Humans have introduced gases and chemicals into the atmosphere that have rapidly depleted the ozone layer in the last century. Let us have a detailed look at the various causes and effects of ozone layer depletion. The thinning is most pronounced in the polar regions, especially over antarctica. This site is like a library, use search box in the widget to get. Various anthropogenic activities such as emissions of cfcs, hcfcs and other organohalogens lead to the depletion of ozone. Besides carbon dioxide, other greenhouse gases are methane, water vapour, nitrous oxide, cfcs and ozone. It is ideal photochemical maker due to its long life and stability 1 34.
Ozone depletion is largely a result of manmade substances. On the role of heterogeneous chemistry in ozone depletion. 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. The ultraviolet uv rays emitted from sun are captured by ozone and thereby provide a stable ontological structure in the biosphere. Depletion of stratospheric ozone o3, as commonly known as the hole in the ozone layer, is an issue of international concern. Ozone depletion free download as powerpoint presentation. The ozone depletion phenomenon the national academies press.
Ozone layer depletion is one of the major environmental issues which is getting thinner day by day as a result of increasing pollution. Ab initio study of the reaction of ozone with bromide ion. In contrast, eruptions increased ozone loss rates over the depletion era from 1980 to 1998. Ozone depletion, ultraviolet radiation, climate change and. However, it provides the basic chemical mechanism for the formation of the ozone layer on top of which other ozone destruction mechanisms act. In 1985 the british antarctic survey reported a startlingly large depletion of ozone in september and october, at the end of the antarctic winter. Like an infection that grows more and more virulent, the continentsize hole in earths ozone layer keeps getting bigger and bigger. Ozone layer depletion cause, effects, and solutions. This website addresses stratospheric ozone issues, including the science of ozone depletion, epas regulatory approach to protecting the ozone layer, epaapproved alternatives to ozone depleting substances, and sun safety. The natural distribution of ozone around the earth is. Chapte r ozone depletion potentials, global warming. Due to stratospheric ozone layer depletion uv radiations are penetrating in earth atmosphere which result in the production of reduced oxygen. Global warming is caused by the greenhouse effect, which is essential to life as we know it on planet earth. It is rich in examples of how basic research often contributes to unanticipated outcomes of immense societal benefit.
Stratospheric ozone is formed naturally by chemical reactions involving solar ultraviolet radiation sun light and oxygen molecules, which make up about 21 % of. Although a combination of weather conditions and cfc chemistry conspire to create the thinnest ozone levels in the sky above the south pole. An analysis of the laboratory measurements the cloocl cross sections and related quantities as well as the challenges associated with the various studies. The global exchange between ozone and oxygen is on the order of 300 million tons per day. Ozone in the stratosphere is necessary to life as we know it because it absorbs energetic uv radiation. Ozone is good in the stratosphere because it absorbs all of the most energetic ultraviolet radiation uvc, most of the uvb radiation and some of the least energetic uv radiation uva. Download chlorofluorocarbons and ozone depletion book pdf free download link or read online here in pdf. The chemistry by which cfcs break down ozone is an extremely complicated process. Ozone depletion occurs when the natural balance between the production and destruction of stratospheric ozone is disturbed. B dobson and other scientists in measuring concentrations of chloride and ozone in the atmosphere g. A p mitra, former director general of the council of scientific and industrial research, clarifies that while there is no trend in the total ozone value, there is some evidence of ozone depletion at higher altitudes at about 30 to 40 km even over the tropics.
If interested, you can purchase this powerpoint from my. Carbon dioxide is the major contributor to global warming. Early investigations dealt with the identification of the processes leading to the ozone depletion and established the role of chlorine species and heterogeneous chemistry as the primary cause of the depletion. The problem of ozone depletion and its adverse consequences have threatened the existence of life on the planet. Causes of ozone layer depletion and its effects on human. Cfc molecules are made up of chlorine, fluorine and carbon atoms and are extremely stable. Unlike molecular oxygen o 2, ozone is very reactive in the presence of most other species. Ozone depletion consists of two related events observed since the late 1970s. The simulation of ozone depletion and its impacts with. Gwps including indirect effects of ozone depletion have been estimated fo r a variety of halocarbons cfcs, halons, hcfcs, etc. Chlorofluorocarbons and ozone depletion answer guide. 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.
