2. • Since 1995, on 16 September each
year, the International Day for the
Preservation of the Ozone Layer is
celebrated.
• This date has been designated by
the United Nations General
Assembly, to celebrate the signing
of the Montreal Protocol on
Substances that Deplete the Ozone
Layer.
3. This year marks the 30th anniversary of
the Vienna Convention for the Protection
of the Ozone Layer, 22 March 1985 an
important milestone in the protection of
the ozone layer.
The theme for the celebration of the
anniversary and this year’s International
Day for the Preservation of the Ozone
Layer to be marked on 16 September is,
“30 years of healing the ozone together.”
The theme is supported by the slogan,
“Ozone: All there is between you and UV.”
4. • The ozone layer is a layer in Earth's
atmosphere containing relatively high
concentrations of ozone (O3).
• Ozone: a gas composed of three atoms
of oxygen and is a bluish gas that is
harmful to breathe.
• The ozone layer, situated in the 15 to
30 km above Stratospheric
atmospheric zone the earth's surface.
• The ozone layer absorbs 97–99% of
the Sun's medium-
frequency ultraviolet light , which
potentially damages exposed life
forms on Earth.
Ozone layer and its importance
5. How it is depleting
• In 1985 a marked decrease
in stratospheric ozone over
the South Pole, in the
Antarctic was found.
• The depletion appeared
during the southern
hemisphere's spring
(October and November)
and then filled in.
• Ozone depletion, to a lesser
degree, now occurs in the
mid-latitudes also.
• The amount of stratospheric
ozone over the northern
hemisphere has been
dropping by 4% per decade.
6. “Ozone-depleting substances" (ODS)
• Certain chemicals (such as chlorofluorocarbons, hydro-
chlorofluorocarbons and halons) are recognized as ozone-depleting
substances (ODS) because they breakdown in the stratosphere and
release chlorine or bromine, which destroy the stratospheric ozone
layer.
• Most ODS are also greenhouse gases.
• Ozone-depleting substances are generally used as refrigerants, foam
blowing agents, solvents, aerosol spray propellants, fire extinguishing
agents and chemical reactants etc.
7. Too much ultra-violet light can result in
• Skin cancer
• Eye damage such as cataracts
• Immune system damage
• Reduction in phytoplankton
• Damage to the DNA in various
life-forms
• Possibly other things too that
we don't know about at the
moment
DNA & UV-B
Effects on Human
Health
8. How individuals can be ozone-friendly
• Do not purchase or use any commercial or
domestic refrigerator that uses ODS as a
refrigerant.
• Do not purchase or use any foam that has been
produced using ODS as a blowing agent
• Do not purchase or use aerosols that contain CFCs
as propellants.
• Convert the usage of ODSs to other ozone-friendly
alternatives. Some of them are given in the table.
