Observation of World Ozone Day, Ozone Chemistry, health effects

1. OBSERVATION
OF
WORLD OZONE DAY, 2021”
MR. BISHU KARMAKAR

2. The United Nation General Assembly on 23.01.95
adopted a resolution 49/114 which proclaims 16th
September as the International Day for the
Preservation of the Ozone Layer, to commemorate the
signing of the Montreal Protocol on the Substances that
Deplete the Ozone Layer which was signed on 16th
September, 1987.
India become party to the Montreal Protocol in June 1992
and prepared the country program in 1993 for phasing
out the Ozone Depleting Substances. In accordance with
the UN resolution 49/114, the Ozone Cell, Government of
India has been celebrating the International Ozone Day
for the Preservation of the Ozone Layer since 1995 at the
national and state level.
HISTORY OF OZONE DAY

3. 2021 :“Montreal Protocol - Keeping Us, Our Food
and Vaccines Cool”
2020 :“Ozone For Life: 35 Years of The Ozone Layer”
2019 : “ Protection“32 years & Healing”
2018 : “Keep Cool and Carry on”
2017 : “Caring for all life under the sun”
2016 :“Ozone and climate: “Restored by a world
united”
2015 :“Ozone: All there is between you and UV”
YEARWISE THEMES FOR WORLD OZONE DAY

4. How Ozone Allowed Life to Evolve on the
Surface of the Earth
• Early in the planet’s history, life existed only in the oceans where
the harmful UV radiation was absorbed and scattered by wave
action, bubbles, and debris floating in the water.
• Photosynthesis in ocean plants converted CO2 and H2O into O2
and the sugars that provide the energy to make the plants grow.
When the ocean became saturated with O2, the amount of
oxygen in the atmosphere gradually increased.
• Gas-phase oxygen was consumed by two mechanisms:
(i) new life forms used O2 and sugars to produce CO2, H2O, and
energy in the reverse-photosynthesis process called respiration,
and
(ii) O3 was formed by the photochemical destruction of O2.
• As concentrations of ozone in the atmosphere began to increase,
less UV radiation reached the Earth’s surface. Because the ozone
absorbed the DNA damaging radiation, life could begin to exist
on the Earth’s surface rather than just under water.

5. HOW OZONE ALLOWED LIFE TO EVOLVE ON THE
SURFACE OF THE EARTH

6. OZONE IN ATMOSPHERE
 Ozone is a gas that is naturally present in our atmosphere.
 Ozone is derived from the Greek word OZEIN, meaning “to
smell.”
 Ozone has a pungent odor that allows Ozone to be detected
even in very low amounts.
 Each Ozone molecule contains three atoms of oxygen and is
denoted chemically as O3.
 Ozone is found primarily in two regions of the atmosphere.
 About 10% of atmospheric Ozone is in the TROPOSPHERE, the
region closest to Earth (up to 10-16 km of altitude).
 The remaining Ozone (90%) resides in the STRATOSPHERE,
primarily between the top of the troposphere and about 40 KM
of altitude.
 Ozone rapidly reacts with many chemical compounds and is
explosive in concentrated amounts.

7. Ozone is formed throughout the atmosphere in multistep
chemical processes that require sunlight.
In the stratosphere, the process begins with the breaking of an
Oxygen molecule (O2) into oxygen radical by Ultraviolet
Radiation from the Sun. The oxygen molecule combine with
oxygen radical to form O3.
CHEMISTRY OF OZONE FORMATION IN THE ATMOSPHERE

8.  The large amount of Ozone in the stratosphere is often
referred to as the “Ozone Layer”.
 The ozone layer resides in the stratosphere and surrounds the
entire Earth.
THE OZONE LAYER
THE OZONE LAYER

10.  Ozone layer protects the harmful
UV radiation from the sun.
 UV-B radiation (wavelength : 280-
315 nm) from the Sun is partially
absorbed in Ozone layer.
 UV-A (wavelength: 315-to-400-nm)
& other solar radiation are not
strongly absorbed by the ozone
layer
 Human exposure to UV-B
increases the risk of skin cancer,
cataracts, and a suppressed
immune system. UV-B exposure
can also damage terrestrial plant
life, single cell organisms and
aquatic ecosystems.
IMPORTANCE OF OZONE LAYER

11. GOOD OZONE VS BAD OZONE
GOOD OZONE
Ozone in the stratosphere absorbs
some of the Sun’s biologically
harmful ultraviolet radiation.
Because of this beneficial role,
stratospheric ozone is considered
“Good Ozone.”
The absorption of UV-B radiation
by ozone is a source of heat in the
stratosphere.
This helps to maintain the
stratosphere as a stable region of
the atmosphere with temperatures
increasing with altitude.
 As a result, ozone plays a key role
in controlling the temperature
structure of Earth’s atmosphere.
BAD OZONE
Ozone is also formed near
Earth’s surface in natural
chemical reactions and by the
presence of man made pollutant
gases. Ozone produced by
pollutants is known as “Bad
Ozone” as more Ozone comes in
direct contact with humans,
plants and animals.
Increased levels of ozone are
generally harmful to living
systems as it reacts strongly to
destroy or alter many other
molecules.
Excessive ozone exposure
reduces crop yields and forest
growth.

