61. EEK! - Hole In The Ozone Layer? The future. Scientists originally predicted that the ozone layer would be the thinnest around 2008, then start recovering. But new http://www.dnr.state.wi.us/org/caer/ce/eek/earth/air/ozonlayr.htm

What is Ozone? Read all about good ozone, bad ozone here. How it all started In the late 1920s, chemicals called chloroflourocarbons (cloro-floro-carbons) or CFCs, were invented. These chemicals were not poisonous and didn’t harm fabrics, plants or people. Companies thought they were great and used them in refrigerators, air conditioners, styrofoam packaging, and spray cans. From the 1920s to the 1970s, billions of CFC molecules were released into the air. In the 1970s, scientists began to wonder what might happen to all those CFCs after they had been in the air for a while. They eventually learned that CFCs could float past the troposphere up into the stratosphere where UV rays would break them down. The chemicals that make up CFCs, mainly chlorine and fluorine, would float around the stratosphere, breaking up ozone molecules This was bad, because scientists knew that ozone in the stratosphere protects the Earth from too many UV rays. Fixing the problem In 1979, many countries, including the U.S., banned CFCs from being made or used. This was a big step toward fixing the problem. Today, no spray cans contain CFCs. Other chemicals are gradually replacing the CFCs in air conditioners. But the CFCs already in the atmosphere can take up to 50 years to reach the stratosphere. Once there, they hang around in the stratosphere for many years, doing damage.

62. Introduction To Ozone: Background Material The protective role of the ozone layer in the upper atmosphere is so vital that scientists believe life on land probably would not have evolved and could not http://www.ucar.edu/learn/1_5_1.htm

Introduction to Ozone This section provides an overview of ozone and why it is considered to be 'bad' when found in the troposphere, and 'good' when found in the stratosphere. Ozone has the same chemical structure whether it is found in the stratosphere or troposphere. The general concepts found in this section include the following: Ozone is a form of oxygen. The molecule contains three oxygen atoms ( Ozone is unstable and will readily combine with other atoms. Ozone is found in the stratosphere, where it blocks the sun's ultraviolet (UV) waves and prevents them from reaching the earth's surface. Ozone is also found in the troposphere, where it can damage living tissue and human-produced objects. It is generated both from certain types of pollution and natural sources. This section includes four classroom activities. Introduction The Ozone Hole. The Ozone Hoax. Pollution. Skin Cancer. The topic of ozone makes headlines on a regular basis, but why does a single molecule merit such media coverage? How important is the ozone in our atmosphere and why are scientists so concerned about its increase near the surface of the earth and its disappearance higher up in the atmosphere? First things first - what is ozone? Ozone is made of three oxygen atoms (

63. Ozone Layer Thinning ozone layer Thinning. A thinner ozone layer is likely to cause a noticeable increase in skin cancer, eye problems, and other diseases. http://www.harc.edu/4site/4siteFCRolt.html

Houston Environmental Foresight Seeking Environmental Improvement Ozone Layer Thinning The layer of ozone in the stratosphere, a layer far above the earth's surface, is critical to life on earth because it blocks out ultraviolet rays. Human activities have reduced ozone concentrations in the upper atmosphere at some times and in some places around the world. A thinner ozone layer is likely to cause a noticeable increase in skin cancer, eye problems, and other diseases. The "ozone hole" is probably the best known result of the thinning of the ozone layer. Scientists are certain that man-made chemicals (chlorofluoro-carbons, or CFCs) have reduced the amount of ozone in the upper atmosphere. The most dramatic effects have occurred over Antarctica, where levels of ozone drop sharply every September forming a "hole" in the ozone layer. The Foresight Committee ranked ozone thinning in the category of least risk because serious effects are not expected in the Houston area. Two findings influenced this ranking. First, ozone layer thinning effects in the United States are strongest in the northwest; there may be effects over Houston, but so far satellite data suggests changes are negligible. Stratospheric Ozone Levels Over North America Satellite Measurements Source: NASA Goddard Space Flight Center.

