Chlorofluorocarbons (CFCs) are man-made gases that do not occur naturally and contain carbon, chlorine, and fluorine. CFCs are involved in both ozone depletion and the greenhouse effect. They are harmful because they destroy ozone in the stratosphere, which protects the earth from UV radiation. The Montreal Protocol was established in 1987 to phase out the production of CFCs and other ozone depleting substances to help the ozone layer recover.

1. TO THE PRESENTATION
MAHDI HASAN
ID-ER17050

3.  Chlorofluorocarbon is an organic compound that does not
occur naturally. They are man-made gas.It contains carbon,
chlorine, and fluorine, produced as a volatile derivative of
methane ethane, and propane.
 CFC is also one of those gases involved in the greenhouse
effect. It is particularly harmful because of its destructive
reactions with ozone particles, which protects the earth from
UV radiations.

4.  Refrigerators and Air Conditioners
 Aircraft Halon
 Aerosol Sprays
 Foams
 Others

5.  Ozone depletion
Man-made compounds such as chlorofluorocarbons
(CFCs), hydrofluorocarbons (HCFCs) and halons
destroy ozone in the upper atmosphere (stratosphere).
The stratospheric ozone layer makes life possible by
shielding the earth from harmful ultraviolet (UV-B)
rays generated from the sun. Decreased concentration
of stratospheric ozone allows increased amounts of
UV-B to reach the earth's surface.

6. Figure:Mechanism of Ozone Layer Destruction
by CFC in Stratosphere

7.  While acting to destroy ozone, CFCs and HCFCs also act to
trap heat in the lower atmosphere ,causing the earth to warm
and climate and weather to change. HFCs, which originally
were developed to replace CFCs and HCFCs, also absorb and
trap infrared radiation or heat in the lower atmosphere of the
earth.
 HFCs, CFCs and HFCs contribute an estimated 11.5% to
present-day effect of GHGs on climate and climate change.

8.  Inhaling CFCs
Inhalation of CFCs affects the central nervous system, according
to the New Hampshire Department of Environmental Sciences.
The result is intoxication similar to that produced by alcohol,
including lightheadedness, headaches, tremors and convulsions
 Immune System Deficiency
CFCs can generally impair the human immune system, and
scientists have linked direct expose to problems with the central
nervous system.These problems might include difficulty
Breathing or injury to the heart, kidneys and liver.
 Skin Cancer and Eye Damage

9.  Air-Conditioning
At present, most domestic systems use HCFC-22, and while
some existing industrial or commercial systems still use CFCs,
equipment is being progressively retrofitted with an increasing
uptake of HCFCs and HFCs.
 Refrigeration
HCFCs have proven to bean efficient and easily accepted
alternative in a number of applications, having many of the same
characteristics as CFCs but with a reduced effect on the ozone
layer. HCFCs however are also ozone depleting – although to a
much lesser extent than CFCs .

10.  Foam
A range of alternatives have replaced CFCs used in these
applications including methylene chloride, hydrocarbons and
HCFCs. HCFCs, particularly HCFC-141b, are an acceptable
interim alternative that has replaced CFC for rigid polyurethane
foam manufacture.
 Aerosol Products
In the 1980s the majority of aerosol products were converted
from using CFCs to hydrocarbon propellants. Medical and
technical specialty products using CFC-12, CFC-11, CFC-113
have converted to alternatives including aqueous sprays and
HFCs,

11.  Montreal protocol
The Montreal Protocol on Substances that Deplete the Ozone Layer
(the Montreal Protocol) is an international agreement made in 1987.
It was designed to stop the production and import of ozone
depleting substances and reduce their concentration in the
atmosphere to help protect the earth's ozone layer.
 Montreal Protocol control measures
1.With the exception of a very small number of internationally
agreed essential uses that are considered critical to human health
and/or laboratory and analytical procedures.
2.Based on 1989 HCFC consumption with an extra allowance
(ozone depletion potential weighted) equal to 2.8% of 1989 CFC
consumption.

12. 3. Up to 0.5% of base level consumption can be used from 2020
until 2030 for servicing existing
refrigeration and air conditioning equipment.
4. Up to 2.5% of base level consumption can be used until 2040
for servicing existing equipment,
subject to review in 2025.
5.All reductions include an exemption for pre-shipment and
quarantine uses.
6.Some countries with economies in transition have a slightly
delayed start to the HFC phasedown, but catch up to other
developed party commitments by 2029.
7. Some developing countries have a delayed start to the HFC
phase-down, starting their freeze in
2028 instead of 2024 and finishing at 85% reduction by 2047

13. Conclusion:
Climate change is not our first planetary pollution crisis. Almost
40 years ago, scientists discovered that chemicals called
chlorofluorocarbons (CFCs) were destroying the fragile ozone
layer that protects us from the sun’s dangerous ultraviolet
radiation.If we had failed to protect the ozone layer, hundreds of
millions of people around the world would be condemned to
suffer dreadful diseases, including skin cancer, eye cataracts and
immune system disorders. And we would be enduring
devastating disruption of world food production, especially in
the developing world.

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