The biggest sandstorm in China history.

In some countries, capitalists or economic agents of production units arbitrarily discharge all kinds of harmful substances into nature in pursuit of high profits, seriously polluting the environment, especially air and water, causing social harm, causing many diseases and seriously threatening the health and life of the broad masses of people. There are many kinds of water pollution, among which Minamata disease is one of the world-famous public hazards in Japan. Minamata disease first occurred in Minamata Town, Kumamoto Prefecture, Kyushu, Japan in 1953. Because the cause is unknown, it was called Minamata disease. According to (Yu)

1950, in the fishing village near Minamata Bay, some cats were found to have unsteady gait, cramped and paralyzed, and finally jumped into the water and drowned. Locals call them "suicide cats". 1953, a strange disease was found in Minamata town. At first, he just had slurred speech, unsteady gait, facial dementia, deafness, blindness and numbness. Finally, he lost his nerve, fell asleep for a while, became excited for a while, bent down and screamed and died. At 1956, more than 50 people with the same symptoms were found in this area. Through the investigation of the disease, it was not until 1962 that Minamata disease was determined to be caused by environmental pollution of mercury, especially chronic methylmercury poisoning caused by eating contaminated fish and shellfish. This is caused by methylmercuric chloride discharged from the factory in Minamata town, which pollutes the sea area and poisons fish and shellfish. 1963 after minamata town, a large number of suicide cats and dogs appeared in Niigata prefecture, Japan. 1973, Minamata disease occurred again in Youming Town and other places along the southern coast of Youming Sea. It is reported that the number of these three cases is above 900. In fact, the number of victims in Japan far exceeds this figure, and there are about 1 10,000 victims in Minamata alone.

Mercury, commonly called mercury, is widely used in many industrial sectors. Mercury and its compounds are harmful substances, especially the alkyl compounds of mercury are more toxic. Mercury and its compounds can enter the human body through the respiratory system or digestive system. After inorganic mercury enters human body, the highest mercury concentration is in kidney and liver. The accumulation of organic mercury in human brain is the most significant, followed by liver and kidney. The clinical symptoms after mercury poisoning are very similar to Minamata disease.

In addition to mercury, there are phenols, cyanogens, chromium, arsenic and some heavy metal salts that cause water pollution. These substances are discharged from factories and scientific research units, causing serious water pollution. As a result, harm to human beings has occurred from time to time at home and abroad. Therefore, in the process of developing the national economy and accelerating the four modernizations, we must pay attention to protecting the environment on which human beings depend, preventing pollution, and enabling human beings to survive and develop in a beautiful and comfortable environment.

Black storm: A kind of sandstorm. The dust raised by strong wind forms a sand wall, and the visibility is almost zero.

Since18th century, a large number of immigrants came to the western plains of the United States, which led to three black storms in 1930s. 1A storm in May, 934, which lasted for three days and nights, blew from the west coast to the east coast, forming a gray-yellow dust belt with a length of 2,400 kilometers from east to west, a width of 2,400 kilometers from north to south and a height of 3,400 kilometers. The storm moved eastward at a speed of more than 100 km per hour, sweeping across the North American continent, sandstorms and dark days. In Kazakhstan in Central Asia, a large number of wasteland was reclaimed in 1950s, resulting in a large area of soil. Wind erosion, similar to the dust storm in the 1930s in the United States, has also occurred. In the desert of1160,000 square kilometers in the north of China, 39% is desertification caused by sandstorms caused by human factors.

Sandstorm is a sudden and high-intensity sandstorm disaster. The direct economic loss caused by this in China is as high as 4.5 billion yuan every year. Northwest China, including Xinjiang, Gansu, Qinghai and Ningxia, as well as central and western Shaanxi and Inner Mongolia, are sandstorm-prone areas in China. 1On May 5, 1993, a severe sandstorm caused huge losses in parts of Gansu, Ningxia and Inner Mongolia, with 85 people killed, 264 disabled and 3/kloc-0 missing, resulting in a direct economic loss of 725 million yuan. Seriously affect the economic development of these areas. Tsunami can be regarded as a natural disaster to some extent, but it wouldn't have caused such a great tragedy if it hadn't destroyed the environment in coastal areas artificially.

