How to protect air from pollution? Ecological recommendations. Ecology and health: how to protect yourself from exposure to harmful impurities in the air

Atmosphere
Control of gas mixtures
the greenhouse effect
Kyoto Protocol
Means of protection
Atmosphere protection
Means of protection
Dry dust collectors
Wet dust collectors
Filters
Electrostatic precipitators

Atmosphere

Atmosphere - the gaseous shell of a celestial body, held around it by gravity.

The depth of the atmosphere of some planets, consisting mainly of gases (gas planets), can be very large.

The Earth's atmosphere contains oxygen, which is used by most living organisms for respiration, and carbon dioxide, which is consumed by plants, algae, and cyanobacteria during photosynthesis.

The atmosphere is also a protective layer on the planet, protecting its inhabitants from solar ultraviolet radiation.

Main air pollutants

The main pollutants of atmospheric air, formed both in the process of human economic activity and as a result of natural processes, are:

sulfur dioxide SO2,
carbon dioxide CO2,
nitrogen oxides NOx,
solid particles - aerosols.

The share of these pollutants is 98% in the total emissions of harmful substances.

In addition to these main pollutants, more than 70 types of harmful substances are observed in the atmosphere: formaldehyde, phenol, benzene, compounds of lead and other heavy metals, ammonia, carbon disulfide, etc.

Main air pollutants

Sources of air pollution are manifested in almost all types of human economic activity. They can be divided into groups of stationary and moving objects.

The former include industrial, agricultural and other enterprises, the latter - means of land, water and air transport.

Among enterprises, the largest contribution to air pollution is made by:

thermal power facilities (thermal power plants, heating and industrial boiler units);
metallurgical, chemical and petrochemical plants.

Atmospheric pollution and quality control

Atmospheric air control is carried out in order to establish the compliance of its composition and content of components with the requirements of environmental protection and human health.

All sources of pollution entering the atmosphere, their working areas, as well as the zones of influence of these sources on the environment (air in settlements, recreation areas, etc.)

Comprehensive quality control includes the following measurements:

the chemical composition of atmospheric air for a number of the most important and significant components;
chemical composition of precipitation and snow cover
chemical composition of dust pollution;
chemical composition of liquid-phase pollution;
the content in the surface layer of the atmosphere of individual components of gas, liquid-phase and solid-phase pollution (including toxic, biological and radioactive);
radiation background;
temperature, pressure, atmospheric air humidity;
wind direction and speed in the surface layer and at the level of the weather vane.

The data of these measurements make it possible not only to quickly assess the state of the atmosphere, but also to predict unfavorable meteorological conditions.

Control of gas mixtures

The control of the composition of gas mixtures and the content of impurities in them is based on a combination of qualitative and quantitative analysis. Qualitative analysis reveals the presence of specific especially dangerous impurities in the atmosphere without determining their content.

Apply organoleptic, indicator methods and the method of test samples. The organoleptic definition is based on the ability of a person to recognize the smell of a specific substance (chlorine, ammonia, sulfur, etc.), change the color of the air, and feel the irritating effect of impurities.

Environmental effects of atmospheric pollution

The most important environmental consequences of global air pollution include:

possible climate warming (greenhouse effect);
violation of the ozone layer;
acid rain;
deterioration of health.

the greenhouse effect

The greenhouse effect is an increase in the temperature of the lower layers of the Earth's atmosphere compared to the effective temperature, i.e. the temperature of the planet's thermal radiation observed from space.

Kyoto Protocol

In December 1997, at a meeting in Kyoto (Japan) dedicated to global climate change, delegates from more than 160 countries adopted a convention obliging developed countries to reduce CO2 emissions. The Kyoto Protocol obliges 38 industrialized countries to reduce by 2008-2012. CO2 emissions by 5% of 1990 levels:

The European Union must cut CO2 and other greenhouse gas emissions by 8%,
USA - by 7%,
Japan - by 6%.

Means of protection

The main ways to reduce and completely eliminate air pollution are:

development and implementation of cleaning filters at enterprises,
use of environmentally friendly energy sources,
use of non-waste production technology,
car exhaust control,
landscaping of cities and towns.

Purification of industrial waste not only protects the atmosphere from pollution, but also provides additional raw materials and profits for enterprises.

