Atmospheric pollution The atmosphere is the air envelope of the Earth. The quality of the atmosphere is understood as the totality of its properties that determine the degree of impact of physical, chemical and biological factors on people, flora and fauna, as well as on materials, structures and the environment in general. Atmospheric pollution is understood as the introduction of impurities into it that are not contained in natural air or change the ratio between the ingredients of the natural composition of air. The population of the Earth and the rate of its growth are the predetermining factors for increasing the intensity of pollution of all geospheres of the Earth, including the atmosphere, since with their increase, the volumes and rates of everything that is extracted, produced, consumed and sent to waste increase. Main air pollutants: Carbon monoxide Nitrogen oxides Sulfur dioxide Hydrocarbons Aldehydes Heavy metals (Pb, Cu, Zn, Cd, Cr) Ammonia Atmospheric dust
Impurities Carbon monoxide (CO) is a colorless, odorless gas also known as carbon monoxide. It is formed as a result of incomplete combustion of fossil fuels (coal, gas, oil) in conditions of lack of oxygen and at low temperatures. At the same time, 65% of all emissions come from transport, 21% - from small consumers and the household sector, and 14% - from industry. When inhaled, carbon monoxide, due to the double bond present in its molecule, forms strong complex compounds with human blood hemoglobin and thereby blocks the flow of oxygen into the blood. Carbon dioxide (CO2) - or carbon dioxide, is a colorless gas with a sour smell and taste, a product of the complete oxidation of carbon. It is one of the greenhouse gases.
Impurities The greatest air pollution is observed in cities where ordinary pollutants are dust, sulfur dioxide, carbon monoxide, nitrogen dioxide, hydrogen sulfide, etc. In some cities, due to the peculiarities of industrial production, the air contains specific harmful substances, such as sulfuric and hydrochloric acid, styrene, benzapyrene, carbon black, manganese, chromium, lead, methyl methacrylate. In total, there are several hundred different air pollutants in cities.
Impurities Sulfur dioxide (SO2) (sulfur dioxide, sulfur dioxide) is a colorless gas with a pungent odor. It is formed during the combustion of sulfur-containing fossil fuels, mainly coal, as well as during the processing of sulfur ores. It is primarily involved in the formation of acid rain. The global SO2 emission is estimated at 190 million tons per year. Prolonged exposure to sulfur dioxide on a person first leads to a loss of taste, shortness of breath, and then to inflammation or edema of the lungs, interruptions in cardiac activity, impaired blood circulation and respiratory arrest. Nitrogen oxides (nitrogen oxide and nitrogen dioxide) are gaseous substances: nitrogen monoxide NO and nitrogen dioxide NO2 are combined by one general formula NOx. In all combustion processes, nitrogen oxides are formed, mostly in the form of an oxide. The higher the combustion temperature, the more intense the formation of nitrogen oxides. Another source of nitrogen oxides are enterprises producing nitrogen fertilizers, nitric acid and nitrates, aniline dyes, nitro compounds. The amount of nitrogen oxides entering the atmosphere is 65 million tons per year. Of the total amount of nitrogen oxides emitted into the atmosphere, transport accounts for 55%, energy - 28%, industrial enterprises - 14%, small consumers and the household sector - 3%.
Impurities Ozone (O3) is a gas with a characteristic odor, a stronger oxidizing agent than oxygen. It is considered one of the most toxic of all common air pollutants. In the lower atmospheric layer, ozone is formed as a result of photochemical processes involving nitrogen dioxide and volatile organic compounds. Hydrocarbons are chemical compounds of carbon and hydrogen. These include thousands of different air pollutants found in unburned gasoline, dry cleaning fluids, industrial solvents, and more. Lead (Pb) is a silvery gray metal that is toxic in any known form. Widely used for paint, ammunition, printing alloy, etc. about 60% of the world's lead production is consumed annually for the production of acid batteries. However, the main source (about 80%) of air pollution with lead compounds is the exhaust gases of vehicles that use leaded gasoline. Industrial dusts, depending on the mechanism of their formation, are divided into the following 4 classes: mechanical dust - is formed as a result of grinding the product during the technological process; sublimates - are formed as a result of volumetric condensation of vapors of substances during cooling of a gas passed through a process apparatus, installation or unit; fly ash - the non-combustible fuel residue contained in the flue gas in suspension, is formed from its mineral impurities during combustion; Industrial soot is a solid highly dispersed carbon, which is part of an industrial emission, and is formed during incomplete combustion or thermal decomposition of hydrocarbons. The main sources of anthropogenic aerosol air pollution are thermal power plants (TPP) that consume coal. Combustion of coal, production of cement and smelting of pig iron give a total emission of dust into the atmosphere equal to 170 million tons per year.
