AIR POLLUTION
any undesirable change in the composition of the earth's atmosphere as a result of the entry into it of various gases, water vapor and solid particles (under the influence of natural processes or as a result of human activity). Approximately 10% of pollutants enter the atmosphere due to natural processes, such as volcanic eruptions, which are accompanied by emissions of ash, pulverized acids, including sulfuric, and many poisonous gases into the atmosphere. In addition, the main sources of sulfur in the atmosphere are sea water splashes and decaying plant residues. It should also be noted forest fires, as a result of which dense clouds of smoke are formed, enveloping large areas, and dust storms. Trees and shrubs emit a lot of volatile organic compounds (VOCs), which form a blue haze that covers most of the Blue Ridge Mountains in the United States (translated as "blue ridge"). Microorganisms present in the air (pollen, molds, bacteria, viruses) cause allergy attacks and infectious diseases in many people. The remaining 90% of pollutants are of anthropogenic origin. Their main sources are: the combustion of fossil fuels in power plants (smoke emissions) and in car engines; industrial processes that do not involve fuel combustion but lead to atmospheric dusting, for example, due to soil erosion, open-pit coal mining, blasting and leakage of VOCs through valves, pipe joints in refineries and chemical plants and from reactors; solid waste storage; as well as a variety of mixed sources. Pollutants entering the atmosphere are transported over long distances from the source, and then return to the earth's surface in the form of solid particles, droplets or chemical compounds dissolved in precipitation. Chemical compounds, the source of which is at ground level, quickly mix with the air of the lower atmosphere (troposphere). They are called primary pollutants. Some of them react chemically with other pollutants or with the main constituents of the air (oxygen, nitrogen and water vapor) to form secondary pollutants. As a result, phenomena such as photochemical smog, acid rain and the formation of ozone in the surface layer of the atmosphere are observed. The source of energy for these reactions is solar radiation. Secondary pollutants - photochemical oxidants and acids contained in the atmosphere - pose a major threat to human health and global environmental change.
HAZARDOUS IMPACT
Air pollution has a harmful effect on living organisms in several ways: 1) by delivering aerosol particles and toxic gases into the respiratory system of humans and animals and into plant leaves; 2) increasing the acidity of precipitation, which, in turn, affects the change in the chemical composition of soils and water; 3) by stimulating such chemical reactions in the atmosphere that lead to an increase in the duration of exposure of living organisms to harmful solar rays; 4) changing the composition and temperature of the atmosphere on a global scale and thus creating conditions unfavorable for the survival of organisms.
The human respiratory system. Through the respiratory system, oxygen enters the human body, which is carried by hemoglobin (red pigments of erythrocytes) to vital organs, and waste products, in particular carbon dioxide, are excreted. The respiratory system consists of the nasal cavity, larynx, trachea, bronchi and lungs. In each healthy lung, there are approximately 5 million alveoli (air sacs), in which gas exchange occurs. Oxygen enters the blood from the alveoli, and carbon dioxide is removed from the blood through them and released into the air. The respiratory system has a number of defense mechanisms against exposure to airborne pollutants. Nose hairs filter out large particles. The mucous membrane of the nasal cavity, larynx and trachea traps and dissolves small particles and some harmful gases. If pollutants enter the respiratory system, the person sneezes and coughs. In this way, polluted air and mucus are evacuated. In addition, the upper respiratory tract is lined with hundreds of thin cilia of ciliated epithelium, which are in constant motion and move mucus up the larynx along with dirt that has entered the respiratory system, which are either swallowed or removed. Constant long-term exposure to by-products of tobacco smoke and polluted air leads to overload and overflow of human defense systems, resulting in the development of diseases of the respiratory system: allergic asthma, lung cancer and emphysema, chronic bronchitis. See also RESPIRATORY ORGANS.
Acid precipitation. The ingress of various acids into the soil or water bodies, such as sulfuric (H2SO4) or nitric (HNO3), as a result of acid precipitation (abnormally acidic rain and snow) causes harm to living organisms and contributes to the destruction of various structures. Such phenomena are quite often observed in areas with a significant concentration of industrial enterprises using fossil fuels. The damage caused to biota by acid precipitation is most pronounced in forests and lakes. Certain types of trees, particularly pines, are particularly sensitive to changes in soil acidity. Large areas of forests in New England, Canada and the Scandinavian countries have been severely affected by acid rain. In some cases, plants serve as indicators of such effects: the leaves become stained or discolored. Acid overload associated with spring runoff to meltwater lakes and rivers can be detrimental to fish and other aquatic life. see also
ACID REDUCTION ;
ENVIRONMENTAL DEGRADATION.
COMPOSITION AND STRUCTURE OF THE ATMOSPHERE
The atmosphere, or "ocean of air", is made up of the gases necessary to sustain life on Earth. According to its height, it can be divided into five layers, or shells, surrounding the globe: the troposphere, stratosphere, mesosphere, thermosphere and exosphere. Their boundaries are determined by sharp changes in temperature due to differences in the absorption of solar radiation. Air density also changes with height. In the upper layers of the atmosphere, the air is cold and rarefied, and near the surface of the Earth, due to gravity, it is denser. The two lower layers of the atmosphere are mainly polluted. See also ATMOSPHERE.
