This is the VOA Special English Environment Report.

Scientists in the United States have reported some good newsabout the ozone in the atmosphere. Recent findings suggest that thedestruction of ozone by pollution is slowing. Ozone is a form ofoxygen. Its presence above Earth protects us from radiation from thesun.

In one study, researchers examined information gathered by NASAspace agency satellites and by equipment on Earth. The findings? Inthe words of Michael Newchurch of the University of Alabama: "Thisis the beginning of a recovery of the ozone layer."

Mister Newchurch led the study. He says the atmosphere was losingabout eight percent of the ozone layer per ten-year period since thelate nineteen-seventies. In the last five years, though, that rateof loss has dropped by half. He says the atmosphere should start togain ozone before long. He says a full recovery, however, is aboutfifty years away, as long as the Montreal Protocol remains in place.

That is an international treaty from nineteen-eighty-seven torestore the ozone layer. The treaty restricts the use of a number ofchemicals that destroy ozone, like chlorofluorocarbons, or C-F-C's.

Wide use of C-F-C's began in the nineteen-thirties. They becamepopular coolants in devices such as refrigerators and airconditioners. C-F-C's remain in the atmosphere for years.

Mister Newchurch says the study provides evidence that theMontreal Protocol is working by reducing C-F-C pollution. But thestudy found the ozone improvement only in the upper stratosphere.The scientists have not yet seen evidence of similar changes in thelower stratosphere. That holds most of the protective ozone.

The Montreal Protocol also restricts the use of methyl bromide, achemical to kill insects. Farmers and shippers are the main users.Natural sources of methyl bromide include oceans and some plants.Scientists say the bromine gas it produces is fifty times moredestructive to ozone than chlorine gas from C-F-C's.

Methyl bromide has never been used as widely as C-F-C's. But aseparate study found a decrease in bromine gas levels in theatmosphere. Researchers at the National Oceanic and AtmosphericAdministration did the study. They reported a thirteen percent dropsince nineteen-ninety-eight. The report is based on eight years ofmeasurements taken at ten stations around the world.

This VOA Special English Environment Report was written by CatyWeaver.