Atmosphere protection

One of the ways to protect the atmosphere from pollution is the transition to new environmentally friendly energy sources. For example, the construction of power plants that use the energy of ebbs and flows, the heat of the bowels, the use of solar plants and wind turbines to generate electricity.

In the 1980s, nuclear power plants (NPPs) were considered a promising source of energy. After the Chernobyl disaster, the number of supporters of the widespread use of atomic energy has decreased. This accident showed that nuclear power plants require increased attention to their safety systems. Academician A. L. Yanshin, for example, considers gas to be an alternative source of energy, which in the future can be produced in Russia about 300 trillion cubic meters.

Means of protection

Purification of technological gas emissions from harmful impurities.
Dispersion of gaseous emissions in the atmosphere. Dispersion is carried out with the help of high chimneys (over 300 m high). This is a temporary, forced measure, which is carried out due to the fact that the existing treatment facilities do not provide complete purification of emissions from harmful substances.
Arrangement of sanitary protection zones, architectural and planning solutions.

A sanitary protection zone (SPZ) is a strip that separates sources of industrial pollution from residential or public buildings to protect the population from the influence of harmful production factors. The width of the SPZ is set depending on the class of production, the degree of harmfulness and the amount of substances released into the atmosphere (50–1000 m).

Architectural and planning solutions - the correct mutual placement of emission sources and populated areas, taking into account the direction of the winds, the construction of roads bypassing populated areas, etc.

Emission Treatment Equipment

devices for cleaning gas emissions from aerosols (dust, ash, soot);
devices for cleaning emissions from gas and vapor impurities (NO, NO2, SO2, SO3, etc.)

Dry dust collectors

Dry dust collectors are designed for coarse mechanical cleaning of coarse and heavy dust. The principle of operation is the settling of particles under the action of centrifugal force and gravity. Cyclones of various types are widely used: single, group, battery.

Wet dust collectors

Wet dust collectors are characterized by high cleaning efficiency from fine dust up to 2 microns in size. They work on the principle of deposition of dust particles on the surface of drops under the action of inertial forces or Brownian motion.

The dusty gas flow is directed through pipe 1 to liquid mirror 2, on which the largest dust particles are deposited. Then the gas rises towards the flow of liquid droplets supplied through the nozzles, where it is cleaned from fine dust particles.

Filters

Designed for fine purification of gases due to the deposition of dust particles (up to 0.05 microns) on the surface of porous filtering partitions.

According to the type of filtering load, fabric filters (fabric, felt, sponge rubber) and granular ones are distinguished.

The choice of filter material is determined by the requirements for cleaning and working conditions: degree of cleaning, temperature, gas aggressiveness, humidity, amount and size of dust, etc.

Electrostatic precipitators

Electrostatic precipitators are an effective way to remove suspended dust particles (0.01 microns) and oil mist.

The principle of operation is based on the ionization and deposition of particles in an electric field. At the surface of the corona electrode, the dust-gas flow is ionized. By acquiring a negative charge, dust particles move towards the collecting electrode, which has a sign opposite to the charge of the corona electrode. As dust particles accumulate on the electrodes, they fall by gravity into the dust collector or are removed by shaking.

Methods of purification from gas and vaporous impurities

Purification of impurities by catalytic conversion. Using this method, toxic components of industrial emissions are converted into harmless or less harmful substances by introducing catalysts (Pt, Pd, Vd) into the system:

catalytic afterburning of CO to CO2;
reduction of NOx to N2.

The absorption method is based on the absorption of harmful gaseous impurities by a liquid absorbent (absorbent). As an absorbent, for example, water is used to capture gases such as NH3, HF, HCl.

The adsorption method allows you to extract harmful components from industrial emissions using adsorbents - solids with an ultramicroscopic structure (activated carbon, zeolites, Al2O3.

Goals:

generalize knowledge about the sources of air pollution, the consequences to which they lead and the rules of air protection;
formulate the rules of personal environmental safety;
develop memory, logical thinking, vocabulary;
cultivate respect for the environment.

DURING THE CLASSES

1. ORGANIZATIONAL MOMENT (1 min)

2. Introduction to the topic of the LESSON (2 min)

Red crow:

Not enough fresh air! I can not breathe! I even changed the color. I'm suffocating! Help!

I propose to help the CROW. Based on her request, how to formulate the topic of the lesson? (How to protect yourself from polluted air). "Appendix 1=Slide 1".

