Uv radiations are disturbing developmental and physiological processes which is decreasing the productivity of crops. Third, depletion of stratospheric ozone and global warming due to the build. In 1987, to address the destruction of the ozone layer, the international community established the montreal protocol on ozone depleting substances. Low temperatures, increase in the level of chlorine and bromine gases in the upper stratosphere are some of the reasons that leads to ozone layer depletion. Understanding stratospheric ozone depletion scientists learn about ozone destruction through a combination of laboratory studies, computer models, and stratospheric observations.
The minimum is a conse quence of the ozone hole, which describes the widespread chemical destruction of ozone by ozonedepleting substances. The thinning is most pronounced in the polar regions, especially over antarctica. According to t he chemical model fo r ozone destruction pr oposed about 20. Others say there is no abnormality at all, that it is just natural warming. Update on ozonedepleting substances odss and other gases of.
The amounts of ozone in the stratosphere vary naturally throughout the year as a result of production and destruction processes, and as a result of winds and other transport processes that. The earths stratospheric ozone layer plays a critical role in absorbing ultraviolet radiation emitted by the sun. 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. Oxygen can combine into molecules with three atoms, however, which are called ozone. There are a number of chemical reactions that can deplete stratospheric ozone. Find, read and cite all the research you need on researchgate. Approximately 90 percent of the atmospheres ozone occurs from 1018 km 611 miles to about 50 km about 30 miles above earths surface. Humans have been depleting the ozone layer with chemical products. 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 key process control parameters are dose, mixing, and contact time.
Destruction of the ozone layer the ozone layer is a layer in earths atmosphere which contains relatively high concentrations of ozone o3. Feb 12, 2018 far above earths surface, the ozone layer helps to protect life from harmful ultraviolet radiation. Dec 14, 2017 scientists are closely monitoring positive signs of recovery of the earths stratospheric ozone layer, which is depleted by the use of chemicals called chlorofluorocarbons cfcs for a range of. We cant make enough ozone to replace whats been destroyed, but provided that we stop producing ozonedepleting substances, natural ozone production reactions should return the ozone layer to normal levels by about 2050.
May 21, 2019 you are probably aware of the danger posed to the earths protective stratospheric ozone layer by the use of chlorofluorocarbons \cfcs\ as refrigerants and propellants in aerosol spray cans. This layer absorbs 9399% of the suns high frequency ultravioletlight, which is potentially damaging to life on earth. The rest of the molecules are mostly nitrogen and oxygen, like the air we breathe. Ozone layer depletion cause, effects, and solutions. Causes, effects and solutions of ozone layer depletion. Normal ozone ozone layer depletion and its effects. Find out what caused the ozone hole, and how the 1989 montreal protocol sought to put an end to ozone depletion. Ozone could be manufactured, stored, transported to the stratosphere, and released in depleted regions. Atmospheric concentrations of most ozonedepleting substances peaked, or their. Twenty questions and answers about the ozone layer. But ozone makes up only one to ten out of every million molecules in the ozone layer.
The unintentional experiment started in the late 1920s, when thomas midgley jr. Ozone layer introduction the ozone layer refers to the ozone within stratosphere, where over 90% of the earths ozone resides. If each chlorine atom released from a cfc molecule destroyed only one ozone molecule, cfcs would pose very little threat to the ozone layer. Some say anthropogenic carbon dioxide co 2 emissions caused the earth to warm. Evidence of ozone depletion in the stratosphere began to appear in the 1980s. But many researchers do not agree with these predictions,14 and express their. 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. It has been found that this protective ozone layer is getting depleted because of the presence of cfc chlorofluorocarbon compounds. As a result of its chemical composition, ozone is regarded as a special type of oxygen as it contains three oxygen molecules o3 as opposed to the usual two oxygen molecules o2. Nearly 90% of earths ozone is in the stratosphere and referred to as the ozone layer. The world meteorological or ganization wmo, 1995 predicted that the depletion of the ozone layer peaked around 1998 and the layer would slowly recover by 2045 12.
Ozone depletion and climate change environment canada. It was the first international treaty to be signed by all countries of the world and is considered the greatest environmental success story in the history of the united nations. But the one and the most important reason for ozone layer depletion is the production and emission of. Ashworth abstract there has been a lot of discussion about global warming. A dynamic equilibrium is maintained between the formation and decomposition of ozone. Pdf there are many situations where human activities have significant effects on the environment. Achievements in stratospheric ozone protection ozone layer. Interactions between climate change and stratospheric ozone may delay recovery of the ozone layer by 1520 years 5.