Troposphere. The composition and structure of the lower layer - the troposphere - is determined by the flow of gases from the earth's crust and the presence of life on the earth's surface. The upper limit of the troposphere is located at altitudes of approximately 17 km above sea level at the equator and approx. 8 km at the poles. This thin layer contains two important gaseous components, nitrogen (N2) and oxygen (O2), which make up 78% and 21% of the volume of the atmosphere, respectively. The nitrogen cycle in nature (nitrogen cycle) plays a very important role in plant nutrition. Atmospheric nitrogen is bound by nodule bacteria contained in the root thickenings of leguminous plants, with the formation of numerous organic compounds, especially proteins. After that, other specialized bacteria in the process of mineralization decompose and convert nitrogen-rich organic residues into simpler inorganic substances, such as ammonia (NH4). Finally, nitrifying bacteria convert them back into nitrogen oxide (NO) and nitrogen dioxide (NO2), which are returned to the atmosphere. Then the cycle resumes.
See also NITROGEN. Oxygen is produced during plant photosynthesis and, in turn, is used by micro- and macro-organisms during respiration, the by-product of which is carbon dioxide.
see also
CARBON CYCLE;
PHOTOSYNTHESIS. In addition to nitrogen and oxygen, the atmosphere includes argon (Ar - 0.93%) and carbon dioxide (CO2 - 0.036%), as well as negligible amounts of neon (Ne), helium (He), methane (CH4), krypton (Kr ), hydrogen (H2), xenon (Xe) and anthropogenic chlorofluorocarbons (CFCs). The source and necessary component of life on Earth, contributing, in particular, to maintaining its surface temperature, is water vapor (H2O), which enters the troposphere mainly as a result of water evaporation from the ocean surface. Its content in the atmosphere varies significantly depending on the time of year and geographical location. For living organisms, consisting mainly of organic compounds of carbon with hydrogen and oxygen, oxygen, water and carbon dioxide play a primary role. Water and carbon dioxide are essential for heating the earth's surface due to their ability to absorb solar radiation.
Stratosphere. Directly above the troposphere at altitudes from 18 to 48 km above the earth's surface is the stratosphere. Although these shells are very similar in composition, the water vapor content in the stratosphere is approximately 1000 times less, and the ozone content is approximately 1000 times greater than in the troposphere. Ozone is formed in the stratosphere by the interaction of oxygen molecules during lightning discharges and ultraviolet irradiation by the Sun. The composition of air pollutants changed significantly after the Second World War. In the 1950s, coal was replaced by diesel fuel, and soon by natural gas. By 2000, most homes were heated by natural gas, the cleanest of all fossil fuels. On the other hand, the exhaust gases generated during the operation of internal combustion engines began to pollute the atmosphere more and more.
MAIN POLLUTANTS
Sulfur dioxide, or sulfur dioxide (sulphurous gas). Sulfur enters the atmosphere as a result of many natural processes, including the evaporation of seawater spray, the dispersal of sulfur-containing soils in arid regions, the emission of gases from volcanic eruptions, and the release of biogenic hydrogen sulfide (H2S).
See also SULFUR. The most widespread sulfur compound is sulfur dioxide (SO2) - a colorless gas formed during the combustion of sulfur-containing fuels (primarily coal and heavy oil fractions), as well as in various industrial processes, such as the smelting of sulfide ores. Sulfur dioxide is particularly harmful to trees, causing chlorosis (yellowing or discoloration of leaves) and dwarfism. In humans, this gas irritates the upper respiratory tract, as it easily dissolves in the mucus of the larynx and trachea. Chronic exposure to sulfur dioxide can cause a respiratory illness similar to bronchitis. By itself, this gas does not cause significant damage to public health, but in the atmosphere it reacts with water vapor to form a secondary pollutant - sulfuric acid (H2SO4). Drops of acid are transported over considerable distances and, getting into the lungs, severely destroy them. The most dangerous form of air pollution is observed in the reaction of sulfur dioxide with suspended particles, accompanied by the formation of sulfuric acid salts, which penetrate into the lungs during breathing and settle there.
carbon monoxide , or carbon monoxide, is a highly poisonous, colorless, odorless, and tasteless gas. It is formed during the incomplete combustion of wood, fossil fuels and tobacco, during the combustion of solid waste and the partial anaerobic decomposition of organic matter. Approximately 50% of carbon monoxide is produced in connection with human activities, mainly as a result of the internal combustion engines of cars. In a closed room (for example, in a garage) filled with carbon monoxide, the ability of erythrocyte hemoglobin to carry oxygen decreases, which slows down reactions in a person, weakens perception, headaches, drowsiness, and nausea appear. Exposure to large amounts of carbon monoxide can cause fainting, coma, and even death. See also CARBON. Suspended particles, including dust, soot, pollen and plant spores, etc., vary greatly in size and composition. They can either be directly contained in the air, or be enclosed in droplets suspended in the air (so-called aerosols). In general, approx. 100 million tons of anthropogenic aerosols. This is about 100 times less than the amount of naturally occurring aerosols - volcanic ash, wind-blown dust and sea water spray. Approximately 50% of anthropogenic particles are released into the air due to incomplete combustion of fuel in transport, factories, factories and thermal power plants. According to the World Health Organization, 70% of the population living in cities in developing countries breathe heavily polluted air containing many aerosols. Often, aerosols are the most obvious form of air pollution, as they reduce visibility and leave dirty marks on painted surfaces, fabrics, vegetation, and other objects. Larger particles are mainly trapped in the hairs and mucous membranes of the nose and larynx and then carried out. It is assumed that particles smaller than 10 microns are the most dangerous for human health; they are so small that they penetrate the protective barriers of the body into the lungs, damaging the tissues of the respiratory organs and contributing to the development of chronic respiratory diseases and cancer. Tobacco smoke and asbestos fibers contained in urban air and indoors are also considered the most carcinogenic and therefore very dangerous to health. Other types of aerosol pollution complicate the course of bronchitis and asthma and cause allergic reactions. The accumulation of a certain amount of small particles in the body makes breathing difficult due to blockage of capillaries and constant irritation of the respiratory system. Volatile organic compounds (VOCs) are poisonous vapors in the atmosphere. They are the source of many problems, including mutations, respiratory disorders and cancers, and, in addition, play a major role in the formation of photochemical oxidants.
