The role of green spaces in cleaning the air of cities is great. Plants take in carbon dioxide and release oxygen. A medium-sized tree in 24 hours restores as much oxygen as is necessary for the breathing of three people. In one warm sunny day, a hectare of forest absorbs 220-280 kg of carbon dioxide from the air and releases 180-220 kg of oxygen. 1 hectare of urban green spaces is released per day up to 200 kg of oxygen.

The results of studying the dust- and gas-holding role of tree and shrub plantings indicate that the dust content of the air among green spaces is 2-3 times lower than in open areas. Species of trees and shrubs with rough, hairy leaves (elm, linden, maple, lilac) have the highest dust-holding capacity.

The gas-protective role of green spaces is due to the ability of plants to capture gases contained in the atmospheric air and resistance to them. Poplar, Canadian maple, honeysuckle can be attributed to the most gas-resistant.

The influence of tree and shrub species on the reduction of harmful gas concentrations in the air occurs mainly through the dispersion of these gases into the upper atmosphere by tree crowns, and to some extent through the absorption of gases by leaves through stomata and leaf cell membranes. It is known, for example, that green spaces capture sulfur dioxide from the atmospheric air and accumulate it in the form of sulfates in their tissues.

Of great importance in improving the air of populated areas is the ability of plants to absorb carbon dioxide and release oxygen. On average, 1 hectare of green spaces absorbs 8 liters of carbon dioxide per hour. The intensity of this process depends on the characteristics of photosynthesis of various species of trees and shrubs.

A medium-sized tree in 24 hours restores as much oxygen as is necessary for the breathing of three people. In one warm sunny day, a hectare of forest absorbs 220-280 kg of carbon dioxide from the air and releases 180-200 kg of oxygen. Poplar has the highest oxygen productivity.

For 1 ton of birch wood growth, oxygen is supplied: in the composition of CO2 1335 kg, in the composition of H2O 488 kg, in total 1823 kg. But the wood itself contains 430 kg of oxygen, and the remaining 1393 kg are released into the atmosphere.

It has been established that 1 ha of a 20-year-old pine plantation, giving an average annual growth of wood of 5 m3 per 1 ha, absorbs 9.35 tons of CO2 every year and releases 7.25 tons of O2. The most obvious in this respect are middle-aged plantations. So, 1 hectare of a 60-year-old pine forest gives an annual increase of an average of 7.51 m3 per 1 ha, absorbing 14.44 tons of CO2 during this time and releasing 10.92 g of O2. Photosynthesis proceeds even more actively in 40-year-old oak plantations, where the absorption of CO2 per year per 1 ha is 18 g, and the release is 13.98 tons.

One hectare of urban plantations absorbs 8 kg of carbon dioxide in 1 hour, which is exhaled during the same time by 200 people. In the conditions of the city, green spaces are a factory of clean air, unsurpassed cleaners and orderlies of the atmosphere. Green spaces absorb not only carbon dioxide from the air, but also purify the atmosphere of carbon monoxide, reduce its concentration to natural - about 0.00001%.

Some plants can absorb the most harmful gases. It has been established that forest communities daily process up to 500 thousand cubic meters of air per 1 ha of forest with an assimilation apparatus. The total air purification capacity of full-fledged forest stands, which form 4 tons of leaves per 1 ha, is about 10 tons of toxic gases during the growing season. Only one tree during the growing season is able to absorb up to 12 kg of sulfur dioxide.

Students of the Kazakh University, together with scientists from the Botanical Garden of the Republican Academy of Sciences, studied the process of adaptation in the city of more than three hundred plant species. Studies have shown that the development of green spaces slows down in an industrial city, but some individuals are rapidly growing. These are juniper, barberry, hawthorn. The rose also belongs to the nursery plants.

The effect of woody vegetation on the content of harmful chemical compounds in the urban air is also manifested in the ability of trees to oxidize the vapors of gasoline, kerosene, diesel fuel, acetone, etc. in the urban air. Many plants can absorb aromatic hydrocarbons, carbonyl compounds, esters and essential oils from the atmosphere. There is information about the absorption of phenols by plants. A large phenol-accumulating ability is possessed by: common lilac, privet, white mulberry. In addition, green spaces are capable of capturing radioactive substances contained in the air.

