"Air pollution - ecological problem". This phrase does not reflect in the least the consequences that a violation of the natural composition and balance in a mixture of gases called air bears.

It is not difficult to illustrate such a statement. The World Health Organization provided data on this topic for 2014. About 3.7 million people have died due to air pollution worldwide. Almost 7 million people died from exposure to polluted air. And this is in one year.

The composition of the air includes 98-99% nitrogen and oxygen, the rest: argon, carbon dioxide, water and hydrogen. It makes up the Earth's atmosphere. The main component, as we see, is oxygen. It is necessary for the existence of all living things. Cells “breathe” it, that is, when it enters the cell of the body, a chemical oxidation reaction occurs, as a result of which the energy necessary for growth, development, reproduction, exchange with other organisms, and the like, that is, for life, is released.

Atmospheric pollution is interpreted as the introduction of chemical, biological and physical substances that are not inherent in it into the atmospheric air, that is, a change in their natural concentration. But more important is not the change in concentration, which, no doubt, occurs, but the decrease in the composition of the air of the most useful component for life - oxygen. After all, the volume of the mixture does not increase. Harmful and polluting substances are not added by simple addition of volumes, but destroy and take its place. In fact, there is and continues to accumulate a lack of food for cells, that is, the basic nutrition of a living being.

About 24,000 people per day die of starvation, that is, about 8 million per year, which is comparable to the death rate from air pollution.

Types and sources of pollution

The air has been polluted at all times. Volcanic eruptions, forest and peat fires, dust and pollen of plants and other substances entering the atmosphere that are usually not inherent in its natural composition, but occurred as a result of natural causes- This is the first type of origin of air pollution - natural. The second is as a result of human activity, that is, artificial or anthropogenic.

Anthropogenic pollution, in turn, can be divided into subspecies: transport or resulting from work different types transport, industrial, that is, associated with emissions into the atmosphere of substances formed in manufacturing process and household or resulting from direct human activity.

Air pollution itself can be physical, chemical and biological.

• The physical includes dust and solid particles, radioactive radiation and isotopes, electromagnetic waves and radio waves, noise, including loud sounds and low-frequency vibrations, and thermal, in any form.
• Chemical pollution is the ingress of gaseous substances into the air: carbon monoxide and nitrogen, sulfur dioxide, hydrocarbons, aldehydes, heavy metals, ammonia and aerosols.
• Microbial contamination is called biological. These are various spores of bacteria, viruses, fungi, toxins and the like.

The first is mechanical dust. Appears in technological processes grinding of substances and materials.

The second is sublimations. They are formed during the condensation of cooled gas vapors and passed through the process equipment.

The third is fly ash. It is contained in the flue gas in a suspended state and is an unburned mineral fuel impurities.

The fourth is industrial soot or solid highly dispersed carbon. It is formed during the incomplete combustion of hydrocarbons or their thermal decomposition.

Today, the main sources of such pollution are thermal power plants operating on solid fuels and coal.

Consequences of pollution

The main effects of pollution atmospheric air are: the greenhouse effect, ozone holes, acid rain and smog.

The greenhouse effect is built on the ability of the Earth's atmosphere to transmit short waves and delay long ones. Short waves are solar radiation, and long ones are thermal radiation coming from the Earth. That is, a layer is formed in which heat is accumulated or a greenhouse. Gases capable of such an effect are called, respectively, greenhouse gases. These gases heat up themselves and heat up the entire atmosphere. This process is natural and natural. It happened and is happening now. Without it, life on the planet would not be possible. Its beginning is not connected with human activity. But if earlier nature itself regulated this process, now man has intensively intervened in it.

Carbon dioxide is the main greenhouse gas. Its share in the greenhouse effect is more than 60%. The share of the rest - chlorofluorocarbons, methane, nitrogen oxides, ozone, and so on, accounts for no more than 40%. It was thanks to such a large proportion of carbon dioxide that natural self-regulation was possible. How much carbon dioxide was released during breathing by living organisms, so much was consumed by plants, producing oxygen. Its volumes and concentration were kept in the atmosphere. Industrial and other human activities, and, above all, deforestation and burning of fossil fuels, have led to an increase in carbon dioxide and other greenhouse gases due to a decrease in the volume and concentration of oxygen. The result was a greater heating of the atmosphere - an increase in air temperature. Forecasts are such that rising temperatures will lead to excessive melting of ice and glaciers and rising sea levels. This is on the one hand, and on the other, increase, due to more high temperature the evaporation of water from the surface of the earth. And that means an increase in desert lands.

Ozone holes or disruption of the ozone layer. Ozone is a form of oxygen and is formed naturally in the atmosphere. This happens when it hits ultraviolet radiation sun to an oxygen molecule. Therefore, the highest concentration of ozone in the upper atmosphere is at an altitude of about 22 km. from the surface of the earth. In height, it extends for about 5 km. this layer is considered protective, as it delays this very radiation. Without such protection, all life on Earth perished. There is now a decrease in ozone concentration in protective layer. Why this happens has not yet been reliably established. This depletion was first detected in 1985 over Antarctica. Since then, the phenomenon has been called the "ozone hole". At the same time, the Convention for the Protection of the Ozone Layer was signed in Vienna.