The latter phenomenon is referred to as the ozone hole. Ozone layer depletion causes, effects and solutions 7. We provide reading comprehension exercises with answers. The ozone layer is a deep blanket in the stratosphere made up of comparatively high concentration of the ozone. The net or overall reaction is that of atomic oxygen with ozone, forming two oxygen molecules. Cfc destruction of ozone major cause of recent global warming. The main things that lead to destruction of the ozone gas in the ozone layer. Sep 30, 2019 the ozone layer has historically protected the earth from the harmful uv rays, although in recent decades this protection has diminished due to stratospheric ozone depletion. Timeline of stratospheric ozone depletion and observations. Reading skills get sharpened by unseen passage reading comprehension test. Without human intervention, the stratospheric ozone layer would be produced and destroyed through natural processes. The ozone depletion process replacing lost ozone in the stratosphere the idea is sometimes put forth that humans could compensate for lost global stratospheric ozone by replacing it.
It sets binding obligations for countries to phase out production of all the major ozone depleting substances. The ozone layer, in the stratosphere, is where about 90% of the ozone in the earth system is found. National aeronautics and the ozone hole space administratio n. Apr 18, 2019 the ozone layer helps to protect life from harmful ultraviolet radiation.
These processes regulate a balance of ozone and form the ozone layer. Ozone is an irritating, corrosive, colorless gas with a smell something like burning electrical wiring. Stratospheric ozone protection awards since 1990, epa has recognized outstanding achievement in ozone layer protection. Ozone depletion consists of two related events observed since the late 1970s. Ozone depletion is one of several factors, includ ing cloud cover and solar elevation, which affect ground level uv radiation. Ozone layer destruction of the ozone layer the causes. An ozone disinfection system strives for the maximum solubility of ozone in wastewater, as disinfection depends on the transfer of ozone to the wastewater. Ozone near the ground is a pollutant, but in the upper stratosphere, it forms a protective layer around the planet that absorbs ultraviolet sunlight, thereby protecting all life from the harmful effects of that radiation. The amount of ozone that will dissolve in wastewater at a. The destruction of ozone in cycle 1 involves two separate chemical reactions. Chemistry of the ozone layer there are natural processes that create and destroy ozone in the stratosphere.
When highenergy ultraviolet rays uvc strike an oxygen molecule o. Ozone layer depletion is one of the major environmental issues which is getting thinner day by day as a result of increasing pollution. This passage is all about the ozone layer and the ozone layer restricts. 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. Stratospheric ozone depletion, ultraviolet radiation and health. Causes of ozone layer depletion and its effects on human. Nearly 500 organizations, teams, and individuals from 40 countries have received stratospheric ozone protection awards for their exceptional leadership, personal dedication, and technical achievements. There isnt much of it, but ozone is powerful, able to block the most.
Learn what cfcs are, how they have contributed to the ozone hole, and how the 1989 montreal. Questions and answers about the environmental effects of the. Ozone is unstable and decomposes to molecular oxygen. One of the main reasons for the widespread concern about depletion of the ozone layer is the anticipated increase in the amounts of ultraviolet radiation received. The ozone layer helps to protect life from harmful ultraviolet radiation. Ozone layer depletion is the thinning of the ozone layer present in the atmosphere. In the last thirty years, it has been discovered that stratospheric ozone is depleting as a result of anthropogenic pollutants. Questions and answers about the environmental effects of the ozone layer depletion and 4 climate change. Further, that loss of ozone itself augments the cooling of the stratosphere.
Pdf causes of ozone layer depletion and its effects on. Ozone absorbs a band of ultraviolet radiation called uvb. Depletion of ozone layer is also causing the problem of food shortage to humans. When cfc is released into the atmosphere, they mix with atmospheric. In laboratory studies scientists are able to discover and evaluate individual chemical reactions that also occur in the stratosphere. Chlorofluorocarbons cfcs have been identified as the main cause of the destruction to the ozone layer, but there are also compounds containing bromine, other halogen compounds and also nitrogen oxides which cause damage.
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