64. Humans Are Not Causing Ozone Depletion. There is overwhelming scientific evidence that manmade chemicals are destroying the ozone layer Nobel prizes have already been awarded for the research. http://www.huppi.com/kangaroo/L-ozone.htm

Myth: Humans are not causing ozone depletion. Fact: NASA has proved it beyond all reasonable doubt. Summary There is overwhelming scientific evidence that man-made chemicals are destroying the ozone layer Nobel prizes have already been awarded for the research. Rush Limbaugh argues that humans are safe, because volcanic chlorine has been working on the ozone layer longer than man-made chlorine, and yet we're still here. But this argument is false. Volcanic chlorine is water soluble, and rained harmlessly out of the atmosphere. Human CFCs are insoluble, and can therefore rise to the ozone layer where they can do their damage. Argument Do man-made chlorofluorocarbons (CFCs) destroy the ozone layer? There are no longer any skeptics left at NASA, the National Academy of Sciences, the National Center for Atmospheric Research, or the World Meteorological Organization. In fact, the three scientists who first sounded the alarm in the early 80s F. Sherwood Rowland, Paul Crutzen and Mario Molina received the 1995 Nobel Prize in chemistry for their work. In 1991, NASA launched the Upper Atmosphere Research Satellite (UARS) in an attempt to determine once and for all if humans were responsible for causing this serious damage to the atmosphere. The data relayed back to NASA clinched the matter beyond all reasonable doubt. "There is a very clear link between man-made chlorofluorocarbons (CFCs) and destruction of the ozone layer," says Dr. Aidan Roche, the Lockheed scientist whose team analyzed the satellite data for years. (1)

65. Thickness Of The Ozone Layer At Uccle Ozone. Thickness of the ozone layer at Uccle. Mean annual variation of the thickness of the ozone layer (expressed in Dobson Units http://www.meteo.be/english/pages/OzonEN.html

Ozone Thickness of the ozone layer at Uccle Mean annual variation of the thickness of the ozone layer (expressed in Dobson Units) at Uccle and the variation of the daily means of the last year. The black line indicates the mean annual variation as determined from the time series from 1971 until now. The grey area represents the zone containing 95% of all the daily mean values. The thickness of the ozone layer (also called ozone column) is expressed in Dobson units (1 DU = 2.686 x 10 molecules of ozone per m²). More information can be found here : ozone research group

66. Statistics: Power From Data! Case Study: Ozone Layer Depletion And The Montréal Case study ozone layer depletion and the Montréal Protocol. The ozone layer is an important part of the global atmosphere and climate system. http://www.statcan.ca/english/edu/power/ch5/case_study/ozone.htm

Information: use in society The ozone layer is an important part of the global atmosphere and climate system. It limits the amount of ultraviolet (UV) radiation from the sun to levels necessary for life on Earth. A depleted ozone layer may likely cause serious consequences including higher rates of sunburn, skin cancer, eye damage and other diseases, as well as reducing plant growth. UV radiation at ground level. State of the ozone layer Mount Pinatubo in the Philippines. However, the effects of this natural disaster have diminished, and levels have returned to values closer to the long-term downward trend. Potential effects of ozone depletion Stratospheric ozone depletion leads to increases in UV radiation reaching the earth's surface. High levels of UV UV-B at ground level. This varies according to the season. In Canada, about 200 species of crops and trees are, to some degree, sensitive to increased levels of UV-B Responses CFCs was 77% lower than its peak in 1988. Canada accounted for less than 1% of global production. Despite this progress, there are still concerns. First, scientists cannot be certain that, even with current elimination targets of

67. The Ozone Layer And Climate Change The ozone layer and Climate Change. by The ozone layer protects all life on Earth from the harmful effects of the Sun s rays. It http://www.globalissues.org/EnvIssues/GlobalWarming/Ozone.asp

Global Warming Email Page to a Friend Printer-Friendly Version You are here: Home Environmental Issues Global Warming The Ozone Layer and Climate Change by Anup Shah The URL of this page is: http://www.globalissues.org/EnvIssues/GlobalWarming/Ozone.asp Please note that side notes and alternative links may not show up if printing this article. In order to get these full details showing when printing, please use the following printer friendly URL: http://www.globalissues.org/EnvIssues/GlobalWarming/Ozone.asp?Print=True Scientists believe that Global Warming will lead to a weaker Ozone layer, because as the surface temperature rises, the stratosphere (the Ozone layer being found in the upper part) will get colder, making the natural repairing of the Ozone slower. NASA, for example, reports that by 2030, "climate change may surpass chlorofluorocarbons (CFCs) as the main driver of overall ozone loss." The Ozone layer protects all life on Earth from the harmful effects of the Sun's rays. It has been depleting for many years now. Scientists have said that currently over Antarctica the Ozone hole is three times the size of the United States and growing Also, according to scientists

