At an altitude of 15-25 km from the earth's surface, the ozone layer surrounding the earth's outer space is formed due to the ultraviolet radiation of the sun. This thick ozone layer is an umbrella for human survival. This is what most people know about ozone. Humans really realized ozone more than 1.50 years ago. German chemist Dr. Bain first proposed that the odor produced by water electrolysis and spark discharge is the same as that produced by lightning in nature. Dr Bein first thought that its smell was similar to OZEIN in Greek (meaning "unpleasant smell"), so he named it ozone.

Most of the ozone in nature is distributed in the atmosphere 20 -50 kilometers above the ground, which we call the ozone layer. The ozone in the ozone layer is mainly produced by ultraviolet rays. As we all know, ultraviolet rays in the sun's rays can be divided into long wave and short wave. When oxygen molecules (including 2 1%) in the atmosphere are irradiated by short-wave ultraviolet rays, the oxygen molecules will decompose into atomic states. Oxygen atoms are extremely unstable and easily react with other substances. For example, it reacts with hydrogen (H2) to produce water (H2O) and with carbon (C) to produce carbon dioxide (CO2). Similarly, when it reacts with oxygen molecules (O2), ozone (O3) is formed. After ozone is formed, it will gradually fall to the bottom of the ozone layer because its specific gravity is greater than oxygen. In the process of falling, with the change of temperature (rising), the instability of ozone becomes more and more obvious, and then it is irradiated by long-wave ultraviolet rays and reduced to oxygen again. The ozone layer keeps the dynamic balance between oxygen and ozone.

How much ozone is there in such a vast area? It is estimated that the atmospheric1100000. If all the ozone in the atmosphere is concentrated together, there is only a thin layer of three centimeters. So, is there ozone on the surface of the earth? The answer is yes. About 1% of solar ultraviolet rays can reach the ground. Especially in forests, mountains and coastal areas with light air pollution, there are more ultraviolet rays and rich ozone.

In addition, lightning also produces ozone, which is distributed on the surface of the earth. Because of this, after the thunderstorm, people feel the air is fresh, and they are willing to go to the forests, mountains and coasts in the suburbs to breathe the fresh air of nature and enjoy the beautiful scenery of nature, so that their bodies and minds can have a refreshing "bath". This is the function of ozone, so some people say that ozone is a clean and refreshing gas.

The atmospheric ozone layer has three main functions. One is protection. The ozone layer can absorb ultraviolet rays with wavelength below 300 microns in sunlight, mainly part of UV-B (wavelength 290 ~ 300 microns) and all UV-B (wavelength < 290 microns =), protecting human beings, animals and plants on the earth from short-wave ultraviolet rays. Only long-wave UV-A and a small amount of medium-wave UV-B can radiate to the ground, and the damage of long-wave UV to biological cells is far less than that of medium-wave UV. Therefore, the ozone layer protects life on earth like a space suit. The second is heating. Ozone absorbs ultraviolet rays from sunlight and converts them into heat energy to heat the atmosphere. Due to this effect, the atmospheric temperature structure has a peak at a height of about 50km, and there is a warming layer above the earth from 15 to 50 km. It is because of ozone that the stratosphere exists. On the other hand, there is no stratosphere because there is no ozone and oxygen on planets other than the earth. The temperature structure of the atmosphere has an important influence on the circulation of the atmosphere, and the reason for this phenomenon also comes from the high distribution of ozone. The third is the role of greenhouse gases. The role of ozone is also very important in the upper troposphere and the bottom of the stratosphere, that is, at this very low temperature. If the ozone at this height is reduced, it will generate the power to reduce the ground temperature. Therefore, the high distribution and variation of ozone is extremely important.