A presentation on ozone depletion according to latest research.

1. OZONE
Group#07
• Urooj Akram (Ozone structure and
formation)
• Hafsa Shakeel (Ozone layer depletion)
• Uroosa Shahid (Strategies to overcome
Ozone depletion
• Kaneez Sakina (Consequences of Ozone
Layer Depletion)

2. ozone structure and formation
Urooj Akram(21-ARID-3020)

3. •ozone:
• Ozone, (O3), triatomic allotrope of oxygen
• Ozone is 1.5 times as dense as oxygen
• it condenses to a dark blue liquid, which freezes at −251.4 °C (−420 °F)
• The gas decomposes rapidly at temperatures above 100 °C (212 °F)
• ozone is much more reactive than oxygen
• it can decolorize many substances

4. • Ozone Layer:
• ozone concentrations are higher in the stratosphere than in the troposphere.The
stratosphere includes the zone commonly called the ‘ozone layer’.
• It plays a crucial role in keeping the planet habitable by absorbing potentially
dangerous ultraviolet (UV-B) radiation from the sun.
• Before its depletion, the ozone layer typically absorbed 97 to 99% of incoming
UV-B radiation.
• This means we need high ozone concentrations in the stratosphere to ensure that
life — including human life — is not exposed to harmful concentrations of UV-B
radiation.

5. •Generation
• In nature, ozone is generated in the upper atmosphere due to
ultraviolet radiation
• can also originate in association with electrical discharges from
lightning.
• Artificially, ozone can be generated in two ways that simulate these
two natural phenomena
• silent corona discharge
• ultraviolet (UV) radiation.

7. •Ultraviolet radiation
• Ultraviolet (UV) generation is like the process of creating ozone in the
upper atmosphere
• It therefore involves the use of a mercury lamp (λ < 240 nm)
O2 —(photon)→ 2O
• The ozone molecule thus formed can now absorb a photon of UV
energy and dissociate into oxygen.
O2 + O2 =O3 + kinetic energy

8. •Corona discharge
• ozone is generated by means of an electric discharge from oxygen that
has been previously cleaned.
O2 → 2O
• Subsequently, they react with an O2 molecule to generate ozone.
O2 + O + M → O3 + M
• M intervenes, which is a third component that absorbs the excess
energy of the reaction.

9. Ozone Layer Depletion
"Ozone layer depletion is the gradual thinning of the earth’s
ozone layer in the upper atmosphere" .
Sources:
• Chlorofluorocarbons
• Nitrogenous Compounds
• volcanic eruptions
• Ozone Depleting Substances
(ODS)

10. Ozone-depleting substances are the substances that are
responsible for the depletion of the ozone layer.”
The different ODS are:
• CFCs
• halons
• carbon tetrachloride
• hydrofluorocarbons
• Methyl chloroform
Source: They are found in Refrigerators, air-conditioners,
solvents, dry-cleaning agents, Fire-extinguishers, Adhesives,
aerosols.

12. Ozone destroying catalyst:
Chlorine is able to destroy so much of the ozone because it acts as
a catalyst.

13.  Ozone depletion process by CFCs
• UV radiation breaks of a chlorine molecule from CFCs
molecule.
• The chlorine atom attacks on ozone Molecule breaking it
apart.
• The resulting in ordinary oxygen molecule and chlorine
monoxide molecule (ClO).
• The chlorine monoxide is attack by free oxygen atom
releasing a free chlorine and oxygen molecule.
• The following reaction displays how Cl atoms have an
ozone destroying cycle:
• Cl+O3→ ClO+O2(step 1)
• ClO+O.→ Cl+O2(step 2)
• O3+O.→ 2O2

14. Ozone depletion process by nitrogen
oxides
• Another group of compound that can destroy stratospheric
ozone are the nitrogen oxide,(Examples of NOx are NO and NO2).
These compounds are come from exhausts of high altitude air
craft and human and natural activities on Earth.

15. Example:
One example of ozone
depletion is the annual
ozone "hole" over
Antarctica that has
occurred during the
Antarctic spring since the
early 1980s. This is not
really a hole through the
ozone layer, but rather a
large area of the
stratosphere with
extremely low amounts of
ozone.

16. TOPIC :
1. International Agreements:
The Montreal Protocol, signed in 1987, is an international treaty aimed at reducing the production and
consumption of ODS. The treaty sets binding targets for countries to phase out ODS and promotes cooperation
and technology transfer. The Protocol has been amended several times to accelerate the phase-out schedule
and expand the list of controlled substances.
2. Alternative Technologies :
Developing and using alternative technologies that do not rely on ODS is crucial for overcoming ozone depletion.
For example:* Hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) are widely used as alternatives to
chlorofluorocarbons (CFCs) in refrigeration, air conditioning, and foam blowing.* Methyl bromide, an ODS used in
fumigation, is being replaced by alternatives like sulfuryl fluoride and phosphine.* Ozone-friendly propellants like
compressed air and nitrogen are being used in aerosol products.
STRATERGIES TO REDUCE/OVERCOME OZONE
DEPLETION :
3. Recycling and Recovery:
Recycling and recovering ODS from existing products and equipment can reduce emissions and prevent further
damage to the ozone layer. For example:* CFCs and HCFCs are recovered from refrigeration and air conditioning
equipment during servicing and disposal.* ODS are recovered from foam products, like refrigerators and freezers,
during recycling.