What questions do we need to answer? / What causes air pollution and what does it lead to? What should be done to protect the air from pollution? How to protect yourself from polluted air? /"Appendix 1=slide 2".

I propose to hold a lesson in the form of a conference at which you will be environmental scientists. Before our environmental conference starts, I would like to remind you of the following information:

"Appendix 1=slide 3" The atmosphere is the layer of air that surrounds the Earth. Its thickness reaches 1000 kilometers. Air does not fly away from the Earth, as it attracts it to itself, like any body. The atmosphere is of great importance for life on Earth: it protects the Earth from meteorites, scatters the sun's rays, which would otherwise burn the Earth and everything on it.

3. Checking knowledge on d / s (12 min).

Atmospheric air is heavily polluted as a result of an increase in air impurities, such as carbon dioxide. It becomes more and more in the air. The expression "nothing to breathe" is increasingly common in the conversations of most citizens.

As the environmental conference progresses, you will fill out the ecologist's sheet "Appendix 2", in which you will enter all the stages of work on this topic.

Name the sources of air pollution, for this, build a chain of harmful substances entering the body. We covered this material in the previous lesson.

1. The car has become the worst enemy of nature and man. It ranks first in terms of emissions of harmful substances into the environment. Please note: 1 car per year emits a little more than a ton of exhaust gases, in which there are 200 types of harmful substances. The same car gives 10 kg of rubber dust. In addition, it raises whole clouds of dust; plants along the roads are contaminated with hard metals. Thus, the car is one of the main sources of pollution.

/ option:

car - exhaust gases - org. breathing
car - dust - soil or plants - org. digestion/

2. There is almost no vegetation around plants and factories, grass, bushes have died, and frail trees stand. The reason is that the plant emits a huge amount of pollutants when burning fuel. When burning 10 tons of coal, 1 ton of sulfur dioxide is released, while 1 ton of dust falls per 1 km per day. Millions of tons of ash are dumped into dumps.

/dumps - smog - org. breathing/

3. The smell of freshness after a thunderstorm is the smell of ozone. Oxygen is converted into it during a lightning discharge. By the way, the same ozone smells near a working photocopier: in the apparatus, under the influence of ultraviolet radiation, oxygen also turns into ozone.

This gas blanket covers the Earth at a height of 18-25 meters. It is it that delays the sun's rays, destructive to all living things.

The reason for its destruction is gases containing chlorine in their molecule. Freon is also dangerous for ozone. This is a volatile substance that is pumped into aerosol cans to create the necessary pressure. More than 20 years ago, scientists discovered the first ozone hole over Antarctica. Here the ozone layer has almost disappeared.

4. Smoke is very small solid particles that appear in the air when wood, coal, fuel burn. Smoke particles are so light that they float for years in the atmosphere.

The smoke is harmful. It irritates the respiratory organs, corrodes the eyes. Heavy metals (lead, mercury) cause changes in the blood.

cigarette smoke - org. breathing
smoke from burning - fog or smog - plants - org.digestion and org. breathing/

5. Accidents. It happened on April 26, 1986 at a nuclear power plant in the city of Pripyat, which is located near Chernobyl. Once there was an explosion and the block caught fire. At the same time, such an amount of radioactive substances was thrown into the air that people who were nearby, and especially firefighters, received a lethal dose of radiation.

Fortunately, such accidents are rare, but millions of minor accidents occur every year.

/ accident - release - acid rain - plants or soil - org. digestion/

/ as students respond, records appear:

1. Exhaust gases

2. Plant emissions

3. Dumps.

5. Volatile substances.

CONCLUSION: So what sources of air pollution have we named? / "Appendix 1 = slide 4"

REFLECTION:

3. PREPARATION FOR ACTIVE MENTAL ACTIVITY (3 min).

"Annex 1 = slide 5"

What effect does air pollution have on plants and animals?

6. SMOG comes from combinations of 2 English words - smoke and fog. This is a harmful fog that forms in cities. In 1959, 4,000 people died in London due to heavy smog, consisting of soot particles, sulfur dioxide and fog droplets.

7. I have such data. In Holland, 1/3 of the trees were affected by acid rain. At the height of summer, the leaves suddenly fell, the roots died, the trees turned yellow, withered, the fish disappeared in the lakes. In the south of Norway, in half of the lakes, fishermen could not catch fish. Architectural monuments are destroyed due to acid rain. But most importantly, human health suffers.

