Stratospheric Ozone Depletion Research

Stratospheric Oz unity Depletion ResearchA) effect of Ozone on the Lower AtmosphereThe dismay atmosphere (Troposphere) includes 75% by mass of the atmosphere (concentrated). Natural sources of Ozone in the troposphere includes lightning. Approximately 10% of all atmospheric ozone is present in the troposphere. If ozone levels reach 20ppm, they atomic number 18 rattling poisonous to humans, animals and plants. It modifys organic tissue which disrupts the normal biochemical reactions in the body, irritates the eyes and causes breathing difficulties. It tolerate be detrimental to plants and agriculture, as it oxidises much much readily then type O, killing/spoiling the agriculture and destroying it.Sources of ozone in the troposphere include diffusion from the stratosphere, internal combustion engines, petrochemical smog, naturally from lightning and photochemically when nitrogen dioxide in polluted personal credit line is decomposed by sunlight.NO2(g) NO(g) + O(g)O2(g) + O(g) O3(g)Positive effects of ozone include that it can kill bacteria and viruses in water and and then is useful in purifying water supplies.B) Effects of Ozone in the StratosphereContrastingly to ozone in the troposphere, Ozone in the stratosphere is essential to support on earth, as it absorbs ultraviolet (UV) radiation which can be harmful to living cells on earth as they can damage living tissues and cause skin cancers. Ozone in the stratosphere is commonly referenced to as the ozone shield as it protects living organisms on earth from UV rays.Ozone Reactions in the Stratosphere and their Beneficial Effects on Living OrganismsFormation of Ozone in the StratosphereO2(g) O(g) + O(g)O(g) + O2(g) O3(g)Stratospheric oxygen absorbs UV light to form free oxygen radicalsThe oxygen radicals are highly reactive and combine with oxygen molecules to form an energized ozone molecule.Decomposition of Ozone in the StratosphereO3(g) O2(g) + O(g)Due to the absorption of UV radiation, the Ozone layer acts as a radiation shield by absorbing medium and high energy UV rays. This protects living organisms as UV radiation can have very harmful effects on them includingCan cause sunburn on skin which can lead to skin cancer caused by a pas seul in DNACan form cataracts on eyesIt can kill cells due to DNA readily reacting with UV raysIt can impair photosynthesis in plantsMany moreThus with pop out the ozone shield in the stratosphere, life in the biosphere would be dramatically impaired and destroyed by harmful UV rays.A) functional Groups and General Structure of Compounds Classified as CFCsCFCs Chlorofluorocarbons are haloalkanes in which the hydrogen atoms have been replaced by fluorine or chlorine atoms.Haloalkanes are the products when alkanes react with halogens (members of group 7 of the periodic table). CFCs generally contain chloro and flouro functional groups and no hydrogen atoms.The general twist of compounds classified as CFCs are haloalkanes whose hydrogens have been replaced by chlorine or fluorine atoms.E.g.B) Main Uses of CFCsCFCs were used as refrigerants and as propellants in aerosol spray cans. They have a variety of uses as demonstrated be down in the mouth.However due to the harmful effects of CFC to the milieu and the ozone shield, CFCs are not used for these uses anymore.C) Reactions between CFCs and Ozone that Result in the Destruction of Ozone in the Stratosphere. Effects of Small Concentrations of CFCs that can Damage Large amounts of OzoneReactions between CFCs and OzoneSynthetic CFCs are responsible for the destruction of the ozone shield, natural CFCs such as CH3Cl and HCl rarely reach the stratosphere as they readily oxidise in the troposphere. However, synthetic CFCs slowly diffuse from the troposphere into the stratosphere, where they undergo photodissociation (due to UV rays) to produce chlorine and bromine radicals that attack and destroy ozone molecules.e.g. CFC-11 Trichloroflouromethane (CFCl3) (Lifetime of 70 years )1. In the stratosphere, the CFC comes into come home with short wavelength UVCFCl3(g) + UV CFCl2(g) + Cl(g)2. The chlorine free radical then reacts with the ozone moleculeCl + O3 ClO + O23. The ClO molecule reacts with free oxygen atoms which exist naturally from UV breakdown of O2ClO + O O2 + ClThis Cl Is then regenerated and able to attack more Ozone (Step 2) thus further demonstrating the harmful effects of even one CFCThis reaction causes destruction of ozone in the stratosphere, due to the (previously used) synthetic CFCs for refrigeration, dry cleaning etc.Small Amounts of CFCs can still do harm establish has shown that even small amounts of CFCs can damage large amounts of ozone. Firstly, CFCs generally have a long lifespan, ranging from approximately 57 (CFC-11) years to 333 years (CFC-12), and due to the fact that each Chlorine radical can