The Times-Tribune from Scranton, Pennsylvania • 21

SCRANTON TIMES, FRIDAY, MARCH 3, 1989. -21 Discovery of High Clouds Spdrked Most Urgent Quest of the Century measure chlorine and other chemicals during the second Antarctic expedition. His team worked "round If AS the clock, seven days a week" to get it ready in time, he said. In Punta Arenas, the team battled temperatures of 10 below zero and 40 mile an hour winds, and the instrument itself had to perform in the far more extreme cold of the ozone hole itself. The pace continued after the return from Chile, he said, as the team scrambled to do the analysis that showed a stunning inverse correlation between the levels of chlorine in the stratosphere and the level of ozone, By the end of 1987, they had made a solid case that the culprits were man-made chemicals CFCs (chlorofiuorocarbons) and halons.

The ER-2 a plane similar to the U-2 spy plane that can fly as high as 75,000 feet is now chasing PSCs in the ozone layer over the North Pole. Teams of scientists, meanwhile, are making flights aboard a specially equipped DC-8 airliner, taking other measurements. The Arctic project became an urgent priority after preliminary tests in northern Canada and Greenland last winter found indications that ozone destruction might be occurring in the Arctic as well. Although there is no comparable ozone hole in the north, Harvard's Anderson described the new data as "a very important and alarming discovery." Scientists would have been "shocked" by the findings, he said, if they had not come on the heels of the Antarctic discovery. "Antarctica numbed us," he said.

"We tend to lose perspective." Last March, an international report concluded that ozone in the higher latitudes of the Northern Hemisphere is disappearing three to four times faster than computer models had predicted. In winter, the report said, ozone losses between 30 and 64 degrees north latitude run as high as 6 percent. Ozone loss was no longer a threat primarily to penguins at the bottom of the planet. It had become an immediate concern for the population centers in Europe, Canada, the United States and the Soviet Union. Although some scientists had long been warning that man-made chemicals known as chlorofiuorocarbons, or CFCs, were jeopardizing the ozone layer, discovery of the Antarctic ozone hole took them by surprise.

It far exceeded any worst-case scenario they had imagined. Ozone, a form of oxygen, is a critical, part of Earth's fife support systems because it is the only gas in the atmosphere that screens out the most harmful types of destructive ultraviolet radiation. A threat to the ozone layer is a threat to life on Earth, so the race was quickly on to discover what was destroying the ozone and what could be done to stop it. The findings from the current Arctic expedition are likely to figure prominently when signers of the Montreal Protocol, a global treaty to sateguara tne ozone layer, meet next year to consider further reductions in ozone-depleting chemicals. The treaty now calls for a freeze on halons and a 50 percent cut in CFC consumption by 1999.

The Arctic expedi-tionteam worried that PSCs would be elusive quarry at the North Pole. Robert Watson of NASA, a leader in the research, said 17 Regular molecules composed 2 oxygen I haons anA -J ORq. TH -nHS ft AIR r.nKiZTT"" "Ullinwtn Mi.ni i i his is expected to be one of the warmer years at the poles because of a natural variation in circulation patterns in the atmosphere. For PSCs to form, temperatures have to be very cold at least 110 degrees below zero. Temperatures over the South Pole are among the coldest on Earth, McCormick noted, so finding PSCs there was never a problem.

At the warmer North Pole, their presence is comparatively sporadic and patchy. But an elated McCormick, in a telephone interview from Stavanger right after the first DC-8 foray, said the expedition was off to an auspicious start. "Tonight it worked," he said. "We found PSCs right where we thought they would be. McCormick is using a lidar a instrument that measures laser light bouncing back from an object in the way radar measures radio waves to examine PSCs above the research plane, since the DC-8 cannot reach the ozone layer or the PSCs.

McCormick and his clouds entered the ozone story after theorists, at a loss to explain how so much Antarctic ozone could disappear so fast, began hypothesizing about a little-understood type of chemistry involving solid particles. PSCs, made up of ice mixed with nitric acid, form high in the strato sphere where the ozone layer is found and could provide the particles. Regular clouds occur only in the lower atmosphere, known as the troposphere. Reactions involving gases and solid particles are an unpredictable frontier known as heterogeneous chemistry. Researchers began to focus on heterogeneous chemistry because the behavior of the ozone hole did not jibe with predictions about how CFCs would attack ozone, noted Michael McElroy of Harvard University, one of the theorists working on the chemistry of struction.

