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Prosperity People

and sustainability

Planet

About ozone

The ozone layer is a layer in the Earth’s atmosphere which contains relatively high concentrations of ozone (O3). This layer absorbs 93-99% of the sun’s high frequency ultraviolet (UV) light, which is potentially damaging to life on Earth. The ozone layer is located mainly in the lower portion of the strato-sphere from approximately 10 – 50 kms above the Earth, though the thickness varies seasonally and geographically.

About World Ozone Day

In 1994, the United Nations General Assembly voted to designate 16 September as World Ozone Day, to commemorate the establishment of the Montreal Protocol on this date in 1987. The theme for 2009 is “Universal participation: Ozone protection unifies the world”.

Observe WOrld OzOne day 16 september 2009

About ozone and the 3Ps

As the ‘Earth’s sunscreen’, ozone is important to sustainable development:

Planet — Most plants have natural mech-anisms that provide some form of UV shielding, but do not always have sufficient amounts for com-plete protection and can suf-fer detrimental effects. In clear oceans and lake waters, UV radiation can penetrate and affect shallow-water fish and plankton.

People — Acute exposure to solar UV radiation causes sunburn and can result in damage to eyesight and, in the long term, skin cancer. It has also been found that UV radiation can nega-tively affect the immune system.

Prosperity —The potential consequenc-es for Prosperity are the result of the impacts to People and Planet and the financial losses incurred in mitigating these impacts.

About ozone depletion

Ozone is the Earth’s natural sunscreen, absorbing and block-ing most of the incoming UV radiation from the sun and protecting life from DNA-damaging radiation. The gas is naturally created and replenished by a photochemical reaction in the upper atmosphere where UV rays break oxygen molecules (O2) into in-dividual atoms that then recombine into three-part molecules (O3) – that is, ozone. As ozone is moved around the globe by upper level winds, it is slowly depleted by naturally occur-ring atmospheric gases. It is a system in natural balance.

But the chlorofluorocarbons (CFCs) in refrigerants and the inert carriers for aerosol sprays, invented in 1928, upset that balance. Researchers discovered in the 1970s and 1980s that while CFCs are inert at the Earth’s surface, they are quite re-active in the stratosphere (10 – 50 kms altitude, or 6 – 31 miles), where roughly 90 percent of the planet’s ozone accumulates. UV radiation causes CFCs and similar bromine compounds in the stratosphere to break up into elemental chlorine and bromine that readily destroy ozone molecules. Worst of all, such ozone depleting substances can reside for several decades in the stratosphere before breaking down.

About the Montreal Protocol

In the 1980s, ozone-depleting substances opened a wintertime “hole” over Ant-arctica and opened the eyes of the world to the effects of human ac-tivity on the atmosphere. By 1987, the World Meteorological Organization and Unit-ed Nations Environment Program had brought together scientists, diplomats, environmental advocates, governments, industry representatives, and non-governmental organizations to forge an agreement to phase out the chemicals. In January 1989, the Montreal Protocol (full name: The Montreal Protocol on Substances That Deplete the Ozone Layer) was brought into force, the first-ever international agreement on regulation of chemi-cal pollutants.

At Montreal, the participants agreed to freeze production of CFCs at 1986 levels and to reduce production by 50% by 1999. After a series of scientific expeditions to the Antarctic produced convincing evidence that the ozone hole was indeed caused by chlo-rine and bromine from manmade organohalogens, the Montreal Protocol was strengthened at a 1990 meeting in London. The participants agreed to phase out CFCs and halons entirely (aside from a very small amount marked for certain essential uses, such as asthma inhalers) by 2000. At a 1992 meeting in Copenhagen, the phase out date was moved up to 1996.

Scientists believe that if the Montreal Proctocol is adhered to, the ozone layer will recover by 2050. Due to its widespread adoption and implementation it has been hailed as an example of exceptional international co-operation.

Ozone-oxygen cycle in the ozone layer

“ Perhaps the single most successful international agreement to date has been the Montreal Protocol.” – Kofi Annan, Former Secretary General of the United Nations

The Montreal Protocol has been ratified by the three

major regions in which Sappi operates – Europe, North

America and South Africa.

At Sappi, we do not use ozone-depleting substances at

any of our manufacturing sites.

Sappi and ozone – at a glanceAbout the way forward

On 02 August 2003, scientists announced that the de-pletion of the ozone layer had slowed down signficantly over the previous decade due

to the international ban on CFCs. Three satellites and

three ground stations confirmed this view. Some break-

down can be expected to continue due to CFCs used by

nations which have not banned them, and due to gases

which are already in the stratosphere.

Ozone-oxygen cycle Source; Wikipedia

FAQ Q // What are CFCs?

A //

Q // What is the “ozone hole”?

A //

Q // Why does the ozone hole occur in spring and why is it more pronounced in Antarctica?

A //

Chlorofluorocarbons (CFCs), invented by Thomas Midgley in the 1920s, were developed as a safe, non-toxic, non-flammable alternative to dangerous substances like ammonia for purposes of refrigeration and spray-can propellants. Their usage grew enormously over the years.

However, one of the elements that make up CFCs is chlorine. Very little chlorine exists naturally in the at-mosphere. But it turns out that CFCs are harmful because they introduce chlorine into the ozone layer. What happens is that the ultraviolet radiation at this altitude breaks down CFCs, freeing the chlorine. Under the proper conditions, this chlorine has the potential to destroy large amounts of ozone. This has indeed been observed, especially over Antarctica.

Given the longevity of CFC molecules, recovery times are measured in decades. It is calculated that a CFC molecule takes an average of 15 years to go from the ground level up to the upper atmosphere, and it can stay there for about a century, destroying up to one hundred thousand ozone molecules during that time.

Each year for the past few decades during the Southern Hemisphere spring, chemical reactions involving chlo-rine and bromine cause ozone in Antarctica to be destroyed, leading to the “ozone hole” – essentially a thinning of the ozone layer. It is a hole in the sense of a hole in the ground, that is, a depression; not in the sense of a hole in a wall.

Nasa images showing past and present ozone levels

NASA projections of stratospheric ozone concentrations if chlorofluorocarbons had not been banned

1974

2020

1994

2040

2009

2060

World Production of CFCs

The Dobson unit is named after Gordon Dobson, a researcher at the University of Oxford. In the 1920s, he built the first instrument to measure ozone, now called the Dobson ozone spectrophotometer. Currently, global average ozone is about 300 Dobson units. Before 1980, ozone less than 200 Dobson units was rarely seen.

The ozone hole occurs during the Antarctic spring, from September to early December, as strong westerly winds start to circulate around the continent and create an atmospheric vortex, or persistent large-scale cy-clone, at the Earth’s poles. The Antarctic vortex is more pronounced and persistent than the Arctic one because the distribution of land masses at high latitudes in the northern hemisphere gives rise to Rossby waves (wave-like patterns in the atmosphere) which contribute to the breakdown of the vortex. In the southern hemisphere, the topography is different, which means the vortex is less disturbed and explains why Antarctica is more affected by ozone depletion than the Arctic.