Industrial emissions of sulfur dioxide and nitrogen oxide into the atmosphere, combined with atmospheric moisture, form sulfuric and nitric acid and cause "acid" rain. Such precipitation is considered to be any precipitation whose acidity is higher than natural, that is, ph<5,6. Это явление присуще всем промышленным регионам в мире. Главное их отрицательное воздействие приходится на листья растений. Кислотность нарушает их восковой защитный слой, и они становятся уязвимы для вредителей, болезней, засух и загрязнений.

Falling onto the soil, the acids contained in their water react with toxic metals in the ground. Such as: lead, cadmium, aluminum and others. They dissolve and thereby contribute to their penetration into living organisms and groundwater.

In addition, acid rain contributes to corrosion and thus affects the strength of buildings, structures and other building structures made of metal.

Smog is a common sight in large industrial cities. It occurs where a large amount of pollutants of anthropogenic origin and substances obtained as a result of their interaction with solar energy accumulate in the lower layers of the troposphere. Smog is formed and lives for a long time in cities, thanks to calm weather. Exists: wet, icy and photochemical smog.

With the first explosions of nuclear bombs in the Japanese cities of Hiroshima and Nagasaki in 1945, mankind discovered another, perhaps the most dangerous, type of air pollution - radioactive.

Nature has the ability to self-purify, but human activity clearly interferes with this.

Video - Unsolved Mysteries: How Air Pollution Affects Health

All industrialized countries are affected to some extent by air pollution. The air of big cities that we breathe contains a huge amount of various harmful impurities, allergens, suspended particles and is an aerosol.

Aerosols are aerodisperse (colloidal) systems in which solid particles (dust), liquid droplets, formed either during the condensation of vapors, or during the interaction of gaseous media, or entering the air without changing the phase composition, can be suspended indefinitely for a long time.

The main sources of artificial aerosol air pollution are thermal power plants that consume high-ash coal, processing plants, metallurgical, cement, magnesite and soot plants that emit dust, sulfur dioxide and other harmful gases into the atmosphere that are released during various technological production processes.

The ferrous metallurgy of smelting pig iron and processing it into steel is accompanied by the emission of various gases into the atmosphere.

Air pollution by dust during coal coking is associated with the preparation of the charge and its loading into coke ovens, with the unloading of coke into quenching cars and with wet quenching of coke. Wet quenching is also accompanied by the release into the atmosphere of substances that are part of the water used.

In non-ferrous metallurgy, during the production of metallic aluminum by electrolysis, a significant amount of gaseous and dust-like fluorine compounds is released into the atmospheric air with exhaust gases from electrolysis baths.

Air emissions from the oil and petrochemical industries contain large amounts of hydrocarbons, hydrogen sulfide and foul-smelling gases. The emission of harmful substances into the atmosphere at oil refineries occurs mainly due to insufficient sealing of equipment. For example, atmospheric air pollution with hydrocarbons and hydrogen sulfide is observed from metal tanks of raw stock parks for unstable oil, intermediate and trade parks for light oil products.

The production of cement and building materials can be a source of air pollution with various dusts. The main technological processes of these industries are the processes of grinding and heat treatment of batches, semi-finished products and products in hot gas flows, which is associated with dust emissions into the atmospheric air.

The chemical industry includes a large group of enterprises. The composition of their industrial emissions is very diverse. The main emissions from chemical industry enterprises are carbon monoxide, nitrogen oxides, sulfur dioxide, ammonia, dust from inorganic industries, organic substances, hydrogen sulfide, carbon disulfide, chloride compounds, fluorine compounds, etc. Sources of atmospheric air pollution in rural areas are livestock and poultry farms , industrial complexes from the production of meat, energy and thermal power enterprises, pesticides used in agriculture. Ammonia, carbon disulfide and other foul-smelling gases can enter the atmospheric air in the area where the premises for keeping livestock and poultry are located and spread over a considerable distance.

The sources of air pollution with pesticides include warehouses, seed treatment and the fields themselves, on which pesticides and mineral fertilizers are applied in one form or another, as well as cotton ginning plants.

Smog is an aerosol consisting of smoke, fog and dust, one of the types of air pollution in large cities and industrial centers. Smog can form under almost any natural and climatic conditions in large cities and industrial centers with severe air pollution. Smog is most harmful during warm periods of the year, in sunny calm weather, when the upper layers of the air are warm enough to stop the vertical circulation of air masses. This phenomenon is often found in cities protected from the winds by natural barriers, such as hills or mountains. The fog itself is not dangerous to the human body. It becomes harmful only when extremely contaminated with toxic impurities.

37) The struggle for the purity of atmospheric air has now become the most important task of domestic hygiene. This task is solved by means of legislative preventive measures: planning, technological and sanitary-technical.

All areas of atmospheric protection can be grouped into four large groups:

1. Group of sanitary measures - construction of ultra-high chimneys, installation of gas and dust cleaning equipment, sealing of technical and transport equipment.

2. A group of technological measures - the creation of new technologies based on partially or completely closed cycles, the creation of new methods for the preparation of raw materials that purify them from impurities before being involved in production, the replacement of raw materials, the replacement of dry methods for processing dusty materials with wet ones, automation of production processes.

3. A group of planning measures - the creation of sanitary protection zones around industrial enterprises, the optimal location of industrial enterprises, taking into account the wind rose, the removal of the most toxic industries outside the city, the rational planning of urban development, urban greening.

4. A group of control and prohibition measures - the establishment of maximum allowable concentrations (MPC) and maximum allowable emissions (MPE) of pollutants, prohibition of the production of certain toxic products, automation of emission control.

