The air we breathe contains. What is air: natural history for adults. Beneficial effects of negative air ions
We all know very well that no one on earth can live without air. Living being. 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 only feel air when we feel it 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 when receiving 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 still part of 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 working 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 abundant element on earth, as far as percentage then the largest percentage of oxygen is found in silicates, which is about 47.4 percent of the solid mass 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. Compressed air let cool until room temperature, and after cooling they ensure its free expansion.
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 compressing and cooling the air, a number of other procedures are performed, as a result of which pure oxygen is separated 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.
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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 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. Carbon dioxide is produced by burning various substances. It is worth noting that when industrial production carbon dioxide 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 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. Respiration 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 electrical as well as protective properties films due to the absence of water, as well as their compaction and reduction of volumetric 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. The percentage composition of 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 at elevated 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 for a short 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 pathological changes in the body. 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 conduct all the necessary tests (research) and give a conclusion on the purity of the air you inhale.
Tatyana Ghazaryan
Conversation« We need air» .
Program tasks:
Strengthen ideas about air and its properties.
Form an idea of meaning air for practical human purposes.
To develop in children cooperation skills and the ability to listen to each other.
Enrich vocabulary stock: transparent, invisible, jet, purification facilities.
I show the children balloon and ask: "What's inside the ball?" (You can’t see anything there, it’s empty).
Let's check: I will untie the ball, and you will put your palms up and say whether you felt something or not.
Children put their palms under the stream air.
So is there something in the ball or not? (YES). After all, we don’t see anything, but we feel something. What is this? Guess riddle:
We need him to breathe
To inflate the balloon.
With us every hour,
But he is invisible to us!
That's right air.
Please tell me what is it air? (Air, this is what we breathe.).
Let's describe him, what is he like? ( Air is transparent, which means everything is visible through it. It is also invisible, odorless and tasteless and very light).
And where it is air? (Everywhere).
And who is breathing? air? (People, birds, animals, insects, plants, fish, trees).
Air is always around us, we breathe air, and not only, but all living beings - everyone needs air to breathe. Take a deep breath everyone. One two Three! Dial more air and hold it, and I'll count to five. On the count of five you release air.
It was difficult for you without air? (Of course yes, I immediately want to inhale air. !
Is it possible to live without air? (No).
A man cannot live without air, if not air, he may suffocate. If someone does not know how to swim and finds himself under water, then he may drown - after all, there is no air.
Air is around us, we don’t see it, but it can be feel: Blow into your palm. Children do you feel air? (Yes).
If you wave your palm, you can feel air. Wave your palms like this. (Children wave). Do you feel something so light? That's what it is air. In the summer, when it's warm, no air visible, but in winter you can see how we breathe - steam comes out of our mouths.
Guess the riddle: He is with us every hour, but is he invisible to us?
Children: This air.
That's right, guys! Air is everywhere around us, and he can help people. For example: the air inflates the sails, because the wind is air, and the boat is moving. The wind blows on windmill, and the mill rotates, helping people grind flour. By using air transports seeds.
Guys, why do you think birds fly and don’t fall? (They have wings).
Right! The bird's wings rest on air and fly. It's the same with airplanes - they have wings, and they rest on them. air and fly. If it weren't for air, then birds and planes would not be able to fly.
Children, where else is there air?
Air found in car tires, bicycle tires, and rubber balls air, only compressed.
We will remember that air is necessary for life on earth. AND you need to take care of it, do not pollute with various plants and factories. And make treatment facilities for cleaning air. And, of course, plant green spaces.
Oxygen is simply necessary for us to live. Without it, a person cannot last even five minutes. We are so accustomed to our breathing that we don’t even notice how it happens. But in fact, this is difficult process, worked to perfection. So what is so important that happens to air when it enters our body?