2. Flood, the flood in 1998 is a good example. A large number of lakes were reclaimed in the lower reaches of the Yangtze River, and the vegetation in the upper reaches was destroyed, causing floods.

3. The greenhouse effect, this problem should gradually appear, because humans destroy a large number of forests, carbon dioxide rises, the earth warms, sea levels rise, and some countries with lower altitudes are threatened, such as the tourist resort Maldives, which will face extinction. More importantly, the greenhouse effect will cause changes in global climate conditions, so the natural disasters in the film The Day After Tomorrow are not groundless. It can be said that it is a great progress for human beings to pay attention to protecting the environment while pursuing their own development.

In ancient times, the relationship between man and nature was unequal. Human beings are weak, limited by nature everywhere, but unable to change nature. Therefore, it has become a rare quality for human beings to regard nature as an enemy and the world as an enemy. The spirit of fools has been praised for thousands of years.

With the advent of the industrial age and the continuous improvement of human science and technology, the relationship between man and nature has been reversed, and man has become a strong man, while "gentle nature" has become an easily injured object. High-purity chemicals, such as pesticides, paints and detergents, pose a great threat to the natural environment; Large-scale energy consumption has changed the composition of the atmosphere, thus changing the climate of the earth; With the improvement of sanitary conditions and the sharp increase of population, human activities have destroyed a large number of forests and wetland resources on the earth. As a result, "gentle nature" has become "ferocious nature", and everything imposed on it by human beings will eventually be returned to human beings. In areas where water and soil are polluted by high-purity chemicals, the incidence of deformed children and terminal diseases is much higher than that of normal people; Once the oil resources are exhausted, the quality of human life and the normal operation of society will inevitably encounter problems; Abnormal climate will inevitably bring floods or droughts, and famine will also be accompanied by various natural disasters. "Cruel nature" will make human beings weak again, and the relationship between human beings and nature will return to the starting point.

In order to change this situation, human beings must protect "gentle nature" and prevent it from deteriorating. Protecting the environment is to protect human beings themselves, which is valuable knowledge after industrialization and extreme expansion of self-confidence.

Countries all over the world are also aware of this problem. 10 years ago, 178 leaders gathered in the Brazilian city of Rio de Janeiro to discuss environmental protection. The leaders plan to protect the earth's environment, reduce greenhouse gas emissions and promote the welfare and development of mankind. 1997, 160 countries signed the Kyoto protocol aimed at reducing carbon dioxide emissions in Kyoto, Japan. However, the United States, the largest emitter of carbon dioxide, refused to implement it because emission reduction hindered economic development. Last year, at the Earth Summit held in Johannesburg, South Africa, world leaders and scientists continued to discuss plans to improve the environment.

10 years have passed, although mankind has made some progress in protecting the environment, the differences are still serious. What is the state of the earth now? What attitude should we take to meet the future?

7 gratifying progress

Awareness of environmental protection is increasing.

After long-term publicity, environmental awareness has been accepted by many people and governments, and people have begun to care about the impact of human activities on nature, hoping that this impact will not worsen the natural environment. Governments began to deal with environmental problems through cooperation. The Rio de Janeiro Summit on 1992, the Kyoto Climate Conference on 1997, and the Johannesburg Summit last year all reflected the strengthening of the world's environmental awareness. Although the United States refuses to implement the Kyoto Protocol for its own benefit, which has caused great damage to future transnational environmental cooperation, the progress of international environmental protection efforts is an irreversible trend.

The clean car came out.

Hybrid electric vehicles have come out and run on the roads of Japan, Western Europe and the United States, which can greatly reduce carbon dioxide emissions. The inventor of the "Super Car" company in Colorado, USA, is developing a zero-emission car. One of the cars is designed to use hydrogen as fuel. The inventor claims that it is unnecessary to bring drinking water when driving this car for a holiday, because it emits 100% pure water. The prospect of electric vehicles is also very promising, and it is likely to become the next generation of personal mobility tools.

