What is ozone What is ozone?
Ozone (O?), also known as superoxide, is an allotropic isomer of oxygen (O?), which is a pale blue gas with a peculiar odor at room temperature. Ozone mainly exists in the ozone layer in the lower stratosphere, which is 20-35 kilometers from the earth's surface. It is less stable at room temperature and pressure and can decompose into oxygen on its own. Ozone has a grassy flavor, inhaling a small amount of beneficial to the human body, inhalation of excessive health hazards (non-combustible, pure matter) Oxygen can be changed into ozone by electric shock.
Ozone is an allotropic isomer of oxygen, and at room temperature, it is a light blue gas with a special odor
. The English word ozone comes from the Greek word ozon, meaning "smell".
Ozone mainly exists in the ozone layer in the lower stratosphere 20 kilometers from the Earth's surface, with a content of about 50 ppm. it absorbs short-wave ultraviolet rays that are harmful to the human body and prevents them from reaching the Earth, in order to shield the living creatures on the surface of the Earth from ultraviolet rays.
In the atmosphere, oxygen molecules are decomposed into oxygen atoms (O) due to high-energy radiation, and oxygen atoms combine with another oxygen molecule to produce ozone. Ozone will also react with oxygen atoms, chlorine or other free substances and decompose and disappear. Due to this repeated generation and disappearance, the ozone content can be maintained in a certain equilibrium state.
What is ozone? What is it used for? Where is it used? Why is it called
Ozone is an allotropic isomer of oxygen, at room temperature, it is a blue gas with a special odor. Molecular formula: O3 The English word ozone comes from the Greek word ozon, meaning "smell". Ozone has an isosceles triangle structure, three oxygen atoms are located at the three vertices of the triangle, the top angle of 116.79 degrees. 1840 German C.F. Scheibain in the electrolysis of dilute sulfuric acid, found that there is a special odor of the gas released, so it will be named ozone. When the photochemistry of oxygen in the atmosphere, ozone is produced, so the ozone layer is formed at a vertical height of 15~25 kilometers above the ground, and its concentration is 0.2 ppm. ozone gas is obviously blue, the liquid state is dark blue, and the solid state is blue-black. Its molecular structure is triangular. Ozone is unstable, slowly decompose at room temperature, 200 ℃ when the rapid decomposition, it is stronger than the oxidizing properties of oxygen, can be oxidized to silver peroxide metal silver, lead sulfide oxidation to lead sulfate, it can also oxidize organic compounds, such as indigo will be decolorized by ozone. Ozone solubility in water is greater than oxygen, 0 ℃ and 1 * 10 Pa, a body of water can dissolve 0.494 volume of ozone. Ozone can *** mucous membrane, it is toxic to humans, long time in the air containing 0.1ppm ozone is not safe to breathe. The ozone layer absorbs most of the short wavelength rays (e.g. ultraviolet rays) and protects human beings and other organisms, but chlorine and nitrogen oxides contribute to the decomposition of ozone into oxygen, destroying the ozone layer and making it one of the most important environmental concerns of mankind. Ozone is usually prepared from oxygen or air by means of a silent discharge, and ozone generators are manufactured according to this principle. Using the difference between the boiling points of ozone and oxygen, concentrated ozone can be obtained by graded liquefaction. Ozone is a powerful bleaching agent used to bleach flour and pulp, and ozone is used to disinfect drinking water, which contains only oxygen and has no special odor. It is also used in sewage treatment. Ozone is highly decomposable and unstable. It is insoluble in liquid oxygen, carbon tetrachloride, etc.. It has strong oxidizing property, which can oxidize silver into silver oxide and lead sulfide into lead sulfate at room temperature. Ozone can decolorize many organic pigments, erode rubber, and easily oxidize organic unsaturated compounds. Ozone is extremely stable in ice, with a half-life of 2000 years. Ozone exists mainly in the ozone layer in the lower stratosphere 20 kilometers from the Earth's surface. It absorbs short-wave ultraviolet light, which is harmful to humans, and prevents it from reaching the earth.In 1785, the Germans found that an odor was produced when the motor was discharged when they were using the motor.In 1840, the French scientist Christian Frédérique identified it as ozone. Ozone can be formed naturally from diatomic oxygen under ultraviolet radiation by electron emission or exposure to sunlight. Industrially, ozone is produced by silent discharge with dry air or oxygen using an AC voltage of 5~25kv. In addition, ozone can be produced by electrolyzing dilute sulfuric acid at low temperatures or by heating liquid oxygen. Ozone is used to purify air, bleach drinking water, sterilize water, treat industrial waste and as a bleaching agent. During the summer months, surface ozone forms and accumulates in agricultural and forested areas, especially around large cities, due to the effects of industrial and automobile exhaust fumes. Surface ozone has an aggressive and damaging effect on the human body, especially on the eyes and respiratory tract. Surface ozone is also harmful to crops or forests....