68. Regulations - Environment - Ozone Layer Protection ozone layer Protection Regulations. Citation. 1 These regulations may be cited as the ozone layer Protection Regulations . Definitions. 2 In these regulations. http://www.gov.ns.ca/just/regulations/regs/env5495.htm

This consolidation is unofficial and is for reference only. For the official version of the regulations, consult the original documents on file with the Registry of Regulations , or refer to the Royal Gazette Part II Regulations are amended frequently. Please check the list of Regulations by Act to see if there are any recent amendments to these regulations filed with the Registry that are not yet included in this consolidation. Although every effort has been made to ensure the accuracy of this electronic version, the Registry of Regulations assumes no responsibility for any discrepancies that may have resulted from reformatting. This electronic version is for your personal use and may not be copied for the purposes of resale in this or any other form. Ozone Layer Protection Regulations made under Section 112 of the Environment Act S.N.S. 1994-95, c. 1 Order in Council 95-293 (April 11, 1995), N.S. Reg. 54/95 Citation These regulations may be cited as the "Ozone Layer Protection Regulations". Definitions In these regulations (a) "Act" means the Environment Act;

69. Ozone Layer ozone layer. The ozone layer is that part of the stratosphere which contains ozone. Ozone is notable for its ability to absorb certain http://www.fact-index.com/o/oz/ozone_layer.html

Main Page See live article Alphabetical index Ozone layer The ozone layer is that part of the stratosphere which contains ozone . Ozone is notable for its ability to absorb certain frequencies of ultraviolet radiation . The ozone layer is not very dense ; if it were compressed to the density of the troposphere , it would be only a few millimeters thick. Ozone in the earth's atmosphere is generally created by ultraviolet light striking oxygen molecules containing two oxygen atoms (O ), splitting them into individual oxygen atoms (atomic oxygen); the atomic oxygen then combines with unbroken O to create ozone, O . The ozone molecule is also unstable and when ultraviolet light hits ozone it splits into a molecule of O and an atom of atomic oxygen, a continuing process called the ozone-oxygen cycle, thus creating an ozone layer in the stratosphere The ozone layer can be destroyed by the presence of atomic chlorine fluorine or bromine in the atmosphere leading to the so-called ozone hole in the polar stratosphere during winter months; these elements are found in certain stable compounds, especially chlorofluorocarbons (CFCs) which may find their way to the stratosphere and there be liberated by the action of ultraviolet light on them. All the gases mentioned are denser than air, so they eventually diffuse to ground level and there are absorbed by reacting with almost anything organic, but have plenty of time to catalyze the breakdown of ozone in the meantime. Chlorine in particular is capable of breaking down approximately one hundred thousand times its

70. The Ozone Depletion Process Location Ministry Home Air Ozone depleting substances How the ozone layer is attacked. HOW THE ozone layer IS ATTACKED. The http://www.ene.gov.on.ca/envision/ozone/process.htm

central site feedback search site map ... Print Printer-friendly version Ministry Home Air Ozone depleting substances HOW THE OZONE LAYER IS ATTACKED Last Modified: Wednesday October 15 2003

71. ScienceMaster - JumpStart - Ozone Repairing the ozone layer*. Scientists have found holes in the ozone layer high above the Earth. What could a thinnedout ozone layer do to people s lives? http://www.sciencemaster.com/jump/physical/ozone.php