Halogen catalysis of ozone degredation halogens are a chemical family containing fluorine, chlorine, bromine and iodine. The roll of ozone is very crucial and significant because it acts as a protective shield in the biosphere ecosystem against their exposure to deadly and dangerous ultraviolet radiation. This is not really a hole through the ozone layer, but rather a large area of the stratosphere with extremely low amounts of ozone. Highly reactive species like hydrogen peroxide is produced which has bad effects on human health. Cfcs has led to a magnified springtime depletion of the protective ozone layer at both earths poles, especially over. The role of halogen chemistry in polar stratospheric ozone depletion february 2009 the role of halogen chemistry in polar stratospheric ozone depletion report from the june 2008 cambridge, uk workshop for an initiative under the stratospheric processes and their role in climate sparc project of the world climate research programme 1.
O 3 reacts readily with radical species compounds with unpaired electrons and compounds containing double bonds. But through domestic and international action, the ozone layer is healing and should fully recover by about 2065. The chlorofluorocarbon and the halons are potent ozone depletors. Stratospheric ozone is formed naturally by chemical reactions involving solar ultraviolet radiation sunlight and oxygen molecules, which make up. The first manmade threat to the ozone layer was noted by harold johnston 1971. Environmental chemistry 401 carbon dioxide crosses the delicate proportion of 0. Read online chlorofluorocarbons and ozone depletion book pdf free download link book now. The role of halogen chemistry in polar stratospheric ozone. Application of ozone in water treatment was performed in 1893 in holland.
This layer absorbs the radiations and prohibits them from entering the outer surface of the earth. Download a pdf of stratospheric ozone depletion by halocarbons by the national research council for free. Perhaps the most wellknown impact of the thinning of the ozone layer is the increased penetration of uvb to the earths surface. The net gwps of halocarbons depend strongly upon the effectiveness of each compound for ozone destruction. 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. Ozone depletion, gradual thinning of earths 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 ozone layer is formed by the action of solar ultraviolet light on oxygen. Ab initio calculations are used to support the development of atmospheric chemistry models, but errors can occur in study of the bromide ozone reaction due to inappropriate treatment of the manyelectron species and the ionic nature of the reaction.
Various anthropogenic activities such as emissions of cfcs, hcfcs. 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. Ozone ozone is a molecule comprised of three oxygen atomsits chemical formula is o 3. The ozone depletion phenomenon the ozone depletion. The ozone layer is a layer of gas about 15 km above the earths surface. The ozone layer is found in the lower portion of the stratosphere from about 20 to 30 km above earths surface. Chemistry equations for ozone depletion the student room. Montreal protocol on substances that deplete the ozone layer. All ozone depleting chemicals contain chlorine and bromine 10. It is an essential factor for many global, biological and environmental phenomena. Ozone depletion ozone depletion chlorofluorocarbon.
The ozone depletion phenomenon national academy of. Global warming and ozone layer depletion are two different problems see the sidebar misconceptions about global atmospheric change on page 95. Due to its environmental significance, the chemistry of atmospheric ozone and ozone depletion has been a subject of much research and discussion. The subtropical ground ozone concentration in northern hemisphere is twice the corresponding region in southern hemisphere 5. This was also the start of intensive research into the chemistry of the atmosphere. 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. Ozone depletion greenhouse gases and climate change. Sop ozone generator ucla chemistry and biochemistry. This depletion makes humans more vulnerable to the uvb rays which are known to cause skin cancer as well as other genetic deformities.
Sherwood rowland, mario molina rowlands postdoc at the time, and paul crutzen and in 1995 they received the nobel prize for their work. Saf on ozone and atmospheric chemistry monitoring part of the gome2 ground segment, providing the level 2 service gome2 is a nadir scanning uvvis spectrometer designed for ozone and trace gas measurements schedule development phase ended feb 2007 continuos development and operations phase cdop march 2007. Atmospheric chemistry division at the national center for atmospheric. Find out what caused the ozone hole, and how the 1989 montreal protocol sought to put an end to ozone depletion. Air pollution and global warming summary of materials related to university of washington course atm s 458 air pollution chemistry taught autumn 2014 by professor joel thornton compiled by michael c. Ozone depletion biology science fair project ideas. The the causes and effects of global ozone depletion have been illuminated in this paper. Timeline of stratospheric ozone depletion and observations.
This study was conducted at university of gujrat during 20142015 as a term paper for master of philosophy. It contains some videos and gif at thte end from an external source. Although global warming and ozone depletion are caused by different gases, scientists have shown that a warming planet may change how the stratosphereand, therefore, the ozone layerworks. Ozone is harmful at ground level but high up the atmosphere ozone layer plays a vital role in the protection of all living beings. All books are in clear copy here, and all files are secure so dont worry about it. 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. Although natural phenomenon can cause ozone depletion but human activities such as cfcs are now accepted as major cause of depletion 9. Normal ozone ozone layer depletion and its effects. Ozone depletion weve known for decades that the ozone layer in our stratosphere is being depleted by humanmade compounds like chlorofluorocarbons cfcs. Ozone layer depletion cause, effects, and solutions biology. Scientific assessment of ozone depletion unep ozone. The most prominent manifestation of stratospheric ozone depletion is the antarctic ozone hole. This timeline shows the chain of events leading to prediction of the ozone depletion phenomenon, recognition of its consequences, and eventual actions to avert a threatened disaster. Ozone and ozone depletion should be seen as an emerging issue in environmental space chemistry.
