The Montreal Protocol has successfully protected the ozone layer by phasing out ozone-depleting substances, allowing the ozone hole to heal. World Ozone Day, celebrated each year on September 16, highlights the continued importance of the Montreal Protocol in protecting human health, economies, ecosystems and the climate from ultraviolet radiation. This year's theme emphasizes how the Montreal Protocol has kept vaccines cool and effective during distribution by curbing gases harmful to the ozone layer and climate. The ozone layer is vital as it filters out much of the sun's harmful ultraviolet rays, and the Montreal Protocol's phase-out of chlorofluorocarbons and other ozone-depleting substances has allowed the ozone layer to begin recovering

1. World Ozone Day
PRESENTATION

2. The Montreal Protocol started life as a global
to protect the ozone layer, a job it
has done well. making it one of the most
successful environmental agreements to
date. A united global effort to phase out
ozone-depleting means that
today, the hole in the ozone layer is healing, in
turn human health, economies and
ecosystems. But, as this year's World Ozone
Day seeks to highlight, the Montreal Protocol
does so much more such as slowing
climate change and helping to boost energy
efficiency in the cooling sector, which
contributes to food security.
The theme for this year is Montreal Protocol
— keeping us, our and vaccines

4. According To
Temperature ,
Atmosphere have
four layers
Components Of Earth
• Lithosphere, hydrosphere, atmosphere
* Troposphere
* Stratosphere
* Mesosphere
* Thermosphere.

5. * Stratosphere: The stratosphere is a layer of Earth's
atmosphere that is stratified
in temperature, with warmer layers higher up and
lower 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
occurs.
LOCATION OF OZONE LAYER

6. 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 sun.
• Without the Ozone Layer the risk of many
factors
increase considerably.

7. How Ozone Is Formed
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 OZONE MOLECULE. O2 + O →O3 O3 UV
RADIATION → O2 + O (PHOTON MOLECULE)
02 + O -+03
U V RADIATION 2 +(PHOTON MOLECULE)
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
RECOMBINATION.

8. SUN
• Ozone is lost by a reaction of the oxygen atom or the ozone molecule with each
other ,or some other trace gas such as chlorine(SLOW)
• Oxygen molecules are photolyzed, yielding 2 oxygen atoms
(SLOW)
• Ozone and oxygen atoms are continuously being
interconverted as solar UV breaks ozone and the oxygen atoms
reacts with another oxygen molecule.
• This interconversion process converts UV radiation into thermal
energy, heating the stratosphere.

9. Ozone depleting substances
• Sherwood Rowland and Mario Molina
* In 1974, Sherwood Rowland
and Mario Molina demonstrated
how CFCs were splitting ozone
molecules into atmospheric
oxygen and chlorine monoxide
molecules, which earned them
the 1995 Nobel Prize in
chemistry.
* The most important process of
ozone depletion is through
catalytic destruction of atomic
chlorine (Cl), and atomic
bromine (Br) molecules and by
free radicals of Nitric oxide (NO),
Nitrous oxide (N2O), and
Hydroxyl radicals(OH).

10. *The main source of these compounds
in the stratosphere is photo-dissociation
of Chloro-fluro-carbon (CFC)
compounds and Bromo-fluro-carbon
(BFC) compounds. They are commonly
referred to as Freons and Halons
respectively. CFCl3+electro magnetic
radiation Cl +CFCl2 Cl+O3→ClO+O2:
*The chlorine atom changes an ozone
molecule to ordinary oxygen
*These highly stable compounds
released on the earth are transported
to stratosphere.
*Bromine is more reactive than Chlorine
but Br concentration is less in the
atmosphere.