What are the effects of ozone on people?
Ozone has a disinfecting function Ozone, also known as rich oxygen, triple oxygen, superoxide, is known to be one of the strongest available oxidants, which can make bacteria, fungi and other organisms of the protein shell oxidative denaturation, so as to kill bacterial propagules and germ cells, viruses, fungi and so on.
Ozone kills more than 99% of Escherichia coli, Streptococcus, Staphylococcus aureus, and kills hepatitis viruses, cold viruses and so on. Ozone has prominent sterilization, disinfection, degradation of pesticides, is considered a highly efficient broad-spectrum bactericide.
Ozone can sterilize and purify the air, prevent cross-infection of diseases, and remove odors from bedrooms, living rooms, kitchens, and bathrooms. Ozone gas is effective in sterilizing, disinfecting, preventing mildew and removing dust mites on indoor bedding, clothes, carpets, closets, shoe cabinets, coins and so on.
The most appropriate way to use ozone sterilization is to dissolve ozone in water to form the so-called "ozone water". Some developed countries in Europe and the United States will be "ozone water" called "universal water".
"Ozone water" sterilization speed than chlorine many times faster. In daily life, the use of "ozone water" for women, children use underwear, ***, diapers, bags and other sterilization treatment, can play a particularly obvious effect.
"Ozone water" on fruits and vegetables and meat have sterilization, antiseptic, freshness, remove the role of odor, and at the same time has the function of degradation of fruits and vegetables surface residues of phosphorus-containing pesticides. We can also use "ozone water" to clean the skin, skin care, to reduce cosmetics on the skin ***.
The use of "ozone water" cold compresses, soaking burns, cuts, bruises, can accelerate wound healing, to prevent infection; the use of "ozone water" to wash the bubble, you can prevent skin diseases and fungal foot fungus caused by diseases; with the use of "ozone water". "Ozone water" hair wash, you can remove the dirt at the hair pores, reduce hair loss. Scientific use of no harm According to experts, the ozone safety, environmental protection has been recognized, its application of technology is quite mature, gray?br> scientific use, the ozone will not cause harm to human health.
In many countries, the ozone is widely used in disinfection of drinking water, air purification, food processing, health care, aquaculture and other fields. 1902, Germany, Paderborn established the first large-scale water treatment with ozone treatment of water quality plant, creating a precedent for ozone water treatment.
Now, the world has thousands of ozone water plants. Europe and the United States of America, the application of ozone has reached a popularized degree of water plants, mineral water, pure water manufacturers are almost all equipped with ozone equipment.
The United States since the early 1970s began to use ozone to deal with domestic sewage, mainly for sterilization, disinfection, removal of pollutants, decolorization, etc. to meet discharge standards. Japan will be in the water shortage areas with ozone treatment of sewage as water use.