The main measures for the protection of atmospheric air include a group of sanitary measures. In this group, an important area of ​​air protection is the purification of emissions in combination with the subsequent disposal of valuable components and the production of products from them. In the cement industry, this is the capture of cement dust and its use for the production of hard road surfaces. In the thermal power industry - the capture of fly ash and its utilization in agriculture, in the building materials industry.

There are two types of effect during the disposal of the captured components: ecological and economic. The environmental effect is to reduce environmental pollution when using waste compared to using primary material resources. So, in the production of paper from waste paper or the use of scrap metal in steelmaking, air pollution is reduced by 86%. The economic effect of the utilization of the captured ingredients is associated with the appearance of an additional raw material source, which, as a rule, has more favorable economic indicators compared to the corresponding indicators of production from natural raw materials. Thus, the production of sulfuric acid from non-ferrous metallurgy gases, in comparison with the production from traditional raw materials (natural sulfur) in the chemical industry, has a lower cost and specific capital investments, higher annual profit and profitability.

Three of the most effective ways to clean gases from gaseous impurities are liquid absorption, solid adsorption, and catalytic cleaning.

In absorption cleaning methods, the phenomena of different solubility of gases in liquids and chemical reactions are used. A liquid (usually water) uses reagents that form chemical compounds with a gas.

Adsorption cleaning methods are based on the ability of finely porous adsorbents (active carbons, zeolites, simple glasses, etc.) to capture harmful components from gases under appropriate conditions.

The basis of catalytic purification methods is the catalytic transformation of harmful gaseous substances into harmless ones. These cleaning methods include inertial separation, electrical settling, etc. With inertial separation, the sedimentation of suspended solids occurs due to their inertia, which occurs when the direction or speed of the flow changes in devices called cyclones. Electrical deposition is based on the electrical attraction of particles to a charged (precipitating) surface. Electric deposition is implemented in various electrostatic precipitators, in which, as a rule, charging and deposition of particles occur together.

The concept of "atmospheric resources"

Atmospheric air as a resource. Atmospheric air is a natural mixture of gases of the surface layer of the atmosphere outside residential, industrial and other premises, which has developed during the evolution of our planet. It is one of the main vital elements of nature.

Atmospheric air performs a number of complex environmental functions, namely:

1) regulates the thermal regime of the Earth, promotes the redistribution of heat around the globe;

2) serves as an indispensable source of oxygen necessary for the existence of all life on Earth. When characterizing the special importance of air in human life, it is emphasized that a person can live without air for only a few minutes;

3) is a conductor of solar energy, serves as protection against harmful cosmic radiation, forms the basis of climatic and weather conditions on Earth;

4) is intensively exploited as a transport communication;

5) saves everything living on Earth from destructive ultraviolet, X-ray and cosmic rays;

6) protects the Earth from various celestial bodies. The vast majority of meteorites do not exceed the size of a pea. With great speed (from 11 to 64 km / s), they crash into the atmosphere of the planet under the influence of earth's gravity, heat up due to friction against the air, and at a height of about 60-70 km they mostly burn out;

7) determines the light regime of the Earth, breaks the sun's rays into millions of small rays, scatters them and creates the uniform illumination that a person is used to;

8) is the medium where sounds propagate. Without air, silence would reign on Earth;

9) has the ability to self-purify. It occurs when aerosols are washed out of the atmosphere by precipitation, turbulent mixing in the surface air layer, and the deposition of polluted substances on the earth's surface.

Atmospheric air and the atmosphere as a whole have many other environmental and socially beneficial properties. For example, atmospheric air is widely used as a natural resource in the national economy. Mineral nitrogen fertilizers, nitric acid and its salts are produced from atmospheric nitrogen. Argon and nitrogen are used in metallurgy, chemical and petrochemical industries (for a number of technological processes). Oxygen and hydrogen are also obtained from atmospheric air.

Atmospheric air pollution by industrial enterprises

Pollution in ecology is understood as an unfavorable change in the environment, which is wholly or partly the result of human activity, directly or indirectly changes the distribution of incoming energy, radiation levels, physical and chemical properties of the environment and the conditions for the existence of living organisms. These changes can affect a person directly or through water and food. They can also affect a person, worsening the properties of the things he uses, the conditions of rest and work.

Intensive air pollution began in the 19th century due to the rapid development of industry, which began to use coal as the main fuel, and the rapid growth of cities. The role of coal in air pollution in Europe has long been known. However, in the 19th century, it was the cheapest and most affordable type of fuel in Western Europe, including Great Britain.

But coal is not the only source of air pollution. Now a huge amount of harmful substances is emitted into the atmosphere every year, and, despite the significant efforts made in the world to reduce the degree of atmospheric pollution, it is located in the developed capitalist countries. At the same time, the researchers note that if there are now 10 times more harmful impurities in the atmosphere over the countryside than over the ocean, then over the city there are 150 times more of them.

Impact on the atmosphere of ferrous and non-ferrous metallurgy enterprises. The enterprises of the metallurgical industry saturate the atmosphere with dust, sulfur dioxide and other harmful gases released during various technological production processes.

Ferrous metallurgy, the production of cast iron and its processing into steel, naturally occurs with the accompanying emissions of various harmful gases into the atmosphere.

Air pollution with gases during the formation of coals is accompanied by the preparation of the charge and its loading into coke ovens. Wet quenching is also accompanied by the release into the atmosphere of substances that are part of the water used.

