Ozone layer depletion ozone layer depletion is the gradual thinning of the earths ozone layer in the upper atmosphere caused due tho release of chemical compounds containing gaseous bromine or chlorine from industries or other human activities. Beyond discovery beyond discovery this article was published in 1996 and has not been updated or revised. Ozone depletion also explains much of the observed reduction in stratospheric and upper tropospheric temperatures. Ozone depletion itself is not the principal cause of global climate change. National seminar on plant science and human welfare. Undp organized backtoback seminars with major technology. More than 190 nations agreed to ban ozonedepleting chemicals.
We do these things almost automatically, not really even thinking about it. Approximately 90 percent of the atmospheres ozone occurs from 1018 km 611 miles to. Ozone is a colourless gas which is found in the stratosphere of our upper atmosphere. Since about the 1970s, there has been a decrease in total volume of the ozone in the ozone. B dobson and other scientists in measuring concentrations of chloride and ozone in the atmosphere g. In response to concerns over the depletion of the global ozone layer, the u. For this science project you will need to develop your own experimental procedure. Ozone depletion describes two distinct but related phenomena observed since the late 1970s. Ozone absorbs a band of ultraviolet radiation called uvb.
The net gwps of halocarbons depend strongly upon the effectiveness of each compound for ozone destruction. If you would like to discuss your ideas or need help troubleshooting, use the ask an expert forum. Pdf causes of ozone layer depletion and its effects on. Ozone in the ozone layer is formed by the action of solar ultraviolet light on oxygen. Apr 12, 2010 presentation on ozone depletion slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. The montreal protocol on the protection of the global ozone layer is a somewhat. Clean air act as amended in 1990 mandates that nasa and noaa monitor stratospheric ozone and ozonedepleting substances. An ozone molecule is made up of three oxygen atoms. Stratospheric ozone depletion is a concern because the ozone layer in the stratosphere keeps 9599% of the suns ultraviolet radiation from striking the earth. Ozone depletion required twenty questions and answers. Powerpoint is the worlds most popular presentation software which can let you create professional depletion of ozone layer powerpoint presentation easily and in no time. Project report on ozone depletion environmental pollution.
The subtropical ground ozone concentration in northern hemisphere is twice the corresponding region in southern hemisphere 5. The term ozone depletion can refer to a number of distinct, but related phenomena. However, these precautions will become more important as ozone depletion worsens. Case study depletion of ozone in the atmosphere the work of g. Apr 14, 2017 the ozone hole is an area where the amount of ozone in the upper atmosphere is much lower than normal. As a result, the realistic effects of ozone depletion cannot be examined, but the mechanism of chlorine catalyzed destruction of ozone can be understood and observed. Ozone depletion, gradual thinning of earths ozone layer caused by the release of chemical compounds containing gaseous chlorine or. Evolution of policy responses to stratospheric ozone depletion. The ozone layer prevents most ultraviolet uv and other highenergy radiation from penetrating to the earths surface but does allow through sufficient ultraviolet rays to support the activation of vitamin d in humans. Carbon dioxide is the major contributor to global warming. Ozone depletion would magnify all of the effects of uv on human health, both positive including production of vitamin d and negative including sunburn, skin cancer, and cataracts.
To this end the parties shall, in accordance with the means at their disposal and their capabilities. Third misconceptions seminar proceedings 1993 paper title. The danger and prevention of ozone layer depletion. Vienna convention for the protection of the ozone layer. The concept of ozone depletion potential odp is widely used wuebbles et al. Ozone depletion simple english wikipedia, the free encyclopedia. Ozone layer depletion causes, effects and solutions 7. Childrens misconceptions and cognitive strategies regarding the understanding of the ozone layer depletion author. The evolution of stratospheric ozone depletion policy can best be understood as a twostage process. Stratospheric ozone depletion leads to surface cooling, while the observed increases in tropospheric ozone and other greenhouse gases lead to surface. Ozone depletion facts and information national geographic.
The latter phenomenon is referred to as the ozone hole. Certain compounds such as chlorofluorocarbons, cfcs, are released into the atmosphere by human activities, and these cfcs particularly, they are very, very unreactive at the atmospherical ground level and they go all the way up to the stratosphere and then. Formation and depletion effect of the montreal protocol on stratospheric cl sunlight incident on earth is very roughly. Stratospheric ozone protection awards since 1990, epa has recognized outstanding achievement in ozone layer protection. Chlorodifluoromethane r22, for example, has an odp of 0. Environmental chemistry 401 carbon dioxide crosses the delicate proportion of 0.