Ban 12 "environmental killer"

At the United Nations General Assembly held in Stockholm, Sweden in 20001year, it was decided to restrict the use of 12 chemicals containing carbon and chlorine preparations worldwide. This move is to protect air, water and soil resources from pollution. The meeting called for limiting or completely eliminating persistent organic pollutants such as chlorine, DDT pesticides and PCBs pesticides. 1987, the agreement prohibiting the use of chlorofluorocarbons has played a role, and the destruction of the earth's ozone layer has slowed down.

Develop eco-tourism

The International Ecotourism Association, headquartered in the United States, describes ecotourism as "responsible tourism that protects the environment and supports the welfare of local people". Eco-tourism and its profits have become an important channel to support the financial revenue sources of developing countries around the world, and it is growing rapidly at an annual rate of 30%. The natural environment, like cultural traditions, has become an important driving force to attract tourists. But environmentalists are still worried that the market economy function of ecotourism is far greater than the significance of protecting the environment.

Corporate environmental protection movement

Large companies are increasingly aware that environmental protection can help them attract more customers. Xerox's "Waste-Free Plan" recycled 80% of the harmless solid waste produced by its factory in 2002. It also took out more than 60,000 tons of buried electronic waste and recycled it. This move by Xerox can save millions of dollars every year. Xerox's sustainable development method has been welcomed by environmental groups. Many large companies are also aware of the great role of environmental recycling. Shell, IBM and other world-renowned companies have launched their own "clean plan".

More environmentally friendly buildings

The most important standard of environmental protection building is to reduce energy consumption. Some houses in Europe began to install tiles to absorb solar energy, while "Trench" company in California began to install high-performance insulating glass on the roof of the office. The environmental protection design of the chesapeake bay Foundation headquarters office building in Annapolis, Maryland, USA is even better. The toilets in the office building are flushed with collected rainwater through a special water storage device. Use solar panels to power the office. Compared with ordinary buildings of the same area, this office building consumes only one-third of electricity and one-tenth of pure water.

Reduce the harm of acid rain

The United States and Europe have proved that the reduction of sulfur dioxide and nitrogen dioxide emissions has greatly improved the earth's surface environment. In 1980s, developed countries began to control the emission of sulfur dioxide to reduce the great harm of acid rain to the environment. They began to ban factories from using carbon as fuel, and instead used cleaner energy sources such as natural gas and purified carbon to generate electricity. Cars have also been modified, using higher gasoline grades, and the emission of nitrogen dioxide after combustion is greatly reduced. The harm of acid rain in the United States and western Europe has been greatly reduced. Take Britain as an example. In the past 15 years, the harm of acid rain has been reduced by half.

Seven worrying signs

Earth warming

Scientists have warned that increasing greenhouse gas emissions will make the climate change sharply and the sea level rise. According to the statistical report of the National Meteorological Administration, the average temperature in the three months from 20011to 2002 1 was the highest since 1895. Similarly, the global average temperature in these three months is also the highest since 1895. The direct threat of rising temperature is rising sea level, which will also lead to other extreme weather phenomena and natural disasters.

Unrestricted demand for oil.

There are many rivers on the earth, but there is one river that we don't realize, and that is the river formed by oil. Every day, the river formed by oil surrounds us, and the flow rate of this river is 1 100 cubic meter per second. Since 1990s, the world oil consumption has increased by 14% and is still increasing. Of the 24 billion tons of carbon dioxide released into the atmosphere every year, 40% comes from the combustion of oil. In human history, the content of greenhouse gases in the atmosphere is the highest in 420 thousand years. Two-thirds of the world's oil reserves are concentrated in the Middle East, which has also become the most important factor of political and economic instability in this region. Sometimes, people will think that God loves the Middle East too much and has given it such a concentrated and rich liquid gold, but although oil is good, it has also brought endless conflicts and disputes to the region. Before the fuel consumption is exhausted, such conflicts and disputes seem endless.