During the production of metallic aluminum by electrolysis, a huge amount of gaseous and dusty compounds containing fluorine and other elements are released into the environment. When smelting one ton of steel, 0.04 tons of solid particles, 0.03 tons of sulfur oxides and up to 0.05 tons of carbon monoxide enter the atmosphere. Non-ferrous metallurgy plants discharge into the atmosphere compounds of manganese, lead, phosphorus, arsenic, mercury vapor, vapor-gas mixtures consisting of phenol, formaldehyde, benzene, ammonia and other toxic substances. .

Impact on the atmosphere of petrochemical industry enterprises. Enterprises of the oil refining and petrochemical industries have a noticeable negative impact on the state of the environment and, above all, on the atmospheric air, which is due to their activities and the combustion of oil refining products (motor, boiler fuels, and other products).

In terms of air pollution, oil refining and petrochemistry rank fourth among other industries. The composition of fuel combustion products includes such pollutants as oxides of nitrogen, sulfur and carbon, carbon black, hydrocarbons, hydrogen sulfide.

During the processing of hydrocarbon systems, more than 1500 tons/year of harmful substances are emitted into the atmosphere. Of these, hydrocarbons - 78.8%; sulfur oxides - 15.5%; nitrogen oxides - 1.8%; carbon oxides - 17.46%; solids - 9.3%. Emissions of solid substances, sulfur dioxide, carbon monoxide, nitrogen oxides account for up to 98% of total emissions from industrial enterprises. As analysis of the state of the atmosphere shows, it is the emissions of these substances in most industrial cities that create an increased background of pollution.

The most environmentally hazardous are the industries associated with the distillation of hydrocarbon systems - oil and heavy oil residues, the purification of oils using aromatic substances, the production of elemental sulfur, and treatment facilities.

Impact on the atmosphere of agricultural enterprises. Atmospheric air pollution by agricultural enterprises is carried out mainly through emissions of polluting gaseous and suspended substances from ventilation installations that ensure normal living conditions for animals and humans in production facilities for keeping livestock and poultry. Additional pollution comes from boilers as a result of the processing and release of combustion products of fuel into the atmosphere, from exhaust gases from motor and tractor equipment, from fumes from manure storage tanks, as well as from spreading manure, fertilizers and other chemicals. It is impossible not to take into account the dust generated during the harvesting of field crops, loading, unloading, drying and finalizing bulk agricultural products.

The fuel and energy complex (thermal power plants, combined heat and power plants, boiler plants) emits smoke into the atmospheric air, which is formed during the combustion of solid and liquid fuels. Air emissions from fuel-burning plants contain products of complete combustion - sulfur oxides and ash, products of incomplete combustion - mainly carbon monoxide, soot and hydrocarbons. The total volume of all emissions is very significant. For example, a thermal power plant that consumes 50 thousand tons of coal containing approximately 1% sulfur every month emits 33 tons of sulfuric anhydride into the atmosphere every day, which can turn (under certain meteorological conditions) into 50 tons of sulfuric acid. In one day, such a power plant produces up to 230 tons of ash, which is partially (about 40-50 tons per day) released into the environment within a radius of up to 5 km. Emissions from thermal power plants that burn oil contain almost no ash, but emit three times more sulfuric anhydride.

Air pollution from the oil-producing, oil-refining and petrochemical industries contains a large amount of hydrocarbons, hydrogen sulfide and foul-smelling gases. The emission of harmful substances into the atmosphere at oil refineries occurs mainly due to insufficient sealing of equipment. For example, atmospheric air pollution with hydrocarbons and hydrogen sulfide is noted from metal tanks of raw material parks for unstable oil, intermediate and commodity parks for light oil products.

There are two main sources of air pollution: natural and anthropogenic.

The natural source is volcanoes, dust storms, weathering, forest fires, decomposition processes of plants and animals.

Anthropogenic, mainly divided into three main sources of air pollution: industry, household boilers, transport. The share of each of these sources in total air pollution varies greatly from place to place.

It is now generally accepted that industrial production pollutes the air the most. Sources of pollution are thermal power plants, which, together with smoke, emit sulfur dioxide and carbon dioxide into the air; metallurgical enterprises, especially non-ferrous metallurgy, which emit nitrogen oxides, hydrogen sulfide, chlorine, fluorine, ammonia, phosphorus compounds, particles and compounds of mercury and arsenic into the air; chemical and cement plants. Harmful gases enter the air as a result of fuel combustion for industrial needs, home heating, transport, combustion and processing of household and industrial waste.

According to scientists (1990), every year in the world as a result of human activities, 25.5 billion tons of carbon oxides, 190 million tons of sulfur oxides, 65 million tons of nitrogen oxides, 1.4 million tons of nitrogen oxides enter the atmosphere. chlorofluorocarbons (freons), organic lead compounds, hydrocarbons, including carcinogenic (causing cancer) Protection of the atmosphere from industrial pollution. / Ed. S. Calvert and G. Englund. - M.: "Metallurgy", 1991., p. 7..

The most common atmospheric pollutants enter it mainly in two forms: either in the form of suspended particles (aerosols) or in the form of gases. By mass, the lion's share - 80-90 percent - of all emissions into the atmosphere due to human activities are gaseous emissions. There are 3 main sources of gaseous pollution: combustion of combustible materials, industrial production processes and natural sources.

Consider the main harmful impurities of anthropogenic origin Grushko Ya.M. Harmful organic compounds in industrial emissions into the atmosphere. - Leningrad.: "Chemistry", 1991., p. 15-27..