The United States, Japan, Germany, France and other countries have established large-scale ozone sewage treatment plants in recent years. Ozone is also used in the industrial gazami crab to write the whetstone frame 3?hiss? aa (6)? Ting (16) but but Jian Borrow? Borrowing? (11) hours of service?br> industry, the application of ozone in the food industry is more popular.
A Swedish beef company to the application of ozone in the storage of beef freshness, since 1870 has been used today. As early as 1904, the use of ozone in Europe on the preservation of milk, meat products, cheese, egg whites and other food preservation treatment.
At the end of the 1930s, 80% of the refrigerated egg banks in the United States have installed ozone generators. Recently, Europe and the United States in the fruit and vegetable preservation will be the use of ozone to storage, manufacturing, transportation and other aspects.
In terms of medical care, Japan as early as World War II, the use of ozone for human physiotherapy. At present, ozone has a variety of uses in health care, such as wards, operating rooms, air disinfection, the use of "ozone water" for the disinfection of medical equipment, the use of ozone for the treatment of dental diseases, the use of ozone and radiation therapy combined with the treatment of cancer, drinking "ozone water" The ozone gas is injected to treat fistulae and varicose veins.
In health care, the Japanese popular inhalation of "strong gas" (containing a low concentration of ozone in the air) in order to strengthen the body, the use of ozonized water to shower the body to kill bacteria and beauty. Ozone kills viruses and bacteria, and is not harmful to the healthy cells of the human body, because the latter have a strong and balanced enzyme system.
As long as the scientific application of ozone, ozone is not dangerous to human health. In fact, ozone has been used for more than 100 years, and so far there has not been a single case of death due to ozone poisoning in the world.
In addition, there is now a theory that the ozone in the disinfection at the same time, you can also "kill" fruits and vegetables in the vitamins and other components beneficial to the human body; but by the Chinese Academy of Preventive Medical Sciences environmental health monitoring test confirmed that the use of qualified ozone equipment for normal operation of the fruits and vegetables soaked for 10 to 15 minutes, on fruits and vegetables, the vitamin C has no significant impact on the fruits and vegetables. Vitamin C has no significant impact. Blindly abused also damage life scientific use of ozone does not cause harm to human health, but if unchecked blind abuse of ozone "detoxification", is not safe.
The ozone itself is a non-toxic safety gas, its "toxicity" mainly refers to the strong oxidizing ability. Experts believe that in the ozone concentration is higher than 1.5ppm above, the personnel must leave the scene, the reason is that the ozone will be *** human respiratory system, serious, can cause injury.
At present, many countries and organizations have developed a person in the ozonated gas environment safety and health standards, its concentration and the product of contact time can be regarded as the reference point: the International Ozone Association standard: 0.1ppm, contact 10 hours; U.S. standard: 0.1ppm, contact 8 hours; Germany, France, Japan and other countries standards: 0.1ppm, contact 10 hours; our standards The American standard is: 0.1ppm, 8 hours exposure; German, French and Japanese standards: 0.1ppm, 10 hours exposure; our standard: 0.15ppm, 8 hours exposure. Some reports show that the ozone concentration in 0.02ppm, smell sensitive people will be able to detect.
Concentration of 0.15ppm for the olfactory threshold, the average person can smell. When the concentration reaches 1~10ppm, it is called the *** range, and above 10ppm is the poisoning limit.
There are also reports that human exposure to high concentrations of ozone may occur in the environment, skin, eye stinging, breathing problems, coughing and headache and other symptoms; exposure time is longer, it will also lead to transient lung function abnormalities, causing lung tissue damage; there are allergies may also lead to chronic lung disease, and even produce permanent damage such as pulmonary fibrosis. Therefore, experts remind consumers to buy ozone generator must check the product safety test certificate and sterilization report.
And, ozone production is not the more the better, 200 mg / m3 of ozone per hour is more suitable for home use generally do not exceed 400 mg / m3 per hour. It takes about 60 minutes to produce drinking water with an ozone machine, and another 15 minutes of.