The largest natural source of VOCs are
plants that produce approximately 350 million tons of isoprene (C5H8) and 450 million tons of terpenes (C10H16) annually. Another VOC is methane gas (CH4), which forms in highly humid areas (such as swamps or rice plantations) and is also produced by bacteria in the stomachs of termites and ruminants. In the atmosphere, VOCs are usually oxidized to carbon monoxide (CO) and carbon dioxide (CO2) oxides. In addition, anthropogenic sources emit many poisonous synthetic organic substances into the atmosphere, such as benzene, chloroform, formaldehyde, phenols, toluene, trichloroethane and vinyl chloride. The main part of these compounds enters the air during the incomplete combustion of hydrocarbons in automotive fuel, at thermal power plants, chemical and oil refineries.
nitrogen dioxide. Oxide (NO) and dioxide (NO2) of nitrogen are formed during the combustion of fuel at very high temperatures (above 650 ° C) and an excess of oxygen. In addition, these substances are released during the oxidation of nitrogen-containing compounds in water or soil by bacteria. Later, in the atmosphere, nitric oxide is oxidized to gaseous red-brown dioxide, which is clearly visible in the atmosphere of most large cities. The main sources of nitrogen dioxide in cities are car exhaust and emissions from thermal power plants (not only using fossil fuels). In addition, nitrogen dioxide is formed during the combustion of solid waste, since this process occurs at high combustion temperatures. NO2 also plays an important role in the formation of photochemical smog in the surface layer of the atmosphere. In significant concentrations, nitrogen dioxide has a sharp sweetish odor. Unlike sulfur dioxide, it irritates the lower respiratory system, especially lung tissue, thereby worsening the condition of people suffering from asthma, chronic bronchitis and emphysema. Nitrogen dioxide increases the susceptibility to acute respiratory diseases such as pneumonia. Photochemical oxidants ozone (O3), peroxoacetyl nitrate (PAN) and formaldehyde are products of secondary atmospheric pollution as a result of chemical reactions under the influence of solar radiation. Ozone is formed when either an oxygen molecule (O2) or nitrogen dioxide (NO2) breaks down to form atomic oxygen (O), which then attaches itself to another oxygen molecule. This process involves hydrocarbons that bind the nitric oxide molecule with other substances. Thus, for example, PAN is formed. Although ozone plays an important role in the stratosphere as a protective shield that absorbs short-wave ultraviolet radiation (see below), in the troposphere, as a strong oxidizing agent, it destroys plants, building materials, rubber and plastics. Ozone has a characteristic odor that is a sign of photochemical smog. Inhalation by humans causes coughing, chest pain, rapid breathing, and irritation of the eyes, nasal cavity, and larynx. Exposure to ozone also worsens the condition of patients with chronic asthma, bronchitis, pulmonary emphysema, and those suffering from cardiovascular diseases.
GLOBAL AIR POLLUTION PROBLEMS
Two global environmental problems associated with air pollution pose a serious threat to the health and prosperity of mankind and other forms of life: abnormally high values ​​of ultraviolet radiation from the Sun coming to the earth's surface, due to a decrease in the ozone content in the stratosphere, and climate change (global warming) caused by into the atmosphere of a large number of so-called. greenhouse gases. Both problems are closely interrelated, since they depend on the entry into the atmosphere of almost the same gases of anthropogenic origin. For example, fluorochlorine-containing freons (chlorofluorocarbons) contribute to the destruction of the ozone layer and play an important role in the occurrence of the greenhouse effect. See also METEOROLOGY AND CLIMATOLOGY. Depletion of the ozone layer. Stratospheric ozone is concentrated mainly at altitudes from 20 to 25 km. Absorbing 99% of the short-wave radiation of the Sun, which is dangerous for all living things, ozone protects the earth's surface and the troposphere from it, protecting people from sunburn, skin and eye cancer, cataracts, and so on. In addition, it does not allow most of the tropospheric oxygen to turn into ozone. Along with the formation of ozone in the atmosphere, the reverse process of its decay takes place, which also occurs during the absorption of solar ultraviolet radiation. Hydrogen oxides (HOx), methane (CH4), gaseous hydrogen (H2), and nitrogen oxides (NOx) in the atmosphere can also deplete stratospheric ozone. If there is no anthropogenic impact, there is a certain balance between the formation and decay of ozone molecules. The global chemical time bomb is artificial chlorofluorocarbons, which help reduce the average concentration of ozone in the troposphere. Chlorofluorocarbons, first synthesized in 1928 and known as freons, or freons, became a marvel of chemistry in the 1940s. Chemically inert, non-toxic, odorless, non-flammable, non-corrosive to metals and alloys, and inexpensive to manufacture, they quickly gained popularity and were widely used as refrigerants. Sources of chlorofluorocarbons in the atmosphere are aerosol cans, damaged refrigerators, and air conditioners. It is obvious that freon molecules are too inert and do not decay in the troposphere, but slowly rise up and after 10-20 years enter the stratosphere. There, ultraviolet radiation from the sun destroys the molecules of these substances (the so-called photolytic decomposition process), as a result of which the chlorine atom is released. It reacts with ozone to form atomic oxygen (O) and an oxygen molecule (O2). Chlorine oxide (Cl2O) is unstable and reacts with a free oxygen atom to form an oxygen molecule and a free chlorine atom. Therefore, a single chlorine atom, once formed from the decay of a chlorofluorocarbon, can destroy thousands of ozone molecules. Due to seasonal decreases in ozone concentration (the so-called ozone holes), which were observed, in particular, over Antarctica and, to a lesser extent, over other regions, short-wave ultraviolet radiation of the Sun, dangerous for a living cell, can penetrate to the earth's surface. According to forecasts, increased doses of ultraviolet radiation will lead to an increase in the number of victims of sunburn, as well as an increase in the incidence of skin cancer (this trend is already observed in Australia, New Zealand, South Africa, Argentina and Chile), eye cataracts, etc.
