The latter phenomenon is referred to as the ozone hole. Following is the list of some of the main ozone depleting substances and the sources from where they are released. Pdf approximate solution to the governing equations is obtained. It is used in purifying water, sterilising air, and bleaching certain foods. Thus, ozone layer depletion has become a major concern among the environmentalists.
Chlorofluorocarbons cfc s, carbon tetrachloride, and methyl chloroform are important humanproduced ozone depleting gases that have been used in many. Ozone depletion describes two distinct but related phenomena observed since the late 1970s. In fact, the 1995 nobel prize in chemistry was awarded to three scientists who revealed the role of manmade chemicals, chlorofluorocarbons, or cfcs, in the ozone depletion process. Ozone formed in the atmosphere is from nitrogen oxides and organic gases emitted by automobiles and industrial sources, however, is a health hazard, and it may cause serious crop. Our experts wont do the work for you, but they will make suggestions and offer guidance if you.
Publications about the ozone depletion theory of global warming. New modelling techniques are helping to unravel the links between these two environmental issues, and to assess the implications of changes. Fire extinguishers contain halons and methyl bromide in the form of pesticides can also be also a cause for the depletion. In this online lecture, sibghat ullah explains 10th class chemistry chapter 14 the atmosphere. Ozone in the stratosphere is necessary to life as we know it because it absorbs energetic uv radiation. Perhaps the two most debated environmental issues in recent years have been climate change and ozone. Causes of ozone layer depletion and its effects on human. This extreme stability allows cfcs to slowly make their way into the stratosphere most molecules decompose before they can cross into the stratosphere from the troposphere.
Find out what caused the ozone hole, and how the 1989 montreal protocol sought to put an end to ozone depletion. The ozone layer lies approximately 1540 kilometers 1025 miles above the earths surface, in the stratosphere. The first manmade threat to the ozone layer was noted by harold johnston 1971. Ozone is much more active chemically than ordinary oxygen and is a better oxidising agent. Cfc molecules are made up of chlorine, fluorine and carbon atoms and are extremely stable. Chemistry of ozone depletion cfc molecules are made up of chlorine, fluorine and carbon atoms and are extremely stable. Although a combination of weather conditions and cfc chemistry conspire to create the thinnest ozone levels in the sky above the south pole, cfcs are mainly.
Ozone layer depletion penn state college of earth and. Ozone depletion, gradual thinning of earth s ozone layer in the upper atmosphere caused by the release of chemical compounds containing gaseous chlorine or bromine from industry and other human activities. Ozone in the troposphere is toxic due to its reactive oxidizing capabilities. Ozone depletion definition of ozone depletion by medical. He and rowland formed a hypothesis about their fate, which suggested that cfcs would deplete the ozone layer. Ozone depletion is the process of destruction of the ozone layer which can cause adverse effects on the living forms by many pollutants releases out from the vehicles, industries etc. A presentation about the chemistry of the ozone layer and how cfc affects the thin layer of atmosphere that contains ozone produced by the interaction of ultraviolet light form the sun with the oxygen in the atmosphere. Apr 18, 2019 the ozone layer helps to protect life from harmful ultraviolet radiation. Like an infection that grows more and more virulent, the continentsize hole in earths ozone layer keeps getting bigger and bigger.
Ozone and environment ozone o3 a gas composed of three atoms of oxygen bluish gas that is harmful to breathe nearly 90% of the earths ozone is in the stratosphere and is referred to as the ozone layer ozone absorbs a band of ultraviolet radiation called uvb ozone depleting substances ods. Education pioneered in australia, with the sunsmart campaign, advising people to cover up when out in the sunshine to reduce the damage caused by uv radiation. Sulfuric acid decomposition chemistry above junge layer in. Ozone layer depletion definition, causes, solutions toppr. Sulfuric acid h2so4 is the seed molecule for formation of stratospheric sulfate aerosol layer that assists ozone depletion by activation of halogen species.
A global thinning of the ozone layer results as ozone rich air from the remaining ozone layer flows into the ozone poor. Ultraviolet radiation from the sun breaks up these cfcs. The aircraft would go up every couple of days, and then they would come back, wed download the data. However, these cause a very nominal contribution to the ozone layer depletion which is near about 1 to 2 percent and therefore these. Use the information in the summary tab as a starting place. Depletion begins when cfcs get into the stratosphere. The thinning is most pronounced in the polar regions, especially over antarctica. It is based on longer observational records, new chemistry. The series is divided into three sections the science of ozone depletion 10, the impacts of ozone depletion 6, and managing ozone depletion 4. Ozone o3 is a molecule made up of three atoms of oxygen o, and is mostly found in the strato sphere, where it protects us from the suns harmful ultraviolet. It is found that the ozone layer gets affected by some natural causes that are sunspots and stratospheric winds. Jun 01, 2002 pdf of this article 607 kb john austin greg bodeker hamish struthers climate change is one problem, ozone depletion is another.
This is the cause for the nearly 80% of the ozone depletion. Halogen catalysis of ozone degredation halogens are a chemical family containing fluorine, chlorine, bromine and iodine. Ozone depleting substances are the substances such as chlorofluorocarbons, halons, carbon tetrachloride, hydrofluorocarbons, etc. The ozone depletion phenomenon the national academies press. The ozone depletion phenomenon the ozone depletion. Twenty questions and answers about the ozone layer. Since india already receives high doses of ultraviolet uvb radiation, and is at the threshold go to speak, effects of ozone layer depletion. Twenty questions and answers about the ozone layer noaaesrl. The earths ozone layer ozone layerthe region of the stratosphere containing the bulk of atmospheric ozone. The 2002 wmounep assessment, scientific assessment of ozone depletion. Government legislation australia in 1989 ozone protection act banning production of import and manufacture of all cfcs.
