The THEORY that the ozone layer in the stratosphere might be damaged by human intervention PRECEDED the actual OBSERVATION of the ozone hole.
Yet, when the hole WAS observed (via satellite) it was almost “missed” because it wasn’t expected . . .
2. On this day, a number of special events such as talks and seminars are held in
Canadian city of Montreal and almost all countries regarding ozone.
This day is mainly intended to spread awareness of the depletion of the ozone
layer and search for the solution to preserve it.
People from all over the world are expected to gather in Montreal on
September, 16 to join the talk and seminars.
This year’s theme (Montreal Protocol: Healing the Ozone Layer and
Combating Climate Change) celebrates three decades of remarkable international
cooperation to protect the Ozone Layer and the climate under Montreal Protocol .
3. This year's theme (Montreal Protocol: Healing the Ozone Layer and Combating
Climate Change) celebrates three decades of remarkable international cooperation to
protect the Ozone Layer and the climate under the Montreal Protocol.
It also reminds the people to keep up the momentum to ensure healthy people and a
healthy planet. In 2018, the latest Scientific Assessment of Ozone Depletion was
This assessment shows that the parts of the Ozone Layer have recovered at a rate of
1-3% per decade since 2000.
Even at the protected rates, Northern hemisphere and mid-latitude ozone will heal
completely by the 2030s.
The Southern Hemisphere will follow in the 2050s and Polar Regions by 2060. No
doubt Ozone Layer protection efforts also contribute in fighting with the climate
Healing the Ozone Layer and Combating
4. Location of ozone layer
• Stratosphere: The stratosphere is a layer of Earth's atmosphere that is stratified
in temperature, with warmer layers higher up and cooler layers farther down.
• Ozone Layer: The layer with the highest concentration of ozone molecules, is
found in the stratosphere. The ozone layer filters much out of the sun's
ultraviolet radiation that would be harmful to most forms of life.
• Troposphere: The troposphere is the lowermost portion of the Earth's
atmosphere and the one in which most weather and the "greenhouse" effect
5. Importance of Ozone Layer
• Ozone Layer acts as a shield to protect the short wave,
more powerful and harmful radiations such as X-rays,
Gamma, Beta and UV radiations (280–315 nm) from
• Without the Ozone Layer the risk of many factors
7. How ozone is
In the stratosphere ozone molecule is dissociated into
molecular oxygen and oxygen molecules when absorbs a
photon from ultraviolet radiation (>240 nm). These singlet
oxygen atoms combines with a oxygen molecule forms a
+ O →O3
UV radiation → O2
This is a continuous process that take place in the ozone layer.
The overall amount of ozone in the stratosphere is determined
by a balance between photochemical production and
9. Ozone-Depleting Substances Sources
Refrigerators, air-conditioners, solvents,
dry-cleaning agents, etc.
Carbon tetrachloride Fire extinguishers, solvents
Methyl chloroform Adhesives, aerosols
fire extinguishers, air-conditioners,
Ozone Depleting Substances (ODS)
“Ozone-depleting substances are the substances such as chlorofluorocarbons, halons, carbon tetrachloride,
hydrofluorocarbons, etc. that are responsible for the depletion of the ozone layer.”
Chlorofluorocarbons or CFCs are the main cause of ozone layer
depletion. These are released by solvents, spray aerosols,
refrigerators, air-conditioners, etc.
The molecules of chlorofluorocarbons in the stratosphere are
broken down by ultraviolet radiations and release chlorine
atoms. These atoms react with ozone and destroy it.
Causes of Ozone Layer Depletion
Unregulated Rocket Launches
Researches say that the unregulated launching of rockets
results in much more depletion of the ozone layer than the
CFCs do. If not controlled, this might result in a huge loss of
the ozone layer by the year 2050.
12. Ozone hole formation
• The ozone hole occurs mostly during
spring season in Antarctic region (from
September to early December) as
strong westerly winds circulate around
the continent and create an
• During this period there will not be
sunlight for three months and
temperature is -80 degrees. This leads
to formation of Polar Stratospheric
• The PSC provide a platform for
chemical reactions whose products will
lead to ozone destruction.
• Within this polar vortex, over 50% of
the lower stratospheric ozone is
13. • A major hole is now over Antarctica, where
there are ice sheets. If these Ice sheets melt, it
could increase coastal flooding causing a violent
shift in climate.
16. Squamous cell carcinomas and Malignant melanoma (less frequent
but more lethal) are two type of cancers caused by UVB radiation.
These cancers are relatively mild and rarely fatal.
Absorption of UVB radiation causes the pyrimidine bases in the
DNA molecule to form dimers, resulting in transcription errors
when the DNA replicates.
The risks are particularly high for young children, the elderly, and
those with asthma or other respiratory difficulties.
whales off the coast of California have shown a sharp rise in sun
Human and Animal Health:
18. Aquatic Ecosystems:
Damage to phytoplankton, fish larvae, shrimp, crabs
Affects marine food chain, resulting in decreased
Paints, rubber, wood and plastic are degraded faster,
especially in tropical regions
Such damages accounts to billions of dollars
Effects on the Environment
Strong ultraviolet rays may lead to minimal growth,
flowering and photosynthesis in plants. the forests
also have to bear the harmful effects of the
19. Limit private vehicle driving- A very easy way to control
ozone depletion would be to limit or reduce the amount of
driving as vehicular emissions eventually result in smog
which is a culprit in the deterioration of the ozone layer.
Reduce the source of Nitrous oxide and CFC.
Minimize high altitude aircraft flights
Minimize rocket flights
Encourage growth of plants that produce oxygen.
Eliminate production and release of ozone depleting chemicals
(such as CFCs and BFCs).
20. Check your fire extinguishers to find
Researches If halogenated
hydrocarbon is the main ingredient,
find a hazardous waste center at
which to recycle it or call your local
fire department for instructions on
how to dispose it. Replace it with a
model without this harmful ozone-
Don’t buy aerosol products with
Although CFCs have been banned or
reduced in many applications, the
only way to be sure is to check the
label on all your hairspray,
deodorants and house hold
22. Drive Less
Although Nitrous oxide is now
the largest ozone –depleting
substance released by human
activities (as well as potent
greenhouse gas) and it is
produced in the internal
combustion that power most cars.
To reduce the amount of nitrogen oxide your car produces,
Driving a hybrid or electrical car
Neutralizing your vehicle’s greenhouse gas emission with a