Keywords: air pollution, junior high school, senior one
This article is suitable for: the first grade of junior high school.
Composition source:
This composition is about Grade One. The title is: "Polluted air-I talk about environmental protection with my mother (II)". Everyone is welcome to contribute enthusiastically.
polluted air
-My mother and I talk about environmental protection (2)
After dinner at noon today, my mother and I went back to my grandmother's house by car. When we arrived at the station, we waited for the bus at the station. Looking at the cars coming and going on the road, I found a phenomenon: there is a pipe behind every car, and this pipe is still smoking. What's going on here?
I asked my mother strangely, and she told me a lot ...
Mom, why is there a smoking pipe behind the car?
Mom: Because many cars use gasoline and diesel, as soon as the car starts, gasoline and diesel will burn in the engine, which will produce a lot of exhaust gas. These exhaust gases must pass through the exhaust pipe before they can be discharged outside the car. The smoking pipe you saw behind the car just now is called the exhaust pipe.
Yao Yao: So smoke is waste gas!
Mom: Yes!
Yao Yao: Will these waste gases pollute the air? I stink!
Mom: Of course. The exhaust gas emitted by automobiles mainly includes carbon monoxide, sulfur dioxide and nitrogen oxides. These are all toxic gases, which will seriously pollute the air if discharged into the air. Especially in big cities, there are many and concentrated cars, and it has turned dark in some places.
F: Will the sky really turn black?
Mom: The cars are all together, and they are all emitting exhaust gas. If the waste gas is not dispersed in time, the sky will turn black.
Yao Yao: Will it be poisoned?
Mom: Of course. In foreign capitals, 10 people have died because of serious air pollution, and all primary schools have been closed to avoid the polluted air endangering the health of primary school students.
Yao Yao: Is the air there polluted by the exhaust gas from cars?
Mom: Not necessarily.
Yao Yao: Why not? What else will pollute the air?
Mom: There are more and more factories now. Factory construction will emit a lot of waste gas and pollute the air. Many vehicles, not only cars, but also trains, planes and ships will produce waste gas and pollute the air; Burning leaves and wheat straw will pollute the air.
Yao Yao: Will such serious pollution be harmful to us?
Mom: It is not only harmful to our health, but also harmful to plants and weather, and even makes a city disappear from the earth!
Yao Yao: Why did this city disappear?
Mom: In the 1980s, a famous industrial city in Northeast China provided a large amount of steel, coal and cement to the whole country every year, but the remote sensing photos taken by satellites could not find this city. Do you find it strange?
F: Is the satellite too high to shine?
Mom: The photos taken by satellite can even be taken with watches worn by people walking on the ground. How can such a big city not be photographed? It is because the city is covered with black smoke and thick dust that satellites can't find the city at all on earth, just like disappearing.
Yao Yao: The air pollution is really serious!
Mom: It's worse! Also in the 1980s, in a city in the northwest of China, the weather was extremely cold, and coal was burned to keep warm for half a year, but the ash in their coal-burning stoves could not be discharged, and more and more coal ash floated into the sky, blackening the snow in the sky.
F: Snow has turned into black snow. It's amazing! Is there any way to prevent air pollution?
Mom: There is no way, but we can reduce pollution through our joint efforts.
What can I do?
Mom: Usually we can take fewer cars and try to ride electric cars, bicycles or walk, which can reduce the pollution of automobile exhaust. We can plant all kinds of trees, because leaves can absorb a lot of floating dust in the air, and dusty leaves can continue to absorb floating dust after being washed by rain, thus purifying the air. In daily life, we should also start from ourselves, not littering or spitting, and protect our environment.
Yao Yao: OK, last time we said that plastic bags won't rot and pollute the environment. During this period, we don't want plastic bags for every discount or shopping. I will stick to it with my mother in the future and continue to protect our environment!
Today, Yao Yao asked about automobile exhaust, looked up some information on the Internet and had a brief chat with her, which gave her a preliminary understanding of air pollution. Although I don't know much about how the environment is polluted, I can't tell you clearly. After all, she is still young. But through our conversation, she already knows the importance of protecting the environment and that she should do her best to protect the environment and start from herself. I hope everyone can take action to protect the environment and our planet, because this is our home!
I searched some knowledge about air pollution from the internet and shared it with you.
There are three main sources of air pollution:
(1) Industry: Industry is an important source of air pollution. There are many kinds of pollutants discharged into the atmosphere by industry, including smoke, sulfur oxides, nitrogen oxides, organic compounds, halides, carbon compounds and so on. Some are smoke and some are gas.
(2) Living stoves and heating boilers: A large number of living stoves and heating boilers in cities need to consume a lot of coal, and coal will release a lot of harmful substances such as dust, sulfur dioxide and carbon monoxide to pollute the atmosphere during combustion. Especially when heating in winter, it often makes the polluted area filled with smoke and makes people cough, which is also a pollution source that cannot be ignored.
(3) Transportation: Cars, trains, planes and ships are the main means of transportation at present, and the waste gas produced by burning coal or oil is also an important pollutant. In particular, the number of cars in cities is large and concentrated, and the pollutants discharged can directly hit people's respiratory organs, which has caused serious air pollution in cities and has become one of the main sources of air pollution in big cities. The exhaust gas emitted by automobiles mainly includes carbon monoxide, sulfur dioxide, nitrogen oxides and hydrocarbons, and the first three substances are very harmful.
