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Air and air pollution
Origin：Hefan Hit： Time：2020-03-12
I. Pure atmosphere
The atmosphere refers to the entire space formed by the air surrounding the earth's surface, and its thickness is 1000 ~ 1400km.
Atmosphere refers to the space between one or all of the gases occupying the atmosphere, or the atmosphere that constitutes the whole or a part of the atmosphere
Body space. It is a concept of geophysical space or geographic space. The total mass of the Earth ’s atmosphere is estimated to be about 3.9 × 10 to the 16th power, accounting for about 1% of the total mass of the earth. 5% of its mass is concentrated in the space below 5km from the earth ’s surface, 75% is concentrated in the space below 10km, % Is distributed in the space below 30kn, and the density is higher as it gets closer to the earth's surface.
Air is purely a material noun, referring to the chemical substances that make up the atmosphere or the atmosphere. It has no geographical spatial meaning. In this sense, the atmosphere is made up of air and ancient geographical space.
It can be seen that the pure atmosphere can only be composed of pure air. Pure air refers to naturally occurring air, mainly composed of nitrogen and oxygen. There are also argon, dioxide and very small amounts of other types of gases. Its specific composition is listed in the table
What is air pollution? According to the definition of the International Organization for Standardization (ISO), air pollution refers to the entry of certain substances into the atmosphere due to human activities or natural processes, showing a sufficient concentration, which persists for a sufficient time, and has endangered the comfort and health of the human body. , Welfare and the degree of harm to the environment.
The so-called comfort and health hazard to the human body refers to the adverse effects on the normal physiological state and function of the human body, that is, causing discomfort, acute disease, chronic disease and even death. The so-called profit refers to the biological, natural resources and human social wealth that coexist in harmony with human beings.
Air pollution can be divided into two categories according to its source: one is pollution caused by human activities, and the other is pollution caused by natural processes. The latter includes air pollution caused by volcanic eruptions, mountain fires, wind, and lightning. At present, human beings cannot completely control the pollution of the atmosphere by natural processes. But these natural processes are mostly accidental and regional, and the same two processes often take longer. Because the environment has a certain capacity and self-purification ability, air pollution caused by natural processes often disappears naturally after a period of time, and has no fundamental harm to the development of the entire human race.
Today, what is most worrying is the pollution of human life and life to the atmosphere. Since human life and production activities are uninterrupted, this pollution has never stopped. Since the 21st century, the rapid development of industry and transportation, the continuous expansion of cities, and the high concentration of population have made air pollution increasingly serious. At present, more than 600 million tons of harmful gases are discharged into the atmosphere every year, and coal dust and other dusts are more than 100 million tons, which seriously pollutes the atmosphere and poses a threat to human health. Since this atmospheric pollution is induced by human activities, it can also be controlled through human activities.