Atmospheric pollution Impurities enter the atmosphere in the form of gases, vapors, liquid and solid particles. Gases and vapors form mixtures with air, and liquid and solid particles form aerosols (dispersed systems), which are divided into dust (particle sizes over 1 µm), smoke (solid particle sizes less than 1 µm) and fog (liquid particle sizes less than 10 µm). ). Dust, in turn, can be coarse (particle size over 50 µm), medium-dispersed (50-10 µm) and fine (less than 10 µm). Depending on the size, liquid particles are divided into superfine mist (up to 0.5 µm), fine mist (0.5-3.0 µm), coarse mist (3-10 µm) and spray (over 10 µm). Aerosols are often polydisperse; contain particles different size. The second source of radioactive impurities is the nuclear industry. Impurities enter the environment during the extraction and enrichment of fossil raw materials, their use in reactors, and the processing of nuclear fuel in installations. Permanent sources of aerosol pollution include industrial dumps - artificial mounds of redeposited material, mainly overburden, formed during mining or from waste from processing industries, thermal power plants. Production of cement and others building materials It is also a source of air pollution with dust. The combustion of hard coal, the production of cement and the smelting of pig iron give a total emission of dust into the atmosphere equal to 170 million tons/year. A significant part of aerosols is formed in the atmosphere when solid and liquid particles interact with each other or with water vapor. Among the dangerous anthropogenic factors that contribute to a serious deterioration in the quality of the atmosphere, one should include its pollution with radioactive dust. The residence time of small particles in the lower layer of the troposphere is on average several days, and in the upper one day. As for the particles that have entered the stratosphere, they can stay in it for up to a year, and sometimes more.
Atmospheric pollution The main sources of anthropogenic aerosol air pollution are thermal power plants (TPP) that consume high-ash coal, processing plants, metallurgical, cement, magnesite and other plants. Aerosol particles from these sources are characterized by great chemical diversity. 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, and asbestos. An even greater variety is characteristic of organic dust, including aliphatic and aromatic hydrocarbons, acid salts. It is formed during the combustion of residual petroleum products, during the pyrolysis process at oil refineries, petrochemical and other similar enterprises.
IMPACT OF ATMOSPHERIC POLLUTION ON HUMANS All pollutants atmospheric air substances to a greater or lesser extent have a negative impact on human health. These substances enter the human body mainly through the respiratory system. The respiratory organs are directly affected by pollution, since about 50% of impurity particles with a radius of 0. µm that penetrate into the lungs are deposited in them. Statistical analysis made it possible to fairly reliably establish the relationship between the level of air pollution and diseases such as upper respiratory tract damage, heart failure, bronchitis, asthma, pneumonia, emphysema, and eye diseases. A sharp increase in the concentration of impurities, which persists for several days, increases the mortality of the elderly from respiratory and cardiovascular diseases. In December 1930, in the valley of the river Meuse (Belgium), severe air pollution was noted for 3 days; as a result, hundreds of people fell ill and 60 people died - more than 10 times the average death rate. In January 1931, in the area of Manchester (Great Britain), for 9 days, there was a strong smoke in the air, which caused the death of 592 people. Cases of severe pollution of the atmosphere of London, accompanied by numerous deaths, were widely known. In 1873 there were 268 unforeseen deaths in London. Heavy smoke combined with fog between 5 and 8 December 1852 resulted in the deaths of over 4,000 residents of Greater London. In January 1956, about 1,000 Londoners died as a result of prolonged smoke. Most of those who died unexpectedly suffered from bronchitis, emphysema, or cardiovascular disease.
