Methane and CFCs both contribute to ozone depletion and global warming. Methane is a potent greenhouse gas that is 21 times more harmful than carbon dioxide. It reacts with chlorine in the stratosphere, protecting ozone, but also attacks ozone directly. CFCs destroy ozone by releasing chlorine atoms when exposed to UV radiation, which then break down ozone molecules. While CFCs have been phased out under the Montreal Protocol, methane emissions continue from sources such as livestock, landfills, and fossil fuel extraction. Both gases trap heat in the atmosphere and are contributing to rising global temperatures.

1. How Alkanes affect the Ozone
Layer
By: Aubrey Vale Sagun

2. The Ozone Layer
• The stratospheric ozone layer shields life
on Earth from the Sun’s harmful ultraviolet
radiation. Chemicals that destroy ozone
are formed by industrial and natural
processes. With the exception of volcanic
injection and aircraft exhaust, these
chemicals are carried up into the
stratosphere by strong upward-moving air
currents in the tropics.

5. Substances that contributes to
the depletion of the ozone layer
• The major ozone-depleting substances are
chlorofluorocarbons (CFCs), halons,
methane (CH4) and nitrous oxide (N2O).

6. Methane
• Methane is the simplest hydrocarbon—a single carbon
atom surrounded by four hydrogen atoms.
• Methane is a colorless, odorless gas with a wide
distribution in nature. It is the principal component of
natural gas.
• Methane plays a double-edged role as an
environmentally important trace gas, both protecting and
altering the earth's atmosphere.
• Methane is a relatively potent greenhouse gas with a
global warming potential.

7. • Methane acts as a greenhouse gas (a gas
that traps heat from the sun within earth’s
atmosphere) and it also attacks ozone.

8. CH4

9. Negative side of Methane
• On methane's negative side, it directly
increases the greenhouse effect in two
ways. First, methane absorbs infrared
radiation well, 20 times better than CO2.
Secondly, increased methane
concentrations increase the amount of
water vapor in the stratosphere, further
trapping heat like the panes
of a greenhouse.

10. • When burned, methane creates nitrous
oxide (NOx), which is one of the most
detrimental compounds to our environ
ment. NOx is more than 310 times mo
re harmful to the atmosphere than carb
on dioxide.

11. Positive side of Methane
• On methane's positive side, it protects the
ozone layer. In the stratosphere methane
reacts with and
removes chlorine atoms. If the chlorine did
not react with methane, methane would
quickly react with
ozone, thus destroying it.

12. How does Methane affect the
ozone layer
• Methane is one of the most harmful green
house gases, twenty one times more harmful
than carbon dioxide.
• The heating effects of methane on the oz
one is 60 percent greater than that of car
bon dioxide
• Methane acts as a greenhouse gas (a gas that
traps heat from the sun within earth’s
atmosphere) and it also attacks ozone.

14. • Why do I care? Methane is the second
most abundant greenhouse gas. If you
contribute to landfills, use natural gas, or
own livestock, you are contributing to that
concentration.

15. Other uses of Methane

16. Methane as bio fuel

17. Effect of Ozone depletion
• The 11 percent methane increase ''will
make the ozone hole over Antarctica more
severe,'

18. Global warming
And
Climate Change

24. Sources of Methane
• Domesticated livestock such as cattle, buffalo, sheep, goat
and also camel produce significant amounts of methane as
part of their normal digestive processes.
• Wastewater treatments
The treatment of sewage and industrial wastewater in
anaerobic conditions produces methane emissions.
• Landfills
Methane is generated in landfills and open dumps as w
aste decomposes under anaerobic (without oxygen) con
ditions.

27. Prevention of Methane emission
• There's no obvious way to control
methane from natural wetlands other than
to keep them from overheating. But at
least half of methane emissions are from
human activities, ranging from cattle-
rearing and natural gas exploration to coal
mining.

28. CFC
The
Chlorofluorocarbon

29. CFC chlorofluorocarbon
• any of a class of compounds of carbon,
hydrogen, chlorine, and fluorine, typically
gases used in refrigerants and aerosol
propellants. They are harmful to the ozone
layer in the earth's atmosphere owing to
the release of chlorine atoms upon
exposure to ultraviolet radiation.

31. How does CFC affect the ozone
layer
• When UV radiation hits a CFC molecule it
causes one chlorine atom to break away. The
chlorine atom then hits an ozone molecule
consisting of three oxygen atoms and takes
one of the oxygen molecules, destroying the
ozone molecule and turning it into oxygen.
When an oxygen molecule hits the molecule
of chlorine monoxide, the two oxygen atoms
join and form an oxygen molecule

33. Uses of CFC
• In the past, CFCs have been widely used as
coolants in refrigeration and air conditioners,
as solvents in cleaners, particularly for
electronic circuit boards, as a blowing agents
in the production of foam (e.g. fire
extinguishers), and as propellants in
aerosols. Indeed, much of the modern
lifestyle of the mid-20th century had been
made possible by the use of CFCs.

34. Sources of CFC

37. Possible health concerns
• Excessive exposure to some
chlorofluorocarbons may affect the brain,
eye, heart, kidney, liver, pancreas,
reproductive system and skin. The
Environment Agency aims to ensure that
environmental exposures are too low to
harm human health.

38. Reduction of CFC
• Because CFCs contribute to ozone
depletion in the upper atmosphere, the
manufacture of such compounds has been
phased out under the Montreal Protocol,
and they are being replaced with other
products such as hydrofluorocarbons
(HFCs)

39. The Montreal Protocol
• The Montreal Protocol on Substances that
Deplete the Ozone Layer (a protocol to the
Vienna Convention for the Protection of the
Ozone Layer) is an international treaty
designed to protect the ozone layer by
phasing out the production of numerous
substances that are responsible for ozon
depletion. It was agreed on 16 September
1987, and entered into force on 1 January
1989,

40. • Researchers generally agree that by trapping
solar heat in a greenhouse, methane, carbon
dioxide and other pollutants are likely to
warm the earth's lower atmosphere by a few
degrees in the next half century.
• They fear this greenhouse effect may cause
crop-threatening droughts and partly melt
polar ice caps, raising sea levels.

42. CFC and Methance as greenhouse gases