The ozone layer and the factors contributing to its destruction

An atmospheric plume formed, consisting of toxic materials such as metals, furans, asbestos, dioxins, PAH, PCB and hydrochloric acid. Most of the materials were fibres from the structure of the building. Asbestos levels ranged from 0. PAH comprised more than 0.

The ozone layer and the factors contributing to its destruction

The latter phenomenon is commonly referred to as the "ozone hole". The detailed mechanism by which the polar ozone holes form is different from that for the mid-latitude thinning, but the proximate cause of both trends is believed to be catalytic destruction of ozone by atomic chlorine and bromine.

The primary source of these halogen atoms in the stratosphere is photodissociation of Chlorofluorocarbon CFC compounds, commonly called freons, and bromofluorocarbon compounds known as Halons, which are transported into the stratosphere after being emitted at the surface.

Both ozone depletion mechanisms strengthened as emissions of CFCs and Halons increased. It is suspected that a variety of biological consequences, including, for example, increases skin cancer, damage to plants, and reduction of plankton populations in the ocean's photic zone, may result from the increased UV exposure due to ozone depletion.

Three forms or allotropes of oxygen are involved in the ozone-oxygen cycle: Oxygen atoms O or atomic oxygenoxygen gas O2 or diatomic oxygenand ozone gas O3 or triatomic oxygen.

Ozone is formed in the stratosphere when oxygen molecules photodissociate after absorbing an ultraviolet photon whose wavelength is shorter than nm. This produces two oxygen atoms.

The atomic oxygen then combines with O2 to create O3. Ozone molecules absorb UV light between and nm, following which ozone splits into a molecule of O2 and an oxygen atom.

The oxygen atom then joins up with an oxygen molecule to regenerate ozone. This is a continuing process which terminates when an oxygen atom "recombines" with an ozone molecule to make 2 O2 molecules. It is theorized that prior to the beginning of the depletion trend, the amount of ozone in the stratosphere was kept roughly constant by a balance between the rates of creation and destruction of ozone molecules by UV light.

These elements are found in certain stable organic compounds, especially chlorofluorocarbons CFCswhich may find their way to the stratosphere without being destroyed in the troposphere.

Once in the stratosphere, the Cl and Br atoms are liberated from the parent compounds by the action of ultraviolet light, and can destroy ozone molecules in a catalytic cycle. In this cycle, a chlorine atom reacts with an ozone molecule, taking an oxygen atom with it forming ClO and leaving a normal oxygen molecule.

A free oxygen atom then takes away the oxygen from the ClO, and the final result is an oxygen molecule and a chlorine atom, which then reinitiates the cycle. The chemical shorthand for these reactions are: A single chlorine atom would keep on destroying ozone for up to two years the time scale for transport back down to the troposphere were it not for reactions that remove them from this cycle by forming reservoir species such as hydrochloric acid HCl and chlorine nitrate ClONO2.

On a per atom basis, bromine is even more efficient than chlorine at destroying ozone, but there is much less bromine in the atmosphere at present. As a result, both chlorine and bromine contribute significantly to the overall ozone depletion.Number: Policy. Aetna considers core decompression medically necessary for the treatment of early/pre-collapse (stage I or II; before X-ray changes are evident) avascular necrosis of the hip (femoral head and/or neck).

Discovery of the hole in the ozone layer showed that human activity has a major impact on Earth. The destruction of ozone in the stratosphere high above the planet's surface has been brought about as the result of the widespread use of chemicals, which under normal conditions are chemically.

Oct 03,  · Since the ozone layer absorbs UVB ultraviolet light from the Sun, ozone layer depletion is expected to increase surface UVB levels, which could lead to damage, including increases in skin cancer.

This was the reason for the Montreal ashio-midori.com: Resolved.

The ozone layer and the factors contributing to its destruction

The main things that lead to destruction of the ozone gas in the ozone layer. 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.

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Ozone has been found to be an extremely safe medical therapy, free from side effects. In a study done by the German Medical Society for Ozone Therapy, therapists were polled regarding their , patients, comprising a total of 5,, ozone treatments administered.

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