EFFECT OF ATMOSPHERIC POLLUTION ON HUMANS Nitrogen oxides and some other substances Nitrogen oxides (primarily poisonous nitrogen dioxide NO2), which combine with ultraviolet solar radiation with hydrocarbons (oleophins are the most reactive), form peroxylacetyl nitrate (PAN) and other photochemical oxidants, including peroxybenzoyl nitrate (PBN), ozone (O3), hydrogen peroxide (H2O2), nitrogen dioxide. These oxidizing agents are the main components of photochemical smog, the frequency of which is high in heavily polluted cities located at low latitudes of the northern and southern hemispheres (Los Angeles, where smog is observed for about 200 days a year, Chicago, New York and other US cities; a number of cities Japan, Turkey, France, Spain, Italy, Africa and South America).
IMPACT OF ATMOSPHERIC POLLUTION ON HUMANS Let us name some other air pollutants that have a harmful effect on humans. It has been established that people who professionally deal with asbestos have an increased likelihood of cancer of the bronchi and diaphragms that separate chest and abdominal cavity. Beryllium has a harmful effect (up to the oncological diseases) on the respiratory tract, as well as on the skin and eyes. Mercury vapor causes disruption of the central upper system and kidneys. Since mercury can accumulate in the human body, eventually exposure to it leads to a disorder mental ability. In cities, due to ever-increasing air pollution, the number of patients suffering from diseases such as chronic bronchitis, emphysema, various allergic diseases and lung cancer. In the UK, 10% of deaths are due to chronic bronchitis, with 21; of the population aged years suffers from this disease. In Japan, in a number of cities, up to 60% of residents are sick chronic bronchitis, the symptoms of which are a dry cough with frequent expectoration, subsequent progressive difficulty in breathing and heart failure (in this regard, it should be noted that the so-called Japanese economic miracle of the 50s and 60s was accompanied by severe pollution of the natural environment of one of the most beautiful regions of the earth ball and serious damage to the health of the population of that country). In recent decades, the number of bronchial and lung cancers, which are promoted by carcinogenic hydrocarbons, has been growing at a rate of great concern. The influence of radioactive substances on the flora and fauna Spreading through the food chain(from plants to animals), radioactive substances enter the human body with food and can accumulate in such quantities that can harm human health.
EFFECT OF ATMOSPHERIC POLLUTION ON HUMANS Radiation of radioactive substances has the following effects on the body: weaken the irradiated body, slow down growth, reduce resistance to infections and the body's immunity; reduce life expectancy, reduce natural growth rates due to temporary or complete sterilization; affect genes in various ways, the consequences of which appear in the second or third generations; have a cumulative (cumulative) effect, causing irreversible effects. The severity of the consequences of irradiation depends on the amount of energy (radiation) absorbed by the body and emitted by the radioactive substance. The unit of this energy is 1 row - this is the dose of radiation at which 1 g of living matter absorbs 10-5 J of energy. It has been established that at a dose exceeding 1000 rad, a person dies; at a dose of 7000 and 200 glad death occurs in 90 and 10% of cases, respectively; in the case of a dose of 100 rad, a person survives, but the likelihood of cancer is significantly increased, as well as the likelihood of complete sterilization.
IMPACT OF ATMOSPHERIC POLLUTION ON HUMANS It is not surprising that people have adapted well to the natural radioactivity of the environment. Moreover, groups of people are known to live in areas with high radioactivity, much higher than the average. the globe(for example, in one of the regions of Brazil, residents receive about 1600 mrad per year, which is several times more than the usual radiation dose). On average, the dose of ionizing radiation received per year by each inhabitant of the planet ranges between 50 and 200 mrad, and the share of natural radioactivity (cosmic rays) accounts for about 25 billion radioactivity of rocks - approximately mrad. It should also take into account the doses that a person receives from artificial sources of radiation. In the UK, for example, a person receives about 100 mrad each year during fluoroscopic examinations. TV radiation - about 10 mrad. Nuclear industry waste and radioactive fallout - about 3 mrad.
Conclusion At the end of the 20th century, world civilization entered a stage of its development when the problems of survival and self-preservation of mankind, the preservation of the natural environment and the rational use of natural resources came to the fore. Modern stage development of mankind has exposed the problems caused by the growth of the population of the Earth, the contradictions between traditional management and the increasing rate of use of natural resources, pollution of the biosphere by industrial waste and the limited capacity of the biosphere to neutralize them. These contradictions hinder the further scientific and technological progress of mankind, become a threat to its existence. Only in the second half of the 20th century, thanks to the development of ecology and the dissemination of environmental knowledge among the population, it became obvious that humanity is an indispensable part of the biosphere, that the conquest of nature, the uncontrolled use of its resources and pollution environment- a dead end in the development of civilization and in the evolution of man himself. That's why essential condition development of mankind - respect for nature, comprehensive care for rational use and restoration of its resources, preservation of a favorable environment. However, many do not understand the close relationship between human economic activity and the state of the natural environment. Broad environmental education should help people to acquire such environmental knowledge and ethical norms and values, attitudes and lifestyles that are necessary for the sustainable development of nature and society.
