Ozone Layer protects life on Earth by absorbing potentially harmful ultraviolet radiation that can cause skin cancer , sunburn, and cataracts, suppress immune system and damage plants life and reduction of ocean plankton population in the photic zone.
Image Credit: https://goo.gl/images/19fvtK
Nasa Scientist confirmed that after direct satellite observations that Ozone Layer has shrunk and they also confirmed chlorine level are rapidly declining in Earth Stratosphere.
Everything possible because of CFC( chloroFluoroCarbon) banned in 1985 after Montreal Protocol.
Montreal Protocol completely phase out of CFC.
Last year Satellite images showed that Ozone Hole had begun to close and could be completely healed by 2060.
How Ozone Layer Formed:
Short wavelength UV radiation splits an oxygen molecules into two oxygen atoms which then combine with other oxygen molecules to form Ozone.
O+O2- O3
Causes Of Ozone Depletion:
Ozone is removed when an oxygen atom and Ozone molecules recombine to form two oxygen molecules
,O + O3 - 2O
Main cause of Ozone Depletion and Ozone Hole i:
Man made chemicals Especially CFC which were used in Aerosol, fridges, air conditioning and packing materials and HCFC.
These materials when reach Stratosphere they are broken apart by Sun's Ultraviolet radiation and released chlorine atoms that destroy Ozone molecules.
CFCs, which were used in aerosols, fridges, air conditioning and packing materials, are so harmful because they rise into the stratosphere, where they are broken apart by the Sun's ultraviolet radiation, releasing Chlorine /Bromine( halogen atom) atoms that destroy ozone molecules into oxygen .
Ozone Hole:
The Ozone Hole occurs during Antarctic
Spring, from September to early December as strong Westerly Wind start to circulate around the continent and create an atmospheric container.
Within this polar vortex, over 50% of the lower stratosphere ozone is destroyed during the Antarctic Spring in the presence of polar stratospheric clouds.
According to recent study by American Geophysical Research Centre, it is confirmed that after banned of CFC, recent Ozone depletion during the Antarctic winter is 20% less than there was in 2005.
Nasa permanently monitor the Ozone hole Arctic region since 2005.
According to NASA , as chlorine from CFC is going down in Ozone hole, the less Ozone depletion is occurring.
CFC are long lived ( 50 to 100 years) chemical compounds that so it will take some times to close the Ozone hole completely upto 2060 to 2080.
To determine how Ozone and other chemicals have changed year to to year, Scientist used data from the Microwave Limb Sounder (MLS) abroad the Aura Satellite which continuously monitored Antarctic Ozone hole and Ozone layer and amount of halogen (Chlorine/bromine).
Scientist compare the MLS measurements of hydrochloric acid and nitrous oxide each year and finally they determine that the total Chlorine levels were declining on average by about 0.8% annually.
MLS measurements of hydrochloric acid and nitrous oxide each year, they determined that the total chlorine levels were declining on average by about 0.8 percent annually.
According to Scientist it will take more time to heal the complete Ozone hole in Antarctic region. By 2060 to 2080 the Ozone hole might be closed permanently.
Source Of Information:
https://eos.org/scientific-press/study-finds-first-direct-proof-of-ozone-hole-recovery?utm_source=rss&utm_medium=rss&utm_content=study-finds-first-direct-proof-of-ozone-hole-recovery
http://www.telegraph.co.uk/science/2018/01/05/hole-ozone-layer-has-shrunk-thanks-ban-cfcs-nasa-confirms/
https://en.m.wikipedia.org/wiki/Ozone_depletion
http://www.moneycontrol.com/news/world/chemical-ban-helping-ozone-hole-recover-nasa-2476943.html