XII Международный конкурс научно-исследовательских и творческих работ учащихся
Старт в науке
Environmental problem: air pollution by solid particles
Автор работы награжден дипломом победителя II степени
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INTRODUCTION
Atmospheric air is the most important life-supporting natural component of the Earth. Pollution of the surface layer of the atmosphere is a powerful factor affecting plants, animals, microorganisms, the quality of human life, the functioning of ecosystems and the biosphere as a whole.
A lot of cars on the roads, factories with pollution emissions - all this is a huge problem for the environment.
Particulate matter is one of the main types of air pollution, and the amount of particulate matter can be reduced by controlling what is released when the fuel is burned.
Thus, the problem of air pollution is urgent, so it is necessary to study the sources and impact of air pollution on people and the environment, and do everything possible to prevent it and clean it up.
Object of research: atmospheric air.
Subject of the study: the content of solid particles in the air and its purification.
Hypotheses:
- when something burns, the air is polluted;
- the amount of solid particles in the air in different areas may differ, due to the congestion of roads;
- features of the structure of the filters help to remove particles of different sizes.
The purpose of the study: to understand the process of air pollution by solid particles, to study air pollution by solid particles in different areas, to design the simplest filtration systems.
Research objectives:
- Analyze the literature on the topic of air pollution.
- To study with the help of experiments the main factors of formation of visible pollution in the atmosphere.
- Manufacture and place «traps» in three different areas to determine the concentration of solid particles in the air, analyze the results obtained.
- Make different air filters and experimentally determine the best one.
- Make a wet scrubber to see the principle of operation and evaluate the effectiveness.
- Formulate conclusions.
Research methods:
Study of information sources, observation, experiment, research, comparison, calculation, analysis.
The development of the problem.
In the preparation of this work, different information sources were used.
To understand the properties of air, we used the book by M. A. Yakovlev, S. V. Bolushevsky "The Big Book of scientific experiments for children and adults", which contains a number of necessary scientific experiments.
In the book "Atmospheric Pollution" by A. N. Golitsyn "Industrial Ecology and monitoring of environmental pollution", the problem of atmospheric pollution is described in detail.
The concept of smog, its formation is described in the work of Chelnokov A. A., Yushchenko, L. F., Zhmykhov, I. N. "Fundamentals of Ecology".
The book "Technological processes of environmental safety" by A. I. Rodionov describes various filters and the principle of their operation.
And also used the "Handbook on Nature Protection" by Mitryushkin K. P. et al., which includes terms related to ecology.
Some answers to the questions were found in Internet resources:
- information on the sizes of different particles,
- explanation of the incomplete combustion principle,
- what is a scrubber and how it works,
- air pollution from road transport.
The practical significance of the study lies in the fact that it can be used to assess the ecological state of the environment, used as a guide in biology, chemistry, physics and extracurricular hours on ecology, as well as to attract interest in environmental problems among students.
Chapter 1. Air pollution research
Air pollution is the ingress of foreign substances into the air or a change in its natural composition.
Causes of air pollution: coal and oil burned by factories and power plants; waste incineration; hydrocarbon fuel burned by vehicles; forest and steppe fires, volcanic eruptions.
The coincidence is traced in every cause – it is the combustion process!
Most major air pollutants are invisible, but particulate matter and smog can be easily seen. Visible particles in the air are tiny particles of solid matter or droplets of liquid. Large amounts are concentrated in the largest cities of the world and sometimes in such quantities that it is impossible to see the sun.
Solid particles can enter the lungs of humans and animals, settle in them, causing serious diseases of the respiratory, cardiovascular system and even cancer.
Settling on the surface of plant leaves, solid particles reduce the intensity of photosynthesis and respiration of plants, their growth, lead to diseases and complete extinction.
1.1 Smog
The word "smog" comes from a combination of the words "smoke" and "fog". It was first used in the early 1900s to describe the combination of smoke and thick fog that sometimes hung over the skies of London (England). Smog is the visible air pollution created by smoke, fog, suspended particles, and chemical vapors.
