Ozone Layer Depletion and Its Effects

The Earth’s Ozone Layer protects all life from Sun’s harmful radiation, but human activities damaged the Ozone shield. Less protection from ultraviolet light from Sun lead to higher skin cancer, cataract rates and corp damage. Over 140 countries from all over the world  taking necessary steps to protect and safeguard the ozone layer.

The Ozone Layer

The Earth atmosphere is divided in to seven layers.

Troposphere – The lowest region which extends from the earth’s surface up to 10 Km in altitude.The tallest mountain on the earth Mt.Everest is just 9 km high.

Stratosphere – The next layer which is 10 Km to about 50 Km high. Most commercial airlines occurs in the lower part of stratosphere. Most Ozone layer is concentrated in this layer which is from 10 Km to 30 Km of earth’s surface.

So, What is Ozone?

Ozone Layer

Ozone is a molecule containing three oxygen atoms. It is blue in color and has a strong odor. Normal oxygen which we breathe has two oxygen atoms and is colorless and odorless.

Ozone is not common like oxygen, if there are ten million air molecules in that only 3 are Ozone. However, even the small number of Ozone plays a key role in atmosphere. The Ozone Layer absorbs the portion of UV Radiation from the Sun and thus preventing it reaching the earth surface. Mainly it absorbs the portion of Ultraviolet light called UVB. The UVB – Ultraviolet is linked to harmful diseases including various types of skin cancer, cataracts and some form of marine life.

Ozone Depletion

For four decades , the Chlorofluorocarbons ( CFC’s)  were thought of as miracle substance. They are stable, nonflammable, low in toxicity, and inexpensive to produce. The chlorine or bromine transported through winds into the stratosphere which damage the protective ozone layer.

In the early 1970’s researchers began to investigate the efforts of various chemicals on the Ozone layer, particulary Chlorofluorocarbons ( CFC’s) which contain Chlorine. 

Chlorine compounds from various sources readily combine with water and repeated measurements show that they rain out of the troposphere very quickly. Chlorofluorocarbons ( CFC’s) are very stable and do not dissolve in rain. Thus there are no natural resources that remove the Chlorofluorocarbons ( CFC’s)  from the lower atmosphere.

The CFC’s are so stable that only exposure to strong UV radiation break them down. Once it breaks down the Chlorofluorocarbons ( CFC’s) releases atomic chlorine and one chlorine atom can destroy over 100,000 ozone molecules. So, the net effect is to destroy ozone faster than it is naturally created. The widely used chemicals produce roughly 85% of the CFC’s and natural sources produce only 15%.

The Ozone depletion is a global issue not just a problem of south pole. The Ozone level falls 5-10% over the United States on the season. The Sun’s output of UVB does not change rather less ozone means less protection and hence more UVB reaches the earth’s surface.

The World’s Reaction

There are several countries in the world including the United States banned the use of CFC’s  as aerosol propellants.There are various conventions taken place and in 1987 the Montreal Protocol was signed. 

Because of the measures take under the protocol, emissions of Ozone depleting substances are already falling.

Assuming continued compliance, stratosphere chlorine levels will slowly return to normal. 

The good news is that the natural ozone production process will heal the Ozone Layer in about 50 years.

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