Ozone Layer Project

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OMTEX CLASSES 2008-09

PROJECT ON OZONE LAYER INDEX

NAME OF THE TOPIC COVERED TeachersSignature

1. The ozone layer: What is it?2. Ozone depletion: Who is

responsible?3. The ozone hole: Why over

Antarctica?4. SOCIETAL ASPECTS5. Ozone depletion and skin cancer: Whats

the connection?

6. What about other illnesses?7. Ozone depletion: Not a farmers best

friend.

8. Collaborative Global GovernmentEfforts9. Ozone and health10.DISCUSSION11. SUMMARY

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I. The ozone layer: What is it?The ozone layer is a portion of earths atmosphere that contains high levels of ozone. Theatmosphere is divided into five layers: the troposphere, the stratosphere, the mesosphere,the thermosphere, and the exosphere. The troposphere is the layer closest to earth and iswhere all weather happenings occur. The stratosphere is located directly above thetroposphere, about 10-50 kilometers above the planet, and houses the ozone layer at analtitude of 20-30 kilometers. The mesosphere is located approximately 50-80 kilometersabove the earth, while the thermosphere rests at an altitude of approximately 100-200kilometers above the earths surface. Finally, the boundary of the outermost layer, theexosphere, extends roughly to 960-1000 kilometers above the earth. For a visual of thelowermost three layers of our atmosphere, refer to Figure 1 below.

Ozone (O 3) is a triatomic molecule , consisting of three oxygen atoms . It is an allotrope of oxygen that is much less stable than the diatomic species O 2. Ground-level ozone is an air

pollutant with harmful effects on the respiratory systems of animals. Ozone in the upper atmosphere filters potentially damaging ultraviolet light from reaching the Earthssurface. It is present in low concentrations throughout the Earth s atmosphere . It hasmany industrial and consumer applications. Ozone therapy is a controversial alternativemedicine practice; mainstream scientific medicine has found ozone to be harmful tohumans and equipment intended to be used for ozone therapy is banned in the UnitedStates. Ozone, the first allotrope of a chemical element to be described by science, wasdiscovered by Christian Friedrich Schnbein in 1840 , who named it after the Greek wordfor smell ( ozein ), from the peculiar odor in lightning storms. [3] The odor from a lightningstrike is from ions produced during the rapid chemical changes, not the ozone itself

Figure 1: Earths atmosphere is divided into layers, which have various characteristics.Source: NOAA Aeronomy Laboratory, 1998

The ozone found in our atmosphere is formed by an interaction between oxygenmolecules (composed of two oxygen atoms) and ultraviolet light. When ultraviolet lighthits these oxygen molecules, the reaction causes the molecules to break apart into single

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atoms of oxygen (UV light + O 2 --> O + O). These single atoms of oxygen are veryreactive, and a single atom combines with a molecule of oxygen to form ozone (O 3),which is composed of three atoms of oxygen (2O + 2O 2 --> 2O 3).

The ozone layer is essential for human life. It is able to absorb much harmful ultraviolet

radiation, preventing penetration to the earths surface. Ultraviolet radiation (UV) isdefined as radiation with wavelengths between 290-320 nanometers, which are harmfulto life because this radiation can enter cells and destroy the deoxyribonucleic acid (DNA)of many life forms on planet earth. In a sense, the ozone layer can be thought of as aUV filter or our planets built in sunscreen (Geocities.com, 1998). Without theozone layer, UV radiation would not be filtered as it reached the surface of the earth. If this happened, cancer would break out and all of the living civilizations, and all specieson earth would be in jeopardy (Geocities.com, 1998). Thus, the ozone layer essentiallyallows life, as we know it, to exist.

In order for scientists to evaluate how much ozone is in the layer, a unit of measurementcalled the Dobson Unit is employed. A Dobson Unit is a measurement of how thick aspecific portion of the ozone layer would be if it were compressed into a single layer atzero degrees Celsius with one unit of atmospheric pressure acting on it (standardtemperature and pressure - STP). Thus, one Dobson Unit (DU) is defined as .01 mmthickness at standard temperature and pressure. Figure 2 shows a column of air over Labrador, Canada. Since the ozone layer over this area would form a 3 mm thick slab,the measurement of the ozone over Labrador is 300 DU.

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II. Ozone depletion: Who is responsible?It is important to recognize the sources of ozone depletion before one can fully

understand the problem. There are three main contributors to the ozone problem: humanactivity, natural sources, and volcanic eruptions (See Figure 3).

Figure 3: Humans cause more damage to the ozone layer than any other source.Source: Geocities.com, 1998

Human activity is by far the most prevalent and destructive source of ozone depletion,while threatening volcanic eruptions are less common. Human activity, such as therelease of various compounds containing chlorine or bromine, accounts for approximately 75 to 85 percent of ozone damage. Perhaps the most evident anddestructive molecule of this description is chloroflourocarbon (CFC). CFCs were firstused to clean electronic circuit boards, and as time progressed, were used in aerosols andcoolants, such as refrigerators and air conditioners. When CFCs from these products arereleased into the atmosphere, the destruction begins. As CFCs are emitted, the moleculesfloat toward the ozone rich stratosphere. Then, when UV radiation contacts the CFCmolecule, this causes one chlorine atom to liberate. This free chlorine then reacts with anozone (O 3) molecule to form chlorine monoxide (ClO) and a single oxygen molecule(O 2). This reaction can be illustrated by the following chemical equation: Cl + O 3 --> O 2

+ ClO. Then, a single oxygen atom reacts with a chlorine monoxide molecule, causingthe formation of an oxygen molecule (O 2) and a single chlorine atom (O + ClO --> Cl +O2). This threatening chlorine atom then continues the cycle and results in further destruction of the ozone layer (See Figure 4). Measures have been taken to reduce theamount of CFC emission, but since CFCs have a life span of 20-100 years, previouslyemitted CFCs will do damage for years to come.