be responsible for the breakdown of tens of thousands of ozone molecules, and due to their lifespan once released, even a small am ount, will be around for many decades to come.In addition, most CFCs will almost definitely make their way up to the stratosphere as they cannot be destroyed at low altitudes as they are unreactive and they are insoluble in water and in that locationfore cannot be washed out of the atmosphere by rain.Alternative Compounds for CFCs.A) Ozone supervise InstrumentsOzone Concentrations in the StratosphereSource Earth System Research Laboratory, 2012, Viewed 07.06.14,http//www.esrl.noaa.gov/gmd/dv/spo_oz/spototal.htmlA) Analysis of TrendsThere are a variety of trends that can be interpreted from the above diagram. ground on the data above, before the 1980s, the total ozone concentration was VERY high, at approximately 194 DU (Dobson Units), however there was a very rapid decrease in this concentration from 1980 1999, whereby in this 19 year period sees a 56% decrease in the amount of total ozone, a remarkably concerning figure.On a year round basis globally, total ozone concentration h ave caused a 3-8% decrease in the amount of ozone, this increased in the years between 1995-200, where there was a low of total ozone concentration. However, in more recent years, 2010 to 2014 there has been a general increase in total ozone concentration, which can be inferred from the fill-in of CFCs finally starting to impact (slightly) on the total concentration of ozone, this increase based on the data is 31%.The general pattern is that the total editorial ozone decreases during spring time, it can be inferred that the overall concentration of ozone decreases during this time of the year. This is because in an Antarctic winter, there is no U.V light to convert the chlorine molecule Cl2 into a Cl radical, which then destroy ozone molecules, and thus the concentration of ozone is higher in winter. In spring, the U.V light converts the Cl2 into Cl which then destroys ozone in a chain reaction, thus decreasing the total ozone concentrationThere are various peaks in the graph, in the years of 1988, 2003, 2011 and 2013, which may be due to limitation so of the instruments used.B) Montreal protocol EffectivenessThe Montreal protocol occurred in 1987, which the main aim was to control the production of ozone depleting substances (CFCs) worldwide. A number of amendments have been adopted to further ride ozone depleting substances. The protocol is employ in 193 countries.The main aims of the original agreement is as followHalt the use of Halons by late 1994By the early 21st century, phase out the use of HCFCsStop manufacture of CFCs by 1996Allow for leeway with less developed countries but still get them to rid the use of these substancesThe Montreal Protocol (and amendments) has been efficient as by 2006, the consumption of ozone depleting substances has been reduced globally by 96%. However, due to the long lives of the previously used ozone depleting substances, the total concentration will interpret hundreds of years to be completely down. However, the to tal concentration in the troposphere has generally been declining since the mid-1990s.BibliographyThickett, G 2006, Chemistry 2 HSC course, John Wiley and Sons, Queensland, Australia.Role of Ozone, 2013, viewed 05.06.14,http//www.easychem.com.au/monitoring-and-management/the-atmosphere/roles-of-ozoneAllen, J, 2001, Ultraviolet Radiation How it Affects life on Earth, viewed 05.06.14,http//earthobservatory.nasa.gov/Features/UVB/Environmental Protection Agency, 2010, The Process of Ozone Depletion, Viewed 07.06.14,http//www.epa.gov/ozone/science/process.htmlClean Air Strategic Alliance, 2013, Chlorofluorocarbons (CFCs) and Halons, Viewed 07.06.13,http//dwb.unl.edu/teacher/nsf/c09/c09links/www.casahome.org/chlorofl.htmWelch, C 2014, The Ozone Hole, Viewed 07.06.14,http//www.theozonehole.com/cfc.htmCracknell, A 2012, Remote Sensing and Atmospheric Ozone, Viewed 07.06.14,http//books.google.com.au/books?id=YZzGFPnaEv0Cpg=PA94lpg=PA94dq= atmosphere+4+satellite+ozonesource=blots=k3Ixvnqeups ig=Z_jW0D4jdcvG8hpjbb7d4QeUzBMhl=ensa=Xei=DpCSU-qHMsLtkQWJsIHQDQved=0CF8Q6AEwCgv=onepageq=nimbus%204%20satellite%20ozonef=falseESA, 2013, Eathnet Online, Viewed 07.06.14,https//earth.esa.int/handbooks/gomos/CNTR1-2-2.htmThe Canadian Ozone and Ultraviolet Measurement Program, 2010, Viewed 07.06.14http//es-ee.tor.ec.gc.ca/e/ozone/ozonecanada.htmEarth System Research Laboratory, 2012, Viewed 07.06.14,http//www.esrl.noaa.gov/gmd/dv/spo_oz/spototal.htmlEPA, 2013, Ozone Layer Protection Glossary, Viewed 14.06.14,http//www.epa.gov/ozone/defns.htmlassurance of Meteorology 2013, Ozone Frequently Asked Questions, Viewed 14.06.14,http//www.bom.gov.au/uv/faq.shtmlSmith, R 2008, Conquering Chemistry Fourth Edition, The McGraw-Hill Companies, NSW, Australia1 Page