Ozone Layer
O3
 Absorbs the sun’s UV radiation
 Stratosphere
 20-50km above the Earth’s
surface

Ultraviolet Radiation
Good: Causes Vitamin D production in
humans
 Bad: Causes skin cancer, cataracts,
and mutations, blindness, sunburn.
 Severe crop damage
 Destroy microorganisms at bottom
of food chain

Ozone Depletion

Antarctic Ozone Hole

http://ozonewatch.gsfc.nasa.gov/
The Chemistry
CFC’s = Chlorofluorocarbons
 CFC’s in UV radiation release a Cl
 Cl + O3  ClO + O2
 ClO + O  Cl + O2



IT’S A CYCLE!!!
US Banned CFC’s in many products in 1978
Montreal Protocol
Complete Phaseout of CFC’s by 1996
Good Example of countries coming
together for the benefit of the
environment
Common name
Compound
Active
Element
Applications
Cl
refrigeration and aerosol
Ozone CFCl
depleting
substances
chlorine sprays
CFCs
(chlorofluorocarbons)
Freon-11
CFCs
(chlorofluorocarbons)
Freon-12
CFCs
(chlorofluorocarbons)
Freon-113
CFCs
(chlorofluorocarbons)
Freon114
halons
methylchloroform
carbon tetrachloride
3
CF2Cl2
Cl
chlorine
refrigeration and aerosol
sprays
C2 F3 Cl3
Cl
chlorine
refrigeration and aerosol
sprays
C2 F4 Cl2
Cl
chlorine
refrigeration and aerosol
sprays
Cl and Br
CF3Br, CF2BrCl, chlorine
fire extinguishers
C2 F4 Br2
and
bromine
1,1,1-TCE
Cl
cleaning solvent and widely
(trichloroethane) chlorine used as an industrial solvent.
CCl4
Cl
chlorine
fire extinguishers, cleaning
solvent and widely used as
an industrial solvent for
lacquers, varnishes and
various organic compounds.


Question: What does the hole in
the ozone layer mean for us?
What can we do to protect
ourselves from UV radiation?
GRAPH: How has the Antarctic
Ozone Hole Changed over
time???