See also ENVIRONMENTAL DEGRADATION. In 1978, the US government banned the use of CFCs as aerosol sprays. In 1987, representatives of the governments of 36 countries held a special meeting in Montreal and agreed on a plan (Montreal Protocol) to reduce emissions of chlorofluorocarbons into the atmosphere by about 35% over the period from 1989 to 2000. At a second meeting in Copenhagen in 1992, held in the face of growing concern about the ozone screen, representatives of a number of countries agreed that in the future it is necessary: ​​to abandon the production of halons (a class of fluorocarbons containing bromine atoms) by January 1, 1994, and chlorofluorocarbons and hydrobromofluorocarbons (halon substitutes) - by January 1, 1996; to freeze the consumption of hydrochlorofluorocarbons at the level of 1991 until 1996 and completely eliminate their use by 2030. It was also noted that most of the previously set goals had been achieved.
The greenhouse effect. In 1896, the Swedish chemist Svante Arrhenius first proposed the heating of the atmosphere and the earth's surface as a result of the greenhouse effect. Solar energy enters the Earth's atmosphere in the form of short-wave radiation. Some of it is reflected into outer space, the other is absorbed by air molecules and heats it, and about half reaches the earth's surface. The surface of the Earth heats up and emits long-wave radiation, which has less energy than short-wave radiation. After that, the radiation passes through the atmosphere and is partially lost in space, while most of it is absorbed by the atmosphere and reflected back to the Earth's surface. This process of secondary reflection of radiation is possible due to the presence in the air, albeit in small concentrations, of impurities of many gases (the so-called greenhouse gases) of both natural and anthropogenic origin. They transmit shortwave radiation but absorb or reflect longwave radiation. The amount of thermal energy retained depends on the concentration of greenhouse gases and how long they stay in the atmosphere. The main greenhouse gases are water vapor, carbon dioxide, ozone, methane, nitrous oxide and chlorofluorocarbons. Undoubtedly, the most important among them is water vapor, and the contribution of carbon dioxide is also significant. 90% of the carbon dioxide annually released into the atmosphere is formed during respiration (oxidation of organic compounds by plant and animal cells). However, this intake is compensated by its consumption by green plants in the process of photosynthesis. See also PHOTOSYNTHESIS. The average concentration of carbon dioxide in the troposphere due to human activity increases by about 0.4% annually. Based on computer simulations, a forecast was made according to which, as a result of an increase in the content of carbon dioxide and other greenhouse gases in the troposphere, global warming will inevitably occur. If it is justified and the average air temperature on Earth rises by only a few degrees, the consequences can be catastrophic: the climate and weather will change, the conditions for the growth of plants, including crops, will be significantly disrupted, droughts will become more frequent, glaciers and ice sheets will begin to melt, which, in in turn, will lead to an increase in the level of the World Ocean and flooding of the coastal lowlands. Scientists have calculated that in order to stabilize the planet's climate, a 60% (relative to the 1990 level) decrease in greenhouse gas emissions is necessary. In June 1992, in Rio de Janeiro, at the UN Conference on Environment and Development, delegates from 160 countries signed the Convention on Climate Change, which encouraged further efforts to reduce greenhouse gas emissions and set a goal up to 2000 to stabilize their entry into the atmosphere at 1990 levels.
see also
CLIMATE;
ENVIRONMENTAL DEGRADATION.
INDOOR AIR POLLUTION
Indoor air pollution is the leading cause of cancer. The main sources of this pollution are radon, products of incomplete combustion, and the evaporation of chemicals.
Radon. Radon exposure is believed to be the second leading cause of lung cancer. This mainly occurs in homes that have been built on unconsolidated sediments or bedrock enriched with uranium-bearing minerals. Radon gas - a product of the radioactive decay of uranium - enters the house, seeping from the soil. The solution to this problem largely depends on the type of building structures. In addition, the improvement of the environmental situation contributes to the ventilation of buildings, such as ventilation windows of foundations. Ventilation pipes inserted into the base of the foundation can remove radon directly from the ground to the outside, into the atmosphere.
products of incomplete combustion. Incomplete combustion of fuels in stoves, fireplaces and other heating devices, as well as smoking, produces carcinogenic chemicals such as hydrocarbons. In homes, carbon monoxide is a major concern, as it is colorless, odorless, and tasteless, making it very difficult to detect. Undoubtedly, the main and very insidious indoor air pollutant, and therefore very dangerous for human health, is cigarette smoke, which causes lung cancer and many other respiratory and heart diseases. Even non-smokers, being in the same room with smokers (so-called passive smokers), put themselves at great risk.
Isolation of chemicals. Mothballs, bleaches, paints, shoe polish, various cleaning products, deodorants are just a few of the wide range of chemicals that every person (especially industrial workers) is exposed to on an almost daily basis and which release carcinogens. For example, plastics, synthetic fibers, and cleaners evaporate benzene, while foam insulation, plywood, and chipboard are sources of formaldehyde. Such emissions can cause headache, dizziness and nausea.
Asbestos. Inhalation of asbestos fibers causes a progressive, incurable lung disease called asbestosis. This problem is especially relevant for owners of houses built before 1972. The fact that asbestos is used as a fire-resistant or thermal insulation material in such buildings does not necessarily represent a health risk. The condition of structures containing asbestos is extremely important.
LITERATURE
Datsenko I.I. Air environment and health. Lvov, 1981 Budyko M.I., Golitsyn G.S., Israel Yu.A. Global climate catastrophes. M., 1986 Pinigin M.A. Atmospheric air protection. M., 1989 Bezuglaya E.Yu. What breathes industrial city. L., 1991 Alexandrov E.L., Israel Yu.A., Karol I.L., Khrgian L.Kh. Ozone shield of the Earth and its changes. St. Petersburg, 1992 Climate, weather, ecology of Moscow. St. Petersburg, 1995