11. Ozone Depletion
A CFC MOLECULE TAKES AN AVERAGE OF ABOUT FIVE TO
SEVEN YEARS TO GO FROM THE GROUND LEVEL TO THE UPPER
ATMOSPHERE, AND IT CAN STAY THERE FOR ABOUT A CENTURY,
DESTROYING UP TO ONE HUNDRED THOUSAND OZONE
MOLECULES IN THIS PERIOD.
THE BREAKDOWN OF OZONE IN THE STRATOSPHERE RESULTS IN
DECREASE IN THE OZONE CONCENTRATION THUS REDUCING
THE ABSORPTION OF ULTRAVIOLET RADIATION. THIS LEADS TO
INCREASE IN THE TEMPERATURES IN THE TROPOSPHERE(EARTH).
1,1,2-TRICHLORO-1,2,2-TRIFLUOROETHANE, ALSO KNOWN AS
CFC113A IS ONE OF FOUR MAN-MADE CHEMICALS
DISCOVERED IN THE ATMOSPHERE. IT IS INCREASING AND
SOURCE IS UNKNOWN. OZONE DEPLETION

12. • 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 atmospheric
container.
• During this period there will not be sunlight for three months and
temperature is -80 degrees. This leads to formation of polar
stratospheric clouds (PSC).
• 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 destroyed.
• The photochemical processes involved are complex but well
understood.
• Most of the chlorine in the stratosphere resides in "reservoir"
compounds, primarily as chlorine nitrate, and as hcl.
• The formation of end products essentially remove cl from the
ozone depletion process.
• During the change in the seasons (antarctic winter and spring)
reactions on the surface of the polar stratospheric cloud particles
convert these "reservoir" compounds into reactive free radicals .
• 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.
Ozone Hole Formation

13. World Ozone Day
On December 19,1994, the
United Nations General
Assembly, proclaimed
September 16 to be the
International day for the
preservation of the ozone layer,
commemorating the date when
Montreal protocol was signed
—
The World Ozone Day was first
celebrated on September 16,
1995.
On this day, a number of special
events such as talks and
seminars are held in Canadian
city of Montreal and allmost 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 talks and seminars.
This year's theme(“32 years and
Healing”) 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 completed.
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 change.

14. Times Of India
India has also launched a new plan to phase
out HCFCs by 2030. India has consciously
chosen a path for environment-friendly and
energy-efficient technologies while phasing
out ODSs. Importantly, India is one among
the few countries and a pioneer in some
cases in the use of technologies, which are
non-ozone depleting and have a low global
warming potential.

15. Conclusion
OZONE LAYER DEPLETION IS A DEEP CRISIS WHICH LEADS TO
INCREASED UV-B RADIATION REACHING THE SURFACE OF THE EARTH
AFFECTING HUMANS AND ALL THE LIVING ORGANISMS.
ANTHROPOGENIC ACTIVITIES THIS HAVE BEEN THE MAIN CAUSE FOR
OZONE LAYER DEPLETION LEADING TO GLOBAL CLIMATIC CHANGES IN
THIS CENTURY.
SOME OF THE MEASURES TO PREVENT OZONE
DEPLETION ARE:
I. PRODUCTS THAT RELEASE CHLOROFLUOROCARBONS
(CFCS) SUCH AS COSMETICS, HAIR SPRAYS, ROOM
FRESHENERS, ETC. SHOULD BE AVOIDED.
2. CHEMICAL FERTILIZERS USED IN AGRICULTURE
SHOULD BE REPLACED WITH ORGANIC ONES.
3. BURNING OF PLASTIC AND RUBBER PRODUCTS
SHOULD BE AVOIDED. EFFORTS SHOULD BE TAKEN
TO REUSE SUCH PRODUCTS AS IT WILL ALSO PROTECT
THE ENVIRONMENT FROM WASTE GENERATION.
4. VEHICLES THAT ARE RELEASING EXCESSIVE
SMOKE SHOULD BE AVOIDED. LIMITED USE OF
PRIVATE OR PERSONAL VEHICLES SHOULD BE DONE.
PUBLIC TRANSPORT SHOULD BE UTILIZED TO
REDUCE AIR POLLUTION.

16. World Ozone
Day
Presentation
CCM HOMESCHOOLING
SADIYA , NAFSEENA AND SWALIH