- The document is a seminar presentation on the causes of ozone layer depletion, its effects, and potential remedies. It discusses how ozone forms a protective layer in the stratosphere that shields the earth from harmful UV rays. Various human activities like CFC emissions lead to ozone depletion, which has adverse health and environmental impacts. The Montreal Protocol was implemented to phase out ozone-depleting substances and allow the ozone layer to recover over time.

1. GLS 429 - Seminar
NNAMDI AZIKIWE UNIVERSITY, AWKA
FACULTY OF PHYSICAL SCIENCES,
DEPARTMENT OF GEOLOGICAL SCIENCES
A SEMINAR PRESENTATION ON THE CAUSES OF
OZONE LAYER DEPLETION, ITS EFFECTS AND
REMEDIATION
BY
OKOYE,DAVID IKECHUKWU
REGISTRATION NUMBER: 2009503377
IN PARTIAL FULFILMENT FOR THE AWARD OF B.SC. (HONS)
IN GEOLOGICAL SCIENCES.
SUPERVISORS
DR. AKPUNONU, E.O.
DR.OKOYEH, E.A.
MR. OMEOKACHIE, A.I.
MR. NDUKA, U.M.
AUGUST 2015

2. Ozone (O3) is a stratospheric layer that plays important role in providing
support to humans for their survival. It is an essential environmental factor.
The ultra-violet (UV) rays emitted from sun are captured by ozone and
thereby provide a stable ontological structure in the biosphere. Various
anthropogenic activities such as emissions of CFCs, HCFCs and other
organo-halogens lead to the depletion of ozone. The ozone depletion
resulted in many adverse effects on plants, humans and environment with
increased number of bronchial diseases in humans. The mutations caused
by UV rays result in variation in morphogenic traits of plants which ultimately
decreases crop productivity. Large ozone depletions in the polar region
become year-round rather than just seasonal as is currently observed in the
Antarctic ozone hole. The tropical cooling that triggers the ozone collapse is
caused by an increase of the tropical upwelling. In response to ozone
changes, ultraviolet radiation increases, more than doubling the erythemal
radiation in the northern summer mid latitudes by 2060. However, UV
radiation is required in optimum intensity for both plants and animals. This
review takes into an account the wide ranging effects of ozone depletion
with a majority of them being detrimental to the plant system.
ABSTRACT

3. • INTRODUCTION
• OZONE
• OZONE LAYER
* Formation of Ozone layers
* Functions of the Ozone layer
* Ozone Layer Depletion
* Ozone hole
• CAUSES OF OZONE LAYER DEPLETION
• EFFECTS OF OZONE DEPLETION
• REMEDIATION FOR OZONE LAYER DEPLETION
• CONCLUSION
PRESENTATION OUTLINEPRESENTATIO OUTLINE

4. There are visible and invisible radiation coming into
the earth through the atmosphere, this includes the
visible red light and the invisible radiations (gamma,
radio, ultraviolet rays, infrared, and x-ray). Of these
invisible rays the ultraviolet ray is a harmful ray which
when transmitted into the earth harms living beings.
This therefore become a matter of concern to us
humans since we count among the living beings.
So, on a closer study, it was discovered that the ozone
layer, a layer found in the stratosphere, shields us from
the harmful effects of this radiation by stopping its
penetration; what a joy! Unfortunately it was discovered
that this ozone layer suffers depletion which finally
makes it unable from stopping uv penetration. What a
danger!
This seminar will therefore discuss the nature of this
ozone layer, causes of its depletion, the effects of its
depletion on living beings and the possible remedy to
these effects.
INTRODUCTION

5. GLS 429 - Seminar
Ozone
* Ozone, or tri-oxygen, is an inorganic molecule with the chemical
formula OO2. It is a pale blue gas and has a distinctively pungent
smell. It is much less stable than the diatomic allotrope O2. Ozone
is formed from di-oxygen by the action of ultraviolet light and also
atmospheric electrical discharges, Ozone absorbs a band of
ultraviolet radiation called UVB.
* In total, ozone makes up only 0.6 ppm of the atmosphere.
* The ozone layer is a consequence of oxygen-only chemistry. It
formed once photosynthetic marine organisms (cyanobacteria)
began “polluting” the atmosphere with oxygen.
Resonance Lewis Structure of the Ozone Molecule

6. OZONE LAYER
• The ozone layer also called ozone shield or
stratospheric Ozone.
• A region of Earth's stratosphere that absorbs most of
the Sun's ultraviolet (UV) radiation.
• It contains high concentrations of ozone (O3) relative
to other parts of the atmosphere, although still very
small relative to other gases in the stratosphere. The
ozone layer contains less than 10 parts per million of
ozone, while the average ozone concentration in
Earth's atmosphere as a whole is only about 0.3 parts
per million.
• The ozone layer is mainly found in the lower portion of
the stratosphere, from approximately 20 to 30
kilometres (12 to 19 mi) above Earth( though it varies
seasonally and geographically).

7. 7
• The thickness of the ozone layer is measured in
Dobson Units(DU). and 100 DU = 1 mm.
“Normal” thickness of the ozone layer is ~ 3 mm
(300 DU), but the average ozone layer’s
thickness above Latvia is between 200 and 500
DU.
OZONE LAYER (contd.)