Let us have a detailed look at the various causes and effects of ozone layer depletion. Ozone layer depletion cause, effects, and solutions. Ozone depletion consists of two related events observed since the late 1970s. Protecting the ozone layer department of the environment. Ground ozone concentration is lower in polar and equatorial regions. The vienna convention for the protection of the ozone layer 3 2. Mar 21, 2020 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. The stratosphere is home to the ozone layer that protects life on. 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 ozonedepleting substances ods. There, it will absorb almost all ultraviolet light which is harmful to many organisms. The research project to be presented in this paper aims at studying. Ozone layer, region of the upper atmosphere, between roughly 15 and 35 km 9 and 22 miles above earths surface, containing relatively high concentrations of ozone molecules. The milestones relate to stratospheric ozone science, international scientific assessments, and the montreal protocol.
The increase of ultraviolet light due to depletion of the ozone layer will not only. A seminar on the depletion of the ozone layer, presented by ozoagu peter cj. This paper traces the evolution of policy responses to stratospheric ozone depletion. The purpose of this seminar is to help article 5 countries smoothly phase out. Ozone gas is perceptibly blue in colour and has a characteristic pungent smell. Most ozone is found in the stratosphere upper part of the atmosphere, more than 10 to 16 kms from the surface of the earth. Ozone depletion simple english wikipedia, the free.
Dec 28, 2016 the ozone layer protects the earth against most uvb coming from the sun. More than 60 highschool students attended these seminars. To help maintain a broad understanding of the relationship between ozone depletion, odss, and the montreal protocol, this component of the scientific assessment of ozone. The so 2f 2 global background mixing ratio increased during recent decades and had reached about 1. Find out what caused the ozone hole, and how the 1989 montreal protocol sought to put an end to ozone depletion. The ozone layer is not really a layer at all, but has become known as such because most ozone particles are scattered between 19 and 30 kilometers 12 to 30 miles up in the earths atmosphere, in a region called the stratosphere. Ozone depletion in the stratosphere and increases in greenhouse gases in the troposphere are both subjects of growing concerneven alarmamong scientists, policymakers, and the public. The buildup of oxygen in the atmosphere led to the formation of the ozone layer in the upper atmosphere or stratosphere. Ozone depletion, greenhouse gases, and climate change. Ozone layer depletion increases the amount of uvb that reaches the earths surface. Our experts wont do the work for you, but they will make suggestions and offer guidance if you come to them with specific questions. We assigned pre and post seminar questionnaires covering the awareness and knowledge of. Internet resources for both ozone information, and neat digitized images of the antarctic ozone hole.
It is always important to protect oneself against uvb, even in the absence of ozone depletion, by wearing hats, sunglasses, and sunscreen. Nearly 500 organizations, teams, and individuals from 40 countries have received stratospheric ozone protection awards for their exceptional leadership, personal dedication, and technical achievements. Ozone is a highly oxidative compound formed in the lower. Technical report on stratospheric ozone depletion this report has been prepared by rivm, eftec, ntua and iiasa in association with tme and tno under contract with the environment directorategeneral of the european. The vienna convention for the protection of the ozone layer. The natural distribution of ozone around the earth is. The ozone layer, located in the upper stratosphere 10 50 km above the earths surface, plays the highly important role in protecting life on this planet by absorbing harmful ultraviolet light uvb with wavelengths of between 280315nm. It is also one of the prime reasons which are leading to global warming. Measurements from satellitebased instruments show that this area of very low ozone concentration has developed over antarctica every year since about 1975. Uncovering the hidden hazard of hairspray a usual morning routine might include a spritz of hairspray, a spurt of shaving cream, or a spray of deodorant. Progress report 2003 united nations environment programme, environmental e. The ozone hole is an area where the amount of ozone in the upper atmosphere is much lower than normal. Laboratory and epidemiological studies demonstrate that uvb causes nonmelanoma skin cancer and plays a major role in malignant melanoma development. Health and environmental effects of ozone layer depletion.
Changes in ozone and climate are directly linked because ozone absorbs solar radiation and is also a greenhouse gas. Since about the 1970s, there has been a decrease in total volume of the ozone in the ozone layer, of about 4%, per decade. 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. Normal ozone ozone layer depletion and its effects. Ozone layer depletion cause, effects, and solutions biology. Depletion of the ozone layer occurs globally, however, the severe depletion of the ozone layer over the antarctic is often referred to as the ozone hole. Increased depletion has recently started occurring over the arctic as well. Effects of ozone depletion ozone depletion is affecting the human health and environment negatively, as it allows the penetration of uv radiations to reach the earth.