Disappearing wetlands

Many people actually don't know the importance of wetlands. Wetlands provide habitats for fish, many birds and amphibians, and become an important part of the ecosystem. In addition, wetlands have a strong ability to digest pollutants. However, worldwide, the area of wetlands is shrinking rapidly. Wetlands are doomed from the Amazon basin to Iraq. The root of the disappearance of wetlands is human agricultural activities, water conservancy activities and other development activities. Reclaim more arable land, build more dams and make wetlands disappear gradually. Scientists estimate that the area of wetlands has decreased by 50% in the past century. 3 1 years ago, 132 countries signed the Wetland Protection Treaty in Iran. But in fact, the binding force and function of the treaty are quite limited.

Super dams are increasing.

People think that building super dams shows their ability to transform nature. It is true that dams transform nature and provide electricity, but they also bring many adverse effects to the environment. The dam changed the natural flow direction of the river and the direction of natural flood discharge. Dams form unnatural reservoirs on the ground, which affects the natural distribution of fish. 1950, there were about 5,000 dams in the world, but by 2000, the number of super dams had soared to 45,000, and the scale was getting bigger and bigger, playing an increasingly important role in transforming nature. On average, two dams with a height exceeding15m are built every day, and most of the new dams are located in developing countries. Some dams are180m high and1500m wide. The cost of building such a dam is staggering. In order to flood a large area of land, countless species have to choose another habitat.

Fewer and fewer coral reefs

Of all marine life, a quarter of the habitats are coral reefs. But in the past 50 years, the number of coral reefs has decreased by 27%. Only in 1998, the number of coral reefs in the world suddenly decreased by 16%. The most direct cause of coral reef death is the warming of the sea. Of course, the increase of solar radiation in the ocean and the savage fishing methods of fishermen are also important reasons for the disappearance of coral reefs.

Overfishing

Human science and technology have made the speed and quantity of fishing exceed the natural replenishment capacity of the ocean. As a result, the number of many fish has dropped sharply, and even endangered. At present, the total amount of fish in the ocean is decreasing at the rate of 1% per year. Scientists propose to designate specific sea areas as protected areas, stop fishing and give nature time and opportunity to save again. But humans seem unwilling to give nature such an opportunity. Restricting fishing will directly affect fishermen's income and quality of life. The fish market only pays attention to price and profit, and never considers species protection.

Disposal of nuclear waste

In 2003, more than 440 commercial nuclear reactors in the world will produce 1 1000 tons of nuclear waste. How to deal with these nuclear wastes poses a difficult problem to mankind. First of all, these nuclear wastes are likely to leak. Secondly, these nuclear wastes are likely to be obtained by terrorists and used for terrible purposes. There are more than 100 nuclear reactors in the United States, which produce about 25% of the world's total nuclear waste, while there are more nuclear waste dumps, including 1, 3 1. * * * More than 1 100 million people live near the nuclear dump 100 km. No matter where nuclear waste is transported, it will inevitably cause pollution to the local area. The more nuclear energy is used, the more similar pollution will occur. While enjoying the super power of nuclear energy, human beings must never forget the hidden worry of nuclear waste.

Seven shocked voices

"At present, people's awareness of protecting the earth's resources is unprecedented, but the large-scale and extensive destruction of wildlife habitats has not slowed down. I am encouraged by the scientific and technological achievements of mankind, but the destruction of species diversity by these scientific and technological achievements makes me desperate. "

E.O. Wilson, a social biologist at Harvard University.