Smog is caused by moisture in the air condensing on smoke/chemical suspended matter particles and forming tiny droplets of smog.
Weather conditions, such as no wind or thermal inversion, can lead to smog. Smog is particularly noticeable during thermal inversion, when the upper layer of warm air traps pollutants above the lower layer of cold air, preventing the normal circulation of the atmosphere (smog cannot rise and dissipate).
The temperature inversion is illustrated by the example of smoke rising from a fire. The smoke will rise vertically, and then, when it reaches the "inversion layer" (when the air temperature increases, instead of the usual decrease), it will bend horizontally. If this situation is created on a large scale, the dust and dirt that rises into the atmosphere remains there and, accumulating, leads to serious pollution.
The process of smog occurrence can be seen through the simplest experience (see Application 1).
Conclusion: the combustion products penetrate into the liquid droplets formed during condensation at different temperatures, and become visible, forming smog, which indicates the presence of large polluting particles in the fog droplets, which have a detrimental effect on humans and nature.
1.2 Incomplete combustion
One of the biggest sources of air pollution is the incomplete combustion of gasoline in automobile engines. The efficiency of the engines is approximately 30% - which means that for every 10 liters of gasoline in the tank, only three liters are actually used to move the car! Some of the remaining gas heats the engine, and some is pushed out of the engine unburned.If the gasoline burned completely, the only by-products would be water vapor and carbon dioxide.
To understand the process of air pollution during the operation of road transport, the following studies were conducted:
- a study to determine the visible pollution resulting from incomplete combustion when the car engine is running;
- experience showing the principle of interaction of the combustion process with air.
1.2.1 Research (see Application 2, paragraph 1)
Using a white cotton sock, it was experimentally established that the car actually emits visible particles of pollution. Black particles - soot-are visible on the sock. This gorenje exhaust gases (carbon dioxide-CO2, carbon monoxide-CO, hydrocarbons and nitrogen oxides), which are products of incomplete combustion, polluting the atmosphere.
1.2.2 Experience (see Application 2, paragraph 2)
Experimentally, by lighting a candle over a tin can, it was found that gorenje soot is formed during the combustion process. After conducting the same experiment, but blowing air through a tube to the bottom of the jar, it was found that with additional air introduction into the combustion process, complete combustion occurs.gorenjeski.
Conclusion: the pollution from combustion products can be seen by observing the smog that has formed over the city and the main pollution is produced by vehicles whose exhaust gases are the result of incomplete combustion, include solid particles that are inhaled by living creatures and that settle on the surface of living plants, causing harm, so it is necessary to design such systems that will provide more accurate control of the ratio of air to fuel.
Chapter 2. Determination of solid particles in the air
Solid particles are often invisible to the naked eye unless they are very concentrated. To study the particles, you need to "catch" them and identify some of them. First, you need to study this information in the place of contamination before working on cleaning up the pollutants. Using this information to develop new technologies, which more effectively prevent and reduce air pollution.
The concentration of harmful substances in the atmospheric air has a detrimental effect on the state of the environment. Soot, which is particularly concentrated near highways, has a particular impact.
2.1 Production of the simplest «traps» for determination of pollution of different areas
To assess the environmental situation in different places, were made of "traps" (see Application 3). A «traps» is a device or device for collecting something. With the help of frames in which the scotch tape was fixed, solid particles floating in the air were caught for two weeks.
Two weeks later, the result was evaluated using a microscope.
A mathematical analysis was performed to calculate the traffic
(see Application 4).
After making calculations on the traffic of vehicles, you can compare this data with the amount of solid particles collected in 2 weeks (it was decided to take into account the amount of visible particles per 9 mm²).
