"Greenhouse Effect" of Carbon Dioxide
"Greenhouse effect" is one of the global environmental problems faced by contemporary human society, which refers to the phenomenon of global warming caused by the increase of carbon dioxide content in the atmosphere caused by human activities. Because factories, vehicles and domestic stoves burn a lot of coal, oil and natural gas, and emit a lot of carbon dioxide, coupled with a large number of deforestation (trees can absorb a lot of carbon dioxide), the content of carbon dioxide in the atmosphere is increasing day by day. Carbon dioxide in the atmosphere has poor absorption ability to solar short-wave radiation, but it can strongly absorb infrared long-wave radiation emitted from the ground, thus increasing the atmospheric temperature. The warming effect of carbon dioxide is very similar to the glass ceiling and surrounding glass windows in a greenhouse. The glass in the glass greenhouse can penetrate the sunlight, so that the heat remains in the greenhouse, which makes the temperature in the greenhouse much higher than that outside. Therefore, people call the warming effect of carbon dioxide gas similar to greenhouse gas "greenhouse effect". It is estimated that if the content of carbon dioxide gas in the atmosphere increases by 1 times, the global annual average temperature will increase by 1.5 ~ 4.5℃. Scientists predict that with the increase of greenhouse gases produced by human activities, the global temperature will rise by 2 ~ 5℃ by 2 100. With the increasing greenhouse effect, it will have a great impact on human living environment and social economy. Some scientists believe that with global warming, polar ice and snow will partially melt, which will lead to sea level rise and some coastal countries and cities will be submerged by seawater. In addition, with the increase of temperature, precipitation and dry and wet conditions in various regions will also change. At present, in temperate farming areas, due to rising temperature and enhanced evaporation, the climate becomes dry and degenerates into grassland; Now the arid areas will become more arid; However, some areas in the cold zone that are not suitable for farming are now suitable for crop growth due to rising temperatures, which has led to changes in the structure of agricultural production worldwide. In addition, climate change will also cause the spread of some diseases and endanger human health. Therefore, the "greenhouse effect" of carbon dioxide has attracted worldwide attention. In order to protect the earth environment on which human beings depend, people are taking measures to prevent the "greenhouse effect" of carbon dioxide from being further enhanced. The measures taken mainly include: reducing the use of fossil fuels such as coal, oil and natural gas, and making more use of energy sources such as nuclear energy, solar energy, wind energy and geothermal energy; Vigorously plant trees and prohibit deforestation, because trees can absorb a lot of carbon dioxide, reduce the carbon dioxide content discharged into the atmosphere because people burn coal or oil, and reduce the "greenhouse effect."
The ozone layer is destroyed.
The destruction of ozone layer is one of the global environmental problems faced by contemporary human society, which is the result of serious air pollution caused by human activities. In recent years, freezers, refrigerators and other refrigeration equipment have been widely used in industrial production and families, and a large number of chlorofluorocarbons (CFCs) and other gases have been discharged into the atmosphere. These chemicals are easy to decompose at low altitude, and can rise to the stratosphere (also called ozone layer) at high altitude, where they are irradiated by sunlight, and chlorofluorocarbons are decomposed into free chloride ions, which participate in a series of reactions that destroy the ozone layer. As a result of the reaction, ozone (O3) changed into oxygen molecules (O2), thus destroying ozone. Ozone in the ozone layer has the ability to absorb a lot of solar ultraviolet rays, thus protecting the creatures on the ground from the damage of solar ultraviolet rays. For this reason, people call the ozone layer "the umbrella of mankind". As human activities reduce the ozone content in the ozone layer, the ultraviolet rays from the sun on the ground will increase, seriously damaging the basic structure of plants and animals on the ground and endangering the survival of marine life. In addition, it will make the climate and ecological environment of the earth mutate, directly affect human health and increase diseases such as skin cancer and cataract. According to scientists' research, every time ozone in the atmosphere is reduced by 1%, the ultraviolet rays irradiated on the ground will increase by 2%. In 1980s, scientists observed that the ozone over Antarctica decreased sharply from September to 65438+ 10 every year. The measurement results published in 1985 show that the concentration of ozone layer over Antarctica is greatly reduced and the "hole" of ozone layer is enlarged. 1987, scientists discovered that there was also a "hole" in the ozone layer over the Arctic. In order to protect the ozone layer from destruction, the whole world has taken the action of "mending the sky". 1985 On March 22nd, the Vienna Convention for the Protection of the Ozone Layer was signed in Vienna, Austria. 1987 On September 6th, the Montreal Protocol on Substances that Deplete the Ozone Layer was signed in Montreal, Canada. On June 29th, 1990, the above agreement was revised. China signed the revised Montreal Protocol on June 199 1. 1992165438+10 In October, the United Nations Environment Programme held the fourth meeting of the Parties to the Montreal Protocol in Copenhagen, Denmark, to further revise and adjust the use time of ozone-depleting substances.