17. 4. Emissions Reduction:
Reducing emissions from existing sources is essential for overcoming ozone depletion. This can be
achieved through:
• Improving the efficiency of refrigeration and air conditioning equipment.
• * Implementing leak detection and repair programs.
• * Encouraging responsible disposal of ODS-containing products.
5. Education and Awareness:
Raising awareness about the causes and consequences of ozone depletion is crucial for encouraging
individuals and industries to adopt ozone-friendly practices. Education and awareness campaigns can:
• Promote the use of ozone-friendly products.
• * Encourage responsible handling and disposal of ODS-containing products.
• * Support policy changes and international agreements.
6. Policy and Regulatory Framework:
A robust policy and regulatory framework is necessary for implementing and enforcing ozone depletion
strategies. Governments can:
* Establish regulations and standards for ODS emissions.
* Implement tax incentives and subsidies for ozone-friendly technologies.
* Enforce bans on ODS-containing products

18. 7. Research and Development:
Continued research and development are necessary for identifying new alternative technologies and
improving existing ones. Focus areas include:
• Developing new ozone-friendly refrigerants and propellants.
• * Improving the efficiency and cost-effectiveness of alternative technologies.
• * Investigating innovative solutions like carbon capture and utilization.
8. Public Participation:
Encouraging public participation in ozone depletion strategies is vital for their success. This can be
achieved through:
* Public awareness campaigns.
* Community-based initiatives.
* Encouraging individual actions like using ozone-friendly products.

19. Reduction in the Use of Vehicles :
Buses, cars, trucks, and other vehicles emit Nitrogen Oxides (N2O) and hydrocarbons which lead to air pollution and also
affect the ozone layer. Therefore, to reduce the rate of ozone depletion, public transport, carpooling, gradual increase in car
speed, hybrid or electric cars, bicycles, or walking can be used for short distant travel. This can help minimize the use of
petroleum-voracious vehicles which in turn reduces air pollution.
Avoid products made with Ozone-Depleting Substances (ODSs)
Some of the products such as cosmetics, aerosol sprays, blowing agents for foams, hairspray, and cleaning products we
make use of are harmful to us and to the environment because they are made of ozone-depleting substances such as
nitrous oxide, halogenated hydrocarbons, methyl bromide, hydrofluorocarbons(HCFCs) which are corrosive, however, they
can be replaced with non-harmful or eco-friendly products such as blue land, drops, common good, vinegar, Ecos, Pur
home, etc
Purchase local products. In this way, one not only gets fresh products but you avoid consuming food that has traveled long
distances. Nitrous oxide will be produced by car engines that bring the food and goods ordered due to long-distance travel.
Hence the need to patronize locally made food and goods, not only for the freshness of the food but for the protection of the
ozone layer.

20. Vehicles emit a large number of greenhouse gases that lead to global warming as well as ozone depletion. Therefore, the use
of vehicles should be minimized as much as possible.
Farmers should reduce the use of pesticides and drift towards natural means of getting rid of pests instead of using
chemicals. Most of the cleaning products as discussed have chemicals that affect the ozone layer. We should substitute that
with eco-friendly products.

21. .
Kaneez Sakina (21-Arid-3040)

22. Effect on human health
• Ozone layer depletion increases the amount of UVB reaching Earth’s
surface. Laboratory and epidemiological studies demonstrate that UVB
causes non-melanoma skin cancer and plays a major role in malignant
melanoma development. In addition, UVB has been linked to the
development of cataracts, a clouding of the eye’s lens.
Because all sunlight contains some UVB, even with normal
stratospheric ozone levels, it is always important to protect your skin
and eyes from the sun. See a more detailed explanation of health
effects linked to UVB exposure.

23. UV radiation damages the DNA in skin cells, which can lead to mutations
and ultimately skin cancer.
• It's essential to protect your skin and eyes from UV radiation by using
• sunscreen, wearing protective clothing, and sunglasses that block UV
rays.
Regular skin checks and eye exams are also important for early detection
and prevention.

24. Damage to the Ecosystem and Food Chain:
• 1. Marine Ecosystems: Ozone depletion allows more ultraviolet (UV) radiation to
• penetrate the atmosphere and reach the Earth's surface, including bodies of
• water.
• UV radiation can harm marine organisms such as phytoplankton, which are
• essential for the marine food chain.
• Phytoplankton serve as the primary producers, and their decline can disrupt the
• entire ecosystem, affecting the populations of fish and other marine life.

25. .

26. Terrestrial Ecosystems: UV radiation
can also damage plants, including
crops,
trees, and other vegetation.
 This can affect ecosystem
dynamics, biodiversity, and agricultural
productivity.
 Plants play a crucial role in the
food chain, providing food and habitat
for various
organisms.
 Damage to vegetation can have
cascading effects on herbivores,
predators, and
decomposers, altering ecosystem
structure and function
.

27. Impacts on Agriculture and Marine Life:
 Ozone depletion can have significant
impacts on agriculture and marine life:
 1. Agriculture: - Crop Damage: Increased
UV radiation due to ozone depletion can
harm crops, leading to reduced yields and
quality. UV radiation can interfere with plant
growth and development, damage plant tissues,
and inhibit photosynthesis.
 Decreased Crop Productivity: Reduced
crop yields can have economic
consequences for farmers and food security for
communities that rely on agriculture.
Crop losses may require farmers to implement
costly mitigation measures, such as
shading or UV-resistant crop variety
• .

28.  Coral Bleaching: Coral reefs are particularly
vulnerable to UV radiation and are
already stressed by factors such as ocean warming and
pollution. Increased UV
exposure can exacerbate coral bleaching, a
phenomenon in which corals expel their
symbiotic algae, leading to widespread coral mortality
and habitat loss.
 Efforts to mitigate ozone depletion and reduce UV
exposure are crucial for protecting
agricultural productivity, preserving marine ecosystems,
and safeguarding biodiversity.
This includes implementing measures to reduce
emissions of ozone-depleting
substances and promoting sustainable practices in
agriculture and marine resource
management. • .