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, which consume high-ash coal, enrichment plants, metallurgical, cement, magnesite and soot plants, which emit dust, sulfur dioxide and other harmful gases into the atmosphere, released during various technological processes. 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 aluminum metal 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. Release to the atmosphere harmful substances in 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.
Sources of air pollution with pesticides include warehouses, seed dressing and the fields themselves, on which pesticides are applied in one form or another and mineral fertilizers and cotton gins.
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. A group of sanitary measures - the 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 landscaping.
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 recycling the captured ingredients is associated with the appearance of an additional raw material source, which, as a rule, has more favorable economic indicators compared with 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.
Man has been polluting the atmosphere for thousands of years, but the consequences of the use of fire, which he used throughout this period, were insignificant. I had to put up with the fact that the smoke interfered with breathing, and that the soot lay in a black cover on the ceiling and walls of the dwelling. The resulting heat was more important for a person than clean air and not sooty cave walls. This initial air pollution was not a problem, for people then lived in small groups, occupying an immeasurably vast untouched natural environment. And even a significant concentration of people in a relatively small area, as was the case in classical antiquity, was not yet accompanied by serious consequences.
This was the case until the beginning of the nineteenth century. Only in the last hundred years has the development of industry "gifted" us with such production processes, the consequences of which at first man could not yet imagine. Million-strong cities arose, the growth of which cannot be stopped. All this is the result of great inventions and conquests of man.
Basically, there are three main sources of air pollution: industry, domestic 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 - 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, 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. Atmospheric pollutants are divided into primary, entering directly into the atmosphere, and secondary, resulting from the transformation of the latter. So, sulfur dioxide entering the atmosphere is oxidized to sulfuric anhydride, which interacts with water vapor and forms droplets of sulfuric acid. When sulfuric anhydride reacts with ammonia, ammonium sulfate crystals are formed. Similarly, as a result of chemical, photochemical, physico-chemical reactions between pollutants and atmospheric components, other secondary signs are formed. The main source of pyrogenic pollution on the planet are thermal power plants, metallurgical and chemical enterprises, boiler plants that consume more than 170% of the annually produced solid and liquid fuels. The main harmful impurities of pyrogenic origin are the following:
- a) 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.
- b) Sulfur dioxide. It is released 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 was 65 percent of the global emissions.
- c) 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.
- d) 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 manufacture of artificial fiber, sugar, coke, oil refineries, and oil fields. In the atmosphere, when interacting with other pollutants, they undergo slow oxidation to sulfuric anhydride.
- e) 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. in year.
- f) 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.
- g) Chlorine compounds. 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 during its processing into steel, various heavy metals and toxic gases are released into the atmosphere. So, in terms of 11 tons of pig iron, in addition to 12.7 kg. 0 sulfur dioxide and 14.5 kg. 0 dust particles that determine the amount of compounds of arsenic, phosphorus, antimony, lead, mercury vapor and rare metals, resin substances and hydrogen cyanide.
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 manufacture of artificial fiber, sugar, coke, oil refineries, and 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, which 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 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 very diverse. 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 flows 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 upper layers Atmosphere physicians attribute the 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 action solar radiation decompose into a number of compounds, of which chlorine oxide destroys ozone most intensively.
