FY 2006 Annual Report on Ozone Layer Monitoring Published

The Ministry of the Environment has compiled the annual report on FY 2006 ozone layer monitoring, covering the status of (i) ozone depletion, (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"). The following are the results of the report. 1 Global total ozone has been declining since the early 1990s. 2 The area of the ozone hole over the Antarctica in 2006 was the second largest in the monitoring history, following the one in 2000. The Antarctic ozone layer is still in a critical condition. 3 Many numeric models have predicted that the total ozone will return to a pre-1980 level in the middle of this century, with a broad range of uncertainty. 4 In the mid-latitude areas of the North hemisphere, the atmospheric concentrations of chlorofluorocarbons (CFCs) have remained flat or have decreased. On the other hand, the concentrations of hydrochlorofluorocarbons (HCFCs) have been increasing rapidly. The concentration of HFC-134a, which does not deplete the ozone layer but has a high greenhouse effect, has also been increasing rapidly, at the rate of 10 % per year.

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