How is acid rain formed?

Tall factory chimneys emit sulfur dioxide into the air, it combines with atmospheric moisture to form droplets of sulfuric acid solution. These poisonous substances impregnate the clouds that the wind carries for thousands of kilometers. This is how acid rain falls.

(Draw on extension board)

DYNAMIC PAUSE (3 min)

4. Learning new material (12 min)

What air protection measures should be taken?

There are a lot of ways. Let's find out the main ways.

Differentiated work:

Strong students solve the problem situation "Where to build a factory", as a result of which a diagram appears in a notebook. (Discussion of the correct option)

Solve the problem and underline the way to protect the air. Average students solve environmental problems:

1.Trees help clean the air from dust and other pollutants.. Deciduous forest, the area of which is equal to the area of a square with a side of 100 m, can retain 68 tons of dust during the year. But a spruce forest of the same area is capable of "swallowing" 32 tons of dust in the same time. By how many tons of dust does a deciduous forest trap more than a spruce forest?

2. In the house where Lena lives, metal, paper, plastic, glass, and food waste are thrown into different containers. Thereby most waste thrown out by the residents of this house, can be recycled and reused. A container for metal contains 12 kg of waste, for glass - 6 kg, for paper - 7 kg, but a container for plastic holds 3 kg less waste than a container for paper. The food waste bin contains 9 kg more trash than the plastic bin. How many kilograms of garbage are contained in each container?

3. In the city where Valya and Tanya live, there are no cleaning filters and dust traps on the pipes of factories, so both girls are collecting signatures under a letter to the authorities with a request build cleaning filters and put dust traps. Valyusha collected 7 signatures, and Tanya - 4 times more. How many signatures did the girls collect in total?

4. You can't light a fire in the forest. Vasya and Kolya forgot about it. From the fire kindled by them, the forest caught fire. 96 trees burned down. The boys were very ashamed, and they decided that they would correct the evil they had caused by planting 4 young trees to replace each burned down through their fault. How many trees were the boys going to plant?

Examination. "Appendix 1=slide 6"

Formulate the rules of personal environmental safety.

(Students with learning difficulties - read page 31 of the textbook and answer the question: "How to protect yourself from polluted air?")

If you are walking along the road and the air is polluted, go to the next street.

Do not stop on the street near a car with a running engine

Do not linger in those places where it is smoky. Cigarette smoke is a dangerous air pollutant.

INITIAL CHECK OF NEW MATERIAL

Add your rules. (Collective compilation of a memo for air purification)

1.As the answers progress, the following slides appear on the board:

Installation of cleaning filters on factory pipes

afforestation

Smoke collector devices

Ban on making fires in forest parks

Waste recycling

Summarizing.

"Appendix 1=slide 7"

REFLECTION:

Mark the correct answer with a traffic light.

5. Fixing the material (up to 4 min)

Take the test and find out what is needed for all life on the planet

/test/ (self-assessment)

1. What substances are included in the air?

A) hydrogen, copper, zinc

B) oxygen, nitrogen, carbon dioxide

D) chlorine, fluorine, iodine

2. What air gas is needed for breathing?

O) oxygen

C) carbon dioxide

3. What gas do plants absorb when they breathe

C) oxygen

H) carbon dioxide

4. Do humans and other living beings need clean air to breathe?

T) No, you don't.

D) Yes, you do.

5. How should the air be protected from pollution?

N) to stop all factories and factories, to stop logging. Prohibit the use of vehicles that emit harmful substances into the environment. Turn the Earth into one huge nature reserve.

Y) Factories and factories must have traps for dust and harmful substances. Transport must be made environmentally friendly. In cities and around them to create belts of gardens, parks and forests. In place of cut down trees, plant young trees

6. Which of the representatives of wildlife can influence the purity of the air?

K) animals

X) plants

C) fungi and microbes

REFLECTION:

Mark the correct answer with a traffic light.

6. Generalization and systematization (2 min)

Let's remember what our environmental conference was dedicated to.

"App1=slide 8"

7. SUMMARY OF THE LESSON (2 min)

Guys, who will explain to the crow the causes of air pollution and tell her what she needs to do in order not to breathe polluted air? And how can we help the residents of our city in the fight for clean air, and what rules should we follow?

