I
A Walk Through
Science
1928
Scientists
synthesize
chlorofluorocarbons (CFCs).
1974
Nobel prize winners Mario Molina
and Sherwood Rowland discover
that CFCs can break down
stratospheric ozone.
1973
1975
Scientists discover
that bromine, used
in fire-retarding
halonsand agricul-
tural fumigants, is
a potent ozone-
depleting
substance.
Scientists detect CFCs in
atmosphere.
1985
British Antarctic Survey
team discovers Antarctic
ozone hole (7.3 million
square miles), marking
the first evidence of stratos-
pheric ozone depletion.
Scientific research reveals
stratospheric ozone layer
depletion has adverse envi-
ronmental and human
health effects.
The ozone layer in the upper atmosphere acts like a shield—
protecting life on Earth from the sun's harmful ultraviolet radia-
tion. In 1985, scientists observed a thinning of the ozone layer
over Antarctica. Since then, research has shown that ozone
depletion occurs over every continent.
In 1987, world leaders signed a landmark environmental treaty,
the Montreal Protocol on Substances That Deplete the Ozone
Layer. Today, almost every country in the world has ratified the
treaty and is phasing out the production and use of chlorofluo-
rocarbons (CFCs) and other ozone-depleting substances.
1991
International scientists
agree that CFCs are
depleting the stratos-
pheric ozone layer in
the northern and south-
ern hemispheres.
2000
Japan Meteorological Agency reports
the hole in the stratospheric ozone
layer over the Antarctic is at its
largest to date—more than twice the
size of Antarctica.
2006
The ozone hole is reported to be the
biggest ever, exceeding that of 2000.
2060-2075
Earliest timeframe
projected for the ozone
layer to recover.
Action
%. > 1975
SC Johnson announces
corporate phaseout
of CFCs as aerosol
product propellents.
1976
United Nations Environmental
Programme (UNEP) calls for an
international conference to dis-
cuss an international response
to the ozone issue.
1978
U.S. bans non-essential uses of
CFCs as a propellant in some
aerosols (e.g., hair sprays,
deodorants, antiperspirants).
Canada, Norway, and Sweden
follow with a similar ban.
United States
Environmental Protection
Agency
Stratospheric Protection Division
Office of Air and Radiation
www.epa.gov/ozone
EPA-430-H-07-002
1981
UNEP develops a global
convention to protect
the ozone layer.
1987
Twenty-four
countries sign
the Montreal
Protocol on
Substances That
Deplete the
Ozone Layer.
1989
All developed coun-
tries that are parties
to the Montreal
Protocol freeze
production and
consumption of CFCs
at 1986 levels.
1996
U.S. eliminates
production and
import of CFCs,
carbon tetrachloride,
trichloroethane, and
hydrobromofluorocarbons.
1994
U.S. eliminates
production and
import of halons.
1993
DuPont™ announces that it
will halt its production of
CFCs by the end of 1994.
1992
U.S. announces an acceler-
ated CFC phaseout date of
December 31,1995, in
response to new scientific
information about ozone
depletion.
1990
Clean Air Act Amendments, includin'
Title VI for Stratospheric Ozone
2004
All developed coun-
tries reduce con-
sumption of
hydrochlorofluorocar-
bons (HCFCs) by 35
percent from baseline
levels.
2010
All developed
countries
reduce con-
sumption of
HCFCs by 65
percent from
baseline levels.
2015
All developed
countries
reduce con-
sumption of
HCFCs by 90
percent from
baseline levels.
2002
All developing countries that
are parties to the Montreal
Protocol freeze methyl
bromide production at
1995-1998 average level.
2030
All developed
countries
scheduled to
complete the
phaseout of
ozone deplet-
ing substances.
2040
All developing countries
that are parties to the
Montreal Protocol
scheduled to completely
phase out HCFCs.
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A
Progress in Ozone
A
A
Computers
Then: Solvents containing CFCs and methyl
chloroform were used to clean circuit boards
during their production.
Now: Some companies have eliminated the
need to clean circuit boards during their pro-
duction. Others use water or have temporarily
switched to HCFCs.
Polystyrene Cups and
Packing Peanuts
Then: Some polystyrene cups and foam
packing "peanuts" were made using CFCs.
Now:These products are made with materials
that do not deplete the ozone layer.
Aerosol Cans
Then: CFCs were the propellant
used in various spray cans.
Now: Pumps and alternative propel-
lants using hydrocarbons are being
used.
Central Air
Conditioners
Then: CFCs were used as
the coolant in household
air conditioners.
Now: HCFCs and MFCs
have replaced CFCs.
Furniture
Then: Foam-blowing agents
containing CFCs were used
in furniture making.
Now: Water-blown foam is
being used.
Refrigerators
Then: CFCs were used in refrigerator
coolants and foam insulation.
Now: MFCs have replaced CFCs, and
substitutes are on the horizon that
will not deplete the ozone layer.
Prior to the 1980s, ozone-depleting substances were all
around us. But now, individuals, businesses, organiza-
tions, and governments worldwide are developing and
using substitutes that are safer for the ozone layer, the
environment, and human health.
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Fire Extinguishers
Then: Halons were commonly used in
hand-held fire extinguishers.
Now: Conventional dry chemicals, which
don't deplete the ozone layer, and water
have replaced halons. MFCs are also used.
CFCs - Chlorofluorocarbons
HCFCs - Hydrochlorofluorocarbons
MFCs - Hydrofluorocarbons
Car Air Conditioners
Then: CFCs were used as the coolant
in automobile air conditioners.
Now: MFCs have replaced CFCs.
Degreasers
Then: CFCs or methyl chloroform were used
in many solvents for degreasing.
Now: Water-soluble compounds and hydrocar-
bon degreasers that do not deplete the ozone
layer are available for many applications.
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