Collier Encyclopedia. - Open society. 2000 .

One of the significant global problems is atmospheric pollution of the Earth. The danger of this is not only that people experience a shortage of clean air, but also that air pollution leads to climate change on the planet.

Causes of Air Pollution

Various elements and substances enter the atmosphere, which change the composition and concentration of the air. The following sources contribute to air pollution:

• emissions and activities of industrial facilities;
• car exhausts;
• radioactive objects;
• Agriculture;
• household and.

During the combustion of fuel, waste and other substances, combustion products enter the air, which significantly worsen the state of the atmosphere. The dust generated at the construction site also pollutes the air. Fuel is burned at thermal stations, and a significant concentration of elements polluting the atmosphere is released. The more inventions mankind makes, the more sources of air pollution and the biosphere as a whole appear.

Consequences of air pollution

During the combustion of various fuels, carbon dioxide is released into the air. Along with other greenhouse gases, it gives rise to such a dangerous phenomenon on our planet as. This leads to the destruction of the ozone layer, which in turn protects our planet from the intense effects of ultraviolet rays. All this leads to global warming and climate change of the planet.

One of the consequences of the accumulation of carbon dioxide and global warming is the melting of glaciers. As a result, the water level of the World Ocean rises, and in the future, islands and coastal zones of the continents may be flooded. Floods will be a constant occurrence in some areas. Plants, animals and people will die.

Polluting the air, various elements fall to the ground in the form of. These sediments enter water bodies, change the composition of water, and this causes the death of flora and fauna in rivers and lakes.

Today, air pollution is a local problem in many cities, which has grown into a global one. It is difficult to find a place in the world where clean air remains. In addition to the negative impact on the environment, atmospheric pollution leads to diseases in people that develop into chronic ones and reduce the life expectancy of the population.

According to the World Health Organization, about two million people die from exposure to polluted air each year. Air pollution is not only a huge problem for people living in the smog of overcrowded cities: through factors such as global warming and ozone depletion, it has the potential to affect us all.

Air allows our living planet to breathe. Air is a mixture of gases that fills the atmosphere, giving life to plants and animals. Air is composed almost entirely of two gases (78% nitrogen and 21% oxygen), with some other gases (such as carbon dioxide and argon) present in quite minute amounts. We can breathe normal air throughout the day without any negative effects, so we can use this fact to determine air pollution.

Air pollution is a gas (or a liquid or solid dispersed in normal air) in sufficient quantities to harm or kill the health of humans, animals, plants, stop them from growing, damage or disrupt other aspects of the environment (e.g. , destruction of buildings), or cause some other unfavorable phenomena (limited visibility, unpleasant smell).

Like water and soil pollution, it is the amount (or concentration) of chemicals in the air that makes the difference between "harmless air" and "polluted". Carbon dioxide (CO2), for example, is present in the air around you at a typical concentration of less than 0.05%, and breathing it in usually causes no harm (you breathe it in all day long), but air with extremely high concentrations of carbon dioxide (e.g., 5-10%) is toxic and can kill you in minutes.

Because the earth's atmosphere is very turbulent, many of us live in windy countries where air pollution dissipates fairly quickly. In less enlightened times, it was believed that if they built tall chimneys, the wind would disperse their smoke and air pollution would not be a problem. However, the problem is that there is much less space on Earth than we think and environmental pollution does not always disappear.

Natural air pollution

When we think about air pollution, we tend to think that it is a problem that people cause out of ignorance or stupidity. This is certainly true, but only occasionally. However, it is important to remember that some types of air pollution occur naturally. Forest fires, volcanic eruptions, and gases released from the radioactive decay of rocks inside the Earth are just three examples of natural air pollution that has extremely devastating effects on people and the planet.

Wildfires (which often start naturally) can produce huge patches of smoke that spread for miles over neighboring cities, countries, and continents. Giant volcanic eruptions can throw so much dust into the atmosphere that they block out a significant amount of sunlight and cause the planet to cool for a year or more. Radioactive rocks, when they decay, can be a source of radon gas, which can accumulate in the basements of buildings and have serious negative consequences for human health.

All these are examples of serious air pollution that occurs without human intervention, although we can adapt to natural air pollution, and we cannot try to reduce or stop it. For the rest of this article, we will consider only the "unnatural" types of pollution: the problems that people cause and those that we can solve.

Top ten gases in air pollution

Any gas can qualify as an environmental pollutant if its concentration has reached high harm values. Theoretically, this means that there are dozens of different pollutant gases. In practice, about a dozen different substances cause the most concern:

What are the causes of air pollution?

All processes that involve burning things, using household and industrial chemicals (substances that cause chemical reactions and can release toxic gases in the process), or produce large amounts of dust have the potential to form air pollution. A few centuries ago, the cause of most air pollution was easy to determine: it was dirty factories, as well as the industrial revolution. Today, with more stringent air pollution laws in place and increased public environmental awareness, this is much more difficult, though not impossible.

Where, then, do modern air pollution come from? By far the biggest culprit is transportation, although plant and factory capacity continues to make a significant contribution. Now let's take a closer look at the three main sources of air pollution.

Motor transport

Today, there are about half a billion cars on the road, an average of one for every two people. Almost all of them run on gasoline and diesel engines that burn oil to release energy. Oil is made up of hydrocarbons (large molecules are made up of hydrogen and carbon), and in theory, burning them with enough oxygen should produce harmless substances such as carbon dioxide and water. But in practice, fuels are not pure hydrocarbons. As a result, engine emissions contain a large number of pollutants, in particular particulate matter (soot of various sizes), carbon monoxide (CO, a poisonous gas), nitrogen oxides (NOx), volatile organic compounds (VOCs), as well as lead and indirectly produce ozone. Mix this noxious mixture and activate it with sunlight, and you get a sometimes brownish, sometimes bluish fog (smog) that can exist over cities for days on end.

Smog

Smog (a combination of the words smoke and fog) is formed when sunlight acts on a mixture of pollutant gases such as oxides of sulfur and nitrogen, unburned hydrocarbons, and carbon monoxide, which is why it is sometimes called photochemical smog (because the chemical reactions are caused by the energy of light). One of the most harmful components of smog is ozone, which can cause severe breathing difficulties and even death. When smog is rich in ozone, it tends to be bluish in color. Otherwise it will be brown.