"In terms of environmental protection, marine protection is relatively backward. Because human beings have always thought that the ocean is so huge and rich, it is hard to imagine how human activities will affect such a behemoth. Unfortunately, we have caused irreparable damage to the ocean. "

Jane? Lubchenko, marine ecologist, University of Oregon, USA

"We must admit that in the past 10 years, human understanding of atmospheric chemical composition has improved a lot. Now almost everyone knows the word "greenhouse gas", and also knows that the exhaust gas emitted by factories and cars causes global warming. However, people are still ignorant of other hazards of' greenhouse gases', just like 10 years ago. "

Shirley? Roland, atmospheric chemist, University of California, Avon.

"When humans grow crops, they also destroy the topsoil of the soil. A large amount of topsoil was scraped up and then washed into the sea with the river. In the ocean, pesticides and insecticides are constantly accumulating, which is increasingly harmful to marine ecology. The key to solving this problem is that human beings should change the types of crops planted and have a variety of deeply planted plants, which is conducive to soil and water conservation. "

Wes? Jackson, a crop geneticist, said: "Greenhouse gases have increased the atmospheric temperature and ocean water temperature." Once the water temperature of the ocean rises, it will be a global disaster, because the movement of ocean currents will make the water temperature of the oceans all over the world as high. "

Richard? Barber, Duke University marine cartographer.

"Synthetic chemicals not only bring convenience to human life, but also interfere with hormones. Synthetic chemicals are everywhere on the earth, affecting the reproduction and development of human beings and all wild animals. But no country can ban synthetic chemicals from appearing in shopping malls, and we will continue to bear the side effects they bring. "

—— Ke Erpeng, Director of Wildlife and Pollutants Department of WWF

"On the issue of human attitude towards nature, the' Earth Summit' can be said to be a turning point. I hope people can realize that the protection of species diversity and the protection of natural environment such as wetlands and forests will affect the future operation mechanism of the earth. "

Hal? Munny, an environmental biologist at Stanford University, said

Seven well-meaning warnings

"If human beings continue their current behavior without making any changes, then by the end of 2 1 century, the species on the earth will be reduced by half. If these data can't change human behavior, what else can warn humans? "

E.O. Wilson, a social biologist at Harvard University.

"When asked,' What do you get from nature?' At that time, most people's answers were food, fiber, drugs and genes. But most people don't know about other services provided by the ecosystem. It purifies air and water, regulates climate, enriches barren soil and controls pests and pathogens. Only when we lose these services will we realize their value. "

Jane? Lubchenko, marine ecologist, University of Oregon, USA

"The El Ni? o phenomenon has raised people's vigilance, but no one can say when the next El Ni? o will come again. No one knows whether its consequences are gradual or sudden. If it is a mutation, it is naturally not prepared to give human beings any chance. "

Shirley? Roland, atmospheric chemist, University of California, Avon.

"The relationship between agriculture and wildlife has always been concerned, but the relationship between agriculture and the ocean has not received enough attention. It has been warned before that the wild world will be destroyed if agriculture is not controlled. Now I want to warn that if agriculture is not controlled, the ocean will be finished. "

Wes? Crop geneticist Jackson, "100 years ago, when a hurricane hit human beings, people at that time would only ask the government,' What the hell is going on?' Now, the government has been able to predict hurricanes, understand the intensity and direction of hurricanes, and minimize people's losses. /kloc-what we need after 0/00 years is that the government should also understand other extreme natural disasters. "

Richard? Barber, Duke University marine cartographer.

"Now there is enough evidence to prove that chemicals can enter the uterus, affecting the development of the human brain and the formation and function of the immune system. Humans need smart descendants and wise decision makers. "

—— Ke Erpeng, Director of Wildlife and Pollutants Department of WWF

"History has proved that the opinions of a few people can awaken the attention of the public and then change the direction of social development. Now that scientists are United as never before, we will present more and clearer evidence to make the public and policy makers change their minds. "

Hal? Munny, an environmental biologist at Stanford University, said

7 ecological paradise

kruger national park

Kruger National Park, located in South Africa, consists of endless prairies and bushes, and is the place with the largest concentration of mammals in the world. The history of Kruger National Park can be traced back to 1898. At that time, it was a hunting area. For the convenience of hunting, there were 147 kinds of wild mammals, including cheetah and white rhinoceros. There are more than 500 kinds of birds. Later, in a rather innovative concept at that time, Kruger was called the national park for short.

