Basic knowledge of the ozone layer and ODS. What is the ozone layer? Ozone (O3): a gas composed of three oxygen atoms. It is formed by the action of oxygen molecules and ultraviolet rays in sunlight. The ozone layer is composed of ozone molecules in the stratosphere. Composition  The ozone layer is like a large bubble surrounding the earth. Basic knowledge of protecting the human body, animals and plants from ultraviolet rays and ozone depleting substances and ozone depleting substances.
1. What is the ozone layer?
Ø Ozone (O3): a gas consisting of three oxygen atoms
Ø Made up of oxygen molecules and ultraviolet rays in sunlight
Ø The ozone layer is composed of ozone molecules in the stratosphere
Ø The ozone layer surrounds the earth like a big bubble
Ø Protect humans, animals and plants from UV rays
Second, the formation of the ozone layer
Ø Oxygen molecules absorb ultraviolet light and decompose to form oxygen atoms;
Ø Oxygen atoms combine with oxygen molecules to form ozone;
Ø Ozone can be decomposed by absorbing sunlight, or it can be combined with oxygen atoms to become oxygen molecules.
Ø M is the third body of reaction, they are nitrogen and oxygen molecules
Third, the role of the ozone layer
v Protection
Absorbs ultraviolet light below 300 nm, mainly a part of medium wave UV-B (290-320 nm) and all short-wave UV-C (
v heating effect
Absorbing ultraviolet light into heat
v The role of greenhouse gases
The reduction of ozone will generate the power of the ground temperature drop, compressing the earth's ozone to 1 atmosphere, and its thickness is only 3mm.
Fourth, the impact of ozone depletion on human health and the environment
• Impact on human health
?? DNA changes, immune mechanisms are reduced
Measles, chickenpox, herpes, bacterial infections, fungal infections, etc.
?? Skin cancer basal cell carcinoma, squamous skin cancer malignant melanoma
?? Cataract
1% reduction in the ozone layer will increase 1-1.5 million cataracts
• Impact on terrestrial plants
?? Reduce production - such as beans, melons, cabbage
?? Change genetics and regenerative capacity
?? Reduce quality
• Impact on aquatic life
?? Reduce plankton
?? Affecting the marine food chain
?? Endanger the early development of fish, shrimp and other animals
• Impact on urban environment and building materials
?? Optical chemical smoke pollution
?? Polymer material aging
5. What is ODS?
v Ozone-depleting substances (ODS) are substances that destroy the ozone layer in the atmosphere, mainly perchlorofluorocarbons (CFCs), halons, carbon tetrachloride, methyl chloroform, methyl bromide, etc.
v Their ability to destroy ozone is called Ozone Depleting Potential (ODP)
Ozone Depleting Substances (ODS) and Ozone Depletion Potential (ODP)
v Perchlorofluorocarbons Chlorofluorocarbons (CFCs) 0.6-1.0 (ODP values)
v Halon Halon 3.0-10.0 (ODP value)
v Carbon tetrachloride (CTC) 1.1 (ODP value)
v methyl chloroform Methyl chloroform (TCA) 0.1 (ODP value)
v Hydrofluorocarbons (HCFCs) 0.001-0.11 (ODP values)
v Hydrobromofluorocarbons (HBFCs) 0.02-1.0 (ODP value)
v Bromochloromethane 0.12 (ODP value)
v Methyl Bromide (MBr) 0.6 (ODP value)
Sixth, the use of ODS
1. Refrigerants: (CFCs, HCFCs) Household, commercial, transportation refrigerators, air conditioners, heat pump systems; motor vehicle air conditioners
2. Blowing agent: (CFC-11) Polyurethane foam and polystyrene, polyethylene extruded foam prepared with CFC foaming agent
3. Cleaning agent: (CFC-113, trifluorotrichloroethane, methyl chloroform, carbon tetrachloride) Cleaning of various components and products for the electronics industry, precision instrument manufacturing, industrial parts and precision mechanical parts Cleaning, metal processing cold cleaning (steam degreasing), dry cleaning and textile industry cleaning, etc.
4. Aerosol: (CFC-11, -12, -113, -114) For deodorants, shaving lotions, perfumes, glass cleaners, lubricants, etc.
5. Disinfectant: a mixture of CFC-12 and ethylene oxide for medical sterilization
6. Fire Extinguisher: Halons & Hydrobromofluorocarbons
7. Fumigant: Methyl Bromide is used for soil pest control and entry and exit quarantine.
8. Raw materials: HCFC & Carbon Tetrachloride is used as a raw material for chemical synthesis.
Leakage during cleaning of direct injection refrigeration and air conditioning systems such as cleaning agents, paints, fire extinguishing agents, aerosol cans, etc. Use of methyl bromide during quarantine and soil disinfection Disposal of leaking refrigerants containing ODS products or equipment such as blowing agents and refrigerants Leakage during the cycle - once the ODS is released into the air, it will reach the stratosphere with the airflow and persist for a long time (the life of Cl is 100 years)
v CFCs have good stability and are not easily decomposed into the stratosphere in the troposphere and are decomposed into Cl radicals by ultraviolet radiation. Cl radicals cause a chain cycle of ozone depletion, a Cl radical can consume 100,000 O3
v Br atom can also cause this reaction
Editor: Mr. Ding (Zhejiang Institute of Analysis and Testing, Chinese Academy of Sciences)
If you need to detect ODP analysis services: Mr. Ding; QQ
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