OZONE LAYER:What's happening? 

Ozone layer seen from space

What is the ozone layer?

The ozone layer is a deep layer in the stratosphere, encircling the Earth, that has large amounts of ozone in it. The layer shields the entire Earth from much of the harmful ultraviolet radiation that comes from the sun. Interestingly, it is also this ultraviolet radiation that forms the ozone in the first place. Ozone is a special form of oxygen, made up of three oxygen atoms rather than the usual two oxygen atoms. It usually forms when some type of radiation or electrical discharge separates the two atoms in an oxygen molecule (O2), which can then individually recombine with other oxygen molecules to form ozone (O3). The ozone layer became more widely appreciated by the public when it was realized that certain chemicals mankind manufactures, called chloroflurocarbons, find their way up into the stratosphere where, through a complex series of chemical reactions, they destroy some of the ozone. As a result of this discovery, an international treaty was signed in 1973 called the Montreal Protocol, and the manufacture of these chemicals was greatly reduced. The ozone layer has since begun to recover somewhat as a result of these efforts, but there is some science which now suggests that the major volcanic eruptions (mainly El Chichon in 1983 and and Mt. Pinatubo in 1991) which have occurred since we started monitoring ozone with satellites in the late 1970's, could have also contributed to the ozone depletion. The amount of stratospheric ozone overhead on any given day and at any given location varies quite a bit. Because of vertical circulations of air in both the troposphere and the stratosphere, there can be greater or lesser amounts of ozone protecting you from ultraviolet radiation. Also, living at higher elevations exposes people to more UV radiation than at low elevations. While stratospheric ozone which protects us from the sun is good, there is also ozone produced near the ground from sunlight interacting with atmospheric pollution in cities that is bad for human health. It causes breathing problems for some people, and usually occurs in the summertime when the pollution over a city builds up during stagnant air conditions associated with high pressure areas.    What is Ozone? Let us understand what is ozone. Ozone, also called trioxygen, is a triatomic molecule that consist of three atoms of oxygen. It was proposed to be a new substance present in air, in 1840. It was named after the Greek verb 'ozein', which means 'to smell', ozone got its name from the peculiar odors after lightning storms. In 1865, its chemical formula O3 was determined. Ozone is a powerful oxidant, and has many industrial and consumer applications related to oxidation. Although being a powerful oxidant it damages, the respiratory tissues in animals and also some plant tissues. However, the layer of ozone that is, the ozone layer, prevents ultraviolet rays emitted by the Sun, from reaching the Earth's surface, that is beneficial for both plants and animals What is Ozone Layer?  Ozone layer, prevents the UV rays to reach Earth. It does so by absorbing the harmful radiation. As its name suggests, the ozone layer is made from is composed of high concentration of ozone. The ozone layer is found at an height of 20-30 km (12-19 mi) from the Earth's surface, and its thickness varies seasonally and geographically.    The ozone layer was discovered in 1913 by the French physicists Charles Fabry and Henri Buisson. Its properties were explored in detail by the British meteorologist G. M. B. Dobson, who developed a simple spectrophotometer (the Dobsonmeter) that could be used to measure stratospheric ozone from the ground. Between 1928 and 1958 Dobson established a worldwide network of ozone monitoring stations, which continue to operate to this day.    The Ozone layer absorbs 97-99% of Sun's ultraviolet radiation. Without the ozone layer all life forms on Earth would be exposed to the Sun's ultraviolet radiation, that can damage them severely. Although, it is surprising to know that ozone is made by ultraviolet rays! When the UV rays strike an oxygen molecule, containing two oxygen atoms, they get split into individual atoms and combine with unbroken oxygen molecules, leading to the formation of ozone molecules  Ozone depletion In 1975, NASA was directed by legislation to research and monitor the upper atmosphere. This led to Upper Atmosphere Research Program and later the Earth Observing System (EOS) satellites in the 1990s to monitor ozone depletion. The first comprehensive worldwide measurements were obtained in 1978 with the Nimbus 7 satellite and NASA scientists at the Goddard Institute for Space Studies.