8. D/Z (2 min)

Draw environmental signs to protect air from pollution.

Come up with symbols for the rules of personal environmental safety.

We have completed the conference program. What new rules will you follow to keep the air clean (Assessment)

Reflection(traffic light red and green light) (1 min)

Determine the degree of significance of this topic for a person.
State your opinion on this issue.
Determine the degree to which you have studied this topic in the lesson.

Atmosphere- the shell of the globe that protects the Earth from overheating. This is the air that people, animals, plants breathe. If there were no atmosphere, then the daily amplitude of temperature fluctuations would reach 2000°C. The ozone layer in the atmosphere protects living organisms from the deadly radiation of the Sun and outer space. Weather and climate are formed in the atmosphere. It affects the development of human economic activity. The modern composition and state of the atmosphere formed over millions of years. Now she needs help.

Consider causes and consequences of atmospheric air pollution. Air pollution is natural and artificial. Natural air pollution occurs during volcanic eruptions, dust storms, forest fires caused by lightning. Various bacteria are constantly present in the atmospheric air, in particular those that cause diseases, as well as fungal spores. But they can disappear over time and do not have a big impact on the composition of atmospheric air.

At the present stage of human development, irreparable damage brings artificial pollution of the atmosphere. The person himself is to blame for this, therefore he must stop the negative processes. Otherwise, humanity may disappear along with plants and animals, the planet will become uninhabitable. To artificial sources of pollution include such.

Activities of industrial enterprises, polluting the atmosphere with gases, mostly toxic. For example, sulfuric gas from coal combustion; carbon disulfide and hydrogen sulfide during the production of artificial fibers. The source of dust is thermal power plants. When burning 2000 tons of coal (power plant of small capacity), 400 tons of ash and 120 tons of sulfuric gas are released into the air per day, etc.
Intensive development of motor transport in the world leads to the fact that millions of tons of harmful gases enter the atmosphere, including 50 million tons of rubber dust annually from the abrasion of car tires alone. And emissions of toxic heavy metals from cars in the world are over 300 thousand tons.
Radioactive pollution of the atmosphere. It is worth remembering the radiation pollution due to the accident at the Chernobyl nuclear power plant, which still affects the health of people in Ukraine, Belarus, and Russia.

Ways to purify the air divided into three main groups:

Rational use of fuel and creation of purification facilities.
Improvement of production technologies and vehicles. Created cars running on gas, solar energy.
Improving the planning of settlements - from city to village, increasing the area of green spaces. material from the site

Of course, this will require the combined efforts of countries around the world. Many states have adopted laws on the protection of atmospheric air. In order to reduce the amount of emissions of toxic gases, ash, dust into the atmosphere in December 1997 at the UN conference, the Kyoto Protocol "On Climate Change" was drawn up. In this protocol, for each state, the amount of emissions into the atmosphere is determined with its gradual reduction. The document was supported by 119 countries, except for the USA and Japan.

Atmosphere - this is not only the basis of life on the planet, but also a kind of "screen" that protects the Earth from the deadly rays of the Sun and outer space. Weather and climate are formed in the atmosphere. The protection of the atmosphere is an urgent task for all mankind.

On this page, material on the topics:

Outdoor Air Pollution - Economic Consequences
website
Man-made air pollution story
Quotes on the topic of the relationship of man, nature, chemistry and
Artificial pollution

Questions about this item:

Protection of the air basin is one of the most urgent problems of environmental protection. Protection of the atmosphere from pollution by industrial and transport emissions is the most important social task, which is part of the set of tasks of the global problem of nature conservation and improvement of the use of natural resources. Air pollution with harmful substances causes significant material damage to the national economy and leads to an increase in the incidence of the population.

The problems of protecting the atmosphere constitute a wide area at the intersection of sciences. It includes both the general tasks of chemical technology, energy, physics and mechanical engineering, as well as issues that are dealt with by doctors, hygienists, etc.

The most effective method of protecting the atmosphere from pollution by harmful substances is the development of new low-waste, resource- and energy-saving technological processes with closed production cycles. However, these issues require large financial costs and the development of new modern technologies and materials. Therefore, without postponing the solution of these issues for the future, at the present stage, for most industrial and transport enterprises, the purification of air emitted into the atmosphere remains the main measure to protect the air basin from pollution.