Conclusion: the level of air pollution in different areas is not the same, and the number of cars directly affects the volume of solid particles released into the air: the more cars, the higher their concentration. The city of Krasnogorsk has the highest concentration of pollutants, because industrial enterprises are located on the territory of the city and the city has a main road – a transport artery connecting the city of Moscow with the nearest cities of the Moscow region in the direction of the Volokolamsk Highway. In the village of Briket and Lenino-Snegiri - the concentration of polluting solid particles in the air is much lower.
Chapter 3. Cleaning of air contaminated with solid particles
Solid particles consist of a variety of small particles, from dirt and ash, to heavy metals such as lead and arsenic. The most important particles are very small particles (less than 2.5 microns — one micron is a millionth of a meter). Because of their microscopic size, our bodies have difficulty filtering out these very small particles of particulate matter, and they can accumulate in our lungs and then cause many different respiratory diseases, such as asthma.
Every day environmentalists work to change the environmental situation. To reduce the impact of particulate matter on the surrounding atmosphere, cleaning devices are being created and systems are being invented to reduce emissions. Engineers design various filters and strive to improve production processes that aim to ensure that the contaminants settle in the filtration systems before they reach the air environment outside. Many systems have already been developed for cleaning: gravity settling tanks, cyclones, electric filters, scrubbers, and fabric or fiber filters.
3.1 Manufacture of air filters
Pollutants that poison our air enter our homes, polluting the indoor air. Such particles, such as soot, asbestos, dust, and chemicals, enter the body through the nasal and throat passages. Coughing, itchy eyes, sneezing, allergies, asthma, and respiratory illnesses (which can even lead to death) are the consequences of these pollutants.
Air filtration systems were created, which are now common in our homes. Filtration systems are designed to purify the air from harmful particles and chemicals. Using various filtration methods, these machines circulate the air, trapping harmful particles and making the air safe to breathe.
To evaluate the effectiveness of different air filters, a device was designed with two chambers separated by a filtration zone: air with solid particles of different sizes was blown into one chamber, and the purified air flow left through the other chamber and settled on the «traps». (see Application 5).
Filter 1.
Large particles (sand and bark) were partially filtered out, stuck between the threads of gauze. Small and medium-sized particles (chalk, sand, and bark) were filtered out using cotton pads. The bottom of chambers 1 and 2 is clean. The «trap» 1 is completely free of particles. Filter 1 has completely filtered out the air.
Filter 2.
Large, medium and small particles (sand and bark) remained completely in the chamber 1. Fine particles (chalk) filtered out (glued) a layer of paper, which is slightly moistened with the inside of the filter – wet wipes. The «trap» 2 is completely free of particles. Filter 2 completely filtered out the air, but large particles remained inside the system.
Filter 3.
Large and medium-sized particles (sand and bark) caught on the fibers of plumbing linen, some of them settled on the surface of the paper and remained on it, unable to fall, thanks to the flax fibers. Fine particles (chalk) were partially filtered out by the flax fibers, and partially settled on the surface of the paper. The bottom of chambers 1 and 2 is clean. On the «trap» 3, small particles of sand and bark are visible on an area of 9 mm². Filter 3 handled large, medium, and small particles (chalk), but small particles (sand and bark) were not filtered out.
Filter 4.
Large and medium-sized particles (sand and bark) passed through. Fine particles (chalk) have settled on the surface of the writing paper. Large, medium and small particles (sand and bark) are visible on the «trap» 4 on an area of 9 mm². Filter 4 was able to filter out only fine particles (chalk).
Conclusions: The filtration efficiency was shown by fibrous materials that are able to hold particles of different sizes between the fibers. Paper filters retain only the smallest particles and must be installed after the large particle filters. It is possible to create an effective filter, taking into account all these parameters.
3.2 Manufacturing of a water filter based on the scrubber principle
A scrubber is a device that is used to clean the exhaust polluted air. The scrubber is considered the most effective device for removing solid particles of any size from gases.