• - Carbon monoxide. It is obtained by incomplete combustion of carbonaceous substances. It enters the air as a result of burning solid waste, with exhaust gases and emissions from industrial enterprises. At least 1250 million tons of this gas enters the atmosphere every year. Carbon monoxide is a compound that actively reacts with the constituent parts of the atmosphere and contributes to an increase in the temperature on the planet and the creation of a greenhouse effect.
• - Sulfur dioxide. It is emitted during the combustion of sulfur-containing fuel or the processing of sulfurous ores (up to 170 million tons per year). Part of the sulfur compounds is released during the combustion of organic residues in mining dumps. In the United States alone, the total amount of sulfur dioxide emitted into the atmosphere amounted to 65% of the global emission.
• - Sulfuric anhydride. It is formed during the oxidation of sulfur dioxide. The end product of the reaction is an aerosol or solution of sulfuric acid in rainwater, which acidifies the soil and exacerbates human respiratory diseases. The precipitation of sulfuric acid aerosol from smoke flares of chemical enterprises is observed at low cloudiness and high air humidity. Leaf blades of plants growing at a distance of less than 11 km. from such enterprises, are usually densely dotted with small necrotic spots formed in places where droplets of sulfuric acid have settled. Pyrometallurgical enterprises of non-ferrous and ferrous metallurgy, as well as thermal power plants, annually emit tens of millions of tons of sulfuric anhydride into the atmosphere.
• - Hydrogen sulfide and carbon disulfide. They enter the atmosphere separately or together with other sulfur compounds. The main sources of emissions are enterprises for the production of artificial fiber, sugar, coke-chemical, oil refineries, as well as oil fields. In the atmosphere, when interacting with other pollutants, they undergo slow oxidation to sulfuric anhydride.
• - Nitrogen oxides. The main sources of emissions are enterprises producing nitrogen fertilizers, nitric acid and nitrates, aniline dyes, nitro compounds, viscose silk, and celluloid. The amount of nitrogen oxides entering the atmosphere is 20 million tons per year.
• - Fluorine compounds. Sources of pollution are enterprises producing aluminum, enamels, glass, ceramics, steel, and phosphate fertilizers. Fluorine-containing substances enter the atmosphere in the form of gaseous compounds - hydrogen fluoride or dust of sodium and calcium fluoride. The compounds are characterized by a toxic effect. Fluorine derivatives are strong insecticides.
• - Compounds of chlorine. They enter the atmosphere from chemical enterprises producing hydrochloric acid, chlorine-containing pesticides, organic dyes, hydrolytic alcohol, bleach, soda. In the atmosphere, they are found as an admixture of chlorine molecules and hydrochloric acid vapors. The toxicity of chlorine is determined by the type of compounds and their concentration. In the metallurgical industry, during the smelting of pig iron and its processing into steel, various heavy metals and toxic gases are released into the atmosphere. So, in terms of 1 ton of pig iron, in addition to 12.7 kg. sulfur dioxide and 14.5 kg of dust particles that determine the amount of compounds of arsenic, phosphorus, antimony, lead, mercury vapor and rare metals, tar substances and hydrogen cyanide.

In addition to gaseous pollutants, a large amount of particulate matter enters the atmosphere. These are dust, soot and soot. Contamination of the natural environment with heavy metals poses a great danger. Lead, cadmium, mercury, copper, nickel, zinc, chromium, vanadium have become almost constant components of the air in industrial centers.

Aerosols are solid or liquid particles suspended in the air. The solid components of aerosols in some cases are especially dangerous for organisms, and cause specific diseases in humans. In the atmosphere, aerosol pollution is perceived in the form of smoke, fog, mist or haze. A significant part of aerosols is formed in the atmosphere when solid and liquid particles interact with each other or with water vapor. The average size of aerosol particles is 1-5 microns. About 1 cubic meter enters the Earth's atmosphere every year. km of dust particles of artificial origin. A large number of dust particles are also formed during the production activities of people. Information on some sources of man-made dust is given in Appendix 3.

The main sources of artificial aerosol air pollution are thermal power plants, which consume high-ash coal, enrichment plants, metallurgical, cement, magnesite and carbon black plants. Aerosol particles from these sources are distinguished by a wide variety of chemical composition. Most often, compounds of silicon, calcium and carbon are found in their composition, less often - oxides of metals: iron, magnesium, manganese, zinc, copper, nickel, lead, antimony, bismuth, selenium, arsenic, beryllium, cadmium, chromium, cobalt, molybdenum, as well as asbestos.

Permanent sources of aerosol pollution are industrial dumps - artificial mounds of redeposited material, mainly overburden, formed during mining or from waste from processing industries, thermal power plants.

The source of dust and poisonous gases is mass blasting. So, as a result of one medium-sized explosion (250-300 tons of explosives), about 2 thousand cubic meters are released into the atmosphere. m. of conditional carbon monoxide and more than 150 tons of dust.

The production of cement and other building materials is also a source of air pollution with dust. The main technological processes of these industries - grinding and chemical processing of semi-finished products and products obtained in hot gas streams are always accompanied by emissions of dust and other harmful substances into the atmosphere.

The main air pollutants today are carbon monoxide and sulfur dioxide (Appendix 2).

