Ozone Layer.pptx

Ozone (O3) is a molecule made up of three atoms of oxygen (O), and very reactive gas.
Bluish gas that harmful to breathe.
Is mostly found in the stratosphere, where it protects us from the Sun’s harmful ultraviolet (UV) radiation.
Although it represents only a tiny fraction of the atmosphere, ozone is essential for life on Earth.
Ozone in the stratosphere— a layer of the atmosphere between 15 and 50 kilometers (10 and 31 miles) above us—acts as a shield to protect Earth’s surface from the sun’s harmful ultraviolet radiation.

1. Amjad Khan Afridi Lecturer, Department of Health & Biological Sciences Abasyn University, Peshawar Ozone Layer Lecturer # 08 Amjad Khan Afridi Lecturer, Department of Health & Biological Sciences Abasyn University, Peshawar

2. Ozone Ozone (O3) is a molecule made up of three atoms of oxygen (O), and very reactive gas. Bluish gas that harmful to breathe. Is mostly found in the stratosphere , where it protects us from the Sun’s harmful ultraviolet (UV) radiation. Although it represents only a tiny fraction of the atmosphere, ozone is essential for life on Earth. Ozone in the stratosphere— a layer of the atmosphere between 15 and 50 kilometers (10 and 31 miles) above us—acts as a shield to protect Earth’s surface from the sun’s harmful ultraviolet radiation.

3. Without ozone, the Sun’s intense UV radiation would sterilize the Earth’s surface. With a weakening of this shield, more intense UV-B and UV-A radiation exposure at the surface would lead to quicker sunburns, skin cancer , cataracts, and even reduced crop yields in plants. However, near the surface where we live and breathe, ozone is a harmful pollutant that causes damage to lung tissue and plants. This “bad” ozone forms when sunlight initiates chemical reactions in the air involving pollutants, particularly a family of gases called nitrogen oxides (released from vehicles and industry during the combustion process) and with volatile organic compounds (carbon-containing chemicals that evaporate easily into the air, such as petroleum products).

4. Stratospheric Ozone: Ozone is good in the stratosphere because it absorbs all of the most energetic ultraviolet radiation (UV-A UV-B UV-C). Ozone is “bad” in the troposphere because it is harmful to breathe and is the primary component of smog in summer.

5. Concept of Ozone Layer Is a layer in Earths atmosphere which contains a lot of concentration of ozone (O 3 ). This layer absorbs 97-99% of the suns ultraviolet light, which is damaging the life on earth.

6. Characteristics The ozone layer is located in the stratosphere Contains relatively high concentrations of ozone (O 3 ) Without the ozone layer, ultraviolet (UV) radiation from the Sun would not be stopped The layer sits at an altitude of about 10-50 kilometers

7. Formation The ozone layer is created in the stratosphere, when highly energetic solar radiation strikes molecules of oxygen (O 2 ) in to two single oxygen atoms, known as atomic oxygen. If a free atom joins into another O 2 is forming the ozone. This process is known as Photolysis.

8. Because there is so much oxygen in our atmosphere, this “ozone-oxygen cycle” is continuously absorbing high-energy ultraviolet radiation (UV-C) and completely blocking it from reaching the Earth’s surface. This process creates heat which warms the upper part of the stratosphere. Ozone is very reactive, and attacks other molecules in the air, often regenerating oxygen in the process.

9. 7 HOW OZONE IS CREATED IN THE STRATOSPHERE

10. Destruction When chlorofluorocarbons ( CFCs) and Hydrochlorofluorocarbons (HCFCs) reach the stratosphere, the ultraviolet radiation from the sun causes them to break apart and release chlorine atoms which react with ozone, starting chemical cycles of ozone destruction that deplete the ozone layer. One chlorine atom can break apart more than 100,000 ozone molecules.

11. UV radiation strikes ozone molecule… … releasing one oxygen atom O O O O O O How ozone is naturally destroyed in the Stratosphere

12. Other Chemicals that affect the Layer Methyl Bromide: used as pesticide Halons: used in fire extinguishers Methyl Chloroform: used as a solvent in industrial processes for essential applications

13. Importance of the Ozone Layer The Ozone Layer acts as a shield for us from very harmful UV rays. If we damage the Ozone Layer we would put ourselves in a big risk. Without the Ozone Layer we wouldn't be able to survive. Exposure to UV rays causes skin cancer, damages crops, harms ocean life and polar shifting. Without the Ozone Layer the risk of these things would greatly increase.

14. Ozone Hole The ozone hole is a region of exceptionally depleted ozone in the stratosphere over the Antarctic that happens at the beginning of Southern Hemisphere spring.

15. How our actions are destroying the layer? Products in spray destroys the Ozone Layer, because this uses chlorofluorocarbons that are chemicals that lasts 100 years in ozone layer and destroys it. Also there is CFC; it is highly used as a coolant in refrigerators and air conditioners. This reacts with an ozone molecule, taking an oxygen atom with it and leaving a normal oxygen molecule.

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17. Thank You