12.  Ozone layer is being destroyed by a group of manufactured
chemicals that are called Ozone Depleting Substances
(ODS) and the destruction is called Ozone Depletion.
 ODS are very stable and nontoxic in the lower atmosphere.
 Their very stability allows them to float up, intact, to the
stratosphere. In stratosphere, they break down by UV rays
releasing highly reactive chlorine atoms (with others) that
in a chain reaction break the Ozone.
 The main ODS are the following:
• Chlorofluorocarbons (CFC 11, CFC 12, CFC 13)
• Methyl bromide (CH3Br)
• Halons (halon-1211, halon-1301, halon-2402)
• Carbon tetrachloride (CCI4)
• Hydrochloroluorocarbons (HCFC 22 and HCFC 123)
OZONE DEPLETION

13. • Another category of halogen source gases contains
bromine. The most important of these are the “halons” and
methyl bromide (CH3Br)
• Halons are halogenated hydrocarbon gases originally
developed to extinguish fires
• Halons are widely used to protect large computers, military
hardware, and commercial aircraft engines. Because of
these uses, halons are often directly released into the
atmosphere.
• Halon-1211 and Halon-1301 are the most abundant halons
emitted by human activities
• Methyl bromide, used primarily as an agricultural
fumigant, is also a significant source of bromine to the
atmosphere.
OZONE DEPLETING SUBSTANCES

14. OZONE DEPLETION

15. ANTARCTIC OZONE HOLE
 The most widely used images of
Antarctic ozone depletion are those from
space-based measurements of total ozone
by Total Ozone Mapping Spectrometer
(TOMS).
 Satellite images made during Antarctic
winter and spring show a large region
centered near the South Pole in which total
ozone is highly depleted.
 This region has come to be called the
“OZONE HOLE” as the concentration of
ozone become less.
 The area of the ozone hole has reached
25 X 106 Km2 . Minimum values of total
ozone inside the ozone hole have fallen as
low as 100 Dobson units (DU) compared
with normal springtime values of about 300
DU.


16. The most common uses of Ozone Depleting
Substances as
 Refrigerants in commercial, home and
vehicle Air conditioners,
 Foam blowing agents,
 Aerosol spray propellants,
 Fire extinguishing agents
 Solvents,
USES OF OZONE DEPLETING SUBSTANCES

17. EFFECTS OF OZONE DEPLETION
Harm to human health:
•Skin cancer
•Eye damage such as cataracts
•Immune system damage
Adverse impacts on agriculture, forestry and natural
ecosystems:
Reduced growth, photosynthesis and flowering in
Plants.
Damage to marine life:
•Reduction in phytoplankton could disrupt the
fresh and saltwater food chains
•Loss of biodiversity in our oceans, rivers and
lakes could reduce fish yields for commercial and
sport fisheries.
Animals:
•In domestic animals, UV overexposure may
cause eye and skin cancers.
Skin Cancer
Cataracts
Pterygium

18. • Regular checking our air conditioner units and
refrigerators for leaks and repair leaky air conditioning
units as early as possible.
• Proper disposal of refrigeration or air conditioning
equipment.
• Protect our self against sunburn, wear sunglasses and
protective clothing with a tight wave.
• Use a broad spectrum sunscreen with a sun protection
factor(SPF) at least 15 and 30 is better.
• The most important thing we can do is spreading
awareness. Our individual efforts will go a long way in
saving the earths blanket and keep our planet earth
livable for us and our future generations.
MEASURES TO BE TAKEN

19. MEASURES TO BE TAKEN

20. ATTEMPTS FOR PHASING OUT ODS TO PROTECT OZONE LAYER
• After realising the harmful effects of the ozone
depletion, efforts are being made of INTERNATIONAL
LEVEL to minimize or phase out the use of CFCs and
other ozone depleting substances (ODS) such as
halons and carbons.
• Vienna convention, 1981
• Montreal protocol, 1987
• Vienna meet, 1995
• Kyto protocol, 1997
• Global environment facility ( GEF)

21.  Complete phase-out of HCFC-141b as on 1st
January, 2020 in foam sector, under Ozone
Depleting Substances (Regulation and Control)
Amendment Rules, 2014 and 2019, issued under
Environment (Protection) Act, 1986.
The issuance of import license for HCFC-141b is
prohibited from 1st January, 2020 under Ozone
Depleting Substances (Regulation and Control)
Amendment Rules, 2019 S.O. No. 4724 (E) dated 31st
December, 2019.
ATTEMPTS FOR PHASING OUT ODS TO PROTECT OZONE LAYER

22. Signs of Recovery???
There have been some signs of recovery
– 1997 satellite showed a decline of several known
ozone-depleting gases
– Satellite images show some slowing down of ozone
loss
However…. Recovery is slow
www.coolantarctica.com/. ../ozone_hole.htm
Antarctica - Dec. 2005

23. 24 November 2021 Dr U Mishra, Professor, NIT, Agartala 23
Images of Antarctica Taken Indicate A Slow
Recovery

24. 24
EFFORTS NEED TO BE CONTINUED
• Effective Enforcement of Montreal Protocol :
– To reduce concentrations of chemicals responsible for ozone
depletion.
• More Scientific Studies:
– To gain a better understanding of the effects of ozone
depletion on organisms living within different ecosystems.
• Monitoring of Chemicals being emitted.
• Application of Molecular Nanotechnology to make
alternatives of ODS.