Ozone

Source

Ozone [O₃(g)] is a pale blue gas that exists in the stratosphere of our atmosphere as the ozone layer. It is formed from atmospheric oxygen by the absorption of ultraviolet radiation of the right energy (wavelength 250 nm).

Ozone itself undergoes photodissociation with 215-295 nm ultraviolet radiation.

Thus, ozone is constantly created and destroyed. The above reaction is responsible for the vital screening effect of ozone.

The presence of chlorofluoroarbons (CFCs) generate reactive chlorine radicals that constantly destroy ozone. The depletion of ozone layer will be discussed later.

Ozone can also be formed in the lower part of the atmosphere. It is formed by reactions between nitrogen oxides and hydrocarbons under sunlight, or by electric sparks which occur in car engines or electrical appliances like photocopiers. In nature, the gas can be generated during lightning.

Health Effects

Ozone is harmless when it is in low concentrations. The gas itself is a respiratory irritant. It penetrates into small airways and the lung, causes pulmaonary oedema at high concentrations. Other illnesses include lung fibrosis and reduces lung function. It precipitates asthma attacks.

Social Effects

Ozone layer in the stratosphere filters out 99% of dangerous ultraviolet radiation from the sun. The thnning of the ozone layer may lead to an increase of skin cancer and eye cataract. The presence of 'ozone hole' over Antarctica and the southern hemisphere has introduced incidence of increasing victums of skin cancer. The yield of crops may also decrease. The expanse in medical cure and economical loss in food is uncountable.