But, of course, we must not forget about freons, or chlorofluorocarbons. Most scientists consider them to be the reason for the formation of the so-called ozone holes in the atmosphere. Freons are widely used in production and in everyday life as refrigerants, foaming agents, solvents, as well as in aerosol packages. Namely, with a decrease in the ozone content in the upper atmosphere, doctors attribute an increase in the number of skin cancers. It is known that atmospheric ozone is formed as a result of complex photochemical reactions under the influence of ultraviolet radiation from the Sun. Although its content is small, its importance for the biosphere is enormous. Ozone, absorbing ultraviolet radiation, protects all life on earth from death. Freons, getting into the atmosphere, under the influence of solar radiation, decompose into a number of compounds, of which chlorine oxide most intensively destroys ozone.

Distinguish natural(natural) and anthropogenic(artificial) sources of pollution. To natural sources include: dust storms, fires, various aerosols of plant, animal or microbiological origin, etc. Anthropogenic emissions into the atmosphere annually amount to more than 19 billion tons, of which more than 15 billion tons of carbon dioxide, 200 million tons of carbon monoxide, more than 500 million tons of hydrocarbons, 120 million tons of ash, etc.

On the territory of the Russian Federation, for example, in 1991, emissions of pollutants into the air amounted to about 53 million tons, including industry - 32 million tons (61%), motor transport - 21 million tons (39%). In one of the largest regions of the country, the Rostov region, emissions of pollutants into the atmospheric air in 1991 and 1996 amounted to 944.6 thousand tons and 858.2 thousand tons, respectively, including:

solids	112.6 thousand tons
sulfur dioxide	184.1 thousand tons	133.0 thousand tons
carbon monoxide	464.0 thousand tons	467.1 thousand tons
nitrogen oxide
hydrocarbons
flying org. conn.

More than half of the total is emissions from vehicles. Pollution is mainly obtained as by-products or wastes from the extraction, processing and use of resources, and can also be a form of harmful energy emissions, such as excess heat, noise and radiation.

Most natural pollutants (eg volcanic eruption, coal burning) are dispersed over a wide area, and their concentration is often reduced to a safe level (due to decomposition, dissolution and dispersion). Anthropogenic air pollution occurs in urban areas, where large amounts of pollutants are concentrated in small volumes of air.

The following eight categories of pollutants are considered the most dangerous and widespread:

1) suspensions - the smallest particles of a substance in suspension;

2) hydrocarbons and other volatile organic compounds in the air in the form of vapors;

3) carbon monoxide (CO) - extremely toxic;

4) nitrogen oxides (NO x) - gaseous compounds of nitrogen and oxygen;

5) sulfur oxides (SO 2 dioxide) - a poisonous gas that is dangerous for plants and animals;

6) heavy metals (copper, tin, mercury, zinc, etc.);

7) ozone and other photochemical oxidizers;

8) acids (mainly sulfuric and nitric).

Consider what these pollutants are and how they are formed.

In large cities, two main types of pollutant sources can be found: point such as CHP chimney, chimney, car exhaust, etc. and non-point- entering the atmosphere from extensive sources.

There are solid, liquid and gaseous substances that pollute the environment.

Solid- are formed during the mechanical processing of materials or their transportation, during combustion and thermal production processes. These include dust and suspensions formed: the first - during the extraction, processing and transportation of bulk materials, various technological processes and wind erosion; the second - in the open burning of waste and from industrial pipes as a result of a variety of technological processes.

Liquid pollutants are the product of chemical reactions, condensation or liquid spraying in technological processes. The main liquid pollutants are oil and products of its processing, polluting the atmosphere with hydrocarbons.

gaseous pollutants are formed as a result of chemical reactions, electrochemical processes, fuel combustion, reduction reactions. The most common pollutants in the gaseous state are: carbon monoxide CO, carbon dioxide CO 2, nitrogen oxides NO, N 2 O, NO 2, NO 3, N 2 O 5, sulfur dioxide SO 2, chlorine and fluorine compounds.

Consider the most dangerous, widespread pollutants. What are they and what is their danger?

1. Dust and suspension- these are fine particles suspended in the air, for example, smoke and soot (Table 4.2). The main sources of particulate matter are industrial pipes, transport and open burning of fuel. We can observe such suspensions in the form of smog or haze.

By dispersion, i.e. degrees of grinding distinguish dust:

Coarse - with particles larger than 10 microns, settling in still air with increasing speed;

Medium-dispersed - with particles from 10 to 5 microns, slowly settling in still air;

Fine and smoke - with particles 5 microns in size, quickly dissipating in the environment and almost not settling.

Table 4.2

Main sources of air pollution

	Aerosols	Gaseous emissions
Boilers and industrial furnaces		NO 2, SO 2, as well as CO, aldehydes (HCHO), organic acids, benzapyrene
Automotive engines		CO, NO 2 , aldehydes, non-carcinogenic hydrocarbons, benzapyrene
Oil refining industry		SO 2 , H 2 S, NH 3 , NO x , CO, hydrocarbons, acids, aldehydes, carcinogens
Chemical industry		Depending on the process (H 2 S, CO, NH 3), acids, organics, solvents, volatile sulfides, etc.
Metallurgy and coke chemistry		SO 2 , CO, NH 3 , NO X , fluorine and cyanide compounds, organic substances, benzapyrene
Mining		Depending on the process (CO, fluorides, organics)
food industry		NH 3 , H 2 S, mixtures of organic compounds
Building materials industry		CO, organic compounds

Dust that can remain suspended in the air for some time is called spray can, in contrast to settled dust, called airgel. Fine dust poses the greatest danger to the body, since it does not linger in the upper respiratory tract and can penetrate deep into the lungs. In addition, fine dust can be a conductor of various toxic substances into the human body, for example, heavy metals, which, on dust particles, can penetrate deep into the respiratory tract.

