Ozone depletion powerpoint presentation
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OZONE LAYER DEPLETION OZONE DEPLETION (OZONE HOLE) 1 OZONE LAYER 20 The ozone layer is a layer is a layer in the earthâs atmosphere which contains 90% of atmospheric ozone (O3). The ozone layer is found in the lower portion of the stratosphere from about 20 to 30 km above earthâs surface. Itâs thickness varies seasonly and geographically. 20-30 FORMATION OF OZONE LAYER The ozone layer or the ozone forms by conversion of atmospheric oxygen(O2) into ozone (O3), this process is called as Chapman cycle . The oxygen get photolyzed by U.V.rays to form oxygen radical. U.V. Light O2 2 O 3 The oxygen radical then react with molecular oxygen and forms ozone molecule (O3). At the same time ozone gets reduce to oxygen by reacting with oxygen radical. O3 O2 2 O O3 O2 O So, ozone is constantly get created and destroyed by Chapman cycle, which is a natural process. OZONE DEPLETION Decrease in concentration of ozone and thinning of ozone layer is called Ozone depletion. From industries and our day to day life many gases like Chlorofluorocarbons (CFCâs) , Hydro- chlorofluorocarbons (HCFCâs) , halons, halogens, etc. get evolved in atmosphere which are mainly responsible for ozone depletion, as it contains or produce Chlorine (Cl) atom. letâs take look at the process of ozone depletion--- PROCESS OF OZONE DEPLETION Due to solar radiation i.e. U.V. Rays CFCâs , HCFCâs breaks and form Cl atom which react with ozone molecule and forms Chlorine monoxide (ClO). Chlorine monoxide then reacts with oxygen radical to form Chlorine atom and molecular oxygen. Cl O3 U.V. Light ClO O2 ClO O Cl O2 NET REACTION : O3 O2 2 U.V. Light O As Cl atom acts as a catalyst , one single Cl atom can destroy much amount of ozone molecules. OZONE HOLE As a result of ozone depletion, over Antarctica the ozone hole is formed. This ozone hole leads to melting of ice of Antarctica, increase in sea level and other harmful effects on itâs environment. OZONE DEPLETING SUBSTANCES Ozone depleting substances are mainly CFCâs, HCFCâs, Halons, etc. which are found in Refrigerators, Cleaning agents, sprays, Pesticides, Air conditioners, car emissions, etc. EFFECT OF OZONE DEPLETION Due to ozone depletion harmful U. V. Rays such as UV-B Radiation reaches to earth which leads to harmful effects on animals, plants, aquatic life as well as on humans also. Effect on Aquatic System: Affects phytoplankton, fish, larval crabs. Decrease in amount of phytoplankton increase the CO2 in atmosphere which contribute the global warming. Effect on Materials: Degradation of paints and plastics. Effect on Climate: Global Warming (Increasing the Average temperature of the Earthâs surface). Effect on Human Health: Damage genetic materials in the cells. Leads to more people suffering from Cataracts. Causes cancer, allergies and some other infectious disease. 10% depletion in ozone layer results in 30% increase in skin cancer infection. PREVENTIONS Limit private vehicle driving to decrease vehicle emissions. By using Eco-friendly household or other cleaning agents. Avoid excess use of pesticides. Replacing CFCâs by other material which are less damaging. Manufacturing and using of ozone depleting chemicals must be stopped, etc. But, for controlling ozone depletion the most important thing is to aware people about it, and thatâs why International Environmental Community declared 16 September as a World Ozone Day . THANK YOU !!