Homework Helper Jumpstart Science Topics Learning Galleries Today is JumpStart - Physical Science Repairing the Ozone Layer Scientists have found "holes" in the ozone layer high above the Earth. The 1990 Clean Air Act has provisions for fixing the holes, but repairs will take a long time. Ozone holes aren't like doughnut holes; they're not empty spaces in the sky. Ozone holes are much like the worn-out places in an old sock or sweater: there are still threads covering the worn-out area, but the fabric can be so thin you can see right through it. Ozone in the stratosphere , a layer of the atmosphere nine to 31 miles above the Earth, serves as a protective shield, filtering out harmful sun rays, including a type of sunlight called ultraviolet B . Exposure to ultraviolet B has been linked to development of cataracts (eye damage) and skin cancer. In the mid 1970s, scientists suggested that chlorofluorocarbons (CFCs) could destroy stratospheric ozone. CFCs were widely used then as aerosol propellants in consumer products such as hairsprays and deodorants, and for many uses in industry. Because of concern about the possible effects of CFCs on the ozone layer, in 1978 the U.S. government banned CFCs as propellants in aerosol cans. Since the aerosol ban, scientists have been measuring the ozone layer. A few years ago, an ozone hole was found above Antarctica, including the area of the South Pole. This hole, which has been appearing each year during the Antarctic winter (our summer), is bigger than the continental United States. More recently, ozone thinning has been found in the stratosphere above the northern half of the United States; the hole extends over Canada and up into the Arctic regions (the area of the North Pole). The hole was first found only in winter and spring, but more recently has continued into summer. Between 1978 and 1991, there was a 4-5 percent loss of ozone in the stratosphere over the United States; this is a significant loss of ozone. Ozone holes have also been found over northern Europe.

72. Ozone Layer Burned By Cosmic Rays EPD ozone layer Protection ozone layer Protection. Image of ozone layer Protection And You, A Concise Guide to ozone layer Protection Ordinance, Guidance Notes for Licence Application. http://focus.aps.org/v8/st8.html

Previous Story Next Story July - December 2001 Archive Phys. Rev. Lett. (issue of 13 August 2001) 2 August 2001 Title and Authors Ozone Layer Burned by Cosmic Rays NASA satellite Cosmic conspiracy. Cosmic rays could be a major contributor to ozone destruction over Antarctica. Cosmic rays may be enlarging the hole in the ozone layer, according to a study appearing in the 13 August print issue of PRL . Researchers analyzed data from several sources, and found a strong correlation between cosmic ray intensity and ozone depletion. Back in the lab they demonstrated a mechanism by which cosmic rays could cause a buildup of ozone-depleting chlorine inside polar clouds. Their results suggest that the damage done by cosmic rays could be millions of times larger than anyone previous believed and may force atmospheric scientists to reexamine their models of the antarctic ozone hole. For the past two decades, scientists have known that human-made chlorofluorocarbons (CFCs) are the major destroyers of the atmosphere's protective ozone layer. Atmospheric scientists have proposed that ultraviolet light breaks down CFCs, releasing active chlorine, which tears apart ozone molecules. But during the months when ozone depletion is greatest, giant clouds of ice particlesso-called polar stratospheric cloudsblock the ultraviolet rays. Experts have not completely solved this piece of the ozone destruction puzzle, but according to one theory, the clouds harbor active chlorine molecules. Yet it's not clear how the chlorine would come to be separated from the CFCs in this ultraviolet-free environment.

73. Ozone Layer encyclopediaEncyclopedia ozone layer. ozone layer or ozonosphere Related content from HighBeam Research on ozone layer. Global Warming and Ozone http://www.infoplease.com/cgi-bin/id/A0837214.html

HOTWORDS CITE PRINT EMAIL in All Infoplease Almanacs Biographies Dictionary Encyclopedia Home Almanacs Atlas Dictionary ... Memorial Day Infoplease Tools Periodic Table Conversion Tool Perpetual Calendar Year by Year ... Site Map Also from Infoplease Search Infoplease Info search tips Search Biographies Bio search tips Encyclopedia ozone layer ozone layer or ozonosphere, region of the stratosphere containing relatively high concentrations of ozone The ozone layer prevents most ultraviolet (UV) and other high-energy radiation from penetrating to the earth's surface but does allow through sufficient ultraviolet rays to support the activation of vitamin D in humans. The full radiation, if unhindered by this filtering effect, would destroy animal tissue. Higher levels of radiation resulting from the depletion of the ozone layer have been linked with increases in skin cancers and cataracts and have been implicated in the decline of certain amphibian species. In 1974 scientists warned that certain industrial chemicals, e.g., chlorofluorocarbons Minimum ozone levels in the Antarctic decreased steadily throughout the 1990s, and less dramatic decreases have been found above other areas of the world. In 2000 (and again in 2003) the hole reached a record size, extending over 10.8 million sq mi (28 million sq km), an area greater than that of North America. In 1987 an international agreement, the Montreal Protocol , was reached on reducing the production of ozone-depleting compounds. Revisions in 1992 called for an end to the production of the worst of such compounds by 1996, and CFC emissions dropped dramatically by 1993. Recovery of the ozone layer, however, is expected to take 50 to 100 years. Damage to the ozone layer can also be caused by sulfuric acid droplets produced by volcanic eruptions.