What is ozone? Is it harmful to the human body?
● Harmful effects of ozone Low concentrations of ozone can disinfect, but excessive ozone is an invisible killer! ▲ It strongly *** human respiratory tract, causing sore throat, chest tightness, cough, bronchitis and emphysema; ▲ Ozone can cause neurotoxicity, dizziness, headache, vision loss, memory loss; ▲ Ozone will play a destructive role in human skin vitamin E, resulting in wrinkled skin, black spots; ▲ Ozone will also destroy the body's immune system, inducing chromosomal changes in the lymphocytes, accelerated aging, resulting in the birth of a baby. The first thing you need to do is to get rid of all the bad stuff, and then you can get rid of all the bad stuff, and then you can get rid of all the bad stuff.
Therefore, the harm caused by ozone and organic waste gas must cause people to pay close attention. Ozone is also known as tri-atomic oxygen, commonly known as "oxygen, super-oxygen, live oxygen", the molecular formula is O3 .
Ozone at room temperature and pressure, light blue gas, accompanied by a natural fresh flavor, the stability of ozone is extremely poor, at room temperature can be decomposed into oxygen, so the ozone can not be stored, the general site production, and immediate use. Ozone is currently known as a broad-spectrum, efficient, rapid, safe, no secondary pollution of the sterilization gas, can kill bacterial germs, viruses, fungi, etc., and can destroy botulinum toxin.
It can kill E. coli, Staphylococcus aureus, Salmonella, Staphylococcus aureus, Fusarium, Icelandic Penicillium, black variegated bacillus, natural bacteria, gonococcus, etc., which are attached to the food of fruits, vegetables, and meats, etc., and it can also kill infectious poisons such as hepatitis A and B, and also can remove pesticide residues in fruits and vegetables, as well as the toxicity of the residual residue of washing supplies. The mechanism of sterilization is to act on the cell membrane of bacteria, so that the cell membrane composition is damaged, resulting in metabolic disorders inhibit its growth until death; the mechanism of killing viruses by directly destroying their ribonucleic acid or deoxyribonucleic acid to complete.
The mechanism of pesticide degradation is realized by directly destroying its chemical bond. Ozone kills viruses and bacteria, while healthy cells have a strong homeostatic system, thus ozone is harmless to healthy cells.
● ozone main function 1, food purification: from the surface to the inside of the degradation of fruits and vegetables, food residues of fertilizers, pesticides and other toxic substances, meat, eggs, antibiotics, chemical additives, hormones, and other harmful substances, kill seafood easy to cause poisoning in the salinophilic bacteria, and keep the disease from entering by mouth. 2, drinking water purification: tap water after ozone treatment is a high-quality drinking water.
Each liter of water only need to pass into the O3 2 minutes to remove residual chlorine in the water, sterilization, disinfection, deodorization, removal of heavy metals, to prevent the generation of carcinogens trichloromethane, increase the oxygen content of the water, the homemade ideal pure drinking water. 3, disinfection and sterilization: after cleaning the food and beverage utensils into the water through the O3 20 minutes, can remove detergent residues, kill bacteria, viruses, instead of electronic sterilizer, to avoid food and beverage utensils infectious diseases.
Can also be clothing, towels, rags, socks, etc. for water-mediated disinfection, deodorization. 4, air purification: the ozone exhaust pipe hanging in the height of 1.7 meters above the discharge of O3 20 - 30 minutes, you can effectively remove indoor soot or decorative materials, odor, dust sterilization, increase air oxygen content, fresh air, so you can enjoy at home after the rain forest fresh air (can be used in the home, office, meeting rooms, entertainment venues in addition to smoke, dust, disinfection, deodorization).
