NEW OZONE HOLE COULD OPEN SOON

                         Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: THURSDAY, February 20, 1992                   TAG: 9202200110
SECTION: NATIONAL/INTERNATIONAL                    PAGE: A-2   EDITION: METRO 
SOURCE: Associated Press
DATELINE: BANGOR, MAINE                                LENGTH: Medium
NEW OZONE HOLE COULD OPEN SOON
A heightened sense of urgency is pressing scientists as they complete their inspection of what looks like the start of an ozone hole over the Northern Hemisphere, a discovery so alarming it's already changed U.S. policy.
Scientists on the NASA project based in Bangor concluded that an ozone hole could develop this winter over the United States, Canada and Europe.
"These two weeks are really the crucial time for detecting the appearance of the ozone hole in this region of the hemisphere," said James G. Anderson, lead scientist for the National Aeronautics and Space Administration project.
The ozone layer in the upper atmosphere, roughly seven miles to 31 miles above Earth, provides a shield from the sun's ultraviolet rays. Without an ozone block, people face greater risks of skin cancer, cataracts and suppressed immunity from disease.
The five-month NASA study, conducted with a converted spy plane and an orbiting satellite, is measuring the presence of ozone-eating chemicals at high altitudes. The study concludes in late March, when NASA plans to issue final results. But when a flight Jan. 20 found ozone-depleting chlorine monoxide at a record concentration of 1.5 parts per billion, the space agency issued preliminary findings and a warning.
A week later, President Bush ordered a halt to production of ozone-eating chemicals, chiefly chlorofluorocarbons, by the end of 1995, with a few exceptions. That's five years sooner than an international treaty requires.
Household use of CFCs can be found in aerosol cans and the refrigerator, and in the driveway in auto air conditioners.
Whether a hole opens in the ozone layer over the Northern Hemisphere will depend largely on the breakup of the polar vortex, Anderson said. A mass of cold air that forms clouds of ice particles, the polar vortex is where sunlight triggers the chemical changes that deplete ozone.
The critical period for ozone loss, scientist say, is in February and March, when sunlight returns to northern latitudes and before the polar vortex breaks up in the warmth.

by Bhavesh Jinadra by CNB