Table 1

The best green filters for biological purification of atmospheric air in cities

Studies have shown that poplar is the best "orderly" in the zone of strong permanent gas contamination. For comparison, over 5 summer months, a 25-year-old oak absorbs 28 kg of carbon dioxide, linden - 16, pine -10, spruce - 6, and an adult poplar - as much as 44 kg. Small-leaved linden, ash, lilac and honeysuckle also have good absorption qualities. In the zone of weak periodic gas pollution, more sulfur is absorbed by the leaves of poplar, ash, lilac, honeysuckle, linden, less - elm, bird cherry, maple.

During the growing season, growing black poplar deposits 44 kilograms of dust, white poplar - 53 kilograms; white willow and ash-leaved maple, respectively, 34, 30 kilograms. One hectare of spruce forest precipitates 32 tons of dust per year, oak - 54, beech - 68 tons. This function is best performed by trees and shrubs with pubescent, viscous, sticky, rough leaves. Elm, for example, retains 6 times more dust than poplar.

The influence of green spaces on the dustiness of the air and the decrease in the concentration of gases depends on the nature of the plantings: their density, configuration, structure.

According to the World Health Organization, mortality and disease duration are inversely proportional to the area of ​​green spaces in the city. Green spaces- "lungs" of cities, they contribute to the improvement of the microclimate, reduce the noise level, clean the polluted air from microbes and dust in a wonderful way.

Hectare forests within an hour it absorbs about 8 kg of carbon dioxide, the amount exhaled by 200 people. The air-protective effect of green spaces depends on their age, composition, condition, nature of planting (array, row), location in relation to the source of pollution. In particular, effective protection of the air environment of residential areas from pollution by vehicles is provided by a multi-row tree-shrub strip of gas-resistant species.

Scientists have conducted studies showing impact of forests on pollution air- up to 30-40% less such pollution under trees. It is estimated that a hectare forests during the year it absorbs at least a ton of harmful gases and purifies up to 18 million m 3 of air. The forest area is able to catch up to 22% of suspended harmful substances contained in the air.

Near roads, the uptake of lead by plants with hairy leaves is about ten times faster than with smooth leaves, and the rate of lead deposition on grass is 4 times greater than on bare soil. It is estimated that one hectare of pine forest can bind up to 30 kg of sulfur dioxide per hectare, deciduous forest - up to 72 kg, spruce forest - up to 150 kg.

The forest purifies the air from harmful substances, from dust, aerosols. It turns out that one hectare of coniferous forests can deposit up to 30-35 tons of dust per year, deciduous forest - up to 70 tons.

In an industrial city, 1 cm 3 of air contains from 10 to 100 thousand of the smallest dust particles, in the forest, mountains, field - about 5 thousand. Bacteria in forest air are hundreds of times less than in urban air. In birch plantations in the cube of air, there are up to 450 pieces of different bacteria, and this is below the norm for operating rooms, where 500 non-pathogenic microorganisms are allowed. There are even fewer microorganisms in the pine, spruce, juniper forest.

The oxygen-producing effect of one tree growing in favorable conditions is equivalent to the effect of ten room air conditioners, and the amount of oxygen produced is equal to the amount needed to breathe 3 people.

The component of atmospheric air is ozone. It prevents the passage to the surface of the earth of short-wave radiation that is detrimental to living organisms. The highest ozone density is at an altitude of 20-25 km. It enters the surface layers of the atmosphere as a result of the movement of air masses, its average density at the earth's surface, depending on the time of day, season, is from 10 to 40 μg / m 3. Regarding content ozone conflicting opinions were expressed in the forest air, studies of recent years have confirmed its presence, in particular, in the air of a coniferous forest. Ozone concentration in the forest varies depending on the biological activity of plants, the density and age of the forest stand, the weather, the season. In a young pine forest, it is 2 times higher than in an old one; in winter, the amount of ozone in the forest is minimal, perhaps not at all, in spring - more than anything. The higher the air temperature, the more intensively the plants emit volatile substances, the more actively terpenes are oxidized and the ozone. Concentration ozone in the forest it rises during lightning discharges, however, this increase is short-term. On the human body ozone at very low concentrations (less than 0.1 mg / m3) it has a beneficial effect - metabolism improves, breathing becomes deeper and more even, and working capacity increases.

atmospheric air contains positive and negative ions, both of which are divided into heavy and light, it is useful for a person to enrich the air with light negative ions. When such air is inhaled, the oxygen content in the blood increases, the level of sugar and phosphorus decreases very much, headaches and fatigue are relieved, well-being and mood improve.

forest air differs from any other by increased ionization (it has been calculated that a cubic centimeter of forest air contains up to 3 thousand light ions). Ionizing factors are resinous, aromatic substances released by plants during the growing season. All of them create a certain biochemical environment and determine a certain composition of the surface air layer.