Scrubbers are used in coal-fired power plants, asphalt plants, and a number of other facilities that emit sulfur dioxide, hydrogen sulfide, and gases with high solubility in water. Inside the wet scrubber, solid particles and gases are trapped as they pass through the water mist. Sometimes the mist is injected with limestone powder to help remove dirt particles. Wet scrubbers are often used for aggressive, acidic, or basic gas flows. The resulting polluted wastewater is processed into sludge, which is used for the production of bricks.
In order to understand how this method functions in the treatment of industrial air pollution, a simple wet scrubber model was constructed. Fog – small water droplets, is a liquid state of water. As an experiment, the mist injected in the scrubbers to capture solid particles was replaced with water. (see Application 6).
Analysis: the polluted air is sucked in from bottle 1 and enters the water in bottle 2. Water in bottle 2 cleanses the air from large particles, changes color when the particles are dissolved in it. A cloud of air, in which invisible particles of pollution can still be found, accumulates in the upper part of bottle 2 and is sucked into bottle 3, in which the next stage – fine cleaning-takes place. That's why there are 3 bottles. The air is cleaned a second time in bottle 3 before being vacuumed, and is released into the environment as clean air.
Conclusion: scrubbers are effective systems for deep cleaning of polluted air released by industrial enterprises, purifying the air from solid particles and exhaust gases.
CONCLUSION
We need to understand what we breathe and study the causes of air pollution. At various stages of the research work, it was studied that when something is burned, air pollution occurs. Humans have begun to produce more pollution than natural weather conditions can dissipate.
Industrial enterprises and cars produce pollutants that are released into the atmosphere – more and more solid particles appear in the air, which adversely affect the environmental situation. A person inhales a lot of solid particles over a long period of time, this can have adverse health effects. After conducting a number of experiments, it was concluded that air pollution in different areas directly depends on the number of vehicles passing on adjacent roads, so engineers need to constantly work on creating more advanced fuel processing systems in the automotive industry.
To clean the air from solid particles, filter systems were designed, which showed the effectiveness of the various materials used. Engineers need to develop systems for cleaning the air from pollution, and they are helped by creativity and design solutions.
Clean air is the future of our planet!
List of information sources:
Golitsyn A. N. Industrial ecology and monitoring of environmental pollution-Moscow: Onyx, 2010 – - 336 p.
Mitryushkin K. P., Berlyand M. E., Belichenko Yu. P., etc. Handbook of nature protection - Moscow: Forest Industry, 1980. - 352 p.
Rodionov A. I. Technological processes of ecological safety. Atmosphere: textbook for universities / A. I. Rodionov, V. N. Klushin, V. G. Sister. - 5th ed., ispr. and add. - Moscow: Yurayt Publishing House, 2020 — - 201 p.
Chelnokov A. A., Yushchenko L. F., Zhmykhov I. N. Fundamentals of Ecology-Moscow: Higher School, 2012 – - 544 p.
Yakovleva M. A., Bolushevsky S. V. Big book of scientific experiments for children and adults-Moscow: Eksmo, 2014. - 280 p.
Types of scrubbers and general characteristics. URL: https://plast-product.ru/skrubber/
Atmospheric air pollution by the automobile and road complex. Pepina L. A., Sozontova A. N. URL: https://alfabuild.spbstu.ru/userfiles/files/AlfaBuild/AlfaBuild_2017_1/8_1.pdf
Characteristic sizes and settling rates of various particles. URL: https://vozdyx.ru/article/xarakternye-razmery-i-skorosti-osedaniya-razlichnyx-chastic/ (accessed: 06.12.2020).
Ecology handbook. Exhaust gases during fuel combustion. URL: https://ru-ecology.info/term/77079/ (accessed: 06.12.2020).
And different internet-resource.
Application 1
Stages of the smog creation experiment
Necessary items: large glass jar, aluminum foil, ice cubes, paper, scissors, matches.
