Send us feedback. See more words from the same year. Accessed 11 Nov. More Definitions for ozone layer. See the full definition for ozone layer in the English Language Learners Dictionary. Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free! Log in Sign Up. Save Word. One chlorine atom can destroy over , ozone molecules before it is removed from the stratosphere. Ozone can be destroyed more quickly than it is naturally created.
Some compounds release chlorine or bromine when they are exposed to intense UV light in the stratosphere. These compounds contribute to ozone depletion, and are called ozone-depleting substances ODS ODS A compound that contributes to stratospheric ozone depletion. ODS include chlorofluorocarbons CFCs , hydrochlorofluorocarbons HCFCs , halons, methyl bromide, carbon tetrachloride, hydrobromofluorocarbons, chlorobromomethane, and methyl chloroform.
ODS are generally very stable in the troposphere and only degrade under intense ultraviolet light in the stratosphere. When they break down, they release chlorine or bromine atoms, which then deplete ozone. ODS that release chlorine include chlorofluorocarbons chlorofluorocarbons Gases covered under the Montreal Protocol and used for refrigeration, air conditioning, packaging, insulation, solvents, or aerosol propellants.
Since they are not destroyed in the lower atmosphere, CFCs drift into the upper atmosphere where, given suitable conditions, they break down ozone. These gases are being replaced by other compounds: hydrochlorofluorocarbons, an interim replacement for CFCs that are also covered under the Montreal Protocol, and hydrofluorocarbons, which are covered under the Kyoto Protocol. All these substances are also greenhouse gases.
See hydrochlorofluorocarbons, hydrofluorocarbons, perfluorocarbons, ozone depleting substance. CFCs , hydrochlorofluorocarbons hydrochlorofluorocarbons Compounds containing hydrogen, fluorine, chlorine, and carbon atoms. Although ozone depleting substances, they are less potent at destroying stratospheric ozone than chlorofluorocarbons CFCs.
They have been introduced as temporary replacements for CFCs and are also greenhouse gases. See ozone depleting substance. HCFCs , carbon tetrachloride carbon tetrachloride A compound consisting of one carbon atom and four chlorine atoms.
Carbon tetrachloride was widely used as a raw material in many industrial uses, including the production of chlorofluorocarbons CFCs , and as a solvent. Solvent use ended when it was discovered to be carcinogenic.
It is also used as a catalyst to deliver chlorine ions to certain processes. Its ozone depletion potential is 1. Methyl chloroform is used as an industrial solvent.
Its ozone depletion potential is 0. ODS that release bromine include halons halons Compounds, also known as bromofluorocarbons, that contain bromine, fluorine, and carbon. They are generally used as fire extinguishing agents and cause ozone depletion. Bromine is many times more effective at destroying stratospheric ozone than chlorine. Methyl Bromide is an effective pesticide used to fumigate soil and many agricultural products. If no button appears, you cannot download or save the media.
Text on this page is printable and can be used according to our Terms of Service. Any interactives on this page can only be played while you are visiting our website. You cannot download interactives. An element is a substance that cannot be broken down into a simpler format. They are distinguished by a unique atomic number. The elements are organized by their atomic number in the periodic table, which highlights elements with similar properties. Water is an example of a compound, a mixture of two or more elements, and is created when two hydrogen atoms bond to an oxygen atom.
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Encyclopedic Entry Vocabulary. The Red Year Louis Tracy. A region of the atmosphere, lying mostly in the stratosphere, containing relatively high levels of ozone, with the greatest concentrations occurring from about 15 to 30 km 10 to 19 mi above the Earth's surface.
The ozone absorbs large amounts of solar ultraviolet radiation, preventing it from reaching the Earth's surface. The concentration of ozone in the ozone layer is usually under 10 parts per million.
Also called ozonosphere See Note at ozone. All rights reserved. The Earth's ozone layer could be at risk because of the action of chlorofluorocarbons , but international treaties have banned the production of these chemicals. The ozone layer is expected to return to normal in a few decades.
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