OZONE DEPLETION

The ozone layer is a belt of naturally occurring ozone gas that sits 9.3 to 18.6 miles (15 to 30 km) above earth and serve as a shield from the harmful UV.B radiation emitted by sun. It is formed slowly over the period of 2500 million years.

what is ozone layer

OzoneOzone is a highly reactive molecule that contains three oxygen atom.

It is constantly being formed and broken down in the high atmosphere 10 to 50 km above earth, in the region called the stratosphere.

Ozone absorbs most of the UV rays of the sun ,which is very harmful to the living organism on the earth.

UV radiations are 3 types they are: UV.A UV.B UV.CIn which UV is known to be most damage in to living organism.

Ozone DepletionWhen ozone deplete in the atmosphere, holes will be formed. Ozone hole or ozone layer depletion implies that, there is a significant decrease in the concentration of ozone in a particular region of atmosphere.

Joseph Foreman and his collegians first discovered ozone layer depletion in 1985. They found that there is a 40 % of depletion of ozone layer. They discovered that the ozone layer depletion started since 1960s and about 30 % of ozone layer has been destroyed.

The quantity of ozone is measured in Dobson unit (DU), which was discovered by K R RAMANANDHAN of Kerala nick named as Mr. ozone.It is estimated that each 1 % deplete in stratospheric ozone will produce 2 to 3 percentage increase in UV radiation on the earth.

OZONE DEPLETING GASES

Name of the chemical

% of contribution sources

CFC 12 45 Aerosols, refrigerator , A/C

CFC 11 26 Aerosols, refrigerator

CFC 13 12 solvents

Carbon tetra chloride

5 solvents

Chloroform 5 solvents

Halon 4 Fire estinguish

EFFECTS OF OZONE LAYER DEPLETION

The ozone depletion in the stratosphere will result more UV radiation reaching the earth. This will effect human beings ,animals ,plants, micro-organism, materials, air quality etc.

EFFECTS ON CLIMATE

As a result of ozone depletion, more UV rays will reach the earth surface. Consequently the temperature will increase. So it also leads to global warming. This cause melting of ice cap and this will rise the sea level. As a result coastal low lands will get submerged. It may cause acid rain too.

EFFECTS ON HUMAN BEINGSThe increase in UV radiation is likely to have a substantial impact on human health . It cause breast cancer, skin cancer ,luckiemia , eye cataracts ,reduced immunity level and infection diseases . Increased exposures of the human bodies to UV rays will weaken their immunity system.

EFFECTS ON ANIMALS

It causes bacterial infections in animals. It also causes bronchiolitis in them.

EFFECT ON PLANT LIFE

Photo synthesis and water use efficiency would be considerably decreased yields of vital crops like corn, rice, soya bean, cotton and wheat. The heavily fertilized crops would be more adversely effected due to their exposure to UV radiation.

EFFECT ON ACQUATIC ECO SYSTEM

Increased exposure to UV radiation shall effect the productivity of aquatic eco system. Ozone depletion may result in the decrease of population of phyto tinokton which forms the foundation of an aquatic food webs. This will effects the population of fish marine animals and in fact the whole aquatic food chain.

REMEDIAL MEASURES

1. To promote reduction in the production and consumption of ozone depleting gases

2. Alternative chemicals for CFC and other ozone depleting gases

3. Follow the provisions included in the MONTRIAL PROTOCOL.

MONTRIAL PROTOCOL

The treaty of Montrial was signed by 40 nations in 1987. this treaty was known as Montrial Protocol. It envisages programme to stop the production and consumption of CFC by 2010. In sep 1987, 96 chemicals were presently controlled by Montrial Protocol. By 1992, 110 countries included and India and china had become party to the protocol.

Under the initiative of UNEP, some measures have been taken at global level for the protection of ozone layer. A global convention was organized in 1985 in Vienna for the protection of ozone layer