Every cell in the human body requires a constant supply of energy to stay alive and perform its function. Cells receive the bulk of their energy through the processing of substances that occurs with the participation of oxygen. This process is called cellular respiration. As a result, a lot of energy is released and carbon dioxide is formed - a harmful product of metabolic processes that must be removed from the body.
Through the nose, air enters the nasopharynx, in which the paths of food and air coincide. Food should go into the esophagus and air into the larynx. Touch your neck with your hand, you will feel the larynx tube. Inside it is the epiglottis - a special soft outgrowth. It works as a regulator - it closes the entrance to the larynx when swallowing. If you talk and eat at the same time, the epiglottis may not cope with its job. So you can choke!
The air then moves through the trachea, a reinforced tube. The mucus in the trachea traps dust and other particulate matter that can damage our lungs. And the cilia covering the walls of the trachea drive this dirt up into the throat. This is why when we breathe dusty air, we feel like coughing. At the bottom, the trachea is divided into two branches - the bronchus, each of which enters the right and left halves of the lungs. There the bronchi branch into narrower tubes, the smallest of which end in millions air bubbles. Due to the very thin shell, gases pass through them easily. The lungs are made up of such bubbles, resembling a porous sponge.
The lungs are located in the chest cavity on either side of the heart. They are protected by a movable chest formed by the ribs, sternum and spine. The lungs are covered on top thin film. There is a liquid underneath that reduces friction. Therefore, when you inhale and exhale, the lungs move, but do not make sounds. Wheezing occurs in them only as a result of illness.
Lungs act as a point of exchange fresh air, which we inhaled, into waste carbon dioxide to exhale. And the carrier of air is blood. Capturing oxygen from the lungs, it rushes to deliver it to every cell of our body. And it also returns unnecessary accumulated carbon dioxide to the lungs.
When we inhale, our ribs rise and expand. The muscle underneath the lungs, called the diaphragm, straightens. Air fills the lungs. When you exhale, the ribs narrow. The diaphragm rises up and the exhaust gases are pushed out.
Although the total volume of the lungs is 5 liters, breathing requires only half a liter of air. The rest is distributed as follows: 1.5 liters is the residual volume of air so that the lungs are never empty, and 3 liters is the reserve for maximum inhalation and exhalation.
We take 1000 breaths per hour, 26,000 per day, 9 million per year. The well-being, health and life expectancy of a person depend on proper breathing. It is important to learn to breathe evenly and deeply. After all, the lungs are an organ that, like muscles, must be constantly trained!
As you know, a person needs to breathe. And any difficulty breathing can lead to extremely adverse health consequences...
Why do we breathe
Breathing is the only way to get the oxygen necessary for the body, without which we cannot do without. After all, if you try to hold your breath, you won’t be able to hold your breath for a long time. And all because the body will persistently “demand” another portion of oxygen.
Why do we need oxygen? Everything is simple and complex at the same time. Without oxygen, metabolism is impossible. Our brain will not be able to work without constant oxygen supply, just like all other internal organs.
It is oxygen that is involved in the breakdown nutrients, promotes the release of energy and supply to every cell of the body. Breathing is also called gas exchange, since air enters the body, from which oxygen is taken, after which carbon dioxide remains, which must be removed from the body.
How we breathe
If you think about how we breathe, you will discover a rather peculiar paradox: breathing is the only function of our body that is subject not only to unconscious control, but can also be controlled by us consciously. As an example of conscious control of breathing, various breathing techniques practiced in yoga, for example, can serve. To understand which organs are involved in breathing, consider the device respiratory system.
Through the nostrils, air enters the nasal cavity, where it is heated and cleared of dust and small particles suspended in the air. The air purified and heated in the nasal cavity enters the larynx. It is a cavity with vocal cords on both sides. The trachea originates at the bottom of the larynx cavity and is a tube consisting of cartilage and soft fabric. In the lower part, the trachea is divided into two tubes - bronchi.