While smog can form in any city, this problem is especially relevant in places like Los Angeles, where the local climate (influenced by the ocean and nearby mountains) regularly causes temperature inversions. As a general rule, air gets colder the higher it rises, and with a temperature inversion, the opposite happens: warm air is at the top, and cold air is closer to the ground. Largely due to heavy traffic, many of the world's busiest cities, including Athens, Beijing, Mexico City, Milan and Tokyo, suffer from smog.

power plants

Renewable energy sources such as solar panels and wind turbines help us get some of our energy each year, but the vast majority of electricity (about 70 percent in the United States, for example) is still produced by burning fossil fuels such as coal, gas, and oil, mainly in conventional power plants. Just like car engines, power plants should theoretically produce carbon dioxide and water, but in practice, power plants produce a range of pollutants, such as sulfur dioxide, nitrogen oxides, and particulate matter. They also release huge amounts of carbon dioxide, which is the main cause of global warming and climate change, as it rises and accumulates in the atmosphere.

Industrial plants and factories

Industrial plants that produce metals such as aluminum and steel, refine oil, manufacture cement, synthesize plastics, or produce other chemicals are among those that are sources of air pollution. Most factories pollute the air with small amounts of harmful substances continuously over a long period of time, and the effects of pollution are cumulative. Sometimes industrial plants emit huge amounts of pollutants in a very short period of time.

Other Causes of Air Pollution

Despite transport emissions, power plants, industrial and chemical plants produce the majority of man-made air pollution. Many other factors also contribute to this problem. In some parts of the world, people still rely on burning wood fuel for cooking and heating, which causes indoor air pollution that can seriously harm the health of its inhabitants (solar stoves are one way to solve this problem). In some areas, garbage is incinerated rather than recycled or landfilled, which can also produce significant air pollution.

What are the consequences of air pollution?

Air pollution can harm human and animal health, damage or stop crops from growing, and make our world unpleasant and unattractive in many other ways.

Human health

Sometimes the link between air pollution and human health is clear, as in London in 1952, when smog caused by burning coal in domestic stoves and coal-fired power plants killed about 4,000 people. In other cases, this relationship is much more difficult to determine. Some estimates suggest that 10-20% of cancers are caused by air pollution, but cancer can take a long time to develop, and proving a direct link to a particular type of air pollution and the disease is very difficult.

According to the World Health Organization (WHO), outdoor air pollution is one of the leading causes of death in the world: about two million people die prematurely every year from this cause. Many of these deaths occur in developing countries (more than half a million in India alone), but wealthy industrialized countries also suffer: in the United States, for example, about 41,000 people a year die early due to air pollution.

Agricultural effects

The 20th century was characterized by a huge growth in industrial agriculture, the use of fertilizers, pesticides, etc., which were used to increase crops and feed the ever-growing world population. It is known that air pollution (together with water pollution) can seriously affect plant growth. Plants that grow near highways can easily find chemical residues (everything from toxic heavy metals like lead and other chemicals). At the same time, the huge increase in carbon dioxide emissions in the atmosphere now, global warming and climate change are expected to have a decisive impact on the world's agriculture (declining yields in some places, but potentially increasing yields elsewhere).

One of the main conditions for the preservation of human health and longevity is clean air. Unfortunately, in today's realities in many parts of the world, achieving compliance with this key requirement seems like an impossible mission. But is it really impossible to make the air we breathe cleaner? And what exactly pollutes the atmosphere the most?

All sources that negatively affect the state of the air basin are divided by ecologists into anthropogenic and natural. It is the first category that causes the greatest damage to the environment - factors associated with human activities. Atmospheric air pollution occurring due to natural causes is not only negligible on a global scale, but is also self-eliminating in nature.

Industry that kills

Industry is the number one source of air pollution in developing and some developed countries. The lion's share of emissions into the atmosphere comes from energy, non-ferrous and ferrous metallurgy enterprises. Less harmful to the air basin, but still dangerous are such industries as oil production and oil refining, mechanical engineering. In places where industrial production is concentrated in the atmosphere, phenols, hydrocarbons, mercury, lead, resins, oxide and sulfur dioxide are present in significant quantities.

In developed countries, air pollution with harmful substances has become a pressing problem a century ago. That is why the process of creating environmental legislation there began earlier than in other states. Thus, the Netherlands was the first to track the emissions of enterprises by adopting relevant laws in 1875-1896. In the United States, an act to control the purity of the air was voted in 1955. In Japan, the law on monitoring and limiting harmful emissions appeared in 1967, in Germany (FRG) - in 1972.

When the charms of civilization harm?

Transport, being a necessary condition for the functioning of modern society, is also the main threat to human health. All machines that use different types of fuel for work pollute the atmosphere to one degree or another. For example, a car actively absorbs oxygen from the air. Instead, it emits carbon dioxide, water vapor and toxic substances (carbon monoxide, hydrocarbons, nitrogen oxides, aldehydes, soot, benzopyrene, sulfur dioxide). The contribution that individual modes of transport make to air pollution is as follows:

• 85% of harmful emissions come from cars and trucks;
• 5.3% - for river and sea vessels;
• 3.7% and 3.5% for air and rail vehicles, respectively:
• agricultural vehicles (seeders, planters, combines, tractors, arable equipment) pollute the atmosphere least of all (2.5%).

Each country solves the problem of air pollution in its own way. Indicative in this regard is the experience of Denmark. After the Second World War, residents of a small Scandinavian country, whose streets were flooded with cars, began to resent gas pollution. When the oil crisis of the 70s broke out, the Danish authorities had no choice but to go along with the public. A developed cycling infrastructure was created in the country, a huge tax was introduced on the purchase and use of a car. The local residents liked the idea: the actions “Copenhagen without cars” and “Sundays without cars” became massive. Now Denmark is the most cycling country in the world, one of the three cleanest and most prosperous states for a person.

Wind, sun and water are our best friends?

Large-scale pollution of atmospheric air with harmful substances is caused by the work of heat and power enterprises. The operation of power plants running on coal, diesel, fuel oil, kerosene and gasoline is accompanied by the release of hazardous compounds of heavy metals, carbon monoxide, carbon, and nitrogen. Outside the city, as a rule, dumps of ash left during the burning of coal accumulate.

