Presentation on theme: "“Life’s Support System Depletion”"— Presentation transcript:
1“Life’s Support System Depletion” OzoneLayerDepletion“Life’s Support System Depletion”
2Outline of Presentation What is the Ozone layer?How is ozone created and destroyed?What is the Ozone hole?What are the causes of Ozone Depletion?
3Outline of Presentation What are Ozone Depleting Substances?Effects of the depleting Ozone to humanity and all living things.Impacts of the Ozone Layer depletion to the Earth.How can the Ozone layer be saved?
4What is Ozone Layer?The Ozone Layer is a thin, fragile shield that envelops the entire earth which efficiently and effectively filters and screens almost all of the harmful ultraviolet rays.
5Ozone is a gas that is naturally present in the atmosphere. air moleculesOzone is a gas that is naturally present in the atmosphere.It is a molecule made up of three oxygen atoms.It’s chemical symbol is O3.
6The AtmosphereEarth’s atmosphere is divided into four layers with different elevation and temperature profile:TroposphereStratosphereMesosphereThermosphere
8The Solar RadiationThe Earth’s atmosphere is exposed to radiation from the sun. Energy is transferred from the sun to the earth in the form of electromagnetic energy. Electromagnetic energy can be divided into spectrum, in which protons that transfer energy have both a wavelength and energy level.This radiation includes ultraviolet, visible and infrared radiations.
9There are three categories of UV: UV-A: Most UV-A is able to reach the earth’s surface.UV-B: 90% of UV-B is blocked off by the ozone layer.UV-C: 100% of UV-C is blocked off by the ozone layer.
16The Ozone Depletion Degradation of the Ozone Layer. When even a small amount of ozone layer is lost, more ultraviolet light from the sun can reach and destroy the Earth.Caused by the chemical reaction involving chlorine and bromine which are also called Ozone Depleting Substances (ODS).
17OZONE DEPLETING SUBSTANCES (ODS) AND THEIR USES CHLOROFLUOROCARBONS or CFCsHALONSContain at least one bromine atomHalons are primarily used in fire extinguishersSimple chemicals containing chlorine, fluorine and carbon.CFCs are used in refrigerators, air-conditioners, spray cans, solvents, foams, other application.
18OZONE DEPLETING SUBSTANCES (ODS) AND THEIR USES CARBON TETRACHLORIDE and METHYL CHLOROFORM are used as solvents.HYDROBROMOFLUOROCARBONS (HBFCs) are used in fire extinguishers.HYDROCHLOROFLUOROCARBONS (HCFCs) were developed as the first major CFC replacement .
19OZONE DEPLETING SUBSTANCES (ODS) AND THEIR USES METHYL BROMIDE (CH3Br) is used as a fumigant and in quarantine treatment.