Find answers to frequently asked questions about the ozone layer, ozone depletion, and the effects of ozone depletion on health and the environment. Mar 21, 2020 ozone depletion, gradual thinning of earths ozone layer in the upper atmosphere caused by the release of chemical compounds containing gaseous chlorine or bromine from industry and other human activities. One example of ozone depletion is the annual ozone hole over antarctica that has occurred during the antarctic spring since the early 1980s. The chemistry climate model consists of a stateoftheart gcm that includes the middle atmosphere fully coupled to a chemical model of stratospheric ozone that includes both homogenous and heterogeneous chemistry steil et al. Pdf causes of ozone layer depletion and its effects on. Ozone depletion describes two distinct but related phenomena observed since the late 1970s. Mar 28, 2020 ozone depletion biology projects, biology science fair project ideas, biology topics for cbse school,icse biology experiments for kids and also for middle school, elementary school for class 5th grade,6th,7th,8th,9th 10th,11th, 12th grade and high school, msc and college students. Ozone depletion facts and information national geographic. The word theory is used in this context because, we should remember, in the mid and late 1970s the notion of stratospheric ozone depletion was still just that a theory. Introduction under the montreal protocol on substances that deplete the ozone layer, article 7 of the protocol requires all parties, both developing countries also called article 5 countries and developed countries.
These compounds are chemically inert and may remain in the atmosphere for 40150 years. 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. The phrase the ozone hole is used to describe the severe annual antarctic springtime ozone depletion that was. The image of stratospheric ozone shows total ozone over antarctica for 6 september 2000, reproduced from ref. The role of halogen chemistry in polar stratospheric ozone depletion section 1. Ozone in the troposphere is toxic due to its reactive oxidizing capabilities. Project report on ozone depletion environmental pollution. This allows more ultravioletb radiation to reach earths. Ask students for their perceptions of the terms cfcs and ozone. Apr 18, 2019 the ozone layer helps to protect life from harmful ultraviolet radiation.
This quick video discusses the role of the ozone layer and how cfcs can cause ozone depletion. A discussion of the in situ and remote observations of clo, cloocl, and related species. Montreal protocol and subsequent treaties ban world. Ozone depletion explains global warming current physical chemistry, 2016, vol. Most ozone is found in the stratosphere upper part of the atmosphere, more than 10 to 16 kms from the surface of the earth. Our powerpoint presentation about ozone depletion, its effects and its causes. Experts blame ozonelayer depletion on manmade chem icals containing chlorine. There are natural processes that create and destroy ozone in the stratosphere.
Ozone o3 is a stratospheric layer that plays important role in providing support to humans for their survival. Ground ozone concentration is lower in polar and equatorial regions. Measurements of the levels of ozone in the atmosphere indicate that ozone levels have been dropping, with significant decreases since the 1970s. Cfcs destroy the ozone in the stratosphere 15 20 km above the earths surface ozone concentrations are measure in dobsen units, 1 dobsen unit represents 1 molecule of o 3 for every 1 billion air molecules ozone loss is greatest over antarctica where the ozone depletion has been recorded and is commonly referred to as the ozone hole. Download a pdf of the ozone depletion phenomenon by the national research council for free. Ozone and atmospheric chemistry monitoring saf o3m saf. The sun propagates ultraviolet radiations which as an adverse effect on living beings. The region of maximum ozone concentration, known as the stratospheric ozone layer, is at an altitude of 25 to 30 km, where the concentration can reach 10 ppm. Additional information on data used for this image is provided by nasa ozone watch 104. 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. Frequently asked questions about the ozone layer ozone.
The so 2f 2 global background mixing ratio increased during recent decades and had reached about 1. An ebook is one of two file formats that are intended to be used with ereader devices and apps such as amazon kindle or apple ibooks. Weve known for decades that the ozone layer in our stratosphere is being depleted by humanmade compounds like chlorofluorocarbons cfcs. The simulation of the antarctic ozone hole by chemistry. Click download or read online button to get ozone depletion greenhouse gases and climate change book now. Introduction the ozone layer or ozone shield is a region of earths stratosphere that absorbs most of the suns ultraviolet uv radiation. Case study depletion of ozone in the atmosphere the work of g. Following is the list of some of the main ozone depleting substances and the sources from where they are released.
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