, so that irreversible changes occur in the cerebral cortex. Air supports many biochemical reactions in our body. And our health largely depends on its quality.
text: Tatyana Gaverdovskaya
We take about 20,000 breaths every day. It is enough to stop the flow of oxygen into the blood for 7-8 minutes, so that irreversible changes occur in the cerebral cortex. Air supports many biochemical reactions in our body. And our health largely depends on its quality.
Atmospheric air at the Earth's surface normally consists of nitrogen (78.09%), oxygen (20.95%), carbon dioxide (0.03-0.04%). The remaining gases together occupy less than 1% by volume, they include argon, xenon, neon, helium, hydrogen, radon and others. However, industrial and transport emissions violate this ratio of components. Only in Moscow, from 1 to 1.2 million tons of harmful chemicals are emitted into the air per year, that is, 100-150 kg for each of the 12 million inhabitants of Moscow. It is worth considering what we breathe, and what can help us resist this "gas attack".
Shortest way
Human lungs have a surface of up to 100 m2, which is 50 times the area of the skin. In them, the air is in direct contact with the blood, in which almost all the substances included in it are dissolved. From the lungs, bypassing the detoxification organ - the liver, they act on the body 80-100 times stronger than through the gastrointestinal tract when swallowed.
The air we breathe is polluted by about 280 toxic compounds. These are salts of heavy metals (Cu, Cd, Pb, Mn, Ni, Zn), oxides of nitrogen and carbon, ammonia, sulfur dioxide, etc. In calm weather, all these harmful compounds settle and create a dense layer near the ground - smog. Under the influence of ultraviolet rays during a hot period, harmful gas mixtures are converted into more harmful substances - photooxidants. Every day a person inhales up to 20 thousand liters of air. And in a month in a large city, he can gain a toxic dose. As a result, immunity decreases, respiratory and neurological diseases occur. Children are especially affected by this.
Taking action
1. Tea from calendula, chamomile, sea buckthorn and rosehip will help protect the body from the penetration of heavy metals into cells.
2. Some plants are successfully used to remove toxic substances, for example, coriander (cilantro). According to experts, it is necessary to eat at least 5 g of this plant per day (about 1 tsp).
3. Garlic, sesame seeds, ginseng and many other plant products also have the ability to bind and remove heavy metals. Apple juice is also effective, in which there are a lot of pectins - natural adsorbents.
City without oxygen
Residents of the metropolis are constantly experiencing a lack of oxygen due to industrial emissions and pollution. So, when burning 1 kg of coal or firewood, more than 2 kg of oxygen is consumed. One car absorbs as much oxygen in 2 hours of operation as a tree releases in 2 years.
The concentration of oxygen in the air is often only 15-18%, while the norm is about 20%. At first glance, this is a small difference - only 3-5%, but for our body it is quite noticeable. An oxygen level in the air of 10% or less is fatal to humans. Unfortunately, in natural conditions there is a sufficient amount of oxygen only in urban parks (20.8%), suburban forests (21.6%) and on the shores of the seas and oceans (21.9%). The situation is aggravated by the fact that every 10 years the lung area decreases by 5%.
Oxygen increases mental capacity, the body's resistance to stress, stimulates the coordinated work of internal organs, improves immunity, promotes weight loss, normalizes sleep. Scientists have calculated that if there were 2 times more oxygen in the Earth's atmosphere, then we could run hundreds of kilometers without getting tired.
Oxygen makes up 90% of the mass of a water molecule. The body contains 65-75% water. The brain makes up 2% of the total body weight and consumes 20% of the oxygen that enters the body. Without oxygen, cells do not grow and die.
Taking action
1. For adequate saturation of the body with oxygen, it is necessary to walk in the forest for at least one hour every day. During one year, an ordinary tree produces the amount of oxygen needed for a family of 4 during the same period.
2. To compensate for the lack of oxygen in the body, doctors recommend drinking salted and mineral alkaline water, lactic acid drinks (skimmed milk, whey), juices.
3. Oxygen cocktails help to get rid of hypoxia. In terms of its effect on the body, a small portion of a cocktail is equivalent to a full-fledged forest walk.
