It eventually became widely used in automobile air conditioners and nontoxic propellants in aerosol cans. Thus CFCs became used all over the world and its business got bigger and bigger until late in Sherwood Rowland and Mario Molina, two distinguished chemists, came up with a surprising result in his calculations concerning the CFCs and ozone layer.
Ozone Hole The so-called ozone hole sometimes is confused with the problem of global warming. Even though there is a connection between the two environmental issues, because ozone contributes to the greenhouse effectthe ozone hole is a separate issue. This article briefly addresses how ozone depletion is measured.
The chemical element oxygen normally forms a molecule containing two atoms O2. But in the presence of ultra-violet light or an electrical spark in the air, oxygen can form a molecule containing three atoms O3.
CFC's The beginning of the CFC(chlorofluorocarbons) era started in , when CFC' were invented by a Du Pont chemist. CFC' were best known as "freons" and became famous as a safe, nonflammable refrigerant. CFC–11 and CFC–12 Production (in tons) USA ROW Aggregate Figure 1. Production of CFC and CFC in the USA and the rest of the world. An Introduction to the Nature of Constellations. words. 2 pages. An Analysis of An atom or an indivisible body and its different theories. words. 1 page. An Introduction to the Way Computers Mimic the Human Mind. 1, words. 2 pages. A Comparison of Plant and Animal Cells. 3, words. 9 .
The molecule of three oxygen atoms is called ozone. Here ozone takes up a greater proportion of the atmospheric column than at any other height. Measuring Ozone Levels Scientists assess ozone by calculating how much there would be if all the ozone over a particular spot on Earth were compressed to a standard atmosphere of pressure—that is, the average pressure of air at sea level.
On average, this would result in a column of ozone no more than 3 millimeters mm thick. The unit of measure used to represent the amount of ozone above a particular position on the surface is the Dobson unit DUwith one unitrepresenting 0.
Therefore, there is typically DU in a column of the normal atmosphere. Dobson was a British physicist who initiated the first regular monitoring of atmospheric ozone using spectrographic instruments in the s. He was able to derive the vertical distribution of ozone from a series of measurements of the relative intensities of two particular wavelengths of light scattered in the zenith sky.
One wavelength is more strongly absorbed by ozone than the other wavelength. Dobson compared the intensities of these two wavelengths with an instrument he constructed using a photomultiplier and an optical wedge; this instrument is now known as a Dobson spectrophotometer.
Dobson found that the ozone in the atmosphere is far from uniformly spread.
The lowest concentrations, around DU, were consistently found at the equator, although the polar winters resulted in periods where their concentrations might fall below the equatorial level.
The highest concentrations were found in higher latitudes, where the variation fluctuated from as high as DU to DU in the upper latitudes of the Northern Hemisphere and between DU and DU in the Southern Hemisphere. The WMO subsequently established ground-based ozone observation stations.
It was designated for cooperative study of the solar-terrestrial environment by the scientists of sixty-seven nations. From the s to the s ozone was measured from the ground. Since the late s scientists have used satellites, aircraft, and balloons to measure ozone levels from above Earth.
The figure below is one example of the results of this data monitoring. Recording Low Ozone Levels In the s a research group with the British Antarctic Survey BAS was monitoring the atmosphere above Antarctica when the scientists first noticed a loss of ozone in the lower stratosphere.
At first they believed their instruments to be faulty, and new instruments were sent to ensure that the readings were accurate.Introduction.
The ozone hole refers to the thinning With the satellite era, more accurate measurements could be obtained from instruments while in an orbit around Earth. The basis for ozone destruction are chemicals called chlorofluorocarbons (CFCs), hydrochlororfluorocarbons (HCFCs, which are very similar in structure to .
CFCs and the Environment: Further Observations INTRODUCTION The introduction of the chlorofluorocarbon (CFC) fluids in the early thirties marked the inception of the organofluorocarbon industry.
potential to deplete stratospheric ozone relative to that of CFC-II. REFRIGERATION The history of commercial refrigeration can be. The beginning of the CFC(chlorofluorocarbons), Free Study Guides and book notes including comprehensive chapter analysis, complete summary analysis, author biography information, character profiles, theme analysis, metaphor analysis, and top ten quotes on classic literature.
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The Evolution of Policy Responses to Stratospheric Ozone Depletion * * ABSTRACT Depletion of stratospheric ozone emerged as a political concern in the early s in the United States in the debate over the development of a commercial fleet . spheric ozone in the post-chloroﬂuorocarbon (CFC) era are investigated using simulations of the recent past and the 21st century with a coupled chemistry-climate model.