All plant organisms(from bacteria to flowering plants) emit gaseous, liquid, solid, volatile, non-volatile, intravital, post-mortem secretions from damaged and intact organs into the environment. These secretions are an important ecological and phytocenotic factor. Those that have a detrimental effect on various pathogens are called phytoncides. Oak, juniper, pine, spruce, bird cherry, moss, and walnut emit especially many phytoncides. On a hot summer day, one hectare of an oak forest (oak forest) releases up to 15 kg of phytoncides, a pine forest - twice as much. The amount of phytoncides emitted by a juniper forest of the same area is sufficient to destroy all microorganisms in the air of a large city.

Except pine, spruce, oak, juniper and other species , high phytoncidity characteristic of birch, maple, aspen, raspberry, hazel (hazelnut), blueberry. Ash, alder, mountain ash, lilac, honeysuckle, caragana have an average phytoncidal activity.

caragana plant

Elm, red elderberry, euonymus, buckthorn have the least phytoncidal activity. It depends on many factors - on the breed of plants, their age, weather, time of day. The air in a young forest is more saturated with volatile substances, compared to an old forest. Such volatile substances are released more on hot days in late spring and early summer, the maximum occurs in the second half of the day, the minimum is at night.

Phytoncides stimulate vital processes, improve metabolism. When inhaling air saturated with pine phytoncides, blood pressure rises in patients, and with oak phytoncides it decreases. Phytoncides of spruce, balsamic poplar, larch inhibit the growth of Escherichia coli. Phytoncides leaves of laurel cherry, bird cherry, black root, grassy elder are toxic to rats. Volatile phytoncides of bird cherry kill a rat in an average of 1.5 hours. Rats leave those places where dried black root or elder grass lie. Small rodents can't stand the smell kanufera (balsamic tansy).

Under the influence of volatile substances, not only air ozonation and an increase in the number of light ions in it occur, but the radioactive background also changes.

Positive effect on the human body forest microclimate- calm, cool air and soil, moderate solar radiation. When approaching the forest, the wind speed decreases by 20-50%, in the forest itself - by 80-90%. Under the crowns of trees, depending on the composition, age, density of the forest stand, as well as the weather, time of day, - season, air humidity is 10-20% higher than in open space, the amplitude of humidity fluctuations is less, the minimum humidity is observed at night, on the surface soil, it is higher than in the crowns of trees, in a pine forest it is lower than in a deciduous one. Illumination under the forest canopy can be 30-70% less than in open space. The total illumination in the summer in the city is 3-15% less than near the forest, in winter - by 20-30%. There are 2 times less ultraviolet rays here, the wind force is reduced by 20-30%. But there is 10% more precipitation, twice as much foggy days, 10 times more dust, 25 times more carbon monoxide, 10 times more carbon dioxide, and 5 times more sulfur dioxide. The dust plume of a large city can cause a decrease in solar radiation within a radius of 40 km.

Forest normalizes temperature fluctuations in different seasons, and also levels out daily temperature fluctuations.

The average annual temperature in the forest is 1-3°C higher than in the treeless area. In winter, it is much warmer in the forest than in an open place, for example, in a field, meadow, in summer it is cooler in the forest during the day, and much warmer at night. During the day it is warmest in the crowns, they are most heated by the sun. In a leafless forest, it is warmer near the soil surface, the forest floor keeps the heat here. The forest is like a universal, biological, natural conditioner without side effects on the human body (with the right behavior in the forest).

Purify the air. Being in a forest or a park, you can feel that the air is completely different, not the same as on dusty city streets. It is much easier to breathe in the shady coolness of the trees. Why is this happening?

Photosynthesis

The leaves of trees are small laboratories in which, under the influence of sunlight and heat, the carbon dioxide contained in the air is converted into organic substances and oxygen.
Organic matter is processed into the material from which the plant is built, i.e. trunk, roots, etc. Oxygen is released from the leaves into the air. In one hour, one hectare of forest absorbs all the carbon dioxide that two hundred people can produce during this time!