8. 8
• The ozone layer prevents the heat
energy reflected by the Earth's surface
from being re-radiated into space. This
process traps heat on the Earth and
keeps it warm.
• The ozone layer protects all living
things on Earth by absorbing some
of the harmful UV rays of the sun.
FUNCTIONS OF THE OZONE
LAYER

9. 9
FUNCTIONS OF THE OZONE
LAYER(contd.)
• Ozone layer is known as the earth’s
umbrella.

10. OZONE DEPLETION
• Ozone depletion or ozone layer
deterioration is simply the breakdown of
the ozone.
• It is decrease in the concentration of
ozone and thinning of the Ozone layer.

11. *A little demonstration of ozone layer
Depletion using boiled water and a chewed
gum.

12. Antarctic Ozone Hole
Ozone Hole
• The ozone hole is
defined as the area
having less than 220
dobson units (DU) of
ozone in the
overhead column
(i.e., between the
ground and space).

13. 13
Ozone Production
( >50km)
Ozone Destruction
(50-15km)

14. THE CAUSES OF OZONE LAYER
DEPLETION
• Natural Factors: Temperature, Weather,
Latitude and Altitude. Also, substances
ejected by natural events(volcanic eruptions).
However, natural phenomena cannot explain
the current levels of ozone depletion.
• Scientifically, ozone is being destroyed by a
group of manufactured chemicals, containing
chlorine and/or bromine.
• These chemicals are called "ozone-depleting
substances" (ODS). And they are;

15. • CFCs,
• HCFCs,
• halons,
• methyl bromide,
• carbon tetrachloride, and
• methyl chloroform.
Ozone-Depleting Substance(s) (ODS):
THE CAUSES OF OZONE LAYER
DEPLETION (contd.)

16. Effects of the Ozone Hole
Effects of the Ozone
Hole
• Skin cancer(on man &Animal)
• Eye Cataracts,
• Weakening of immunity,
• Decline in crop production(the
phytoplankton & Zooplankton as in fish
hauls),
• DNA damage , and
• Sunburn in animals.

17. REMEDIATION FOR OZONE LAYER
DEPLETION
• Montreal Protocol (1987) – phase-out of
CFCs and replacement with HCFC.

18. OTHER WAYS OF REMEDIATION.
• Keep your automobile well tuned and
maintained.
• Carpool, use mass transit, walk, bicycle,
and/or reduce driving, especially on hot
summer days.
• Be careful not to spill gasoline when filling up
your car or gasoline-powered lawn and
garden equipment. During the summer, fill
your gas tank during the cooler evening
hours.

19. • Make sure your car's tires are properly
inflated and your wheels are aligned.
• Participate in your local utility's energy
conservation programs.
• Seal containers of household cleaners,
workshop chemicals and solvents, and
garden chemicals to prevent VOC from
evaporating into the air. Dispose of them
properly.
OTHER WAYS OF
REMEDIATION(Contd.).

20. • The threat posed by ozone layer depletion is
an unusual environmental issue. Unlike many
other environmental problems, it potentially
affects the well-being of every individual in
every country. It is neither a developed
country problem nor a developing country
problem; it is a global problem. As such,
countries should regulate the production or
uses made of CFCs and other ODS in order
to reduce further depletion of the ozone layer
enhancing its recovery.
CONCLUSION

21. REFERENCE
Brady et al, 1994. B.B. Brady, E.W. Fournier, L.R. Martin, and R.B.
Cohen, Stratospheric Ozone Reactive Ozone Reactive Chemicals
Generated by Space Launches Worldwide, Aerospace Corporation
Report No. TR-94(4231)-6, Nov. '94
Brady et al, 1995. B.B. Brady & L.R. Martin, Modeling Solid Rocket
Booster Exhaust Plumes in the Stratosphere with SURFACE
CHEMKIN, Aerospace Corporation Report No. TR-95(5231)-9, Sept.
’95
Denison et al, 1994. M.R. Denison, J.J. Lamb, W.D. Bjorndahl, E.Y.
Wong and P.D. Lohn, "Solid Rocket Exhaust in the Stratosphere:
Plume Diffusion and Chemical Reactions", J. of Spacecraft and
Rockets, Vol. 31, pp. 435-442, May-June '94
Hanning-Lee et al, 1996. M.S. Hanning-Lee, P.M. Felker, J.A. Syage,
The Potential for Ozone Depletion in Solid Rocket Motor Plumes by
Heterogeneous Chemistry, U. of Calif. Los Angeles with The
Aerospace Corporation & TRW Space & Electronics Group, Dec ‘95
(Revised: Aug. '96)

22. NASA, 1994. NASA’s UARS Confirms CFCs Caused Antarctic
Ozone Hole, NASA Press Release 94-215, Washington, D.C.,
Dec. ‘94.
Pergament et al, 1977. H.S. Pergament, R.I. Gomberg, and I.G.
Poppoff, "NOx Deposition in the Stratosphere from the Space
Shuttle Rocket Motors," Appendix G of Proceedings of the
Space Shuttle Environmental Assessment Workshop on
Stratospheric Effects, NASA Technical Memorandum X-58198,
NASA, Houston, TX, Jan. ‘77.
Prather et al, 1990a. M. J. Prather, M. M. Garcia, A. R. Douglass,
C. H. Jackman, M. K. W. Ko and N. D. Sze, "The Space
Shuttle's Impact on the Stratosphere," Journal of Geophysical
Research, Vol. 95, pp. 18,583-18,590, 1990.
REFERENCE

23. GLS 429 - SEMINAR
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