Over the last 30 years manmade cfcs have been the main cause of stratospheric ozone depletion. The concept of ozone depletion potential odp is widely used wuebbles et al. At last, the montreal protocol has resulted in stopping additional ozone loss and investigated by 300 experts ver 4 years survey on ozone depletion earth day was first observed on 22 april 1970. Ozone in the ozone layer is formed by the action of solar ultraviolet light on oxygen. Harmful radiation from the sun can reach the earths surface. Basic ozone layer science ozone layer protection us epa. Ib chemistry on resonance, delocalization and ozone. Some chemicals, particularly cfcs, destroy ozone in the upper atmosphere. Ozone depletion and industrial output ozone depletion and industrial output for years, we have heard about the ozone crisis. From wikibooks, open books for an open world chemistry and impacts on free shipping on qualified orders. To help foster a continued interaction, this component of the scientific assessment of ozone depletion.
Chemistry of ozone depletion fire protection association nz. The questions address the nature of atmospheric ozone, the chemicals that cause ozone depletion, how global and polar ozone depletion occur, and what could lie ahead for the ozone layer. Chemistry of the ozone layer there are natural processes that create and destroy ozone in the stratosphere. As a result, there has been a general thinning of the ozone layer over most of the globe, including between five to nine per cent depletion over australia since the 1960s. Publications about the ozone depletion theory of global warming. Air pollution not only harms buildings and plant life, but it negatively impacts human health as well. The next layer is stratosphere extending from troposphere upto a height of 50 to 55 km. Cfc molecules are made up of chlorine, fluorine and carbon atoms and are extremely stable. The ozone layer flashcards in a level and ib chemistry. The ozone layer prevents most ultraviolet uv and other highenergy radiation from penetrating to the earths surface but does. Environmental chemistry video centering on the information needed for the ib chemistry sl paper 3 on the topics of ozone depletion and dissolved oxygen in water. Depletion of this layer by ozone depleting substances ods will lead to higher uvb levels, which in turn will cause increased skin cancers and cataracts and potential damage.
International baccalaureate chemistry, an interactive ib syllabus. This ozone is passed through a solution of the alkene, first producing an ozonide. The earths ozone layer ozone layerthe region of the stratosphere containing the bulk of atmospheric ozone. Chlorodifluoromethane r22, for example, has an odp of 0. Cfc 11, or r11 has the maximum potential amongst chlorocarbons because of the presence of three chlorine atoms in the molecule.
Ozone layer depletion is one of the major environmental issues which is getting thinner day by day as a result of increasing pollution. When highenergy ultraviolet rays uvc strike an oxygen molecule o. Environmental chemistry 401 carbon dioxide crosses the delicate proportion of 0. Ozone depletion over india with so much worry about the rapid ozone depletion taking place in various parts of the earth, indian scientists are closely monitoring the ozone layer over india for possible depletion trends. The ozone layer is a specific area in the stratosphere of maximum ozone concentration. 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. Cfcs however, are not the only ozonedepleting chemicals. The ozone depletion was analyzed by our top scientists in our research and development lab. 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.
The first manmade threat to the ozone layer was noted by harold johnston 1971. Once there they react with ozone and in the long term can lead to the depletion of ozone. Besides carbon dioxide, other greenhouse gases are methane, water vapour, nitrous oxide, cfcs and ozone. Without the ozone layer, all but very simple life forms would be destroyed by the action of ultraviolet light. Companies are finding substitutes for cfcs, and people in general are becoming more awareness of the dangers of ozone layer depletion. Destruction of the upper atmospheric layer of ozone gas, caused by substances formed from breakdown of ozone depleting substances. The questions address the nature of atmospheric ozone, the chemicals that cause ozone depletion, how global and polar ozone depletion occur, and what. Depletion of stratospheric ozone o3, as commonly known as the hole in the ozone layer, is an issue of international concern. Ozone depletion potential an overview sciencedirect topics. The energy required to promote one of the double bond electrons in oxygen, making a diradical, is considerably higher that the corresponding energy required to promote an electron in. The problem is worsened as cfcs are a primary cause of the damage and they remain in the stratosphere for up to 100 years.