5, fruit and vegetable preservation, mold: family fruit and vegetable preservation just to the bagged fruits and vegetables into O3 2 minutes, can extend the freshness period of 7 days, can also be used for cellar mold, fruit and vegetable transportation. 6, bathing, beauty, health care: washing ozone bath has become fashionable in foreign countries, through the ozone bath treatment of disease has been many years of history, which is another magical effect of O3.
Often wash the ozone bath can eliminate toxins in the body, activate epidermal cells, eliminate acne, whiten the skin, rheumatism, skin diseases, gynecological diseases, diabetes and gray nails, etc. have a good therapeutic effect. 7 , fish farming, watering flowers: watering flowers, greenhouse vegetables sprinkler irrigation, can avoid pests, reduce the use of pesticides.
Fish farming, aquaculture, O3 into the water to release the primary ecological oxygen, eliminate bacteria, viruses, oxidize impurities, prevent water spoilage, increase the nutrients in the water. 8, deodorization: Because ozone has a strong oxidative decomposition ability, can quickly and completely eliminate the air, water, a variety of odors.
Ozone has an adverse effect on the human body is generally too large a concentration or insufficient purity. Ozone on the human body caused by the adverse effects of the case, most of the industrial ozone used in the family, its concentration is higher than the life of the ozone concentration of tens of times, and sometimes even up to hundreds of times.
The concentration is too high, causing harm to the human body. Insufficient purity is purely a technical problem; too much nitrogen oxides can cause serious harm to the human body.
In addition, the ozone machine for home use, if not used properly, there will be adverse effects. For example, blowing the jet directly into the mouth to remove bad breath; letting babies and young children inhale ozone from the nose in pursuit of health or continuously spraying ozone throughout the night for no apparent reason, and so on.
It's like medicine prescribed by a doctor, if you take it the wrong number of times and in the wrong amount, it can have side effects that are harmful to the human body. The same is true for ozone, which can also be dangerous if used in the wrong way.
The powerful oxidizing power of high concentrations of ozone can *** eyes, nose, throat mucous membranes, the bronchial tubes and lungs and other respiratory system. As mentioned earlier, over a certain concentration, there will be breathing difficulties, pulmonary edema and other self-conscious symptoms.
Currently, there is no domestic environmental benchmark for ozone, however, the Japanese Society for Industrial Hygiene has a permissible concentration of 0.1 ppm, the United States is also 0.1 ppm, and Russia has 0.1 kg/m3 (0.05 ppm). The concentration of ozone in nature is 0.001-0.003ppm in summer when the weather is good, and it is roughly 0.004-0.006ppm in forest baths and ozone baths which are good for the body.
Ozone's bactericidal, disinfectant and deodorizing effects can work at a concentration of 0.0004ppm. The characteristic of ozone is its unique odor, and the concentration at which we can feel the odor is roughly 0.01-0.015 ppm, and the concentration at which most people feel uncomfortable with the odor of ozone is 0.1 ppm.
The licensing standards of the Japan Society of Industrial Hygiene are the same as this concentration, and if the purpose is to purify the room, such a high concentration is not needed at all. In other words, a concentration of a few tenths of a percent is enough to produce an effect, so there is no need to go to a concentration of 0.1ppm at all.
So there is no need to worry about the effects on the human body. If you can still smell the odor of ozone, table.
What is the role of ozone?
The roles of the ozone layer are essential to life on earth, and these roles are not interrelated, and there are also some roles that are detrimental to humans.
1. Absorption of UV-B band ultraviolet light
In the solar spectrum, there are ultraviolet and visible light that can reach the Earth's surface, of which UV-B band ultraviolet light is absorbed by O3. The wavelength range of UV-B band ultraviolet light is 240~320nm, and the wavelength of ultraviolet light is 200~400nm. Ultraviolet light can promote the reaction of synthesizing vitamin D on the human skin, which is beneficial for the generation and protection of bone tissues, but the excessive irradiation of UV-B band can cause skin cancer, immune system, and eye diseases, and also harms to the plants and animals. Therefore, by absorbing UV-B band ultraviolet light, the ozone layer protects life on earth. The ozone layer allows visible light from the sun to pass through and absorbs more than 99% of the harmful ultraviolet radiation, so some people call the ozone layer the "protector", "umbrella" or "ozone barrier" of life on earth. "This is a favorable role of the ozone layer to affirm.