74. Tracking The Ozone Layer. Currents 3:1 Tracking the ozone layer. What is the ozone layer and How Does It Affect You? Most references to the ozone layer mean the ozone found in the stratosphere. http://www.arn.org/currpage/31main.htm

Tracking the Ozone Layer What is the Ozone Layer and How Does It Affect You? By Forrest M. Mims III Sprinkled throughout the atmosphere are pale blue molecules of a toxic gas that are essential to most life on Earth. This gas is ozone. Ozone is toxic because it is highly reactive. This is why it can sterilize drinking water, eliminate odors, bleach colors, and decompose rubber. Fortunately, the amount of ozone at ground level is usually too low for these effects to be observed. However, high concentrations of various air pollutants and sunlight can increase ozone levels near the ground from a few tens of molecules per billion molecules of air (ppb) to a few hundred ppb. These levels of ozone can damage plants, cause eye irritation, inflame mucous membranes and impair the performance of athletes. Ozone is essential to life because it shields the Earth from the damaging, even lethal, ultraviolet radiation emitted by the sun. This filtering ability is particularly remarkable when you consider the relative scarcity of ozone molecules. For every billion molecules in the atmosphere, only around 300 are ozone. Imagine you could poke a tube through the entire atmosphere over your head and bring all the ozone molecules in the tube down to the surface. If they were then subjected to the same temperature and atmospheric pressure (standard temperature and pressure or STP) as you are, they would form a layer only about 3-millimeters thick.

75. Renewingindia.org: Ozone Layer Depletion dedicated to energy and environment in India, Climate Change Convention Protocol, GHG, Agenda 21, kyoto protocol, CDM, early action, ozone layer depletion. http://www.renewingindia.org/cliozone.html

Home About Us Contact Us Members Ozone Layer Depletion For over 50 years, chlorofluorocarbons (CFCs) were thought of as miracle substances. They are stable, nonflammable, low in toxicity, and inexpensive to produce. Over time, CFCs found uses as refrigerants, solvents, foam blowing agents, and in other smaller applications. Other chlorine-containing compounds include methyl chloroform, a solvent, and carbon tetrachloride, an industrial chemical. Halons, extremely effective fire extinguishing agents, and methyl bromide, an effective produce and soil fumigant, contain bromine. All of these compounds have atmospheric lifetimes long enough to allow them to be transported by winds into the stratosphere. Because they release chlorine or bromine when they break down, they damage the protective ozone layer. The discussion of the ozone depletion process below focuses on CFCs, but the basic concepts apply to all of the ozone-depleting substances (ODS). In the early 1970s, researchers began to investigate the effects of various chemicals on the ozone layer, particularly CFCs, which contain chlorine. They also examined the potential impacts of other chlorine sources. Chlorine from swimming pools, industrial plants, sea salt, and volcanoes does not reach the stratosphere. Chlorine compounds from these sources readily combine with water and repeated measurements show that they rain out of the troposphere very quickly. In contrast, CFCs are very stable and do not dissolve in rain. Thus, there are no natural processes that remove the CFCs from the lower atmosphere. Over time, winds drive the CFCs into the stratosphere.

76. International Symposium On Environmental Issues Is there a relationship between the ozone layer and phytoplankton? What effects would changes in the ozone layer have on Antarctica s penguin population? http://www.itdc.sbcss.k12.ca.us/curriculum/ozone.html

77. The Ozone Layer backgrounder The ozone layer The stratospheric ozone layer protects people, plants, and animals from harmful ultraviolet (UV) radiation. http://www.ucsusa.org/global_environment/archive/page.cfm?pageID=549