Ib chemistry on resonance, delocalization and ozone destruction 1. Ozone can be produced in the lab using a machine called an ozonator. Learn ozone depletion biology with free interactive flashcards. Ozone depletion also explains much of the observed reduction in stratospheric and upper tropospheric temperatures. Pdf causes of ozone layer depletion and its effects on. Publications about the ozone depletion theory of global. Ib chemistryenvironmental chemistry wikibooks, open.
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. Ground level ozone is a irritant its an oxidand and bad for lungs and eyes. Ozone in the stratosphere forms naturally and protects us from damage that can be caused by solar radiation such as skin cancer. For more information about legal and policy issues, see the books by benedick and litvin, and the following web sites. The latter phenomenon is referred to as the ozone hole. Protecting the ozone layer department of the environment. Timeline of stratospheric ozone depletion and observations. To acquire the knowledge of terms, concepts, processes, techniques and principles related to the subject. Ozone o 3 is present in stratosphere and, therefore, stratosphere is also called as ozonosphere it is rich layer of ozone that absorbs 9990 harmful ultraviolet radiations from the sun. They break through the ozone layer and might get to outer space. Chemistry equations for ozone depletion the student room. Causes of ozone depletion source impact cfcs the increase in the size of the hole in the ozone layer is directly linked to increased production of cfcs since the 1950s in aerosols, plastic foam, fast food packaging and. The natural distribution of ozone around the earth is.
The presence of small amounts of ozone in the upper atmosphere is necessary for human health. It was only until recently, 1990s in fact, that the chemistry of ozone creation and destruction was developed by f. Sherwood rowland, mario molina rowlands postdoc at the time, and paul crutzen and in 1995 they received the nobel prize for their work. Ozone depletion consists of two related events observed since the late 1970s. Ozone depletion is largely a result of manmade substances. The ozone layer lies approximately 1540 kilometers 1025 miles above the earths surface, in the stratosphere. These processes regulate a balance of ozone and form the ozone layer. This depletion makes humans more vulnerable to the uvb rays which are known to cause skin cancer as well as other genetic deformities. The answers are updates of those first presented in the previous ozone assessment, scientific assessment of ozone depletion. This was also the start of intensive research into the chemistry of the atmosphere.
These radiations can cause severe diseases in humans such as skin cancer, eye damage and genetic mutations etc 9. 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. The ozone layer is essential for complex living organisms like you and me to exist. The ozone layer is a region of the atmosphere where there is an equilibrium between molecular oxygen and ozone gases. 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. To acquire skills in proper handling of apparatus and chemicals.
Scientific assessment of ozone depletion 2006 twenty. The lower most atmospheric layer is troposphere extending upto 8 to 10 km at poles and 16 to 18 km at equator. Initially this interest reflected the diagnostic role of ozone in the understanding of atmospheric transport processes. List of books and articles about ozone layer online. The chemistry by which cfcs break down ozone is an extremely complicated process. National aeronautics and the ozone hole space administratio n. Since that time, its use has spread in europe and the us due to its strong oxidizing properties, ozone is currently known as one of the most efficient and fastest microbicides breaks the cell membrane resulting in. Clean air, healthy children teachers guide and activities. Cfcs are highly reactive and so will react violently with ozone which is dangerous.
If you continue browsing the site, you agree to the use of cookies on this website. Choose from 500 different sets of ozone depletion biology flashcards on quizlet. Though generally thought of as an urban dilemma, it poses a health threat in rural areas as well. Delocalizationof electron resonance structuresozone resonance structure 1 resonance structure 2 resonance hybrid all bond oo are identical in length strength hybrid of 2 resonance structure no oo single or oo double bonds found only o o bond intermediate in character bet single and double bond. Models of stratospheric chemistry have been primarily directed toward an understanding of the behavior of stratospheric ozone. The thinning of the ozone layer has increased the risk that australians already face from overexposure to. Humans have introduced gases and chemicals into the atmosphere that have rapidly depleted the ozone layer in the last century. Ozone depletion in the stratosphere biology discussion. Application of ozone in water treatment was performed in 1893 in holland. Causes of ozone layer depletion and its effects on human.