Next are the lungs. They are located in the chest cavity on either side of the heart. The lungs and heart are protected by the rib cage (ribs and sternum). Below the lungs is the diaphragm, a dome-shaped muscular partition that separates the chest cavity from the abdominal cavity. In order for us to inhale, we need to increase the volume chest, for this there are so-called respiratory muscles located between the ribs.
The diaphragm moves down, the intercostal muscles push the ribs apart and air begins to enter the respiratory system. When you exhale, the diaphragm rises up, the ribs return to initial position and press the lungs, accordingly, the air is pushed out.
The shape of the lungs resembles a cone, the base of which is directed downwards. Each lung is covered with a special “sac” - the pleura. It consists of two layers, between which there is a small amount of liquid. The outer layer of the pleura is adjacent to the surface of the chest and diaphragm, and the inner layer is directly adjacent to the lungs. The pleura protects the lungs and aids breathing.
How the lungs work
The bronchi are the basis of the lungs. They branch out like a tree and form a kind of “skeleton” for the soft tissues of the lung. Due to its shape and appearance The branches of the bronchi are also called the “bronchial tree”.
The right and left lungs are slightly different in structure. It is customary to divide each lung into lobes. The right one consists of three lobes, and the left one of two. The lobes, in turn, are divided into smaller segments. Each of them is no more than 25 millimeters in length and 15 millimeters in width, and they resemble a pyramid in shape. The bronchus enters the apex of the pyramid, and inside it is divided into 18-20 bronchioles.
The walls of the bronchioles consist of small sacs called alveoli. They consist of connective tissue and fibers that can stretch and shrink. There are up to 400 million alveoli in each adult lung. The inhaled air, passing through the airways, bronchi and bronchioles, enters the alveoli. There, oxygen enters the blood capillaries through the walls of the alveoli. In the same way, carbon dioxide returns to the lungs and is expelled from them when you exhale.
If you “roll out” the lungs, which are only the size of a human palm, they will occupy the area of a judo mat - approximately 200 square meters, and the volume of the lungs - 5 liters. But it is far from being fully used. For breathing, 0.5 liters is enough for us, 1.5 liters is the residual volume of air, and 3 liters form a reserve volume of air.
IN different ages We breathe differently: the older we get, the less often we breathe. It is estimated that a newborn inhales and exhales 35 times per minute, a child - 25 times, a teenager - 20 times, and an adult only needs to inhale and exhale 15 times per minute. By simple arithmetic calculations we get the average respiratory cycle throughout our lives - 18 times per minute.
We take 1000 breaths per hour, 26,000 in a day, 9 million in one year. Men and women take an unequal number of inhalations and exhalations: a man takes 670 million and a woman takes 746 million. The volume of air that is vitally needed in one minute is 8.5 liters, 500 liters per hour, 12,000 liters per day, 4 million liters per year. During a lifetime, a man inhales 317 million liters of air, and a woman 352 million liters.
You need to take care of your lungs, as well as your entire body. So even a “mild” cough should not be left to chance: the consequences can be unpredictable. If you have doubts about the well-being of the respiratory system, go to the doctor and have fluorography done regularly, this will help prevent some diseases.
The statement that we breathe without thinking is not entirely true. Have you noticed how outside the city you want to take a deep breath and there is lightness in your body? Having left the carriage of the return train, we involuntarily hold our breath - the body resists inhaling the city smog. Plants are also “not indifferent” to the composition of the surrounding atmosphere, and air mode refers to direct environmental factors.
Basic gases
In the atmosphere, the percentage of such main gases as nitrogen (N 2 - 78.1%), oxygen (O 2 - 21%), carbon dioxide (CO 2 - 0.03%), argon (Ag 2 - 0.9% ), is relatively constant, and their importance for plant life is unequal. Nitrogen gas is inert and in this form is not vital for either animals or plants.
