Ozone O3O3 Ozone Depletion Ozone (O 3 ) –Absorbs harmful UV radiation from sun ozone is produced...
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Transcript of Ozone O3O3 Ozone Depletion Ozone (O 3 ) –Absorbs harmful UV radiation from sun ozone is produced...
Ozone Depletion
• Ozone (O3)– Absorbs harmful UV radiation from sun
ozone is produced during lightning storms
• Chlorofluorocarbons (CFC’s) destroy ozone– CFC’s production was banned in 1977– CFC’s “live” for hundreds of years
banned in U.S. in 1996
Depletion of the Ozone Layer
Ozone (O3) in upper atmosphere blocks ultraviolet (UV) light from Sun.
UV causes skin cancer and cataracts.
O3 depletion is caused by chlorofluorocarbons (CFCs).
O3 is replenished with each strike of lightning.
aerosol propellantsUses for CFCs:
refrigerants
CFCsCFCs
Freon (CFC’s)
Trichlorofluoromethane (Freon-11)
Dichlorodifluoromethane (Freon-12)
F
Cl
CCl Cl
Cl
F
CCl F
CFC-11 and CFC-12 are odorless, nontoxic, nonflammable, and very stable.
chlorofluorocarbons
Mechanism of Ozone Depletion
• Initiation CCl2F2 Cl + CF2Cl
• Propagation Cl + O3 ClO + O2
ClO + O Cl + O2
• Termination
Solar radiation
A single chlorine molecule can destroy thousands of ozone molecules.
.
..
. . .
.
“free radical”
Ozone Hole Grows Larger
Ozone hole has increased 50% from 1975 - 1985
Ozone, O3
Monthly Change in OzoneTOMS Total Ozone Monthly Averages
Ultraviolet Radiation
• Skin cancer
• Cataracts
• Sun-glassesUVA & UVB protection
Greenhouse Effect vs. Ozone Hole
Greenhouse Effect
Depletion of O3
(ozone layer)...causes skin cancer
and cataracts
Caused by CFC's(chlorofluorocarbons)
destroying ozonelayer
Replace CFC's inAC & refrigerators
Global Warmingby trapping heat
on Earth
Caused by buildup of CO2
carbon dioxide
Plant trees toslow down and burn
less fossil fuels that produce CO2
Alike Different
Related toEarth's
Atmosphere
Man-made problem
Environmental Issues
OzoneHole
Different
Topic Topic