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CFCs and Ozone Depletion

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CFCs and Ozone Depletion Powered By Docstoc
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        <p>Climate change is the most important concern for the world in
the 21st century. Since the second half of the twentieth century, the
world has experienced a number of changes that can be attributed to
climate change. Climate change results from increase global warming which
is attributed to increases emission of green house gases that destroys
the ozone layer. Depletion of ozone layer can be described as two
distinct but closely related observations. First, there is slow but
steady decline in the total volume of the ozone layer found on the earths
stratosphere which has been observed since 1970s. It is recorded that
the ozone layer has decreased by 4 percent for every decade. Second,
there is larger but seasonal decrease in the stratospheric ozone covering
the earth's Polar Regions which has happened during the same time period
(Benedick, 1991). Â The latter is regarded as ozone hole that plays
important role in regulation of the world's temperature. In addition to
these two common phenomena, recent studies shows that ozone depletion is
complemented by troposphere ozone depletion events which mostly takes
place in the polar region surface in spring.</p>
<p>In order to understand the mechanism of <a rel="nofollow"
onclick="javascript:_gaq.push(['_trackPageview',
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href="http://www.topscorepapers.com" title="Writing Custom Essays">ozone
depletion</a> is important to understand the process through which ozone
is depleted. The most important process that has been used to explain
depletion of ozone layer is the catalytic destruction with chlorine and
bromine. Â These are to atoms which are considered very destructive to
the ozone layer. These two atoms are mainly contributed to the
stratosphere through photodissociation of cholorofluorocarbon (CFC)
compounds. CFC compounds are mainly found in the in freons and
bromofluorocarbon compounds referred to as halons (Benedick, 1991). Â The
catalytic reaction that destroys ozone layer takes place in stratosphere
which means these compounds have to travel all the way to the
stratosphere once they are released on the earth's surface. It is has
been observed that ozone depletion mechanism grow in strength with
increased emission of CFS and halons in the stratosphere.</p>
<p>CFC and other chlorine and bromine containing compounds are the main
elements that have increased ozone depletion catastrophe. Â CFCs were
developed in 1930s and have been used for various industrial uses. They
are also used in commercial and household applications like mattresses.
CFCs are:</p>
<ul>
<li>non-toxic substances</li>
<li>Non-flammable </li>
<li>Non reactive </li>
</ul>
<p>Due to the above characteristics, they have been found most suitable
to make household appliances that may be threatened by the above
conditions. They are also very stable as far as their thermodynamic
characteristics are concerned. This makes them ideal to be used as
coolants for both commercial and home refrigeration (Roan, 1989). They
are also used as aerosol propellants, electronic cleaning solvents, and
also as blowing agents. The production of CFCs has been fueled by the
demand in the above mentioned conditions. Their increased use has
continued to harm the environment by accelerating destruction of the
ozone layer.</p>
<p>It was not until 1973 when chlorine was confirmed to be a catalytic
agent that was playing a greater role in the destruction of ozone
layer. The catalytic destruction process takes place when the destroyer
removes an odd oxygen species. Normally ozone layer is made of three
atoms of oxygen i.e. O3. Chlorine removes the extra unstable oxygen
molecule but it is left unaffected which means it continues to persist in
the environment. Â It is through this process that chorine has been
confirmed to be destructive to the environment. Â In 1984, it was
conclusively discovered that chorine was playing a major role in
catalytic reactions that led to destruction of the ozone layer. The
process of ozone depletion was difficult to note before this discovery
was made. Scientists noted that polar ozone had been greatly depleted in
Antarctica and this prompted scientists to carry out more experiments
which confirmed that in deed ozone layer was being destroyed by
chlorine.</p>
<p>The chemistry behind ozone depletion is complex and can be explained
in the following ways:</p>
<p>CFCs can lead to complex reactions in stratosphere which leads to
ozone depletions. These reactions have been found to be more common in
Antarctica regions where there is an ozone hole. Scientists have
discovered that there is a complex scenario in the atmosphere that
pertains to ozone depletion. They discovered that complex reactions at
the stratosphere which are caused by CFCs and chlorine had overall effect
on solar radiation. They discovered that the process was notable in the
Polar Regions in Antarctica and northern hemispheres especially when warm
temperatures were more prevalent (Newman, Kawa and Nash, 2004).</p>
<p>The ozone layer is a allotrope of oxygen that is made up of three
oxygen molecule. (O3). The ozone is poisonous if breathed by humans but
it plays important role in life. It has been known to filter out and
abuser short wavelengths of ultraviolet radiation which range between 280
– 320 mm. These wavelengths can cause serious harm to human skin
leading to cancers and other disorders like eye disorders (Weatherhead
and Andersen, 2006).</p>
<p>CFCs are inert and insoluble. This means that once they are released
to the environment, they are not destroyed nor are they dissolved by
rain. Â They tend to remain in the atmosphere for a very long period of
time from where they can diffuse into the stratosphere.</p>         <!--
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