Necessary oxygen
In the Earth's atmosphere, oxygen is of biogenic origin and was formed due to the activity of ancient autotrophic organisms. Like us, plants need it for respiration, but there is no shortage of it in the atmosphere, but a lack of it in the soil can be a limiting factor in the spread of flora. Air exchange between the atmosphere and the soil occurs through pores formed by soil organisms, as well as the roots of trees and shrubs.
In waterlogged soil, there is always less oxygen than plants need. Poor aeration of the upper soil layer may be a consequence of excess precipitation coupled with poor evaporation, high level ground and soil water. The complex of conditions listed is typical for tundras, swamps and boreal coniferous forests. These communities are inhabited by psychrophytes, oxylophytes and hygrophytes, adapted to the lack of O 2, which is observed in structureless clay soils, water-saturated forest floor and peat.
Poor aeration is observed in grass cover with dense turf or with a layer of green moss, which is why in gardening it is customary to periodically scarify the lawn, creating air passages in the turf. Ice crust in winter also promotes aerobic conditions, but plants tolerate them better when they are dormant.
The roots are the first to suffer from a lack of oxygen in the soil, and the higher the ambient temperature, the greater the need for oxygen. So tropical forest plants more often encounter the problem of poor soil aeration, the solution to which can be considered by changing the morphology of the roots: board-shaped outgrowths on their upper part, stilted and aerial adventitious roots. Respiratory roots (pneumatophores) in swamp cypresses ( Taxodium distichum) is a classic example of adaptation to marshy habitats. The process of seed germination is no less dependent on oxygen; due to its lack, germination is sometimes delayed for decades, and then occurs under a fortunate combination of circumstances.
The aquatic environment can experience both a lack of oxygen and an excess of it. In the current clear water aquatic plants They feel very comfortable and, as a result of photosynthesis, enrich the water with oxygen so much that it is even released into the air. That’s why we feel so soothingly well on a fine day by the river. There is not enough oxygen in standing water, so hydrophytes have morphological adaptations in the form of air cavities in stems, leaves and roots (cattail, reeds, reeds), as well as branched and thin-walled shoots (elodea, pondweed), reminiscent of algae thalli.
The recorded threefold increase in methane content in the atmosphere is associated with future climate warming and is considered one of the reasons.
Even temporary flooding can cause damage 
Pnematophores of swamp cypress 
Air saturated with water pores stimulates the growth of epiphthous mosses
Carbon dioxide for photosynthesis
The most important process of plant life, photosynthesis, directly depends on the content of carbon dioxide in the air surrounding the plants, which is released during the respiration of soil organisms. Volcanic eruptions and the decomposition of carbonate rocks contribute to the replenishment of the atmosphere with this gas. Plants also release carbon dioxide when they respire.
The carbon dioxide cycle in the atmosphere natural communities begins with photosynthesis, during which CO 2 is bound to form carbohydrates and O 2 is released. Part of the carbohydrates (up to 30%) is consumed by the plants themselves for respiration, the rest goes to feed heterotrophic organisms, which also respire, and after the end of their lives decompose with the release of CO 2. In different plant communities The dynamics of carbon dioxide concentration is different. It accumulates most in the lower tier of forests, which to some extent compensates green plants lack of light there. The carbon dioxide content increases in the dark, when photosynthesis does not occur and the respiration of organisms continues. In dense forests, the difference in CO 2 content at the base of the trunks and inside the crowns at night can reach 25%, but due to air convection inside the tree stand, the gradient gradually levels out. The seasonal rhythm of community development also affects the CO 2 content, and this is directly related to the frequency and intensity of photosynthesis. In particular, in the spring northern latitudes The consumption of carbon dioxide by vegetation exceeds its release by the soil.
Anaerobic processes occur without oxygen, and in aerobic processes oxygen participates as an oxidizing agent..
Typical habitats of the hygrophytic Lysichiton americana 
Plants at high altitudes use high levels of carbon dioxide to
intensive photosynthesis 
Waterlogged soils near hot springs are low in oxygen
And all the rest…
In addition to the above gases, the air may contain sulfur dioxide (SO 2), carbon monoxide (CO), methane (NH 3), nitrogen oxide (NO 2), as well as dust and soot particles, water vapor and even aromatic and phytoncidal secretions of plants. Their content is highly diverse and variable, depending on the climate, habitat characteristics, season and time of day.