The original ozone de- concerns about ozone loss, he said, had focused on chemical reactions that could take place only in the highest part of the stratosphere, roughly 21 to 27 miles above the Earth's surface. The classic ozone depletion theory put forward in the early 1970s by F. Sherwood Rowland and Mario Molina had held that chlorine released by the decomposition of CFCs would facilitate ozone's destruction via a catalytic process. The reaction could take place only at a very high altitude, because it requires the presence of atomic oxygen, which can survive only in thinner air. This Ultraviolet light from the sun breaks up oxygen molecules into single oxygen atoms.

surface, causing more skin cancer in light-skinned people, more cataracts in eyes and other health problems. Research also indicates these rays suppress the body's disease-fighting immune system. Research is showing that other forms of life are also susceptible to damage, so a thinning zone layer could also have serious implications for crop yields and the world's fisheries. Ultraviolet radiation can damage floating fish eggs and larvae as well as the tiny plants, or phytoplankton, that are the foundation of the ocean food chain. Q.

What Is the ozone hole? A. For at least a decade now, a part of the ozone layer has been disappearing in springtime over Antarctica a phenomenon that has been dubbed the "ozone hole." Scientists first discovered the ozone hole, which is many times larger than the United States and deeper than than Mt. Everest is high, in 1985. Since then, the problem appears to be worsening. In 1987, the worst year to date, virtually all the ozone disappeared in the heart of the ozone layer over Antarctica.

Altogether, 60 percent of the ozone overhead was missing, allowing much more ultraviolet radiation to beat down on penguins, plankton and other living things in that part of the world. Q. What causes the ozone hole? A. Man-made chemicals chlorofiuorocarbons (CFCs) and halons are ultimately responsible, scientists concluded in 1987. The CFC family of fns I iU By DIANNE DUMANOSKI Boston Globe In 1978, M.

Patrick McCormick was laboring in relative obscurity doing basic atmospheric research when an instrument he had designed for the Nimbus 7 research satellite began picking up something unexpected over the North Pole clouds in the stratosphere, many miles higher than normal clouds. Four years later, McCormick, who has worked for years at NASA's Langley Research Laboratory on arcane basic science studies of tiny aerosol particles in the Earth's atmosphere, described his finds in the highly specialized Journal of Atmospheric Science. He named, them "polar stratospheric clouds," or PSCs. It was interesting, he recalls now, but "so what? This was all of academic interest. Pure research." No more.

Since British scientists reported a dramatic hole in the Earth's ozone layer over Antarctica in May 1985, McCormick and his clouds have been propelled to center stage in one of the most urgent scientific quests of the century. As it turned out, these curious ice clouds proved to be the key to understanding how man-made chemicals, released from such everyday things as auto air conditioners and fire extinguishers, were causing rapid destruction of the protective ozone layer. Right now, researchers are flying grueling high-altitude missions over the North Pole in a hunt for PSCs there, a project that may yield vital clues to the fate of the ozone. The fragile 6-mile-thick layer of ozone, a variant of oxygen, screens out most of the deadly ultraviolent radiation from the sun that would otherwise be fatal to most life forms. Flying out of the city of Stavanger on Norway's southwest coast, the researchers already have found evidence of one type of PSC in the polar stratosphere, and they are pressing the hunt for a second type that may play a crucial role in ozone depletion.

Armed with data from McCor-mick's findings, the team in Stavanger is using computers to try to predict where the clouds will develop. These forecasts, McCormick explained, guide the flights of two research planes as they scour the northern skies for PSCs. For scientists who have been working at a breakneck pace to solve the ozone hole mystery, the demanding routine has become grindingly familiar. This Arctic expedition follows closely two major efforts in Antarctica, including a series of research flights out of Punta Arenas in Chile in the fall of 1987. "The pace has been killing," said NOAA scientist Susan Solomon, who led the first Antarctic expedition.