acid rain
Acid rain, as the name implies, is acid rain. At present, precipitation with PH less than 5.6 is generally called acid rain. The analysis shows that the acidity of acid rain is mainly caused by sulfuric acid and nitric acid, which account for more than 90% of the total acidity. The formation of acid rain is mainly due to the burning of factories, automobiles, airplanes and oil and natural gas, which constantly releases sulfur and nitrogen into the atmosphere. Gases such as sulfur dioxide and nitrogen oxides entering the atmosphere are enriched in some areas, dissolved in water during the condensation process of water, and then formed into sulfuric acid or nitric acid through complex atmospheric chemical and atmospheric physical processes such as oxidation. These two kinds of strong acids fall to the ground with rain, snow, hail and fog, and then form acid rain and acid snow. It can be seen that acid rain is also the result of serious air pollution caused by human activities and one of the global environmental problems faced by contemporary human society.
Acid rain is very harmful. Acid rain falling on rivers and lakes will acidify rivers and lakes, affect the growth and reproduction of fish and even die in large numbers; Acid rain falling on the soil will acidify the soil, endanger the growth of crops or forests, and further endanger human health; Acid rain can also corrode buildings, bridges, railway tracks, etc. Even cultural relics, stone carvings and stone carvings that have been preserved for centuries will be mottled and unrecognizable by acid rain. Acid rain does great harm to human survival and development, and is called "death in the air". The most fundamental way to prevent acid rain is to reduce the emissions of man-made sulfur oxides and nitrogen oxides. The artificial emission of sulfur dioxide is mainly caused by burning high-sulfur coal. Therefore, studying the comprehensive development and utilization of sulfur resources in coal is an effective way to prevent acid rain.
water pollution
Water pollution refers to the process that human activities discharge pollutants into water bodies that exceed the self-purification capacity of water bodies, resulting in deterioration of water quality and destruction of the original use of water bodies. Water pollution is mainly caused by the arbitrary discharge of industrial wastewater and urban sewage. The main water pollutants are: ① inorganic pollutants such as acid, alkali and salt. Industrial wastewater such as metallurgy, metal processing and man-made fiber is the main source of water pollution. Industrial wastewater from papermaking, alkali production, tanning and oil refining is the source of alkali pollution in water. Cyanide in electroplating and mining can also cause serious pollution to water. ② Heavy metal pollution. Mercury, cadmium, chromium, vanadium, cobalt and copper will cause heavy metal pollution in water. ③ Oxygen-consuming organic pollution. Urban domestic sewage, food and paper industry wastewater contain a lot of organic matter, which will consume dissolved oxygen when entering the water, so people call these organic matter oxygen-consuming organic matter. Oxygen-consuming organic matter reduces the dissolved oxygen content in water, and the organic matter is decomposed by anaerobic microorganisms, which leads to corruption and produces odorous substances such as methane, hydrogen sulfide and ammonia, which deteriorates the water quality. ④ Pollution of plant nutrients. Sewage rich in nitrogen, phosphorus and other plant nutrients enters the water body, which makes algae and other plankton multiply rapidly, reduces dissolved oxygen in the water body, deteriorates the water quality, and leads to a large number of deaths of fish and other aquatic organisms (eutrophication of the water body). ⑤ Refractory organic pollution. Sewage containing organochlorine pesticides (DDT), polychlorinated biphenyls (PCB) and organophosphorus pesticides enters the water body, which is difficult to be decomposed by microorganisms and gradually concentrated through the food chain, causing harm. ⑥ Thermal pollution. The cooling water of thermal power plants and some factories is the main source of hydrothermal pollution. Thermal pollution increases the water temperature, which not only directly leads to the death of some aquatic organisms, but also reduces the dissolved oxygen in the water, seriously affecting the growth of aquatic organisms. According to the statistics of 1994 China Environmental Status Bulletin, 32% of the seven major river systems and key river sections of inland rivers in China meet the Environmental Quality Standard for Surface Water, 29% meet the requirements of Class I and II, and 39% meet the requirements of Class IV and V.
