In recent years, people say that there are "holes" on the surface of the earth. What does this mean? On the necessity and urgency of protecting ozone layer from the perspective of environmental protec

In recent years, people say that there are "holes" on the surface of the earth. What does this mean? On the necessity and urgency of protecting ozone layer from the perspective of environmental protection. The destruction of the ozone layer

1. reason: there is a protective film on the earth, which exists in the atmosphere around the earth, that is, the ozone layer, which will block ultraviolet rays from the outside of the earth and protect the creatures on the earth from harm. Humans have produced a large number of substances that will destroy the ozone layer, which will destroy the ozone layer in the north and south poles of the earth.

2. Impact: The destruction of the ozone layer causes the increase of ultraviolet rays on the earth. Ultraviolet rays can destroy biomolecules, including DNA, and increase the probability of skin cancer and cataract, which is related to many immune system diseases. The plankton in the ocean is fatally affected and the marine ecosystem is destroyed. The output of crops has decreased. Strengthen the greenhouse effect.

What should we do: use chlorofluorocarbons and buy air conditioners, refrigerators, cars, sprays, etc. You should buy products that do not contain chlorofluorocarbons.

4. Supplementary information: Most of the ozone in the atmosphere is concentrated in the upper stratosphere about 25~30 kilometers from the ground, which is called the "ozone layer". Although it is nominally a layer, in fact, the ozone distribution is not uniform everywhere, and the total ozone in the atmosphere is very small, less than 1ppm. This extremely thin ozone layer is very important for life on earth, because ozone can absorb ultraviolet rays in sunlight. These ultraviolet rays are short in wavelength and deadly in radiation, and only a very small amount can reach the surface by converting these ultraviolet rays into heat energy.

Because ozone keeps a dynamic balance with oxygen, oxygen atoms and other ultraviolet rays in the stratosphere, the oxygen consumption of the main part of the biosphere and substances (such as chlorine atoms) that may participate in or affect such reactions (including O3═O2+O'+2O3═3O2) are discharged upward, which may threaten the ozone content of the "ozone layer". Therefore, we call for energy conservation and emission reduction, afforestation and conscious maintenance of ecology.

Ozone is an allotrope of oxygen (composed of the same elements but with different molecular structures). As the name implies, ozone is another pungent smell, so it is notorious. At the height of 10 km to 50 km in the atmosphere, there is a considerable concentration of ozone, which is called the ozone layer.

After the depletion of the ozone layer, its ability to absorb ultraviolet radiation is greatly weakened, resulting in an obvious increase in ultraviolet B reaching the earth's surface, which brings many hazards to human health and ecological environment. At present, people have paid extensive attention to the impact on human health, terrestrial plants, aquatic ecosystems, biochemical cycles, substances, tropospheric atmospheric components and air quality.

Excessive use of chlorofluorocarbons (CFCs) is the main reason for destroying the ozone layer. Chlorofluorocarbon (CFC) is a man-made chemical substance, which was put into production by DuPont Company of the United States on 1930. After World War II, especially after 60 years, it began to be widely used, mainly as aerosol, refrigerant, foaming agent, chemical solvent and so on. In addition, halons (used in fire extinguishers) and nitrogen oxides can also cause ozone layer depletion.

In the stratosphere, the concentration area of ozone is 20~30 kilometers from the ground, in which there is a dynamic balance of oxygen atoms (O), oxygen molecules (O2) and ozone (O3). However, nitrogen oxides, chlorine, bromine and other active substances and other active groups will destroy this balance and make it shift to the direction of ozone decomposition. The extraordinary stability of CFCs makes it easy to gather in the stratosphere, and its influence will last for a century or more. Under intense ultraviolet irradiation, they photolyse chlorine atoms and bromine atoms, and become catalysts for destroying ozone (one chlorine atom can destroy 654.38+ million ozone molecules).