Global ozone research and monitoring projectreport no. Chemistry of ozone depletion fire protection association nz. The composition of our air, air pollutants, concentration terms, protecting the ozone layer, the chapman cycle, antarctic seasonal ozone depletion, energy from combustion, first law of thermodynamics, heat of combustion, catalytic reforming, fuel alternatives, water for life, neutralizing the. One chlorine atom can break apart more than 100,000 ozone molecules. Sulfuric acid decomposition chemistry above junge layer in earths. Request pdf on the role of heterogeneous chemistry in ozone depletion and recovery we demonstrate that identification of stratospheric ozone changes attributable to ozone depleting substances. Chemistry equations for ozone depletion the student room. On the role of heterogeneous chemistry in ozone depletion. Pdf causes of ozone layer depletion and its effects on. Far above earths surface, the ozone layer helps to protect life from harmful ultraviolet radiation. Ozone depletion is primarily caused by human activities. This timeline highlights the average area of the ozone hole between september 7th and october th as observed by nasa spacedbased instruments see colored bars and scale. If you would like to discuss your ideas or need help troubleshooting, use the ask an expert forum.
Ozone layer research and technical resources us epa. Unlike global warming, however, ozone depletion has actually been successfully controlled by international cooperation, perhaps providing a model for other efforts at global environmental protection. How the world came together to heal the ozone layerand the. Carbon dioxide is the major contributor to global warming. Due to its environmental significance, the chemistry of atmospheric ozone and ozone depletion has been a subject of much research and discussion. Ozone depletion consists of two related events observed since the late 1970s. We can differentiate this profile into two key zones. Basic ozone layer science ozone layer protection us epa. Management of ozonedepleting substances reported to the. Pdf the decomposition of sulfuric acid molecule in the stratosphere contributes to the depletion of ozone layer and therefore requires improved.
Ozone layer depletion essay sample new york essays. These advances add to the scientific basis for decisions made by the parties to the montreal protocol. The main effect of ozone depletion is an increase in uvb rays reaching the earths surface. The global exchange between ozone and oxygen is on the order of 300 million tons per day. Ozone plays a different role in atmospheric chemistry at different heights in the earths atmosphere. Cfc 11, or r11 has the maximum potential amongst chlorocarbons because of the. Each year since the late 1970s, much of the protective layer of stratospheric ozone above antarctica has disappeared during september, creating what is popularly known as the ozone hole. Publications about the ozone depletion theory of global. Ozone chemistry in aqueous solution ozone decomposition and stabilisation margareta eriksson licentiate thesis department of chemistry. Childrens models of the ozone layer and ozone depletion article pdf available in research in science education 264. Together, they describe what ozone, the ozone layer, ozone depletion and the ozone hole are, how ozone depletion occurs, mankinds influence, its impacts, and.
The ozone layer and its depletion linkedin slideshare. Ozone is an invisible, poisonous gas molecule o 3 that exists in trace minimal amounts in the stratosphere 630 miles above the earth. Free environmental chemistry books download ebooks online. What is the impact of volcanic ash on the ozone layer.
Ozone layer depletion cause, effects, and solutions. Stratospheric ozone depletion and climate change rsc publishing. Pdf childrens models of the ozone layer and ozone depletion. Pdf sulfuric acid decomposition chemistry above junge layer in. These chemicals are found in cleaning agents, aerosols, insulating foam, and refrigerants. Ozonedepleting substances reported to tri many class i and class ii ozonedepleting substances are included on the tri chemical list, and hence, the quantities released to the environment or otherwise managed as waste are reportable to epas tri program. List of books and articles about ozone layer online. Prezi s director of product marketing on working from home and finding balance. Cfcs, hcfcs, halons, methyl bromide, carbon tetrachloride, and methyl chloroform. It is underlain by the flat arctic ocean from which it is separated by a crackridden. Ozone layer depletion is one of the major environmental issues which is getting thinner day by day as a result of increasing pollution. Chlorine atoms react with ozone, starting a chemical cycle that destroys the good ozone in that area. Ozone depleting substances ods generally contain chlorine, fluorine, bromine, carbon, and hydrogen in varying proportions and are often described by the general term halocarbons. Computer models of the atmo sphere employing this information.
The ozone depletion potential odp of a chemical compound is the relative amount of degradation to the ozone layer it can cause, with trichlorofluoromethane r11 or cfc11 being fixed at an odp of 1. There is a corresponding hole over the arctic that similarly appears in the spring, although in some years warmer winters there do not result in a major depletion of the ozone layer. Environmental chemistry lecture notes by asoka marasinghe. Chlorodifluoromethane r22, for example, has an odp of 0. What are the causes and effects of ozone depletion. For this science project you will need to develop your own experimental procedure. Sulfuric acid h2so4 is the seed molecule for formation of stratospheric sulfate aerosol layer that assists ozone depletion by activation of. Ozone depletion facts and information national geographic. Besides carbon dioxide, other greenhouse gases are methane, water vapour, nitrous oxide, cfcs and ozone. Montreal protocol and subsequent treaties ban world. Environmental chemistry 401 carbon dioxide crosses the delicate proportion of 0.
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