Trees clean the air by absorbing pollutants

The leaf surface is able to capture airborne particles and remove them from the air (at least temporarily). Airborne microscopic particles can enter the lungs, which can lead to serious health problems or tissue irritation. So it is very important to reduce their concentration in the air, which trees successfully do. Trees can remove both gaseous pollutants (sulfur dioxide, nitrogen dioxide and carbon monoxide) and particulate matter. Purification mainly occurs with the help of stomata. Stomata are small windows or pores on the leaf through which water evaporates and gas exchanges with the environment. Thus, dust particles, before reaching the ground, settle on the leaves of trees, and under their canopy the air is much cleaner than above the crowns. But not all trees can tolerate dusty and gassy conditions: ash, linden and spruce suffer greatly from them. Dust and gases can lead to blockage of stomata. However, oak, poplar or maple are more resistant to the harmful effects of a polluted atmosphere.

Trees cool the temperature during the hot season

When you walk under the scorching sun, you always want to find a shady tree. And how nice it is to take a walk in a cool forest on a hot day. Being under the crown of trees is more comfortable not only because of the shade. Thanks to transpiration (that is, the process of water evaporation by a plant, which occurs mainly through the leaves), lower wind speed and relative humidity, a certain microclimate is created under the trees by the fallen leaves. Trees suck up a lot of water from the soil, which then evaporates through the leaves. All these factors together affect the air temperature under the trees, where it is usually 2 degrees cooler than in the sun.

But how does lower temperatures affect air quality? Many pollutants begin to be released more actively with increasing temperature. A perfect example of this is a car left in the sun in the summer. Hot seats and door handles create a suffocating atmosphere in the car, so you want to turn on the air conditioner faster. Especially in new cars, where the smell has not yet disappeared, it becomes especially strong. In particularly sensitive people, it can even lead to asthma.

Trees emit volatile organic compounds

Most trees emit volatile organic substances - phytoncides. Sometimes these substances form haze. Phytoncides are able to destroy pathogenic microbes, many pathogenic fungi, have a strong effect on multicellular organisms and even kill insects. The best producer of medicinal volatile organic substances is pine. In pine and cedar forests, the air is practically sterile. Pine phytoncides increase the general tone of a person, have a beneficial effect on the central and sympathetic nervous system. Trees such as cypress, maple, viburnum, magnolia, jasmine, white locust, birch, alder, poplar and willow also have pronounced bactericidal properties.


Trees are vital to keeping the air and the entire ecosystem clean on Earth. Everyone understands this, even small children. However, deforestation is not slowing down. World forests have decreased by 1.5 million square meters. km for 2000-2012 for non-anthropogenic (natural) and anthropogenic reasons. In Russia, the Far East is especially affected by deforestation. The map of deforestation can now be viewed using a service from Google and see the real state of affairs in forestry, which inspires great concern.

The trees cut down in Bishkek until that time will be distributed for firewood to needy families. According to the Zelenstroy enterprise, more than a thousand cubic meters of firewood will be distributed to residents. Well, the places of cut down trees are still empty. Part of the territory is occupied by the road, the other part will be planted with trees, the city authorities assure. The municipality announced a tender for the purchase of 11,000 seedlings.

“Before that, they said that trees would be planted on Toktonaliev Street, the street would return to a green look. We are currently holding a tender for the purchase of three-leaf maple and linden seedlings. In addition to these trees, different types of shrubs will be planted. We have chosen those trees that adapted for city streets, can cope with dust and gas emissions.They have a closed root system, in other words, we will start planting in July, without waiting for spring or autumn.A tender has been announced for the purchase of 11,000 seedlings for a total of 51 million soms.The results will be summed up in the coming days, after which planting," the chief agronomist of the Zelenstroy enterprise informed Elnura Zholdosheva .

On Bishkek's Toktonaliev Street, perennial trees were cut down approximately 10 days ago in connection with a street widening project. These actions aroused the indignation of the townspeople, it came to protests. In response, the city authorities promised that new, young seedlings would be planted instead of those cut down, saying that a corresponding competition was being held. But according to a separate opinion, the crops that are planned to be planted will not bring a good effect for Bishkek.

"Elm, poplar, oak are most suitable for landscaping in Bishkek. They purify the air very well, seedlings are cheap, these trees suit our environmental conditions. The seedlings currently planted by the mayor's office have low environmental and climatic potential. In most cases, they an attractive view, and this is taken into account. But there is less benefit to citizens and nature, "says the city dweller Atai Samybek.

According to other experts, elm and poplar, which were planted before that time, are the most suitable for Bishkek, because they have high bactericidal properties.