Of the total amount of air pollutants,

coming from anthropogenic sources, about 90% are various kinds of gaseous, and 10% - solid and liquid substances.

Suspended substances in the air are called aerosols, which are usually divided into three classes: dusts, fumes and fogs.

Dusts are polydisperse systems of solid suspended particles ranging in size from 5 to 100 microns.

Smokes are aerosols with particle sizes from 0.1 to 5 microns.

Mists are liquid aerosols consisting of liquid droplets. They may contain dissolved substances or solid particles. They are formed as a result of the condensation of steam or the atomization of liquids. The particle size in the first case is close to smoke, and in the second - to dust.

A special place is occupied by soot and ash formed during the combustion of fuel.

Soot is a toxic fine powder, 95% consisting of carbon particles.

Ash is the unburned fuel residue, consisting of mineral impurities.

In the technology of dust collection and gas purification, the dispersed composition of the dust is of decisive importance, since, depending on this, the appropriate dust collection equipment is selected.

The most typical gaseous air pollution include:

sulfur dioxide ( SO 2 ),

carbon monoxide ( SO),

nitrogen oxides and dioxides ( NO, NO 2 ),

hydrocarbons (fumes of gasoline, methane, etc.),

heavy metal compounds (lead, mercury, cadmium, etc.),

carbon dioxide ( CO 2).

Naturally, there may be other harmful gaseous substances in the air, due to the presence of one or another production nearby. Air emissions are divided into:

1 - combined-cycle and aerosol;

2 - technological and ventilation;

3 - organized and unorganized;

4 - hot and cold.

According to the 1st classification, steam-gas emissions are a mixture of gases that do not contain solid or liquid particles. Aerosol emissions are a mixture of gases containing solid or liquid particles.

Depending on the harmfulness of the gas components and the aerosol particles contained in them, it is necessary to clean either one component of the mixture, or the mixture as a whole. In the latter case, either combined cleaning in one apparatus, or a combination of sequential arrangement of apparatuses is required.

Technological emissions are formed as a result of technological processes and are blowdown emissions, emissions from safety valves, from boiler pipes, vehicles, etc. As a rule, they are characterized by a high concentration of pollutants. Ventilation emissions are characterized by large volumes of gas-air mixture, but low concentrations of pollutants. At the same time, due to the large volumes of the gas-air mixture, gross emissions of pollutants with them can be significant.

Organized emissions include emissions removed by pipes or gas ducts, which makes it possible to use gas and dust collection installations quite easily. Unorganized emissions include emissions from depressurized equipment, emissions from unequipped places for loading or unloading materials, from transport systems, etc.

Hot or cold emissions are distinguished by the temperature difference between the gas and the environment. At a temperature difference of up to 30°C, emissions can be considered cold.

The operation of any particulate removal device is based on the use of one or more settling mechanisms. The main ones with the greatest application are: gravitational settling, centrifugal settling, inertial settling, engagement (touch effect), diffusion settling, electrodeposition. Modern methods include thermophoresis and exposure to an electromagnetic field. The influence of one or another mechanism on the deposition of particles is determined by a number of factors, primarily their size.

Gravitational settling occurs as a result of the vertical settling of particles under the action of gravity. When a dust particle falls, it experiences the resistance of the medium, so the rate of fall or settling is determined by the condition of equality of gravity and hydraulic resistance. Therefore, particles of a smaller diameter will have a lower settling rate, and to clean the air from such particles, more time will be required for the dusty flow to remain in the dust settling chamber.

Centrifugal dust settling is noted during the curvilinear motion of a dusty flow, when, under the action of centrifugal forces developed, dust particles are thrown onto the settling surface. In devices based on the use of centrifugal forces, two fundamental design solutions can be used. In one case, the dust-gas flow rotates in a fixed body of a cylindrical or conical apparatus. And in the second case, the dust and gas flow moves in a rotating rotor. The first solution is carried out in cyclones, and the second - in rotary dust collectors.

Inertial settling occurs when the mass of a dust particle cannot follow along with the gas along a streamline that envelops a substance that is dense compared to air, by inertia, when the flow turns, it continues to move in a straight line. In this case, the dust particle collides with an obstacle and settles on it. Inertial settling of dust particles is effective for particles larger than 1 µm.

