The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
All other sections in this Literature Study Guide are owned and copyrighted by BookRags, Inc.
Halons and other halocarbons (carbon- and halogen-containing compounds), such as chlorofluorocarbons (CFCs), are responsible for the breakdown of stratospheric ozone and the creation of the Antarctic ozone hole. Halons are a subset of a more general class of compounds known as halocarbons. Halons contain carbon, bromine, fluorine, and, in some cases, chlorine. Halons are entirely human-made and are used primarily in fire extinguishers.
One of the most common halons has the chemical formula CBrClF2, denoted as H-1211 in an industry-devised shorthand. The compounds live long enough in the atmosphere (eleven years in the case of H-1211) to reach the stratosphere, an upper region of the atmosphere located between fifteen and fifty kilometers above the earth's surface, where the sun's more intense ultraviolet (UV) radiation breaks down the molecule and releases chemically active bromine and chlorine atoms. These free atoms enter into cycles of chemical reactions that destroy ozone.
An international agreement known as the Montréal Protocol was forged in 1987 and subsequently amended to phase out and eventually end the use of ozone-depleting chemicals. Under the terms of the agreement, developed countries must first phase out the use of halons and other halocarbons. Developing countries are given additional time to acquire the new technologies needed to meet the requirements.
World Meteorological Organization. (2003). Scientific Assessment of Ozone Depletion: 2002. Global Ozone Research and Monitoring Project, Report No. 47. Geneva: Author.