1. Cut off a strip of paper about 15 cm x 1 cm. Fold the strip in half lengthwise and twist it.
2. Make a lid on the jar from a piece of aluminum foil.
3. Put the ice cubes on top of the foil to pre-cool it (simulating a cold layer of atmosphere).
4. Light a strip of paper and throw it together with a match in the jar.
5. Place the foil on the jar and close it tightly.
6. Put the ice cubes back in the middle of the foil lid.
7. Wait for the appearance of a white haze in the bank-imitation of smog.
Application 2
1. Exhaust gas research
Necessary items: white cotton sock, car, microscope.
Stages:
1.1 Put the sock on the cold exhaust pipe.
1.2 Start the car for 2 minutes.
1.3 Evaluate the visible contamination with a microscope.
2. The "incomplete combustion" experience»
Necessary items: candle, matches, tin can, straw,
paper towel.
Steps:
2.1 Light the candles.
2.2 Place the bottom of the jar directly over the flame for a few seconds.
2.3 Consider the bottom of the jar (it is black with soot).
2.4 Wipe with a paper towel.
2.5 Evaluate the contamination with a microscope.
2.6 Repeat the procedure, but using a straw to gently blow air into the bottom of the jar.
7. Consider the bottom of the jar (clean).
Application 3
Creating «traps» of solid particles to determine the level of contamination.
Necessary items: plastic signs, tape, thread, microscope.
Duration of the experiment: 2 weeks.
Steps:
1.Rectangular plates of different sizes with a rectangular hole were cut out of the plastic container.
2. The tape is glued inside.
3. The finished plates were placed at three control points:
- Moscow region, Krasnogorsk, ul. Boulevard of Cosmonauts, 7, entrance;
- Moscow region, Ruzsky district, Briket village, Kuzminova str., 1, sports hall window sill (outside);
- Moscow region, Istra district, Lenino-Snegiri village, club Zastava "Rubezh", economic structure (outside).
4. After 2 weeks, the signs were removed.
5. With the help of a microscope, the assessment of stuck small particles on an area of 9 mm² was carried out.
Krasnogorsk – 38, Briket – 22, Lenino-Snegiri – 26.
7.The count of passing cars at control points was carried out for 10 minutes.
8. The number of cars was brought to the average value of 14 days.
8. Processing the results.
Application 4
Calculation of the average value of traffic of vehicles (cars) for 14 days (2 weeks).
The passing vehicles were counted at the control points from 18.10 to 18.20 (10 minutes): Krasnogorsk - 382, Briket – 136, Lenino-Snegiri – 274.
We will divide the day conditionally into 6 time periods of 6 hours each:
1. 00.00 – 06.00
2. 06.00 – 12.00
3. 12.00 – 18.00
4. 18.00 – 00.00
Let's determine the average number of cars passing in an hour, for which we multiply the number by 6 (1 hour is 10 minutes multiplied by 6).
1. 382*6=2292 (cars) - traffic per hour at the checkpoint in Krasnogorsk in the period of 4;
2. 136*6=1056 (cars) - traffic per hour at the checkpoint in the village of Briket in the period 4;
3. 274*6=1644 (cars) - traffic per hour at the checkpoint in the village of Lenino-Snegiri in period 4.
Suppose that the lowest traffic in 1 time interval, in 2 and 4 is 6 times higher than in 1, in 3 time interval the traffic is 3 times lower than 2 and 4. The number of cars was counted in the 4 time period. Let's denote the number of counted cars per hour in a certain time interval - X.
Let's determine the average number of cars per day by adding the average values per hour and multiplying each by 6 (the number of hours in the time interval), taking into account the traffic at different times, for this we will make a formula according to the time intervals and multiply by the number of days of the experiment-14:
(x/6*6+x*6+x/3*6+x*6)*14
1. (2292/6*6+2292*6+2292/3*6+2292*6)*14=34 380*14= 481 320 (cars) for 2 weeks at the control point in Krasnogorsk;
2. (1056/6*6+1056*6+1056/3*6+1056*6)*14=15 840*14= 221 760 (cars) for 2 weeks at the control point in Briket;
3. (1644/6*6+1644*6+1644/3*6+1644*6)*14=17 016*14=238 224 (cars) for 2 weeks at the control point in Lenino-Snegiri.
