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Publication of the FY 2008 Annual Report on Ozone Layer Monitoring

August 28, 2009

The Ministry of the Environment has compiled its FY 2008 annual report on ozone layer monitoring, covering the status of (i) ozone layer, (ii) atmospheric concentrations of ozone depleting substances (ODS), and (iii) solar ultraviolet radiation, pursuant to the Law Concerning the Protection of the Ozone Layer through the Control of Specified Substances and Other Measures (the "Ozone Layer Protection Law").

(i) A current condition of the ozone layer
- The global total ozone has been largely reduced from 1980s to the first half of 1990s, but has been maintaining its current state recently.
- The ozone hole over Antarctica rapidly expanded from the 1980s to the 1990s. Since then, such holes have formed almost every year on a large scale. An area of the ozone hole over Antarctica formed in 2008 was larger than the average area in recent decades. The Antarctic ozone layer is still in critical condition.
- Many models have predicted that the total ozone will return to its pre-1980 value in middle of this century, if all countries meet the requirement of the Montreal Protocol on Substances that Deplete the Ozone Layer concerning the ozone-depleting substances.

(ii) Concentrations of ozone-depleting substances in the atmosphere
- In the mid-latitude areas of the Northern hemisphere, atmospheric concentrations of chlorofluorocarbons (CFCs) have remained flat or decreased, as observed in Hokkaido. On the other hand, concentrations of hydro chlorofluorocarbons (HCFCs) have been rapidly increasing. The concentration of HFC-134a, which does not deplete the ozone layer but has high greenhouse effects, has been rapidly increasing.
- CFCs stay in the atmosphere a very long time; however, it is predicted that from now on, its concentration will be reduced very slowly due to complete abandonment of its production. As to HCFCs, it is predicted that its concentration in the atmosphere will increase and reach its peak within 20 to 30 years. HCFCs are expected to be reduced due to advanced international restrictions.
- The current concentration of ozone-depleting substances in the atmosphere is relatively higher than one of 1980s. Therefore, it is necessary to decrease the concentration of substances more to improve the stratospheric ozone layer.

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