78. Ozone Layer May Be On The Mend Damage to the ozone layer, caused by chlorofluorocarbon (CFC) chemicals and other pollutants, may be starting to reverse itself according to data collected by http://adventuretravel.about.com/b/a/015818.htm

zJs=10 zJs=11 zJs=12 zJs=13 zc(5,'jsc',zJs,9999999,'') About Travel Adventure Travel Home ... Selecting Outdoor Guides zau(256,152,180,'gob','http://z.about.com/5/ad/go.htm?gs='+gs,''); Travel Essentials Outdoor Adventures Destinations Haunted Adventures ... Help zau(256,138,125,'el','http://z.about.com/0/ip/417/0.htm','');w(xb+xb); Stay Current Subscribe to the About Adventure Travel newsletter. Search Adventure Travel Ozone Layer May Be on the Mend Adventure Travel Blog Main August 07, 2003 Ozone Layer May Be on the Mend Damage to the ozone layer, caused by chlorofluorocarbon (CFC) chemicals and other pollutants, may be starting to reverse itself according to data collected by NASA satellites. National Geographic News is reporting the danger of ozone erosion isn't over, but the future may be brighter than thought. Email a Friend Display Latest Headlines Read Archives Most Popular How To De-Bug Your Adventure America's Top Beach - South Padre Island, Texas El Yunque, the Caribbean National Forest, America's only U.S... Five Star RV Adventure Resorts ... Great God! Great White Shark Adventure What's Hot Five Star RV Adventure Resorts Tikal, Guatemala, ancient city of the Maya - Tikal travel

79. Wind Flows Tear At Ozone Layer | Csmonitor.com Sci/Tech Environment from the August 08, 2002 edition Wind flows tear at ozone layer. By Robert C. Cowen Special to The Christian Science Monitor. http://www.csmonitor.com/2002/0808/p13s02-sten.html

WORLD USA COMMENTARY LEARNING ... MonitorTalk Search: Environment Internet Also see: In this week's Sci/Tech section: Cosmos at full throttle 'Dead zones' threaten fisheries Ancient critters' dinner menu: glass Egypt gets its own 'central park' ... more projects... Most-viewed stories: (for 05/25/04) US closes in on deal with Iraqi cleric 'Gas roots' protest over pump prices National Parks fast falling into disrepair In grade-obsessed society, learning gets left behind ... Environment from the August 08, 2002 edition Wind flows tear at ozone layer By Robert C. Cowen Climate change is giving scientists a new perspective on Northern Hemisphere ozone depletion. Ozone chemist Neil Harris says "it's now clear" that shifts in large-scale wind flows dilute the stratosphere's ozone and open mini ozone holes at northern mid-latitudes even when ozone-eating chemicals are not directly involved. He adds that this implies that we won't return to the pre-ozone-loss atmosphere even when the chemical culprits are gone. International efforts to curb the use of such ozone-eaters as chlorine-containing refrigerants and bromine-containing fire suppressants are beginning to pay off. Their concentration in the atmosphere should gradually decline. But, as Dr. Harris explains, this won't eliminate concern about increased exposure to solar ultraviolet (UV) radiation for heavily populated parts of the Northern Hemisphere. E-mail this story Write a letter to the Editor Printer-friendly version Related stories: It's not another ice age, but at least it's cooler

80. UNIVERSITY OF MALTA University of Malta. SAVING THE ozone layer. Today, most people are quite familiar with the fact that a gas called ozone is present http://www.um.edu.mt/pub/ozone.html

SAVING THE OZONE LAYER Today, most people are quite familiar with the fact that a gas called ozone is present in the upper atmosphere, many miles above the earth's surface. It is this layer of ozone that helps to screen out much of the radiation from the sun, which would otherwise reach us, with very sinister implications for our health. And yet, it was only twenty five years ago that scientists discovered that certain chemicals produced by man and known as chlorofluorocarbons (in short CFCs) were finding their way up to the upper atmosphere, reacting with this ozone layer and depleting it. By the early 1980's, the damage to the ozone layer had become even more apparent and an initiative was taken to convene the nations of the world to discuss global corrective measures. As a direct result, a 'Convention for the Protection of the Ozone Layer' was concluded at an international meeting, held in Vienna in 1985. This was followed by a protocol, adopted in Montreal in 1987, for co-operation amongst nations towards the implementation of measures to drastically reduce the production of substances that deplete the ozone layer. This protocol has subsequently been updated and amended twice: in London in 1990 and in Copenhagen in 1992. Malta signed and became a party to the Vienna Convention and the Montreal Protocol in 1988 and has since taken a number of concrete measures to comply with its international obligations, and hence to do its small part towards the protection of the ozone layer.

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