Water vapor is important for transpiration and respiration of plants; a lack of moisture in the air surrounding them can cause the stomata to close and prevent the absorption of oxygen and carbon dioxide, and therefore inhibit the process of photosynthesis. Hygrophytes, which are especially sensitive to this factor, wither when the air is slightly dry, as do alpine and tundra plants, which are difficult to cultivate on plains blown by drying winds.
Humid air scatters light more strongly, which also makes adjustments to the process of photosynthesis, especially in multi-tiered forest communities. Excessive aeration, on the contrary, leads to excessive drying of the upper soil horizon, which is often observed on structureless silty soils.
Vapors of sulfur dioxide and hydrogen sulfide (H 2 S) are present near natural sources and in areas of seismic activity on the Earth. In swampy habitats, during anaerobic decomposition of organic residues by bacteria, methane, which is a greenhouse gas, is released. Interest in it has recently experienced a real boom. The recorded threefold increase in its content in the atmosphere is associated with future climate warming and is considered one of the reasons.
The influence of ethereal secretions from plants is a little studied topic, although their influence on microorganisms, insects, pathogenic fungi and effects on psycho-emotional state humans and animals. Phytoncides kill pathogens and have a beneficial effect on human health. There is an opinion about the mutual influence of plants through volatile compounds, and the observed patterns are used, in particular, in organic gardening and vegetable gardening.
Since air pollution is a relatively new environmental factor, plants do not have special adaptations to it.
Damage to ash maple leaves 
Herbaceous plants react less to pollution 
Lichens are indicators of clean air
Industrial gases and smoke
Along with natural mechanisms of absorption and excretion biologically necessary substances In the era of industrialization, plants react to increased concentrations of industrial gases in the air: sulfur dioxide (SO 2), nitrogen oxide (NO 2), fluorine and hydrogen fluoride (F, HF), chlorides. In areas of industrial emissions, the climate and weather conditions are deformed, the level of lighting and air humidity decreases. Plants develop leaf burns and physiological and biochemical processes are disrupted. As a result, they are stunted, individual developmental disorders (deformities) occur, and the productivity of communities decreases. Externally, this is expressed in a decrease in the size of plants and their individual organs, the appearance of chlorosis and necrotic spots on the leaves, and drying out of the tops of the crowns.
Last summer left no one indifferent and fueled interest in the impact of fires on one’s own health and on the state of nature. During massive fires, the content of carbon dioxide and carbon monoxide, nitrogen oxides, methane, water vapor, ozone. During the smoke process, phenols, suspended solid particles of soot and burning appear.
Since the air pollution factor is quite young in comparison with other environmental factors, plants do not have special adaptations to it. They develop resistance to air pollution based on long-term existing devices to extreme values of other factors. In particular, the greatest endurance in the city and near industrial enterprises xeromorphic species are drought- and heat-resistant.
Due to pollution air environment In cities and industrial areas, two properties of plants are noted: gas sensitivity and gas resistance, which may be the same or different for a particular biological species. The first characterizes the speed and degree of manifestation of pathological reactions, and the second characterizes the ability to maintain viability without reducing growth and reproduction. Classic example At the same time, a sensitive and resistant species is larch, which has delicate needles, poorly protected by a cuticle and exposed to toxic gases, which have the natural property of falling off annually without accumulating the resulting damage. Of the conifers, larches withstand urban conditions best of all, among hardwood– poplars, ash-leaved maple. Herbaceous plants are damaged less than tree species. The increased sensitivity of lichens to pollution allows them to be used as indicators of air purity.
Psychrophytes are plants of moist and cold soils.
Oxylophytes are plants of sphagnum bogs.
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