The hazards of air pollution mainly include the following aspects:
(1) Harm to human health: People need to breathe air to maintain their lives. An adult breathes about 20,000 times a day and inhales 1.5 ~ 20 cubic meters of air. Therefore, polluted air has a direct impact on human health.
The harm of air pollutants to human body is various, mainly manifested in respiratory diseases and physiological dysfunction, as well as the irritation of mucosal tissues such as eyes and nose.
When the concentration of pollutants in the atmosphere is high, it will cause acute pollution poisoning, or aggravate the symptoms, and even kill thousands of people within a few days. In fact, even if the concentration of pollutants in the atmosphere is not high, breathing this polluted air all the year round will cause chronic bronchitis, bronchial asthma, emphysema, lung cancer and other diseases.
(2) Harm to plants: Air pollutants, especially sulfur dioxide and fluoride, are very harmful to plants. When the concentration of pollutants is high, it will cause acute damage to plants, damage to the surface of plant leaves, or directly cause leaves to wither and fall off; When the concentration of pollutants is not high, it will cause chronic damage to plants, make the leaves of plants fade, or have no harmful symptoms on the surface, but the physiological functions of plants are affected, leading to the decline of plant yield and deterioration of quality.
(3) Impact on weather and climate: The impact of air pollutants on weather and climate is very significant, which can be explained from the following aspects:
(1) Reduce the amount of solar radiation reaching the ground: A large number of smoke particles discharged into the atmosphere by factories, power stations, automobiles, household heating equipment, etc. make the air very turbid, which blocks the sunlight and reduces the amount of solar radiation reaching the ground. According to observation and statistics, in the days when smoke and dust are not scattered in large industrial cities, the direct sunlight on the ground is reduced by nearly 40% compared with the days without smoke and dust. In cities with serious air pollution, people, animals and plants will be stunted due to lack of sunshine every day.
(2) Increase atmospheric precipitation: Many particles emitted by large industrial cities have the function of water vapor condensation nuclei. Therefore, when there are other precipitation conditions in the atmosphere, there will be precipitation weather. In the downwind areas of large industrial cities, there is more precipitation.
③ Acid rain: Sometimes, the rain falling from the sky contains sulfuric acid. This kind of acid rain is the oxidation of sulfur dioxide, a pollutant in the atmosphere, to form sulfuric acid, which falls with the precipitation in nature. Sulfuric acid rain can destroy large areas of forests and crops, corrode and destroy paper products, textiles and leather products, degrade metal antirust coatings and reduce their protective effects, and also corrode and pollute buildings.
(4) Raise the atmospheric temperature: Over large industrial cities, the air temperature near the ground is higher than that in the surrounding suburbs due to a large amount of waste heat discharged into the air. This phenomenon is called "heat island effect" in meteorology.
⑤ Impact on global climate: In recent years, people have gradually noticed the impact of air pollution on global climate change. After research, people think that carbon dioxide plays an important role in various air pollutants that may cause climate change. About 50% of the carbon dioxide released into the atmosphere by countless chimneys and other exhaust pipes on the earth remains in the atmosphere. Carbon dioxide can absorb long-wave radiation on the ground and raise the air temperature near the ground, which is the so-called "greenhouse effect". It is roughly estimated that the near-surface temperature will increase by 0.5 ~ 2℃ for every 25% increase of carbon dioxide content in the atmosphere. If 100% is increased, the near-surface temperature can be increased by 1.5 ~ 6℃. Some experts believe that the carbon dioxide content in the atmosphere will increase at the current rate, which will melt the ice in the North and South poles in a few years, leading to global climate anomalies.
Prevention and control of air pollution (1) Reasonable industrial layout: This is an important measure to solve air pollution. Factories should not be too concentrated to reduce pollutant emissions in an area. In addition, chemical plants with raw material supply relations should be put together to reduce waste gas emissions through comprehensive utilization of waste gas. (2) District heating and central heating: stoves scattered in thousands of households and short chimneys as dense as trees in cities are the main pollution sources of soot dust pollution. It is an important measure to eliminate soot by central heating and district heating, that is, to replace the stoves of thousands of households in several large thermal power plants with efficient dust removal equipment set in the suburbs. (3) Reduce the pollution of traffic exhaust: The key to reduce the pollution of automobile exhaust is to improve the combustion design of the engine, improve the combustion quality of gasoline, and make the engine oil burn fully, thus reducing harmful exhaust.
(4) Changing fuel composition: changing coal into gas, and stepping up research and development of other new energy sources, such as solar energy, hydrogen fuel and geothermal energy. In this way, the pollution of smoke can be greatly reduced.
(5) Afforestation: Dense forests can reduce wind speed and a lot of dust carried in the air. The surface of leaves is rough, some have fluff, and some can secrete mucus and oil, so they can absorb a lot of floating dust. Dusty leaves can continue to absorb dust after being washed by rain. Such reciprocating blocking and adsorption of dust can purify the air.