The ozone layer in the stratosphere which blocks the dangerous ultraviolet rays is vital to our health and life. Increase of skin cancers are noticed when it is thinning or a hole is there. Aerosols, coolants and chlorofluorohydrocarbons cause ozone depletion. When they reach the stratosphere they will exist at least for 50 years.

Many countries have banned these substances but the industry nations refuse to ban. Even if we reduce or stop this pollution, the effect would be seen only after several decades. It is an Antarctic phenomenon and really a problem. In Australia there are restrictions to go in the sun because of ozone hole.

The triatomic molecule of ozone contains three oxygen atoms and it is less stable than oxygen molecule. It is a pale blue gas with irritating odour and is highly toxic on the respiratory system. At the same time ozone in the upper atmosphere filters damaging ultraviolet light from reaching the earth. It is also very strong oxidation agent.

Ozone is produced in the stratosphere which is 10 to 50 km away from the earth, between the reaction of molecule oxygen and ultraviolet light in the presence of hydrocarbons and nitrogen oxides and the amount present here is 20mg per cubic meter. Air in the upper troposphere contains 2mg per cubic meter and in the lower part depending on the time in a day it is present between 0.004 and 2mg per cubic meter.

The half life period of ozone is very short, only seven minutes. Ozone decays in houses and buildings very rapidly, will not also be formed once again, the amount in the open place is more than the buildings. It is not emitted by the automobiles or industry.

Photocopy machines produce ozone and it is better to use ozone filter.

Ozone is regarded as a pollutant by the World Health Organization.

Normally in Western countries through television and radio public is informed if the concentration of the ozone is high. It is advisable to do this in other countries also. During that time it is not advisable to do any hard work outside. Children, aged and sick people must stay in their home because there the concentration is less compared to outside.

When we do hard physical work, sport and any other tedious work, we take the most ozone.

Exposure up to 1 ppm produces irritation in the respiratory passages, headaches and burning of eyes.

2 to 10 ppm with an exposition of 1 to 2 hours will damage the eyes.