Nevertheless, when it became clear something might also be going wrong in the northern hemisphere, the scientists jumped right into other expedition. Solomon is one of about 75 scientists from government agencies and U.S. and European universities who will be working out of Stavanger until mid-February: The pressure has been particularly intense, said James Anderson, a Harvard atmospheric chemist, because limited funding has meant that few scientists are trained to do this research. The critical work has fallen to about 25 scientists, he said, and "there are no backups" for most of them. "Our instrument was created in six months from nothing," Anderson said, referring to a device mounted on the ER-2 research plane as it flew into the Antarctic ozone hole to zone: Boston Globe Q.

It's confusing. For years, ozone was described as a harmful pollutant. Now everyone is concerned because something Is destroying the ozone layer. Is ozone good or bad, and did ozone destruction have anything to do with the air pollution problems we had last summer? A Whether ozone is beneficial or harmful depends entirely on where it is. Ozone smog and the ozone layer contain the same gas.

Basically, ozone found high above the Earth in the ozone layer is beneficial; it forms a protective screen from the sun's harmful ultraviolet rays. When it forms near the ground in the air we breathe, it causes premature aging of the lungs and damages crops, trees and other plants. Tne damage to the ozone layer had nothing to do with last summer's ozone air pollution at ground level. Q. Just what Is ozone? A.

Ozone is a gas composed of three oxygen atoms; regular oxygen is composed of two atoms. Ozone is produced naturally when ultraviolet light from the sun breaks up molecules of oxygen into single atoms (atomic oxygen), which then collide and combine with other molecules of two-atom oxygen and form three-atom ozonate. Without human interference, the Earth's ozone levels would remain fairly constant. The ozone in smog is created when pollutants from automobiles, gasoline, stations and other sources inter investigating other chemical reactions that could operate at the lower altitudes. Their investigations also suggested that the depletion processes involved chlorine, created by breakdown of man-made CFCs, and bromine, which occurs from the breakdown of halons, an increasingly popular man-made chemical used in fire extinguishers.

But for these processes to work, McElroy said, there would have to be an abnormally low level of nitrogen dioxide, a gas normally found in the atmos phere. The key to this mystery turned out to be the elusive PSCs, which David Golden of SRI International, a chemical research firm, described as a "a double whammy" that set up ideal conditions for runaway ozone destruction First, the clouds' remove nitrogen compounds that would otherwise shut off chemical 'hi ozonated molecules formed, type of ozone-depletion chemistry, he said, would be "eating away at ozone from the top," which is not where ozone is concentrated, "so we were worried about the reduction of a few percent." But in Antarctica, McElroy noted, "the ozone was not being destroyed at 40 kilometers (about 25 miles high), but in the heart of the ozone layer, where there is no atomic oxygen, so it was immediately clear the old chemistry could not be the answer." Theorists such as McElroy, Molina, Solomon and Rowland began Single oxygen atoms collide with other oxygen molecules. TIMES GRAPHIC 3-atom oxygen are oxygen are of atoms. the Good, the Bad and the 'Hole' reactions that destroy ozone. This happens, McCormick explained, because PSCs form from nitric acid and water.

As the air gets colder, Type 1 PSCs change into Type 2's, with larger, heavier ice crystals. Because of their size and weight, these particles begin snowing down to lower parts of the atmosphere, taking the critical nitrogen with them. Secondly, chemical reactions take place on the surface of the ice particles in PSCs, transforming what McCormick calls "friendly" nondestructive chlorine and bromine into an "unfriendly" radical form that destroys ozone. This all happens in the dark of the long polar winter. It takes the return of sunlight in spring to set the ozone destruction in motion, said Daniel Albritton of the National Oceoanic and Atmospheric Administration's Aeronomy Laboratory, because the chemistry "is light-driven." When dawn arrives, he said, "it's like lighting a match in a laden atmosphere." Ozone is eaten away with breathtaking speed the victim, in Anderson's words of "a runaway chain reaction in which a tiny amount of chlorine can destroy a massive amount of ozone." truth century.

An international treaty to protect the ozone layer, the Montreal Protocol, went into effect this month, but scientists now believe that it will be inadequate. Its provisions call for a 50 percent cut in CFCs by 1999 and a freeze on halon production. The treaty does provide a mechanism for periodic reviews as scientific understanding increases and for tightening controls on ozone-depleting chemicals in the future. The question of a total phase-out will almost certainly come up when the treaty's signers meet over the next 15 months to review the situation. Q.

