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http://dailynews.yahoo.com/htx/ap/20000829/sc/un_ozone_layer_2.html

Tuesday August 29 9:29 AM ET Ozone Hole Expected To Increase

GENEVA (AP) - The hole in the ozone layer over the Antarctic is expected to increase in size this year as early measurements show significant ozone depletion, the United Nations weather agency said Tuesday.

Four observation stations in the Antarctic this month reported a decrease in ozone of between 20 and 35 percent compared with the period between 1964 and 1976, before the ``ozone hole'' was observed, said Taysir al-Ghanem, spokesman for the World Meteorological Organization.

``We cannot be optimistic with these latest measurements,'' al-Ghanem said. ``We are expecting that the ozone hole this year is going to be quite large, probably more than last year.''

Ozone depletion in the region starts in July and intensifies during August. WMO says the biggest hole yet was recorded in 1998, when it reached some 4.63 million square miles, partly helped by strong polar winds.

Last year, the hole reached 3.86 million square miles. The protective ozone layer shields the earth from damaging ultraviolet rays.

Reduction of the ozone layer can let rays from the sun reach the earth's surface. Too much UV radiation can cause skin cancer and destroy tiny plants at the beginning of the food chain.

One cause of ozone depletion is chlorine and bromine released by manmade chemical compounds such as chlorofluorocarbons, contained in some aerosols.

WMO has said those chemicals have leveled off thanks to the Montreal Protocol, which commits countries to eliminating production and use of ozone-depleting substances.

But the agency says it could be 20 years before ozone levels recover noticeably. Full recovery can be expected around 2050.

-- K (infosurf@yahoo.com), August 30, 2000