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Publication of the FY 2009 Annual Report on Ozone Layer Monitoring

August 26, 2010

Based on the Law Concerning the Protection of the Ozone Layer through the Control of Specified Substances and Other Measures; (Law No. 53 of 1988), "Ozone Layer Protection Law "the Ministry of the Environment has complied the annual report on FY 2009, covering the status of the ozone layer and the atmospheric concentrations of ozone depleting substances , "ODS".

(Points of the report)
1. The condition of the ozone layer
(1) The total quantity of ozone has been decreased rapidly on a global scale from the 1980s to the early 1990s, and it still stays unrecovered.
(2) The ozone hole over the Antarctic region expanded rapidly from the 1980s to the 1990s, and the large-scale formation has been observed almost every year ever since. The size of the ozone hole over the Antarctic region in 2009 was a little smaller than the average of the last decade. However, currently, this cannot be regarded as a sign of its contraction. The ozone layer over Antarctica is still in a critical condition.

2. The atmospheric concentrations of ozone depleting substances, etc.
(1) Chlorofluorocarbons (CFCs) and Hydrochlorofluorocarbons (HCFCs) are determined as ODS, and their production has been controlled, based on the Montreal Protocol and the Ozone Layer Protection Law. However, according to surveillance results of the Ministry of the Environment in the mid-latitude areas of the northern hemisphere (an observation point in Hokkaido); HCFCs are increasing rapidly, while CFCs are declining or at least maintain the same level. In addition, HFC-134a has shown extremely high increasing rate in its atmospheric concentration. HFC-134a is one of a kind of Hydrofluorocarbons (HFCs) which are strong global-warming gases though not depleting the ozone layer.
(2) As the life of CFCs in the air stays relatively long, their atmospheric concentration is predicted to decrease quite moderately with time. On the other hand, it is believed that HCFCs concentrations will keep increasing and reach its peak in the next twenty or thirty years, and then start decreasing. However, it is hoped that the decrease can start earlier by accelerating the international regulations.
(3) The current atmospheric concentrations of ozone depleting substances are rather high, compared to those in around 1980. Therefore, a further decrease of ODS in the air is essential to improve the condition of the ozone layer in the stratosphere.

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