Industrial enterprises as sources of environmental pollution
The industrial wastes of enterprises of the metallurgical, chemical, petrochemical, machine-building and other industries pollute the environment, which emit into the atmosphere a huge amount of ash, sulfur dioxide and other harmful gases emitted during various technological production processes. These enterprises pollute reservoirs and groundwater, affect flora and fauna. What characterizes these industries in terms of environmental protection? Black and non-ferrous metallurgy are the most polluting industries and rank first in terms of emissions of toxic substances. The share of metallurgy accounts for about 40% of the total Russian gross emissions of harmful substances, including about 26% for solids and about 34% for gaseous substances. Ferrous metallurgy enterprises are the main environmental pollutants in the cities and regions in which they are located. Dust emission per 1 ton of cast iron produced is 4.5 kg, sulfur dioxide - 2.7 kg and manganese - 0.6 ... 0.1 kg. Together with blast-furnace gas, compounds of arsenic, phosphorus, antimony, lead, as well as mercury vapor, hydrogen cyanide and tarry substances are emitted into the atmosphere. Permissible rate sulfur dioxide emissions during ore agglomeration 190 kg per 1 ton of ore. At the enterprises of the industry, there continues to be a large volume of discharges of polluted Wastewater containing chemicals: sulfates, chlorides, iron compounds, heavy metals. These discharges are so large that they turn rivers and reservoirs in their places into "extremely dirty". Ferrous metallurgy enterprises discharge 12% of polluted wastewater, which is more than a quarter of all toxic waste of Russian industry. The volume of polluted water discharges increased by 8% compared to previous years. Novolipetsk, Magnitogorsk, Zlatoust, Satka metallurgical plants became the largest industry sources of water pollution. Ferrous metallurgy enterprises affect the state of groundwater through filter tanks. Thus, the Novolipetsk Iron and Steel Works has become a source of groundwater pollution with rhodonides (up to 957 MPC), cyanides (up to 308 MPC), oil products and phenols. It should also be noted that this industry is a source of soil pollution. According to aerospace survey data, the soil cover contamination zone can be traced at a distance of up to 60 km from the pollution source. The main reasons for significant emissions and discharges of pollutants, as experts explain, is the incomplete equipment of enterprises treatment plants or their non-working state (according to different reasons). Only half of the wastewater is treated to the norm, and the neutralization of gaseous substances is only about 60% of the total emission. At the enterprises of non-ferrous metallurgy, despite the decline in production, the reduction of harmful environmental pollutants did not occur. As noted above, non-ferrous metallurgy continues to be the leader in environmental pollution in Russia. Suffice it to mention only the Norilsk Nickel Concern - the main supplier of non-ferrous and precious metals, which, along with the production of metal, supplies about 12% of the gross discharge of pollutants from the entire industry of Russia into the atmosphere. In addition, there are enterprises "Yuzhuralnickel" (Orsk); Sredneuralsky copper smelter (Revda); Achinsk Alumina Refinery (Achinsk); Krasnoyarsk aluminum plant; Mednogorsk copper-sulfur plant. Atmospheric pollution by these enterprises is mainly characterized by emissions of SO2 (more than 80% of the total emissions into the atmosphere), CO (10.5%) and dust (10.45%). Emissions to the atmosphere influence the formation of chemical fluxes over long distances. At non-ferrous metallurgy enterprises, there are large volumes of wastewater that are contaminated with mineral substances, fluorine reagents containing cyanides, petroleum products, xanthates, heavy metal salts (copper, lead, zinc, nickel), as well as arsenic, fluorine, antimony, sulfates, chlorides, etc. Heavy metals were found in the soil cover where the enterprises are located, exceeding the MPC by 2 ... 5 times or more. For example, around Rudnaya Pristan (Primorsky Territory), where a lead plant is located, soils with a radius of 5 km are contaminated with lead - 300 MPC and manganese - 2 MPC. There is no need to give examples of other cities. And now let's raise the question, what is the zone of pollution of the air basin and the earth's surface from the center of pollutant emissions. Here is an impressive example of research carried out by the Russian Ecological Fund on the degree of impact of pollution by non-ferrous metallurgy enterprises on ecosystems. On fig. 2.3 shows the zones of destroyed ecosystems from the center of harmful emissions. As can be seen from the figure, the configuration of the pollution field is close to circular; it can be in the form of an ellipse and other geometric shapes depending on the wind rose. According to the integral coefficient of conservation (IC,%) obtained (experimentally), the following zones of ecosystem disturbance were established: - complete destruction of ecosystems (technogenic wasteland); - severe destruction of the ecosystem. The average life expectancy of needles (coniferous forest) is 1...3 years instead of 11...13 years. There is no regeneration of coniferous forest; - partial disturbance of ecosystems. Precipitation of sulfate ion during the day is 3...7 kg/km2, non-ferrous metals - tens of grams per 1 km2. The resumption of life in the coniferous forest is very weak; - the initial stage of destruction of ecosystems. The maximum concentrations of S02 are 0.4...0.5 kg/km2. Non-ferrous metal concentrations exceed background values; - the initial stage of degradation of ecosystems. There are almost no visible signs of damage to vegetation, however, in the needles of spruces, a background state of heavy metals is observed, which exceeds the norm by 5...10 times.