2. The ozone layer causes inverse temperature phenomenon
Ozone absorption of ultraviolet radiation, is bound to increase the temperature, which makes the stratosphere warming, so that the temperature of the stratosphere with the height of the height of the rise, resulting in inverse temperature phenomenon. This inverse temperature phenomenon and tropospheric inversion of the same phenomenon, increase the stability of the atmosphere, meaning that the atmosphere of the upper and lower convection is difficult to carry out, the atmosphere discharged waste in the vertical direction of the mixing is very slow, but they are in the horizontal aspect of the propagation and the relatively fast, in a week or so can be spread to the earth's longitude of all the regions, within a few months can reach all latitudes of the region. Therefore, those substances that destroy the ozone layer, wherever they are emitted on the earth, spread globally, and so, like CO2, the problem of the ozone layer becomes a global problem, and there is nothing that any one country or region can do to protect the ozone layer above it.
3. Ozone is a greenhouse gas
The previous section has dealt with the greenhouse effect, O3 is also a greenhouse gas, which has absorption in the wavelength band of the atmospheric window, and an increase in O3 in the troposphere contributes to higher atmospheric temperatures, so an increase in the concentration of O3 in the troposphere close to the ground causes the intensification of the greenhouse effect, which is a detrimental effect on human beings.
4. Ozone formed by photochemical smog
Photochemical smog is a secondary pollutant formed under the action of sunlight by exhaust emissions from automobiles and other vehicles, and O3 is one of the main components of photochemical smog, which causes damage to the human respiratory system and harms plants and animals, so at the bottom of the troposphere, the localized increase in the concentration of q can cause increased atmospheric pollution.
What is ozone - () A, oxygen B air pollutants C organic matter D rare gases
Choose B reason: O3 (ozone) is an air pollutant exceeding the ozone is an invisible killer of humans! ▲ It strongly *** human respiratory tract, causing sore throat, chest tightness, cough, bronchitis and emphysema; ▲ Ozone will cause neurotoxicity, dizziness, headache, vision loss, memory loss; ▲ Ozone will play a destructive role of vitamin E in the human skin, resulting in wrinkled skin, black spots; ▲ Ozone will also destroy the body's immune system, inducing chromosomal changes in the lymphocytes, accelerated aging, causing pregnant women to have deformities. ▲ Ozone also destroys the immune system, induces chromosomal changes in lymphocytes, accelerates aging, and causes pregnant women to give birth to deformed babies; ▲ Ozone generated by the heat of the toner in photocopying machines and organic exhaust is a strong carcinogen, which can cause various types of cancer and cardiovascular disease. Therefore, the harm caused by ozone and organic waste gas must cause people to pay close attention.
Does ozone really stink? (Why is it called ozone?)
