2. INTRODUCTION
The ozone layer is a deep layer in the stratosphere, encircling the
Earth, that has large amounts of ozone in it. This natural sunscreen,
known as Earth's ozone layer, absorbs and blocks the majority of the
sun's UV radiation. Without this barrier in place, all of the radiation
would reach Earth, damaging the DNA of plants and animals, like us
humans. Within days of the ozone layer's disappearance, many plants
would die.
3. Ozone layer
Ozone is formed in the atmosphere when energetic ultra violet
radiation dissociates molecules of oxygen into separate oxygen atoms.
Free oxygen atoms can recombine to form oxygen molecules but if a
free oxygen atom collides with an oxygen molecule, it joins up ,
forming ozone.
Over the Earth’s surface, the ozone layer’s average thickness is about
300 Dobson Units or a layer that is 3 millimeters thick.
4.
5. Ozone layer depletion
ozone layer depletion consist of two related events observed
since the late 1970s:a steady lowering of about four percent in
the total amount of ozone in Earth’s atmosphere, and a much
larger springtime decrease in stratospheric ozone around Earth’s
polar regions. The latter phenomenon is reffered to as the
ozone hole.
6. Causes
The ozone layer depletion is a major concern and is associated with a
number of factors. The main causes responsible for the depletion of the
ozone layer are listed below:
Chlorofluorocarbons
Chlorofluorocarbons or the CFC are the main cause of ozone layer
depletion. These are released by soaps, solvents, spray aerosols,
refrigerators, air-conditioners, etc.
The molecules of chlorofluorocarbons in the stratosphere are broken
down by the ultraviolet radiations and release chlorine atoms. These
atoms react with ozone and destroy it.
7. Unregulated Rocket Launches
The unregulated launching of rockets result in much more depletion of ozone layer than the
CFCs do.
Nitrogenous Compounds
The nitrogenous compounds such as NO2, NO, N2O.
Natural Causes
Sun-spots and stratospheric winds. But it does not cause more than 1-2% of the ozone layer
depletion.
The volcanic eruptions.
9. Effects of ozone layer depletion
For humans, direct exposure to UV rays can lead to:
•Skin cancer such as melanoma, basal cells or squamous cell carcinomas.
•Premature aging and other skin damage.
•Eye damage such as cataract problems, photokeratitis or snow blindness.
•Damage or weak the immune system.
In plants, ozone layer depletion can cause problems such as changes on how
nutrients are distributed, on developmental timing phases and on secondary
metabolism.
10. Prevention
•Buying and using recycled products.
•Saving of energy:
• Change your light bulbs to CFL
• Use less heat and air conditioning
• Buy energy-efficient products
• Use less hot water
• Use the “off” switch
•Reducing fossil fuels emissions by using public transport.
•Plant a tree (or two!).
•Spread awareness and encourage others to make a change.
11. Conclusion
2019 Ozone Hole is the Smallest on Record Since Its Discovery. Abnormal
weather patterns in the upper atmosphere over Antarctica dramatically
limited ozone depletion in September and October, resulting in the
smallest ozone hole observed since 1982, NASA and NOAA scientists
reported today.
We all have the responsibility to save our Earth for the next generation.