Is the ozone problem connected somehow with the warnings about the greenhouse effect and global warming? A. Not directly, although the two problems do have many interconnections. Greenhouse warming is not destroying the ozone layer and the destruction of the ozone layer is not causing the greenhouse effect. CFCs and halons, however, are actors in both problems. They can spend decades in the lower atmosphere, where they help trap the sun's heat along with other greenhouse gases, such as carbon dioxide.

This is referred to as the greenhouse effect. A single CFC molecule absorbs as much heat as 10,000 molecules of carbon dioxide, the most common greenhouse gas. CFCs account for about 15 percent of the greenhouse effect. Much less is known about halons' efficiency. I BY CARLA KIWK3R stop using these chemicals? A.

Not very quickly. Even if we stopped releasing all halons and CFCs today, scientists estimate the Antarctic would have an ozone hole through the 21st century. Ozone destruction would continue for decades, because the CFCs and halons released in the past are still in the air and gradually making their way up to the stratosphere. The chlorine molecule running wild today in the Antarctic ozone hole might have been released into the air when your grandmother threw out her old refrigerator in 1950. Q.

Didn't we ban Freon a decade ago? A. Only partially. The United States and several other countries banned the use of Freon or CFCs in aerosol cans in the late 1970s, but CFCs are still used in spray cans elsewhere. The United States ban slowed the production of ozone-depleting chemicals for a time, but in recent years worldwide CFC use has been climbing as other uses for the chemical have expanded. In the United States, auto air conditioners are the single largest source of CFCs, accounting for about 25 percent of the total released.

Q. Is there anything that can be done to stop ozone depletion? A. Many scientists urge the complete phase-out of halon and CFC use as quickly as possible. DuPont and other chemical companies hope to develop substitutes for the most damaging CFCs by the end of the act in sunlight. Q.

What exactly Is the ozone layer? A. The ozone layer is a relatively concentrated belt of ozone gas in the stratosphere, the upper part of the Earth's atmosphere. At the equator, the stratosphere starts about nine miles above the surface and extends up to 31 miles, while over the poles it extends from roughly 7 to 27 miles high. -The ozone layer is one of the Earth's key life-support systems, because ozone is the only gas in the atmosphere that blocks the sun's harmful ultraviolet radiation from reaching the Earth's surface. The ozone layer is the planet's sun screen, its protective umbrella.

Over mid-latitude areas such as Boston, the heart of the ozone layer is roughly 11 miles above our heads. But even in the area of peak concentration, ozone is a small component in the atmosphere, roughly one molecule in every 100,000. Q. What will happen If the ozone layer disappears? A. If the ozone layer disappears altogether, the Earth will be in deep trouble.

Life as we know it would cease to exist, because most humans, plants and animals would not be able to withstand the increased ultraviolet radiation. These damaging rays destroy the DNA in cells, the genetic blueprint for life. Scientist say losing just 10 percent of the ozone would be very serious. The thinning of the ozone layer likely would allow more ultraviolet radiation to reach the Earth's chemicals, which contain chlorine, were developed in the 1930s as a coolant for refrigerators. CFCs (sometimes known by the brand name Freon) are still used in refrigerators and air conditioners, in some aerosol cans, as blowing agents to puff up styrofoam and foam cushions and as solvents to clean computer chips.

Halons, a newer chemical containing bromine, are gaining favor as a firefighting tool because they leave no water damage or chemical residues'. Halon production has quadrupled in a decade. Bromine is 100 times more destructive to ozone than chlorine. Q. How do these chemicals get to the ozone layer and destroy It? A.

CFCs and halons are very stable chemicals, so when they are released into the atmosphere, they can drift around unchanged for decades. Eventually, they filter up to the stratosphere, where ultraviolet light breaks them down, liberating the chlorine and bromine that attack ozone. In regions such an Antarctica, ice clouds in the vicinity of the ozone layer set up ideal conditions for ozone destruction. The clouds not only capture and remove the nitrogen compounds that would otherwise act as brake on ozone destruction, but also unleash the active forms of chlorine and bromine that attack ozone. One chlorine molecule can destroy hundreds of thousands ozone molecules.

Q. Will the ozone hole go away If we.