To control and further prevent water pollution, we should start with controlling wastewater discharge and combine prevention, treatment and management. "Prevention" refers to reducing the amount of industrial wastewater discharged from pollution sources, reducing the concentration of water as much as possible, and controlling the pollutants entering the water body to the lowest level by adopting methods such as transformation process, wastewater reuse and recovery of useful products. "Treatment" refers to the harmless treatment of wastewater entering the water body under the premise of considering the self-purification ability of the water body, so that it will not affect the sanitary characteristics and economic value of the water body. "Management" means strengthening the monitoring and management of water bodies and their pollution sources, and carrying out targeted and step-by-step water pollution prevention and control.
solid waste pollution
Solid waste pollution refers to the pollution of living environment caused by solid and mud discarded by human beings in production and life. Solid waste mainly includes waste rock and coal gangue from mining industry; Blast furnace slag and steel slag in industrial production; Straw, human and animal manure in agricultural production; Radioactive waste from the nuclear industry and some medical units; Urban garbage, etc. The serious environmental problems caused by solid waste stacking mainly include: ① occupying land and destroying the surface. More and more urban garbage, mining tailings, coal gangue and industrial waste residue occupy a lot of land, which directly affects agricultural production, hinders urban environmental sanitation, buries green plants and destroys the ecological balance of nature. ② Pollution of soil, water and atmosphere. Solid wastes and secretions piled on the ground will change the composition and structure of soil, and toxic wastes will also kill microorganisms and animals in soil and reduce soil fertility. When solid waste enters the water body, on the one hand, it reduces the area of the water body and is easy to cause floods; On the other hand, it pollutes the water body and affects the survival of aquatic organisms and the utilization of water resources. ③ Harm to human health. Toxic substances and pathogens contained in solid waste not only spread through the atmosphere, water and soil, but also spread diseases through various pests, such as plague.
In fact, what people usually call solid waste is not all useless waste, but relatively useless in a certain process or aspect. Wastes produced in one production process can usually be used as raw materials for another production process. For this reason, people also call waste "raw materials used in the wrong place". Since 1960s, many countries have developed and utilized solid waste as a resource. At present, the main measures for pollution prevention and resource utilization of solid waste are: reforming production technology to reduce waste generation; Develop material utilization technology to make the waste of the last product become the raw material of the next product; Incorporate solid waste into the category of resource management and formulate laws and regulations on solid waste management. The utilization methods of solid waste mainly include: using mineral waste as building materials and filling materials; Do metallurgical, chemical, light industry and other industrial raw materials; Recovering energy from wastes containing carbon, oil or other organic matter; Using wastes containing nutrients needed by soil and plants to make soil improvers and fertilizers. It is believed that with the development of science and technology, more solid waste can be turned into useful resources.