OZONE THREAT GROWS

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

DATE: TUESDAY, February 4, 1992                   TAG: 9202040258
SECTION: NATIONAL/INTERNATIONAL                    PAGE: A-1   EDITION: METRO 
SOURCE: The Washington Post
DATELINE: WASHINGTON                                LENGTH: Medium
OZONE THREAT GROWS
The danger that a new ozone "hole" could open over densely settled areas of the Northern Hemisphere, exposing the population to increased amounts of harmful radiation, is greater than previously suspected, scientists reported Monday.
New findings of ozone depletion by NASA satellite and multi-agency airborne instruments are so alarming, the scientists said, that they decided to release them before completion of the data analysis in late March.
Two weeks ago, detectors aboard a converted spy plane flying over New England and eastern Canada recorded the highest level of the ozone-destroying chemical chlorine monoxide ever measured anywhere around the globe. The level - 1.5 parts per billion - was approximately 50 percent greater than any previously seen over Antarctica, the site of the infamous ozone hole first discovered in the early 1980s.
Chlorine monoxide, which results from the presence of man-made chlorofluorocarbons (CFCs), is a potent ozone-destroyer by itself. And when combined with small amounts of its chemical cousin, bromine monoxide - which the NASA researchers also found at elevated levels - the effect is enough to destroy ozone at a rate of about 1 or 2 percent per day for brief periods in late winter, said Michael Kurylo, NASA's program manager for the airborne studies.
Ozone in the stratosphere protects the Earth's surface by absorbing much of the ultraviolet radiation that causes skin cancer, cataracts and immune-system damage in humans and is disastrous to many microscopic marine organisms.
Weather conditions permitting, ozone over parts of the Northern Hemisphere could be depleted by 30 percent to 40 percent, the scientists said. By comparison, about 50 percent of the ozone has been depleted from the ozone hole over Antarctica.
In addition, researchers found evidence of reduced concentrations of nitrogen oxides in the lower stratosphere. Nitrogen oxides help preserve ozone by reacting with chlorine and bromine compounds before they can damage the ozone layer.
"Our conclusion is that the `immune system' of the atmosphere" - its nitrogen-mediated ability to fight ozone-destroying elements - "is weaker than we had suspected before," said James G. Anderson of Harvard University, lead scientist for the airborne observations program. "None of the news is good."
Ozone-depleting elements in the stratosphere from the Arctic as far south as the central Caribbean were found to be much more abundant than computer analyses had predicted. Part of this is a result of the eruption of Mount Pinatubo in the Phillipines last September, the scientists said.
The Antarctic hole was discovered in 1985. Concern has grown since then that Earth's ozone shield is being destroyed by human industry, primarily by the release into the atmosphere of CFCs used as refrigerants, thermal insulators and in cleaning solvents. These break down into chlorine atoms or compounds, which interact with and destroy ozone.

by Bhavesh Jinadra by CNB