What is ozone Humans have been discovering ozone for a hundred years. In the distance from the Earth's surface 15-25 kilometers high altitude, due to the sun's ultraviolet radiation, the formation of the ozone layer surrounded by the Earth's outer space, this thick ozone layer is the umbrella on which human survival. This is all most people know about ozone. Human beings really know ozone or in more than 150 years ago, by the German chemist Schanbein (Schanbein) Dr. for the first time in the electrolysis of water and spark discharge in the odor, with the same in the natural world after the lightning produced the same smell, Schanbein Dr. that the smell is similar to the Greek OZEIN (meaning "unpleasant"), and thus named it OZEIN. Dr. Bain thought the odor was similar to the Greek word OZEIN (meaning "unpleasant"), and thus named it OZONE (ozone). Ozone, also known as triatomic oxygen, is named for its fish-like odor. Its molecular formula is O3, is an allotropic isomer of oxygen, with its own unique properties: 1. In natural conditions, generally it is a light blue gas, with a source of oxygen artificially produced in high concentrations, ozone for the blaze of white; 2. It has a fishy odor similar to that after the lightning; 3. In the standard pressure and at room temperature, it is 13 times more soluble in water is oxygen; 4. Ozone is heavier than the air, is 1.658 times more heavy than air; 5. 1.658 times; 5. Ozone has a strong oxidizing power, is known as one of the strongest oxidants; 6. Under normal circumstances, ozone is extremely unstable, easy to decompose into oxygen; 7. Ozone molecules are antimagnetic, easy to combine with an electron to become a negative ion molecule; 8. Ozone in the air half-life is generally 20-50 minutes with the temperature and humidity of the increase and accelerate; 9. Ozone in the water half-life of about 35 minutes with the water quality and water temperature varies; 10. ozone in the ice is extremely stable, its half-life of 2000 years ....
What is the ozone hole? Causes and hazards?
The ozone hole refers to the phenomenon of destruction and reduction of the atmospheric ozone layer due to the diffusion and erosion of air pollutants. The ozone layer is located 20-25 kilometers above the ground, is the fight against solar radiation ultraviolet, the protection of the Earth's biosphere the most effective "umbrella". In 1982, scientists first found ozone reduction over the Antarctic, and then people in the Arctic and Tibetan high altitude over the discovery of a similar ozone hole. The cause of the ozone hole: HCFCs, which are used in large quantities as refrigerants, aerosols, blowing agents and other chemical agents, are the "main culprits" in the ozone reduction. In addition, cold is a key to the thinning of the ozone layer, which is why the ozone hole first appeared in the coldest regions of the Earth's North and South Poles. Data indicate that the ozone hole is likely to continue to grow and that it will take at least 20 years for the Antarctic ozone layer to recover significantly, with the real possibility that the oxygen hole will not be completely eliminated until 2050. This refers to the phenomenon of destruction and reduction of the atmospheric ozone layer due to the spread and erosion of air pollutants, especially aerosol pollutants such as nitrogen oxides and halogenated hydrocarbons. Causes of the ozone hole: HCFCs, which are used in large quantities as refrigerants, sprays, blowing agents and other chemical agents, are the "main culprits" in the reduction of the ozone layer. In addition, cold is a key to the thinning of the ozone layer, which is why the ozone hole first appeared in the coldest regions of the Earth's North and South Poles. The hole in the ozone layer threatens the survival of human beings. For more than 10 years, scientists have been studying that every 1% decrease in atmospheric ozone will increase the amount of ultraviolet light reaching the ground. Ultraviolet light to the ground will increase by 2%, human skin cancer will increase by 3%, but also by cataracts, immune system deficiencies and developmental stagnation and other diseases attack. Now live closer to Antarctica in Chile's southern tip of Cape Helena residents, has tasted the pain, as long as out of the house, you have to in the clothes can not cover the skin surface, coated with sunscreen, wearing sunglasses, otherwise half an hour later, the skin will be sunburned into a bright pink, accompanied by itchy and painful; sheep are more often suffer from cataracts, almost completely blind. It is said that rabbits there are so blind that hunters can easily pick them up by the ears and take them home, and that all the fresh fish caught in the river are blind. By extension, if the ozone layer is completely destroyed, the sun's ultraviolet rays will kill all terrestrial life, and human beings will be "doomed", and the earth will become a barren land without any life. It is clear that the hole in the ozone layer has threatened the survival of mankind. In 1987, the major industrialized nations signed the Montreal Convention to phase out the use of chemicals that harm the ozone layer. And now, a healthier, third-generation refrigerant is available: ammonia. Ammonia is a naturally occurring substance composed of the elements hydrogen and nitrogen and has a negligible impact on the environment.