Cfc 11, or r11 has the maximum potential amongst chlorocarbons because of the presence of three chlorine atoms in the molecule. Ozone layer depletion penn state college of earth and. The stratospheric ozone layer, through absorption of solar ultraviolet radiation, protects all biological systems on earth. The danger and prevention of ozone layer depletion humans cause ozone depletion with air conditioners and refrigerators, of all things. This helps you give your presentation on depletion of ozone layer in a conference, a school lecture, a business proposal, in a webinar and business and professional representati.
Chapte r ozone depletion potentials, global warming. Protecting the ozone layer and reducing global warming undp. Tracking down lingering source of carbon tetrachloride emissions. It shields the entire earth frommuch of the harmful uv radiationthat comes from the sun 3. Nearly 90% of earths ozone is in the stratosphere and referred to as the ozone layer. The thinning is most pronounced in the polar regions, especially over antarctica. Ppt a seminar on the depletion of the ozone layer, presented by. 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. Pdf ozone depletiona warning of global warming researchgate. The layer of ozone gas is what which protects us from the harmful ultraviolet radiations of the sun. These radiations can cause severe diseases in humans such as skin cancer, eye damage and genetic mutations etc 9. Ozone layer depletion is one of the most serious problems faced by our planet earth. Depletion of stratospheric ozone o3, as commonly known as the hole in the ozone layer, is an issue of international concern.
However, if you would like to change the initial conditions of the system, you might find out that the time threshold will be reduced or augmented. Solomon and albritton, 1992 as a measure of the effectiveness of a given compound in removing ozone, relative to a standard compound, which is taken to be cfc11. The ozone layer helps to protect life from harmful ultraviolet radiation. 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.
Awareness and knowledge on the ozone depletion and its outreach. Use the information in the summary tab as a starting place. More recently, interest in stratospheric ozone has arisen from concern that human activities might affect the amount of stratospheric ozone, thereby affecting the ultraviolet radiation reaching the earths surface and perhaps also affecting the climate with various potentially severe consequences for human welfare. Ozone is a gas that is present in the ozone layer in the stratosphere of the earth. The fact is that ozone is also used for disinfection of air, water and for a lot of other industrial processes such as bleaching of paper pulp. Gwps including indirect effects of ozone depletion have been estimated fo r a variety of halocarbons cfcs, halons, hcfcs, etc. Policy responses to ozone depletion mario molina and sherwood rowland showed in 1974 that cfc gases destroy ozone coordinating committee on ozone layer ccol established by unep in the 1970s vienna convention for the protection of the ozone layer held in 1985 montreal protocol to ban substances that deplete the ozone layer held in 1987 amendments to the. Ozone depletion potential an overview sciencedirect topics. In this picture we are seeing how the ozone layer is destroyed and the effects of that destruction. List of books and articles about ozone layer online.
Approximately 90 percent of the atmospheres ozone occurs from 1018 km 611 miles to about 50 km about 30 miles above earths surface. The protective ozone layer in the earths upper atmosphere has stopped thinning and should largely be restored by mid century thanks to a ban. Aerosols are common, convenient, and harmless, right. Ozone is a very reactive molecule that has a very strong oxidizing ability. Pdf there are many situations where human activities have significant effects on the environment. B dobson inferred correctly that the cause of the warm stratosphere was heating by the absorption of ultraviolet solar radiation by ozone, and he set out to. Ozone depletion and climate change environment canada. The treaty was opened for signature on september 16, 1987 and.
In addition, increased surface uv leads to increased tropospheric ozone, which is a health risk to humans. These incidents were soon followed by the signature by the us and 180 countries of the montreal protocol on substances that deplete the ozone layer, an international treaty designed to phase out the production of a number of substances believed to be responsible for ozone depletion. Cfcs, hcfcs, halons, methyl bromide, carbon tetrachloride, and methyl chloroform. Besides carbon dioxide, other greenhouse gases are methane, water vapour, nitrous oxide, cfcs and ozone. The vienna convention for the protection of the ozone layer is a multilateral environmental agreement signed in 1985 that provided frameworks for international reductions in the production of chlorofluorocarbons due to their contribution to the destruction of the ozone layer, resulting in an increased threat of skin cancer. The atmosphere is mostly transparent to the visible except for scatter. 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. Ozone is a highly oxidative compound formed in the lower atmosphere from gases originating to a large extent from anthropogenic sources by photochem istry driven by solar radiation. Its been nearly 30 years since the discovery of the ozone hole over antarctica, and the realisation that chlorine, in the form of chlorofluorocarbons or cfcs, was the chemical culprit behind. Causes of ozone layer depletion and its effects on human. Ozone layer is a thin, fragileshield that contains relatively highconcentrations of ozone. The process of ozone depletion pennsylvania state university.
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