Diffusion settling will occur when the particles, which are mostly small in size, are subject to Brownian motion.

molecules. As a result, they have an increased probability of contact with a streamlined body. The efficiency of diffusion deposition is inversely proportional to particle size and gas flow velocity.

The deposition of dust particles under the influence of an electric current consists in charging the particles with their subsequent separation from the air under the influence of an electric field. Electric charging of dust particles can be carried out during the generation of an aerosol, due to the diffusion of free currents and with a short discharge. In the latter case, dust particles are charged with one sign, which makes it possible to increase the efficiency of their subsequent removal from the air stream.

Thermophoresis is the repulsion of particles by a heated body, caused by the movement of the air medium as a result of free convection. During thermophoresis, the concentration of particles in areas with high and low temperatures becomes different, which leads to thermal diffusion of particles towards lower temperatures. In practice, this can be observed in the form of dust deposition on the outer walls against central heating appliances.

The sedimentation of suspended particles upon contact of a gas flow with a liquid can be carried out on drops, bubbles and on the surface of the liquid.

The capture of suspended particles by drops is based on kinematic coagulation resulting from the difference in the velocities of particles and drops.

This may happen:

When the aerosol moves at low speed and the liquid drops fall under the force of gravity;

When the aerosol and droplets move in the same or opposite directions at different speeds.

When bubbles of polluted air move through a layer of liquid (bubbling), a pulsation of gases occurs inside the bubbles. Suspended particles stick to the surface of the water surrounding the gas bubble.

When solid particles are deposited on the surface of a liquid, in the case when the gas flow moves along the liquid surface, the particles are deposited in water in the volume of a thin film, i.e. surface water pollution occurs.

Filtration of gas through porous materials consists in passing the aerosol through filter septa, which allow the passage of air but retain aerosol particles. The filtration process in the most common filters can be conditionally taken as the process of flow around a cylinder located across the flow. Dust particles are retained on the surface of the fibers by the forces of molecular interaction. Filtering a dusty flow through a porous material is much more difficult, since it includes not only the process of sticking to the material as a result of the flow, but also due to collision with a fiber or thread. It should be taken into account that there are usually several rows of fibers in the path of the dusty flow, which increases the cleaning efficiency.

When extracting gaseous impurities, absorption, adsorption, catalysis and thermal oxidation methods are used.

Absorption treatment is based on the ability of liquids to dissolve gases or chemically interact with them. Absorption is the transition of a substance from the gas phase to the liquid phase. The substance in which the absorbed gas components dissolve is called the absorbent. The rest of the gas stream, which is not absorbed into the liquid, is usually referred to as inert gas. During physical absorption, the absorbed component is physically dissolved in a solvent (absorbent). There are no chemical reactions taking place. This process occurs when the partial pressure of the absorbed component in the gas is greater than the equilibrium partial pressure above the surface of the solution.

In chemical absorption (chemisorption), the absorbed component enters into a chemical reaction with the absorber (liquid), forming new chemical compounds in the liquid phase. Chemisorption processes provide a more complete extraction of components from gas mixtures. The amount of gases that can be dissolved in a liquid depends on the properties of the gas and liquid, the temperature, and the partial pressure of the gas over the liquid.

The absorption process refers to the absorption of a gas component by a solid. The phenomenon of adsorption is due to the presence of attractive forces between the molecules of the adsorbent (solid) and the absorbed gas at the interface between the adjoining phases. The process of transition of molecules from the gas to the surface layer of the adsorbent occurs if the attractive forces of the adsorbent exceed the forces of attraction from the side of the carrier gas. Molecules of the adsorbed substance, passing to the surface of the adsorbent, reduce its energy, resulting in the release of heat.

During physical adsorption, gas molecules do not enter into chemical interaction with adsorbent molecules. With an increase in temperature, the amount of physically adsorbed substance decreases, and an increase in pressure leads to an increase in the amount of adsorption. The advantage of physical adsorption is the easy reversibility of the process.

Chemical adsorption is based on the chemical interaction between the adsorbent and the adsorbed substance. The forces acting in this case are much greater than in physical adsorption, and more heat is released. Gas molecules, having entered into chemical interaction with adsorbent molecules, are firmly held on the surface and in the pores of the adsorbent. It is characteristic that at low temperatures the rate of chemical adsorption is low, but it increases with increasing temperature.