Rice. 2.3. Preservation of Ecosystems Depending on the Distance to the Center of Harmful Emissions Studies show that as a result of the uncontrolled activities of a metallurgical plant, the natural environment has been practically destroyed over large areas. Forests were destroyed and damaged on an area of about 15 thousand hectares, and signs of the initial stage of destruction of forest ecosystems were recorded on 400 thousand hectares. The analysis of the pollution of this territory made it possible to establish the rate of destruction of the ecosystem, which amounted to 1 ... 1.5 km / year. What will happen next with such indicators? All wildlife at a distance of up to 30 km from the plant (according to the wind rose) can completely degrade within 20...25 years. Heavy metals have a harmful effect not only on water bodies, but also on ordinary mushrooms, berries and other plants, the toxicity of which reaches 25 MPC, and they become completely unsuitable for human consumption. Pollution of water bodies located near the plant is more than 100 MPC. In residential areas of the city, the concentration of SO2, nitrogen oxides and heavy metals exceeds the maximum allowable level 2... 4 times. Hence the incidence of diseases in the population endocrine system, blood, sense organs and skin. This fact is also curious. In the vicinity of the plant, the first colony of moles was found at a distance of 16 km from the center of emissions, voles were captured no closer than 7...8 km. Moreover, at these distances, animals do not live permanently, but only temporarily enter. This means that with an increase in anthropogenic load, biogeocenosis, as it were, is simplified primarily due to the loss or sharp reduction of consumers. Thus, the cycle of carbon (and other elements) becomes two-term: producers - reducers. At the enterprises of the chemical and petrochemical industries, the very nature of the raw materials speaks of their negative impact on the environment, since we are talking about the production of plastics, synthetic dyes, synthetic rubber, carbon black. According to the report, in 2000 alone, these industries emitted more than 427,000 tons of polluted substances into the atmosphere, while the volume of toxic waste increased and amounted to more than 13 million tons. This is 11% of the volume of toxic waste generated per year in Russian industry. Chemical and petrochemical industries emit a variety of toxic substances (CO, SO2, solids, nitrogen oxides), most of which are dangerous to the human body. This affects the hydrochemical state of water bodies. So, for example, the waters of the Belaya River (upstream from the city of Sterlitamak, Bashkiria) belong to the III class of harmfulness (or simply dirty). Almost the same thing happens with the waters of the Oka River after discharges from the factories of Dzerzhinsk (Nizhny Novgorod region), which contain elements of methanol, cyanide, and formaldehyde. There are many such examples. They pollute not only surface waters, but also underground ones, which makes it impossible to use aquifers for drinking water supply. Pollution of groundwater with heavy metals, methanol, phenol exceeds the MPC up to hundreds of thousands of times. Around the enterprises of the chemical industry (more precisely, cities), the soil is also polluted, as a rule, within a radius of up to 5 ... 6 km. Of the 2.9 km3 of wastewater, about 80% is polluted, which indicates an extremely inefficient operation treatment facilities. The composition of wastewater includes sulfates, chlorides, phosphorus and nitrogen compounds, petroleum products, as well as specific substances such as formaldehyde, methanol, benzene, hydrogen sulfide, carbon disulfide, heavy metal compounds, mercury, arsenic, etc. The building materials industry covers a wide range of enterprises not only cement plants, but also plants for the production of reinforced concrete products, various ceramic and polymer products, plants for the production of asphalt-bitumen mixture, concrete and mortar. Technological processes these industries are mainly associated with grinding and heat treatment charges (at cement plants), unloading of cement and preparation of semi-finished products. In the process of obtaining products and materials, dust enters the atmospheric air, various gases, and in sewer networks - untreated sewage. Asphalt-mixing plants of various capacities currently operating in Russia emit from 70 to 300 tons of suspended chemicals into the atmosphere per year. Installations emit carcinogens into the air. Purification equipment, according to the report on environmental protection, does not work on any of them or does not meet the technical condition.
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