4. Oxygen therapy is a treatment method based on breathing a gas mixture with an increased (in relation to the oxygen content in the air) oxygen concentration.
home trap
According to WHO experts, a city dweller spends about 80% of his time indoors. Scientists have found that indoor air is 4-6 times dirtier than outdoor air and 8-10 times more toxic. These are formaldehyde and phenol from furniture, some types of synthetic fabrics, carpets, harmful substances from building materials (for example, urea from cement can release ammonia), dust, pet hair, etc. At the same time, oxygen in urban areas is significantly less, which leads to oxygen deficiency (hypoxia) in humans.
A gas stove can also negatively affect the atmosphere in the house. The air of gasified buildings in comparison with the outside air contains 2.5 times more harmful nitrogen oxides, 50 times more sulfur-containing substances, phenol - by 30-40%, carbon oxides - by 50-60%.
But the main scourge of the premises is carbon dioxide, the main source of which is a person. We exhale 18 to 25 liters of this gas per hour. Recent studies by foreign scientists have shown that carbon dioxide adversely affects the human body, even in low concentrations. In residential premises, carbon dioxide should not be more than 0.1%. In a room with a carbon dioxide concentration of 3-4%, a person suffocates, headaches, tinnitus appear, and the pulse slows down. Nevertheless, a small amount (0.03-0.04%) of carbon dioxide is necessary to maintain physiological processes.
Taking action
1. It is very important that the air in the room is “light”, i.e. ionized. With a decrease in the number of air ions, oxygen is absorbed worse by red blood cells, hypoxia is possible. The air of cities contains only 50-100 light ions per 1 cm³, and heavy (uncharged) - tens of thousands. In the mountains, the highest air ionization is 800-1000 per 1 cm³ or more.
2. According to a study by the US Space Agency, some houseplants act as effective biofilters. Chlorophytum, nephrolepis fern help in the fight against formaldehyde. Xylene and toluene, which are released, for example, by varnishes, neutralize Benjamin's ficus. Azalea can handle ammonia compounds. They emit a lot of oxygen and absorb harmful substances of sansevier, philodendron, ivy, dieffenbachia.
3. Do not forget about regular ventilation. This is especially important in the bedroom, where people spend a third of their lives.
Dangers on the road
Motor transport supplies the lion's share of air pollutants: for Moscow it is about 93%, for St. Petersburg - 71%. There are almost 4 million cars in Moscow, and every year their number is growing. By 2015, according to experts, Moscow's car fleet will be more than 5 million cars. In a month, an average passenger car burns as much oxygen as 1 hectare of forest emits in a year, while emitting annually about 800 kg of carbon monoxide, about 40 kg of nitrogen oxides and about 200 kg of various hydrocarbons.
The most serious danger for those who often use cars is carbon monoxide. It binds to blood hemoglobin 200 times faster than oxygen. Experiments conducted in the United States have shown that due to the influence of carbon monoxide in people who spend a lot of time driving, the reaction is disturbed. At a carbon monoxide concentration of 6 mg/m3, the color and light sensitivity of the eyes decreases within 20 minutes. Exposure to large amounts of carbon monoxide can cause fainting, coma, and even death.
Taking action
1. Lactic ferments and acids remove carbon monoxide decomposition products. With normal tolerance, you can drink up to a liter of milk per day.
2. To neutralize the effect of carbon monoxide, it is recommended to eat as many fruits as possible: green apples, grapefruits, as well as honey and walnuts.
Kind with healthy
German scientists have found that sexual arousal activates the cardiovascular system and increases blood flow. As a result, tissues are better oxygenated and the risk of heart attack or stroke is reduced by 50%.
What breathes the subway
Scientists from the Karolinska Institute in Sweden have concluded that more than 5,000 Swedes die every year from inhaling microscopic particles of coal, asphalt, iron and other pollutants in the air of the Stockholm metro. These particles have a more destructive effect on human DNA than the particles contained in car exhaust and formed as a result of burning wood fuel.
Sky over Moscow
According to Roshydromet observations, in 2011 the degree of atmospheric air pollution in the cities of the Moscow region was assessed as: very high - in Moscow, high - in Serpukhov, increased - in Voskresensk, Klin, Kolomna, Mytishchi, Podolsk and Elektrostal, low - in Dzerzhinsky, Shchelkovo and Prioksko-Terrasny Biosphere Reserve.