Other examples can be given: the combination of sulfur dioxide with dust irritates the skin and mucous membranes, with an increase in concentration it leads to respiratory failure and chest pain, and at very high concentrations, far exceeding the MPC, causes death from suffocation.

In machine-building enterprises, especially in the shops of hot and cold metal processing, a lot of dust, toxic and irritating gases are released into the air of working areas. The modern standard sets the MPC for harmful substances of about 1000 types. According to the degree of impact on the body, harmful substances are divided into four classes:

1st - substances are extremely dangerous;

2nd - highly dangerous substances;

3rd - moderately dangerous substances;

4th - substances of low danger.

The hazard class of substances is established depending on the norms and indicators (Table 4.3).

Table 4.3

Hazard classes and pollution levels

The maximum permissible concentrations of harmful substances in the air of the working area are concentrations that, during daily 8-hour (except weekends) work or for other durations (but not more than 41 hours per week) during the entire working experience, do not cause diseases or deviations in the state health.

The maximum permissible concentration represents the primary standard, which is a criterion for pollution, this is the maximum level of pollution that a person can tolerate without harm to health, plus 10-15% as a margin of safety.

2. hydrocarbons are organic compounds of carbon and hydrogen. In engineering and industry, they are used as energy carriers, for example, natural gas, propane, gasoline, solvents for paints and cleaning products, etc. Among the most dangerous hydrocarbons, benzapyrene occupies an important place - a component of vehicle exhaust gases and atmospheric emissions from coal-fired ovens.

3. Carbon monoxide. With the complete combustion of fuel and waste, which are organic compounds, carbon dioxide and water are formed:

CH 4 + 2O 2 \u003d CO 2 + 2H 2 O.

In the case of complete combustion, carbon dioxide is released into the air, also called carbon dioxide (CO 2) with incompletely oxidized carbon - carbon monoxide (CO).

Carbon dioxide, a colorless gas with a slight odor, is formed during the respiration of living organisms, as well as during the combustion of coal, oil and gas at thermal stations, boiler houses, etc. In small quantities, carbon dioxide is not dangerous, but in very large doses it leads to death. The content of CO 2 in the air is constantly growing, which is associated with an ever-increasing amount of burning coal and oil. Over the past 100 years, the content of carbon dioxide in the air has increased by about 14%. An increase in the carbon dioxide content in the air contributes to an increase in the temperature on Earth, since the carbon dioxide layer creates a powerful screen that does not let the heat emitted by the Earth into space, which disrupts the natural heat exchange between the planet and its surrounding space. This so-called greenhouse, or greenhouse effect.

Carbon monoxide (CO) is not completely oxidized carbon, the so-called carbon monoxide. CO is a poisonous gas that is colorless and odorless. Inhalation of carbon monoxide blocks the flow of oxygen into the blood, leads to oxygen starvation of tissues, followed by fainting, paralysis of the respiratory tract and death.

4. nitrogen oxides(NO x) - gaseous compounds of substances produced by microorganisms; can also be formed in the products of fuel combustion in automobile engines, in the chemical industry, for example, in the production of nitric acid. At high combustion temperatures, part of the nitrogen (N 2) is oxidized, forming monoxide (NO), which in air, reacting with oxygen, is oxidized to dioxide (NO 2) and / or tetroxide (N 2 O 4).

Nitrogen oxides contribute to the emergence of photochemical smog formed from the products of the reaction between nitrogen oxides and unsaturated hydrocarbons under the active influence of ultraviolet radiation from the Sun.

Nitrogen oxides irritate the respiratory organs, mucous membranes, especially the lungs and eyes, and also have a negative effect on the human brain and nervous system.

5. Sulfur dioxide or the so-called sulfur dioxide (SO 2 ) - a sharp-smelling, colorless gas that irritates the respiratory tract of humans and animals, especially in fine dust environments. The main sources of air pollution with sulfur dioxide are fossil fuels burned in power plants. Fuel and waste that enter the air during combustion contain sulfur (for example, in coal from 0.2 to 5.5% sulfur). During combustion, sulfur is oxidized to form SO 2 . Sulfur dioxide causes serious damage to the environment - under the influence of SO 2, plants partially die off chlorophyll, which adversely affects agricultural crops, forest trees, water bodies, falling out in the form of so-called acid rain.

6. Heavy metals, polluting the environment, bring great harm to man and nature. Lead, mercury, cadmium, copper, nickel, zinc, chromium, vanadium are permanent components of the air in large industrial centers. Heavy metal impurities can contain coal, as well as various wastes.

Examples: where tetraethyl lead is used as an additive in gasoline to cheaply prevent engine knocking (in a number of countries this method of addition is prohibited), the air is significantly polluted with lead. Released with exhaust gases, this harmful heavy metal remains in the air and, before settling, is carried by the wind over long distances.

Another heavy metal, mercury, getting from polluted air into water in the process of bioaccumulation in lakes, enters the organisms of fish, which creates a serious danger of human poisoning along the food chain.