The use of liquid fuels can reduce ash formation, but such a replacement does not affect the amount of nitrogen and sulfur oxide emissions. Nuclear power plants pollute the air with aerosols, radioactive gases and iodine. All types of traditional fuels are certainly harmful. Perhaps conditionally harmless is the gas.

How to avoid ? Alternative energy sources make the air cleaner. Another argument speaks in favor of using the energy of the tides, wind and sun - the limited reserves of gas and oil. China, India, the USA, Japan, the EU can boast of advanced experience in the field of energy. Alternative sources in these countries account for up to 20% of the total energy generation. Tidal power plants are being built in coastal regions, and solar power plants are being built in southern countries. Geothermal power plants, which generate energy from the natural heat of the planet, are located near thermal springs.

Eco farms are the future

Agricultural production causes more damage to water bodies, land and trees than air, but is still considered one of the main sources of . As a result of the use of manure in livestock companies, ammonia is released. Pesticides used in agriculture also pose a danger to humans, animals and plants. The solution to the problem could be a new type of agricultural complexes that operate without the use of herbicides and pesticides. The introduction of the concept of environmentally friendly farms is in full swing in European countries, Canada, and the USA. Successful farms for the production of healthy products operate in Russia.

Dust storm pollution

Among natural sources, soil weathering is the largest contributor to air pollution. Strong dust content is typical for areas with a low degree of soil moisture and poorly developed vegetation. Global air pollution with dust occurs in the Takla-Makan, Gobi, Sahara deserts, local - in the Mongolian and Central Asian region. In Europe, dust clouds that change the composition and quality of the atmospheric boundary layer dominate in the southeastern and eastern parts. The speed and distribution area of ​​pollution depends on the particle size. Fine dust is kept in the air for 1.5-3 weeks, spreads throughout the hemisphere. Large particles spread over hundreds of kilometers, settling within hours or days.

How does soil weathering affect human health? If our body is able to filter out large particles, then fine dust easily penetrates through the upper respiratory tract and settles in the lungs. According to WHO studies, an increase in the content of suspended particles in the air by 10 μg / m 3 leads to an increase in mortality by 0.5–1%.

Dust storms harm not only humans. They are dangerous for the entire planet. The accumulation of hundreds of thousands of dust particles interferes with the normal outflow of excess heat from the Earth. How to solve the problem of wind erosion of soils? To prevent dust storms, a system of windbreaks and forest belts is being created, and agricultural activities are being carried out to increase the adhesion of soil particles.

Volcanism and forest fires

A volcanic eruption is a rare event, accompanied by catastrophic consequences. Every year, during a natural disaster, the atmosphere is replenished with 40 million tons of substances. Most of the gases emitted by volcanoes are water vapor. Eruptions are one of the reasons for the increase in the concentration of carbon dioxide in the atmosphere. Polluted air is also dangerous because the sulfur oxide released by the volcano, reacting with water, turns into sulfuric acid.

During the hot period, the problem of forest fires is acute. The cause of fire can be both solar activity and non-compliance with human safety rules. During a natural disaster, atmospheric air is polluted with aerosols, vapors, and toxic gases. Forest fires are the second source of methyl chloride release after the ocean. Indirect air pollution also occurs: due to the destruction of vegetation, oxygen production decreases.

Other sources of pollution

Oceans and seas slightly affect the degree of air pollution in the world. In the process of evaporation, crystals of sea salts (potassium bromide, calcium chloride, magnesium, sodium) enter the atmosphere from the water. The proportion of substances that enrich the air masses noticeably increases during a storm. Evaporation of sea salts in itself is not dangerous, however, along with them, other, toxic, compounds can be present in the water. Thus, air pollution is inextricably linked to the ecological state of the ocean.

In addition to substances of terrestrial origin, cosmic dust is also present in the atmosphere. Scientists have calculated that 40,000 tons of such particles settle on our planet every year. This means that dust from space is a tiny source of air pollution that does not cause serious problems. However, if its quantity increases, it can significantly affect the climatic conditions of the Earth.

Finally, no matter how trite it may sound, the air is polluted daily by people who smoke. The composition of cigarettes includes about 400 substances, including ammonia, nitrobenzene, formaldehyde, toluene and many other toxic compounds. All of them inevitably get into the air along with tobacco smoke and do not dissolve, but settle, for example, on the soil. One can draw an analogy with passive smoking and conclude that our planet suffers from it, and the only way out is for already addicted people and to prevent the younger generations from being involved in this process.

So, the main sources of air pollution are associated with human activities. Anthropogenic factors that worsen the state of the air basin include industrial production, transport, and thermal power engineering. The degree of influence of each of these causes in different regions of the world varies markedly. Among natural sources, the ecological state of the atmosphere is most threatened by soil weathering.

Hello my dear students! I welcome you to the pages of the ShkolaLa blog.

Today in the section "Projects" there is an important topic dedicated to the problem of modernity. Air pollution is a global issue that humanity has had to face. Who is to blame for the fact that over the past 200 years the level of concentration of harmful substances has increased by 30 percent, and environmental pollution has led to environmental damage and climate change on the planet? Is it possible to stop this process and how to protect our Earth?

We'll figure out.

Lesson plan:

Why and from what does the atmosphere get polluted?

Atmospheric air pollution is the ingress of chemical, physical and biological substances into it that affect the quality of the atmosphere. This is the main reason for changing the natural state of the environment. Air pollution occurs due to natural processes, but most of all as a result of human activities. Therefore, the sources of harmful emissions are divided into:

• natural, coming from nature itself, and
• artificial, man-made.

Natural springs are of mineral or vegetable origin.

Volcanoes

When they erupt, a huge amount of gases, solid particles and ash, water vapor and dust are released into the air, which are kept in the atmospheric layers for several years.