Application 5
Manufacture of filtration devices and air filters.
Necessary items: 5 «traps» (cardboard frame with scotch tape glued inside), scissors, various accessories for making filters (gauze, cotton pads, wet paper, plumbing linen, paper towels, writing paper, jute thread), shoe box, napkin, glue, salt shaker, visible solid particles (sand, crushed bark, crushed chalk), hair dryer, marker, microscope.
Stages of manufacturing the test apparatus:
1. Cut a hole under the nozzle of the hair dryer from the end of the box.
2. Completely cut out the opposite end of the box.
3. Make the filter clips from cardboard and paste them inside the box, dividing the inner space of the box in half into two chambers: chamber 1 (on the side of the nozzle of the hair dryer) and chamber 2 (on the side of the open end of the box).
4. Glue a napkin to the open end so that it completely covers the open space, to monitor the amount of outgoing air flow in order to control overheating.
5. Cut a round hole on the top of the box to feed the solid particles into the system, approximately in the middle between the air flow nozzle and the placed filter.
Stages of filter manufacturing:
1. Cut out several cardboard frames the size of the width of the boxes.
2. Filter 1:
- the frame is wrapped with gauze,
- cotton pads are placed inside.
3. Filter 2:
- a paper towel is glued to the frame on one side,
- the next layer is a wet cloth (it will be located between two layers of paper),
- a paper towel is glued to the opposite side of the frame.
4. Filter 3:
- a paper towel is glued to the frame on one side,
- holes of different sizes are made,
- plumbing linen is glued to these holes.
5. Filter 4:
- jute thread is wound on the frame,
- strips of writing paper are glued to the thread.
Stages of the filtration experiment:
1. Mark the «trap» from 1 to 4 with a marker.
2. Mark the filters from 1 to 4 with a marker.
3. Insert the filter 1 into the retainers inside the device.
4. Install the «trap» 1 on the side of the camera 2 at a distance equal to the width of the napkin.
5. Turn on the hair dryer.
6. Place a salt shaker in the solid particle feed hole.
7. Make observations of the napkin to indicate the outgoing air flow.
8. Turn off the hair dryer after a minute.
9. Replace «trap» 1 with «trap» 2.
10. Replace filter 1 with filter 2.
11. Follow steps 5-11.
12. Repeat manipulations with the remaining filters and «trap».
13. Perform the analysis by visual inspection and using a microscope.
14. Draw conclusions.
15. Evaluation of the results.
Application 6
Required items: scotch tape, crushed chalk, 3 clear glass bottles, silicone tubes, 3 rubber stoppers with holes (2 of them with 2 holes, 1 with one hole), water, vacuum cleaner.
Stages:
1. Pour the crushed chalk into the first bottle.
2. Fill bottle 2 and bottle 3 1/3 with water.
3. Insert the tubes into the hole as follows:
- in 1 bottle, one end of the tube is inserted to the chalk pile, the other end of the tube is inserted into the hole of the second bottle and deepened so that part of the tube is submerged in water,
- the next tube is inserted with one end into the second hole 2 of the bottle approximately to the middle of the bottle, without touching the water, the other end is inserted into the hole 3 of the bottle, deepening so that part of the tube is submerged in water,
- the last tube is inserted into the second hole 3 of the bottle, approximately to the middle, without touching the water, the other end into the narrow nozzle of the vacuum cleaner,
4. The nozzle of the vacuum cleaner and the tube are tightly rewound with tape for tightness, so that the sucked air enters the vacuum cleaner from the tube.
5. Turn on the vacuum cleaner for a few minutes,
6. Conduct observations of the ongoing process,
7. Turn off the vacuum cleaner,
8. Perform the analysis using a visual inspection and a microscope,
9. Draw conclusions.