Catalytic gas purification is used to convert impurities into harmless compounds. The process takes place on the surface of solid bodies - catalysts. The selection of catalysts is mainly decided empirically.

Temperature has a great influence on the process of catalysis. At relatively low temperatures, when the reaction rate is low compared to the rate of diffusion of gases, the purification process is relatively slow. With an increase in temperature, the rate of a chemical reaction increases, while increasing the rate of diffusion of gases. However, the diffusion rate increases more slowly and a moment may come when the gas purification process will be determined only by the rate of supply of reactants, and the use for this, as at the initial stage of the process, of the inner surface of the catalyst is close to zero. In this case, catalysis passes into the region of external diffusion. In this case, the small pores of the catalyst no longer play any role, but the role of the outer surface increases.

The most important characteristic of catalysts is the "ignition" temperature - the minimum temperature at which the catalyst begins to exhibit its properties.

Thermal oxidation of emission components refers to oxidation at temperatures up to 1000°C. Oxidation is applied both to gases and combustible components of the dispersed phase of aerosols. This method is used to extract resins, oils, volatile solvents and other components from gas streams. Of decisive importance in the organization of the process is the preparation of gases for the reaction, i.e. heating the mixture to the required temperature and ensuring the mixing of combustible gases with the oxidizer.

Sources of air pollution	Wastewater treatment plant	Note
Oil fired boiler house	Cyclone or battery of cyclones Bag filters	Calculation p.4.6 Calculation p.4.7
Boiler house running on gaseous fuel	Self Offerings	Description of the method
Solid fuel boiler house	Battery of cyclones Bag filters	Calculation p.4.6 Calculation p.4.7
Painting and drying chamber	Adsorber	Calculation p.4.8
Welding shop: welding production	Venturi scrubber (KMP scrubber)	Calculation p. 4.3
Mechanical shop: machine tools	Dust chamber Cyclone TsN	Calculation p. 4.2
Woodworking shop	Dust chamber Cyclone Giprodrevprom	Calculation p. 4.2 Calculation p.4.6
Electroplating shop	Mesh mist eliminator	Calculation p.4.4

The protection of air from pollution has become one of the priorities of society today. After all, if a person can live without water for several days, without food - for several weeks, then without air one cannot do even a few minutes. After all, breathing is a continuous process.

We live at the bottom of the fifth, airy, ocean of the planet, as the atmosphere is often called. Without it, life on Earth could not have arisen.

Composition of air

The composition of atmospheric air has been constant since the advent of mankind. We know that 78% of air is nitrogen, 21% is oxygen. The content of argon and carbon dioxide in the air together is about 1%. And all the other gases in total give us a seemingly insignificant figure of 0.0004%.

What about other gases? There are many of them: methane, hydrogen, carbon monoxide, sulfur oxides, helium, hydrogen sulfide and others. As long as their number in the air does not change, everything is fine. But with an increase in the concentration of any of them, pollution occurs ...

It is known that a person can live without food for more than one month, without water - only a few days, but without air - only a couple of minutes. So it is necessary for our body! Therefore, the question of how to protect the air from pollution should be at the forefront of the problems of scientists, politicians, statesmen and officials of all countries. In order not to kill itself, humanity must take urgent measures to prevent this pollution. Citizens of any country are also obliged to take care of the cleanliness of the environment. It just seems that practically nothing depends on us. There is hope that by joint efforts we can all protect the air from pollution, animals from extinction, forests from deforestation.

Earth's atmosphere

The Earth is the only planet known to modern science on which life exists, which was made possible thanks to the atmosphere. It ensures our existence. The atmosphere is primarily air, which must be suitable for ...

How to protect yourself from polluted air

Sections: Elementary School

generalize knowledge about the sources of air pollution, the consequences to which they lead and the rules of air protection; formulate the rules of personal environmental safety; develop memory, logical thinking, vocabulary; cultivate respect for the environment.

DURING THE CLASSES

1. ORGANIZATIONAL MOMENT (1 min)

2. Introduction to the topic of the LESSON (2 min)

Red crow:

– Not enough fresh air! I can not breathe! I even changed the color. I'm suffocating! Help!

Appendix 1.

- I propose to help the CROW. Based on her request, how to formulate the topic of the lesson? (How to protect yourself from polluted air). “Appendix 1=Slide 1”.