International Day for the Preservation of the Ozone Layer
Act Ozone Friendly - Stay Sun Safe!  

Reflecting the urgent need to preserve the ozone layer, which filters sunlight and prevents the adverse effects of ultraviolet radiation reaching the Earth's surface, thereby preserving life on the planet. Designated by the United Nations to commemorate a very important day in world history. In 1987, 24 countries met in Montreal and announced to the world that the time had come to stop destroying the ozone layer. In so doing, these countries committed themselves, via the Montreal Protocol on Substances that Deplete the Ozone Layer - to rid the world of substances that threaten the ozone layer.

Why was international action to protect the ozone layer so necessary? The answer is simple: life depends on it.

The ozone layer acts as a giant umbrella over the earth and protects us from exposure to the sun's ultraviolet radiation. When the ozone layer thins, high levels of UV radiation reach the earth's surface and threaten our health and our environment dramatically. Each 1 per cent reduction of the ozone layer leads to a 2 per cent increase in the incidence of non-melanoma skin cancer as well as to a higher incidence of cataracts and blindness.

Ozone, a very unstable molecule made up of three oxygen atoms, constitutes a layer in the atmosphere, at 15 to 50 km above the Earth's surface, that filters out much of the Sun's ultraviolet rays. Excessive exposure to UV radiation causes skin cancer, eye cataracts and even blindness, as well as the destruction of plant life.

Some 90 chemical products used in farming and industry, particularly for refrigeration, air conditioning and fire-fighting equipment, destroy ozone molecules when they reach the stratosphere, especially near the Earth's poles.

Among these substances are CFCs (chlorofluorocarbons), halons, carbon tetrachloride, hydrobromofluorocarbons, methyl bromide and bromochloromethane.

When they arrive in the upper reaches of the atmosphere, catalytic chemical reactions occur that break down ozone. Scientists first identified these reactions 40 years ago over Antarctica, and they also occur over the North Pole.

To date, 184 countries have ratified the Montreal Protocol, which seeks the elimination of substances that destroy the ozone layer as its final objective.