7. Ozone and various active organic compounds, which are formed in the process of chemical interactions of nitrogen oxides with volatile hydrocarbons, stimulated by the rays of the sun. The products of these reactions are called photochemical oxidants. For example, under the influence of solar energy, nitrogen dioxide decomposes into monoxide and an oxygen atom, which, combining with O 2, forms ozone O 3.

8. acids, predominantly sulfuric and nitric, which form acid rain.

What objects of sources of atmospheric pollution constitute the main danger to the health of the planet?

The main air pollutants in industrialized countries are cars and other modes of transport, industrial enterprises, thermal power plants, large complexes of the military industry and nuclear energy.

Motor transport pollutes the air of cities with carbon and nitrogen monoxide, hydrocarbons and other harmful substances. Annual car emissions in Russia in the early 90s amounted to 36 million tons or 37% of the total emissions (about 100 million tons / year), including: nitrogen oxides - 22%, hydrocarbons - 42%, carbon oxides - about 46% (the largest volume of emissions from cars was noted in Moscow - more than 840 thousand tons / year).

Now in the world there are several hundred million only private cars, almost half of them - about 200 million - in the Americas. In Japan, due to the limited territory, there are almost 7 times more motorists per unit area than in the United States. On the conscience of the car - this "chemical factory on wheels" - more than 60% of all harmful substances in the city air. Vehicle exhaust gases contain about 200 substances that are harmful to health and nature. They contain unburned or incompletely decomposed fuel hydrocarbons. The amount of hydrocarbons increases dramatically if the engine is running at low speeds or at increased speed, for example, when starting at intersections at traffic lights. At the moment of pressing the accelerator pedal, a large number of unburned particles are released (10-12 times more than in normal mode). In addition, the unburned exhaust gases of the engine during normal operation contain about 2.7% carbon monoxide, the amount of which increases with a decrease in speed to about 3.9-4%, and at low speed - up to 6.9%.

Exhaust gases, including carbon monoxide, carbon dioxide and many other engine emissions, are heavier than air, so they all accumulate near the ground, poisoning people and vegetation. With the complete combustion of fuel in the engine, part of the hydrocarbons turns into soot containing various resins. Especially in the event of an engine failure, a black plume of smoke trails behind the car, containing polycyclic hydrocarbons, including benzapyrene. Exhaust gases also contain nitrogen oxides, aldehydes, which have a pungent odor and irritating effect, and inorganic lead compounds.

Ferrous metallurgy is one of the major sources of air pollution with dust and gases. In the process of smelting pig iron and processing it into steel, dust emissions per 1 ton of hot metal are 4.5 kg, sulfur dioxide - 2.7 kg and manganese - 0.5-0.1 kg.

A significant role in air pollution is played by emissions from open-hearth and converter steel-smelting shops. Emissions from open-hearth furnaces mainly contain dust from iron trioxide (76%) and aluminum trioxide (8.7%). With an oxygen-free process, 3000-4000 m 3 of gases are released per 1 ton of open-hearth steel with a dust concentration of about 0.6-0.8 g/m 3 . In the process of supplying oxygen to the zone of molten metal, the formation of dust increases significantly, reaching 15-52 g/m 3 . At the same time, hydrocarbon and sulfur burn out, and therefore the emissions of open-hearth furnaces contain up to 60 kg of carbon monoxide and up to 3 kg of sulfur dioxide per 1 ton of steel produced.

The process of obtaining steel in converter furnaces is characterized by the emission of flue gases into the atmosphere, consisting of particles of oxides of silicon, manganese and phosphorus. The composition of the smoke contains up to 80% carbon monoxide, and the concentration of dust in the exhaust gases is about 15 g/m3.

Emissions from non-ferrous metallurgy contain technical dust-like substances: arsenic, lead, fluorine, etc., therefore they pose a serious danger to human health and the environment. In the process of aluminum production by electrolysis, a large amount of gaseous and dusty fluorine compounds are emitted into the atmosphere. To obtain 1 ton of aluminum, from 33 to 47 kg of fluorine is consumed (depending on the power of the electrolyzer), more than 65% of which enters the atmosphere.

Chemical industry enterprises are among the most dangerous sources of air pollution. The composition of their emissions is very diverse and contains many new, extremely harmful substances. We know little about the potentially harmful effects of 80% of these substances on humans, animals and nature. The main emissions of chemical industry enterprises include carbon monoxide, nitrogen oxides, sulfur dioxide, ammonia, organic substances, hydrogen sulfide, chloride and fluorine compounds, dust from inorganic industries, etc.

The fuel and energy complex (thermal power plants, combined heat and power plants, boiler plants) emits smoke into the atmospheric air, which is formed during the combustion of solid and liquid fuels. Air emissions from fuel-burning plants contain products of complete combustion - sulfur oxides and ash, products of incomplete combustion - mainly carbon monoxide, soot and hydrocarbons. The total volume of all emissions is very significant. For example, a thermal power plant that consumes 50 thousand tons of coal containing approximately 1% sulfur every month emits 33 tons of sulfuric anhydride into the atmosphere every day, which can turn (under certain meteorological conditions) into 50 tons of sulfuric acid. In one day, such a power plant produces up to 230 tons of ash, which is partially (about 40-50 tons per day) released into the environment within a radius of up to 5 km. Emissions from thermal power plants that burn oil contain almost no ash, but emit three times more sulfuric anhydride.

Air pollution from the oil-producing, oil-refining and petrochemical industries contains a large amount of hydrocarbons, hydrogen sulfide and foul-smelling gases.

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