Tubataha Coral Reef National Park

This is an ecological reserve located on the remote coast of the Pacific Ocean, aiming at protecting marine fish. Tubataha Reef National Park was established in 1988, with the aim of limiting local uncontrolled fishing activities. Tubataha Reef National Park covers an area of 330 square kilometers, where more than 450 kinds of marine fish live comfortably. In Tubataha Reef National Park, any fishing activity is illegal. Unfortunately, there are few such marine protected areas in the world.

Prespa park

Prespa Park is a transnational nature reserve, which was established in 2000. In 2000, Albania, Greece and Macedonia signed an agreement to establish a nature reserve among the three countries. Prespa Park mainly protects the wetland resources in this area. There are more than 160 kinds of birds living here, and hundreds of other birds pass by here or will stay here for a short time. Now Prespa Park has become the last paradise for many rare birds.

Bahuay Ason National Park

The Bahia Sone National Park in Peru is the largest forest reserve in the world. Bahia Sonene National Park covers an area of 1 1,000 square kilometers, where there are dense forests. In the reserve, all acts of sabotage are strictly prohibited. In addition, Bahia Sonene National Park also protects the water resources of the three rivers flowing through the park, and fishing in these rivers has been banned since 2000. In this green world, there are more than 200 species of mammals, more than 900 species of birds and 1200 species of butterflies.

Nahani National Park

The Nahani National Park in the northwest of Canada covers an area of 4,760 square kilometers and protects the most rugged and natural land in Canada. Nahani National Park has no roads and no traces of human activities. There are many natural wonders here, including the natural grand canyon and the magnificent waterfall with a drop of 92 meters (the drop of this waterfall is twice that of the world-famous Niagara Falls). However, the Canadian government prohibits the development of the natural beauty here as a tourist resource, and only about 900 explorers enter Nahani National Park every year. Nahani National Park, founded in 1976 and 1978, was selected as a world natural heritage by the United Nations. Among many national parks and nature reserves, Nahani National Park is unique.

Royal Chitwan National Park

The Royal Chitwan National Park, located on the border between Nepal and India, is a very distinctive nature reserve in South Asia. Here, crocodiles swim freely in the river, and rare mammals including Bengal tigers also live here. Since the establishment of 1973, Royal Chitwan National Park, which belongs to the Royal Nepalese, has become a local tourism project, and the number of tourists has increased from 1000 per year in 973 to more than 1000 per year now. But this is not a good thing for nature reserves, but fortunately, the species and number of mammals here are increasing year by year.

