Precious Ozone The Size of it - Source

Precious Ozone The Size of it
What is ozone?
Ozone is a special form of oxygen with the chemical formula O3. The oxygen we breathe and that is so vital to life on earth is O2. Ozone constitutes a very small part of our atmosphere, but its presence is nevertheless vital to human well-being. Most ozone resides high up in the atmosphere, between 10 and 40km above Earth's surface. This region is called the stratosphere and it contains about 90% of all the ozone in the atmosphere.
Why do we care about atmospheric ozone?
Ozone in the stratosphere absorbs some of the Sun’s biologically harmful ultraviolet radiation. Because of this beneficial role, stratospheric ozone is considered “good” ozone. In contrast, excess ozone at Earth’s surface that is formed from pollutants is considered “bad” ozone because it can be harmful to humans, plants, and animals. The ozone that occurs naturally near the surface and in the lower atmosphere is also beneficial because ozone helps remove pollutants from the atmosphere.
The hole in the ozone layer
Following the publication of the findings of a British Antarctic Survey article in May 1985, the phenomenon of ozone depletion over Antarctica was referred to as the "ozone hole", a phrase first attributed to Nobel Prize winner Sherwood Rowland. The satellite image of the ozone hole has become a global symbol of this environmental threat that has helped mobilize public support for the Montreal Protocol. The work of atmospheric scientists and environmental researchers continues to play a paramount role in informing the policymaking under the Montreal Protocol. Images and scientific bulletins about ozone depletion are useful communication tools to the public about progress made and challenges ahead.
Latest ozone measurements
Global ozone map
Meteorological Service of Canada & Environment Canada
Status of the ozone layer over the South Pole
NASA Ozone Watch
Some Ozone Depleting Substances in Different Industry Sectors
Aerosols, Sterilants and Carbon Tetrachloride
CFCs are used in aerosol products, as sterilants of medical equipment, and in a range of miscellaneous applications including food freezing, tobacco expansion, fumigation and cancer therapy. Carbon tetrachloride is used as a feedstock in the production of CFC-11 and CFC-12, in the production of key pharmaceuticals and agricultural chemicals, and as a catalyst promoter. CFCs and carbon tetrachloride are ozone depleting substances whose production and consumption is controlled under the Montreal Protocol. With support from the Protocol's Multilateral Fund delivered by UNEP, UNDP, UNIDO, the World Bank and bilateral agencies, developing countries are phasing out these ozone depleting chemicals in this sector.
Foams
CFCs have been used extensively in the manufacture of polyurethane, phenolic, polystyrene and polyolefin foam polymers, used in many different products. Common blowing agents have included CFC-11, CFC-12, CFC-113 and CFC-114. CFCs are ozone depleting substances whose production and consumption is controlled under the Montreal Protocol. With support from the Protocol's Multilateral Fund delivered by UNEP, UNDP, UNIDO, the World Bank and bilateral agencies, developing countries are phasing out these ozone depleting chemicals in this sector.
Halons
Halon 1211 has been widely used in portable fire extinguishers. Halon 1301 has seen widespread use in fixed systems throughout the industrial, commercial, marine, defence, and aviation industries. Halon 2402 has primarily been used in the defence, industrial, marine and aviation sector in some countries. Halons are ozone depleting substances whose production and consumption is controlled under the Montreal Protocol. With support from the Protocol's Multilateral Fund delivered by UNEP, UNDP, UNIDO, the World Bank and bilateral agencies, developing countries are phasing out these ozone depleting chemicals in this sector.
The strategy for the halon sector essentially consists of two approaches: replacing halons with alternatives, and halon banking. Alternatives to halons include halocarbon alternatives, inert gases, water mist, fine particulate aerosols and streaming agents. In some cases, fire protection strategies may be re-considered and the need for halons eliminated. Halon banking, which includes recovery, recycling and establishing inventories, is used by companies and countries for managing existing halon supplies to cover remaining critical uses.
Source:
www.un.org/en/... ‪@UNEP‬