OZONE DEPLETION

OZONE DEPLETION: CAUSE AND EFFECT

OZONE DEPLETION: CAUSE AND EFFECT

Abstract

The depletion of Ozona layer has become one of the most serious environmental issues, over a period of past few decades. Ozone is essentially a layer of gas that provides a cover for protection to the upper atmosphere of earth. Ozone layer provides the earth's environment with the protection against the harmful ultraviolet radiations (high frequency rays that come embedded with the sunlight). However, this protective layer is being depleted significantly by the human activities and chemical usage. The gases emerging from the industries such as Chlorofluorocarbons (CFCs) and halogens are considered to be mainly responsible for the Ozone layer depletion. The depletion may cause harmful effects for the environment and life on earth. This paper describes the causes and effects of Ozone layer depletion.

Ozone Layer Formation

The Ozone gas is formed ultraviolet photons are absorbed by the oxygen molecules, and these molecules undergo a chemical reaction. The chemical reaction known as photolysis results in breaking down a single oxygen molecule into two oxygen atoms. An oxygen molecule (O2) is then combined with the free oxygen atom (O), in order to form Ozone molecule (O3). The Ozone layer significantly absorbs the harmful ultraviolet radiations, coming as a component of the sunlight (Daniel, 1998).

The Ozone gas is mainly found in the stratosphere's lower portion, lying approximately 10 to 15 km above the earth's surface. This layer filters out the harmful ultraviolet radiations included in the spectrum (wavelengths from 310 to 200 nm). At altitude of approximately 19 to 30 km above the earth's surface, the richest form of Ozone is found. This layer serves not only the mankind, but almost all the living species on the earth. If the Ozone layer was not present, a lot of harmful ultraviolet radiations would have entered into the earth's environment. These ultraviolet radiations may cause damage to living species, such as skin cancer.

Ozone Hole

In 1980, the British Antarctic Survey observed a severe depletion of Ozone layer over Antarctica region. After getting the alarming level of Ozone depletion confirmed, the scientists named the phenomena as Ozone Hole.

The term Ozone hole refers to the concept of Ozone depletion, near the polar regions of earth. In the region of Ozone hole, the depletion of stratospheric Ozone falls below a critical level of 200 Dobson Units (D.U.); it is to be noted that the normal level of Ozone concentration ranges from 300 to 350 D.U (AFEAS, 1995). The man-made and industrial chemicals play a significant role in the Ozone depletion, mainly for the Antarctica region.

Ozone Depletion: Causes

The major cause of Ozone layer depletion is the disturbance of balance between the production and destruction of stratospheric Ozone. The natural phenomena such as braking of Ozone by sunlight, and natural chemical reactions of Ozone with nitrogen and hydrogen can play a part in the depletion process. However, the contribution of natural processes for Ozone depletion remains very low in the unpolluted environment (Sivasakthivel and Reddy, 2011), and the ...