Gualugo triangle

Goualougo Triangle is a protected area, which successfully combines commerce and nature conservation. This famous forest reserve in Africa is also a stage for big logging companies to perform. Logging companies have proved to the world that they don't always play the role of saboteurs. In fact, in the Goualougo Triangle, when logging companies gain benefits, the regeneration of forest resources is also guaranteed. Goualougo Triangle is the largest nature reserve in the Democratic Republic of Congo, where the density of gorillas and chimpanzees is the highest in the world. When the content of some substances in the air exceeds the normal level, it will do harm to animals and plants and affect their survival. The normal contents of C0, NH3, SO2, H2S, Cl2, O3 and NO2 in the atmosphere are all below a few parts per million, which has no obvious adverse effects on animals and plants. However, since the19th century, due to the development of industry and transportation, these substances have been discharged into the atmosphere in large quantities, which has made air pollution increasingly serious, affecting the life activities of animals and plants and even human health. Some sources of pollutants come from nature (such as volcanic ash erupted by volcanoes), and some come from human activities, among which the exhaust gas produced by industry and transportation is the main pollution source. Air pollution can be divided into gas pollutants and aerosol pollutants. Gaseous pollutants include SO2, O2, O2, O2, NO2, NO2, NO2, NO2, NO2, SO2, NO2, NO2, NO2, NO2, NO2, NO2, NO2, NO2, NO2, NO2, NO2, SO2, SO2, SO2, SO2, SO2, SO2. SO2, SO2, SO2, SO2, SO2, SO2, SO2, SO2, SO2, SO2, SO2, SO2, SO2, SO2, SO2, SO2, SO2, SO2, SO2, SO2, SO2, SO2, SO2, SO2, SO2, aerosol pollutants include solid particles (dust, soot gas) and Pollutants discharged directly into the air are called major pollutants. The interaction between air and pollutants produces a reaction, or the photochemical reaction in air leads to the deterioration of pollutants, resulting in new pollutants called secondary pollutants. There are many kinds of air pollutants, among which there are more than ten that threaten agriculture, such as SO2, HF, C 12 and photochemical smog. Influence of meteorological conditions on air pollutants Horizontal wind speed and tropospheric height are two meteorological factors that affect the ability of air to dilute air pollutants. When the dominant wind direction over farmland comes from pollution sources, farmland is easily affected by harmful gases; The intensity of wind affects the diffusion speed of air pollutants, and the concentration of pollutants in the air is inversely proportional to the average wind speed; Usually, the turbulence is strong in the afternoon, and when the air is in an unstable state, it is conducive to diffusion. There is no wind in clear sky at night, and the inversion layer near the ground can make pollutants stagnate and accumulate on the ground, which will aggravate the degree of air pollution. In addition, in the quasi-static high-pressure system, the pollution layer with a thickness of nearly several hundred meters can be formed because the subsidence inversion prevents the pollutants emitted from the lower layer from spreading to the upper atmosphere. Many serious air pollution incidents in various countries are mostly formed after a few days of low inversion layer, low wind speed and no rain. Some pollutants in the air, such as sulfur dioxide and pesticide particles suspended in the air, are leached by rain and fall to the ground, which will also pollute soil and plants. The harm of pollutants to plants generally enters plant tissues through stomata, which interferes with the action of enzymes and hinders metabolic function. Some toxic substances can be further decomposed or participate in the synthesis process in the body, producing new harmful substances, invading cell tissues, inhibiting photosynthesis, hindering growth, reducing yield and deteriorating quality. Its hazards are divided into acute, chronic and invisible hazards. High concentrations of pollutants caused acute injuries, resulting in a sharp decline in output. Low concentration pollutants, under long-term action, cause chronic harm, and the general symptoms are not obvious. Invisible hazards only cause physical obstacles and generally have no symptoms. The damage degree of plants by air pollution is mainly affected by the following factors: the concentration of pollutants and the time when plants are exposed to pollutants; The influence of plant structure, development period and environmental conditions. Such as sufficient light, suitable temperature, good water supply and air humidity, high CO2 concentration, etc., will lead to the opening of leaf pores and easy to be polluted. The purification effect of plants on the atmosphere Many plants have a potential detoxification ability with enzymes as catalysts, which can decompose some toxic substances or form some macromolecular complexes, which can temporarily reduce toxicity. 1 ha forest can absorb more than 30 tons of dust every year, 1 ha Cryptomeria fortunei forest can absorb more than 700 kilograms of SO2 every year, and the leaves of citrus trees can absorb and store sulfur as high as 1%. Populus davidiana and mulberry trees have strong ability to absorb lead dust, and Canadian poplar, ginkgo, elm, phoenix tree and eucalyptus are all better "natural vacuum cleaners". The ability of lawn to absorb dust is dozens of times greater than that of bare grass. Therefore, one of the tasks of environmental science is to give full play to the role of plants in purifying the atmosphere. Choose plants with strong ability to absorb pollution, expand the afforestation area, and form closed or isolated forest belts according to the location of pollution sources, the topography of pollutant collection areas, the wind direction and the seasonal distribution of pollution gases, so that the dust airflow in motion can be absorbed by the Woods. On the other hand, measures to control or reduce pollutant emissions should be studied to ensure that air quality meets the prescribed standards.