"Trees often pose a danger to citizens. For example, some trees are ready to collapse, others grow in the wrong place. Until that time, there have been cases when people died crushed by a tree. In addition, there are many cases when the streets are narrow, which causes traffic jams. As a result, the city authorities decided to cut down the trees for a number of reasons.Of course, quality trees should be planted instead of those cut down.Before that, traditional elm and poplar were planted, but now they are no longer planted because of poplar fluff.But there will be no fluff if you plant male seedlings, not female If more of these trees are planted, then our city will be green. After all, poplar perfectly cleans the air, compared to other trees, it has 60% more bactericidal properties."

During the Soviet Union, Bishkek was rightfully called a green city. But today he radically said goodbye to this status, experts say. The first reason is untimely landscaping work, and secondly, trees are cut down for the construction of large buildings. Another part of the plantations dried up due to lack of watering. Observers say the city government lacks the funds to plant the city's streets to look like the top of Manas Avenue, where poplars grow despite the cold and polluted air.

Everyone knows that trees purify the air. Being in a forest or a park, you can feel that the air is completely different, not the same as on dusty city streets. It is much easier to breathe in the shady coolness of the trees. Why is this happening?

Photosynthesis

The leaves of trees are small laboratories in which, under the influence of sunlight and heat, the carbon dioxide contained in the air is converted into organic substances and oxygen.

Organic matter is processed into the material from which the plant is built, i.e. trunk, roots, etc. Oxygen is released from the leaves into the air. In one hour, one hectare of forest absorbs the entire, which two hundred people can work out during this time!

Trees clean the air by absorbing pollutants

The leaf surface is able to capture airborne particles and remove them from the air (at least temporarily). Airborne microscopic particles can enter the lungs, which can lead to serious health problems or tissue irritation. So it is very important to reduce their concentration in the air, which trees successfully do. Trees can remove both gaseous pollutants (sulfur dioxide, nitrogen dioxide and carbon monoxide) and particulate matter. Purification mainly occurs with the help of stomata. Stomata are small windows or pores on the leaf through which water evaporates and gas exchanges with the environment. Thus, dust particles, before reaching the ground, settle on the leaves of trees, and under their canopy the air is much cleaner than above the crowns. But not all trees can tolerate dusty and gassy conditions: ash, linden and spruce suffer greatly from them. Dust and gases can lead to blockage of stomata. However, oak, poplar or maple are more resistant to the harmful effects of a polluted atmosphere.

Trees cool the temperature during the hot season

When you walk under the scorching sun, you always want to find a shady tree. And how nice it is to take a walk in a cool forest on a hot day. Being under the crown of trees is more comfortable not only because of the shade. Thanks to transpiration (that is, the process of evaporation of water by a plant, which occurs mainly through the leaves), lower wind speed and relative humidity, and fallen leaves under the trees, a certain microclimate is created. Trees suck up a lot of water from the soil, which then evaporates through the leaves. All these factors together affect the air temperature under the trees, where it is usually 2 degrees cooler than in the sun.

But how does lower temperatures affect air quality? Many pollutants begin to be released more actively with increasing temperature. A perfect example of this is a car left in the sun in the summer. Hot seats and door handles create a suffocating atmosphere in the car, so you want to turn on the air conditioner faster. Especially in new cars, where the smell has not yet disappeared, it becomes especially strong. In particularly sensitive people, it can even lead to asthma.

Trees emit volatile organic compounds

Most trees emit volatile organic substances - phytoncides. Sometimes these substances form haze. Phytoncides are able to destroy pathogenic microbes, many pathogenic fungi, have a strong effect on multicellular organisms and even kill insects. The best producer of therapeutic volatile organic substances is the pine forest. In pine and cedar forests, the air is practically sterile. Pine phytoncides increase the general tone of a person, have a beneficial effect on the central and sympathetic nervous system. Trees such as cypress, maple, viburnum, magnolia, jasmine, white locust, birch, alder, poplar and willow also have pronounced bactericidal properties.

Trees are vital to keeping the air and the entire ecosystem clean on Earth. Everyone understands this, even small children. However, deforestation is not slowing down. World forests have decreased by 1.5 million square meters. km for 2000-2012 for non-anthropogenic (natural) and anthropogenic reasons. In Russia, the Far East is especially affected by deforestation. The map of deforestation can now be viewed using a service from Google and see the real state of affairs in forestry, which inspires great concern.