Ozone Depletion.

Ozone Layer is a protective layer or shield around the earth which covers the earth from the harmful Ultra Violet Rays of Sun. It is also a very significant part of the earth's second atmospheric layer known as the stratosphere. It is found in the lower part of the Stratosphere at a height of 15 to 35 km. Going back in its history it was discovered by the French physicist Charles Fabry and his partner Henri Buisson in the year 1913. It contains a high concentration of ozone molecules (O3). The very high concentration of ozone molecules here results in the absorption of high or medium frequency Ultra Violet Rays coming from SUN which otherwise would potentially raise health concerns.
Our understanding of ozone depletion is a result of laboratory studies, computer models, and atmospheric observations. The wide variety of chemical reactions that occur in the stratosphere have been discovered and studied in the laboratory. Chemical reactions between two gases follow well-defined physical rules. Some of these reactions occur on the surfaces of stratospheric clouds formed in the winter in the stratosphere. Reactions have been studied that involve many different molecules containing chlorine, bromine, fluorine, and iodine and other atmospheric constituents such as carbon, oxygen, nitrogen, and hydrogen. These studies have shown that several reactions involving chlorine and bromine directly or indirectly destroy ozone in the stratosphere. 
The main factors of Ozone Depletion or the causes behind Ozone Destruction are discussed here.

Causes:

• Ozone Hole: Ozone hole is the primary cause of ozone depletion at higher levels. It is causing the ozone layer much damage that its consequences are being faced on each and every day. The Antarctic ozone hole is an area of the Antarctic stratosphere in which the ozone levels have dropped to as low as 33 percent of the values recorded in 1975. The ozone hole occurs during the Antarctic spring, starting from September to early weeks of  December, as strong western winds start to circulate around the continent and create an atmospheric container. Within this polar vortex, over 50 percent of the lower stratospheric ozone is destroyed during the Antarctic spring. The primary cause of ozone depletion is the presence of chlorine-containing source gases primarily Coloro Flouro Hydrocarbons. In the presence of UV light, these gases after dissociating release chlorine atoms, which then go on through the air to the stratosphere to where they destroy the ozone layer. The Cl-catalyzed ozone depletion can take place in the gas phase, but it is dramatically enhanced in the presence of polar stratospheric clouds (PSCs).

Effects of Ozone Depletion:

1. Increased UV:  Since the ozone, layers are being destroyed by earth's gasses and it's bad atmosphere so the layer which prevents Ultra Violet rays from SUN reaching earth's surface is also being destroyed so this increase the amount of Ultra Violet Rays coming to earth form SUN. Which is quite a horrible thing and is surely not good for the earth's atmosphere.  In the Year 2008 October, the Ecuadorian Space Agency published a report called HIPERION. The study used ground instruments in Ecuador and the last 28 years data from 12 satellites of several countries, and found that the UV radiation reaching equatorial latitudes was far greater than expected, with the UV Index climbing as high as 24 in Quito; the WHO considers 11 as an extreme index and a great risk to health. The report concluded that the ozone depletion levels around the mid-latitudes of the planet are already endangering large populations in these areas. Later many countries use their own resources and published their studies which also resembles the studies that Ecuador published earlier.

1. Biological Effects: The main effects ozone depletion is on humans and especially their health issues are raising at a high pace and this is probably the main and the only concern about ozone depletion at the moment. And this is the biggest challenge in battling climate change. The one major disease that is killing human beings is CANCER. Different forms of cancer are due to exposure to Ultra Violet Radiation and this disease is incurable. Ozone depletion would magnify all of the effects of UV on human health, both positive including the production of vitamin D and negative including sunburn, skin cancer, and cataracts. In addition, increased surface UV leads to increased tropospheric ozone, which is a health risk to humans.
2. Effects On Animals: The depletion of ozone also has effects on Animals especially in the areas situated in antarctic or in its neighbors. Because in those areas they are directly exposed to the UV radiation coming from the Sun. In November 2011 scientists of Institute of Zoology of London published a report that says whales off the coast of California have shown a sharp rise in sun damage, and these scientists "fear that the thinning ozone layer is to blame" The study photographed and took skin biopsies from over 150 whales in the Gulf of California and found "widespread evidence of epidermal damage commonly associated with acute and severe sunburn", having cells that form when the DNA is damaged by UV radiation.

The Effects of Ozone Depletion is being seen by the scientist in every field of human life. This is a matter of concern for humans that we have to reduce our needs and minimize the usage of things that damages the OZONE layer and making holes in it. Because if we didn't think of it right now then it might be late.