Facts. In 1883, during the eruption of the Krakatoa volcano, a black cloud 27 kilometers high rose into the air, 80 kilometers up, 150 billion dust and ash were thrown up. Gases, sand and dust dispersed over a distance of 827,000 kilometers.

Forest and peat fires

Smoke from burning forests pollutes the air and spreads over large areas. The cinders from peat bogs fill the air with fine suspended particles.

Facts. In 2010, due to peat fires in the capital of Russia, an emergency environmental situation developed. The maximum allowable standards of pollutants were exceeded dozens of times. Due to the smog, residents of Moscow could not breathe freely and used respirators and gas masks. Many were forced to leave the city.

dust storms

They happen with a strong wind, which lifts rock fragments from the ground and carries them over long distances. Tornadoes and hurricanes pollute the atmospheric air with tons of dust.

Facts. In 1928, in Ukraine, a powerful wind lifted up 15 million tons of black soil and carried it to the west at an altitude of 750 meters. A layer of earth settled in the Carpathians, Romania and Polshuna with an area of ​​6 million square kilometers.

Artificial air pollutants are the most dangerous. They can be solid, liquid and gaseous.

Household waste

They appear when fuel is burned indoors, for example, when cooking, smoke from stove heating, as well as what is left of human consumption, in other words, household waste.

Production

They are obtained as a result of the work of industry and represent emissions from technological processes. The most dangerous of them are radioactive substances, the sources of which are explosions of atomic bombs, the work of enterprises that use radioactive components, nuclear power plants and reactors.

Transport

Sources of such pollutants are cars, aircraft and ships, trains.

Facts. In 1900, there were only 11 thousand cars in the world, in 1950 there were 48 million, by 1980 the number increased to 330 million, and today there are about 500 million. The gases exhausted by machines contain approximately 280 components harmful to atmospheric air.

What pollutes the air?

Scientists have identified the main air pollutants that most adversely affect human health.

carbon monoxide

A colorless and odorless gas, which is also called carbon monoxide. It is formed during incomplete combustion of fuel with a lack of oxygen and low ambient temperature. When it enters the human body, it blocks the flow of oxygen into the blood. This is one of the causes of frequent human poisoning, leading to loss of consciousness and death.

Carbon dioxide

The gas we breathe out is colorless, but it has a sour smell. Its excess content in the air we breathe leads to headaches, depression and weakness.

sulphur dioxide

A colorless gas with a pungent odor, produced by the combustion of sulfur-containing fuels such as coal. Long-term exposure to it on a person leads to loss of taste, difficulty breathing, disruption of the heart and pulmonary edema.

nitrogen oxides

They are formed during combustion, for example, during the operation of cars and heating plants, and are also obtained during the activities of enterprises that produce nitrogen fertilizers, acid and dyes. Exceeding the permissible norms of this gas can lead to diseases of the respiratory tract and organs of vision.

Ozone

Considered the most toxic of all gaseous pollutants. It is formed from photochemical processes and is found in emissions from industry, transport, and chemical solvents. Prolonged exposure to ozone in humans leads to lung diseases.

Lead

The toxic silvery metal is used in the manufacture of paints, in printing houses and in the manufacture of ammunition. Exhaust gases are the main source of lead. The accumulation of lead in the body leads to impaired mental activity, affects the liver, kidneys and skeletal system.

Facts. Russia occupies a strong position among countries with poor ecology. Only in 15 cities the atmospheric air complies with the established norms. 125 Russian cities record an excess of the level of concentration of harmful substances by 5-10 times. Among the most polluted cities are Magnitogorsk, Cherepovets, Chelyabinsk, there are both Moscow and St. Petersburg, but Norilsk is on a par with the world's dirtiest Mexico City, Cairo and Los Angeles. The main source of pollution in Russia is industry.

How to help nature?

Human activity leads to irreparable consequences for the life of the planet. Up to 20 billion tons of carbon dioxide enters the air every year. And he belongs to the greenhouse. An increase in the amount of greenhouse gases and aerosols heats the lower layer of the atmosphere and entails a change in temperature in the oceans, disrupts circulation.

Rising temperatures could lead to ice melting, which would raise water levels and gradually cover small areas of land. Due to the shift in climatic zones, floods, droughts and dust storms are possible. Environmental impacts include acid rain, which results from emissions of acid oxides.

Facts. The cleanest air today is in the Sinai Peninsula in Egypt. The list of favorable areas includes Antarctica, Chilean Patagonia, the Brazilian city of Natal. But in China it is more and more difficult to breathe atmospheric air every year. Big cities are covered in smog. Among the dirty countries are Pakistan, Iran, India and Qatar. Once upon a time, clean air was bad in Japan, and in the 70s, oxygen bars appeared there, where you could breathe pure oxygen. But in the dirty cities of China they carry clean Canadian mountain air in cylinders of 7.7 liters. A piece of freshness costs $15 and is enough for 15 breaths.

Environmental protection includes measures to protect nature.

• Use of ecological types of energy - solar, wind and geothermal.
• Landscaping. All plants actively absorb carbon dioxide, releasing oxygen back. Some indoor flowers, such as geranium, ficus and asparagus, are biological filters, absorbing heavy metal particles and toxins.
• Emission regulation. To do this, they install special equipment in the mechanisms of machines and develop environmentally friendly fuel. In addition, mechanical engineering is gradually moving to electric vehicles.
• Protective filters. To clean the waste released into the air from the activities of industry, enterprises install modern treatment systems.
• Juristic documents. Documents adopted by international organizations regulate harmful emissions in the course of enterprises' activities. The money paid by organizations goes to measures to overcome the effects of global warming.

If we can only have a small impact on natural phenomena, then reducing the human impact on environmental pollution is our direct responsibility. Let's take care of nature and try to prevent what you see in the video below.

I hope the information was useful to you. And also I recommend to look also to find out when the World Environment Day is celebrated.

On this I say goodbye to you. See you soon on interesting projects.

Evgenia Klimkovich.