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Figure 4: A pictorial explanation of how the interaction of CFCs and UV radiationdamage the ozone layer.Source: Geocities.com, 1998

Natural sources also contribute to the depletion of the ozone layer, but not nearly as muchas human activity. Natural sources can be blamed for approximately 15 to 20 percent of ozone damage. A common natural source of ozone damage is naturally occurringchlorine. Naturally occurring chlorine, like the chlorine released from the reaction

between a CFC molecule and UV radiation, also has detrimental effects and poses danger to the earth.

Finally, volcanic eruptions are a small contributor to ozone damage, accounting for oneto five percent. During large volcanic eruptions, chlorine, as a component of

hydrochloric acid (HCl), is released directly into the stratosphere, along with sulfur dioxide. In this case, sulfur dioxide is more harmful than chlorine because it is convertedinto sulfuric acid aerosols. These aerosols accelerate damaging chemical reactions,which cause chlorine to destroy ozone.

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III. The ozone hole: Why over Antarctica?When the topic of the ozone layer arises, many people immediately think of the hole

over Antarctica, but few know why the hole is actually there. In 1985, British scientistsdiscovered this hole. A special condition exists in Antarctica that accelerates thedepletion of the ozone layer. Every Arctic winter, a polar vortex forms over Antarctica.A polar vortex is a swirling mass of very cold, stagnant air surrounded by strongwesterly winds (Roan, 126). Since there is an absence of sun during Arctic winters, theair becomes incredibly cold and the formation of ice clouds occurs. When the sun returnsin the spring, the light shining on the nitrogen oxide filled ice particles activates theformation of chlorine. This excess of ozone destroying chlorine rapidly accelerates thedepletion of the ozone layer. Finally, when the polar vortex breaks up, the rapiddissolution decreases. It is evident that the effects of the polar vortex are dramatic. For about two month every southern spring, the total ozone declines by about 60% over mostof Antarctica. In the core of the ozone hole, more than 75% of the ozone is lost and atsome altitudes, the ozone virtually disappeared in October, 1993 (Nilsson, 19). The

average size of the ozone hole is larger than most continents, including South America,Europe, Australia, and Antarctica, and the maximum size of the ozone hole in 1996 waslarger than North America (See Figure 5). Finally, one must note that the hole over Antarctica is truly a hole only in the Antarctic spring, when the depletion is extremelysevere due to the vortex.

Figure 5: On average, the size of the ozone hole is larger than many countries.Source: Geocities.com, 1998

The hole above Antarctica has clearly proven to be detrimental. Plankton, organisms thatlive on carbon, light, and nutrients such as nitrogen, are near the bottom of the food

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chain, and are accustomed to low levels of UV. In December of 1994, on the island of Bacharcaise off Antarctica, increased levels of UV radiation decreased the number of

photoplankton dramatically. Photoplankton are the main source of food for krill, whichin turn are the main source of food for various birds and whales in the Antarctic region(See Figure 6).

Figure 6: Ultraviolet radiation proved detrimental to this Arctic food chain in December,1994.

Source: Nilsson, 1996

At this time, due to the decreased number of photoplankton, the krill level was so lowthat it could not support the penguin population. Thus, some penguins were forced totravel up to two hundred miles in search of food, but most returned with none.Furthermore, when summer came, only approximately ten of the 1800 hatched penguinchicks survived. This tragedy illustrates the fact that even underwater creatures are not

protected from harmful UV rays, and is a perfect example of the entire food chain beingaffected due to an increase in the UV radiation as a result of the thinning ozone layer.

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SOCIETAL ASPECTS

The most obvious, and perhaps most important connection between society and the ozonelayer is the fact that scientific research suggests depletion of the ozone layer directly and

indirectly endangers the health of the population. Research has focused on connections between the depleting ozone layer and skin cancer, immuno-suppression, cataracts, andsnow blindness.

IV. Ozone depletion and skin cancer: Whats the connection?Exposure to UV radiation increases the risk of skin cancer and causes damage to theDNA in the skin cells. DNA is extremely sensitive to UV radiation, especially UV-Bradiation. UV radiation is located in the optical radiation portion of the electromagneticspectrum, while UV-B radiation is a subdivision of the ultraviolet spectrum and consistsof a wavelength of 280 to 315 nanometers. Thus, DNA is especially sensitive toradiation with a wavelength between 280 and 315 nanometers (See Figure 7).

Figure 7: UV-B, the most harmful radiation to humans and plants, has a wavelength of 280-315 nanometers, as measured on the electromagnetic spectrum.

Source: Nilsson, 1996

When UV radiation hits the skin, it can cause the cell to lock up and scramble or deleteDNA information. This action causes confusion in the DNA, and the body loses controlof the growth and division of the cell. If the conditions are right, the cell may becomecancerous. It is important to note that not all affected cells turn into skin cancer, for many can repair themselves. However, continual exposure to UV radiation increases therisk of skin cancer due to cumulative damage of the DNA.

Skin cancer can be divided into two categories: melanoma and non-melanoma. Themelanoma form of skin cancer is the more dangerous of the two. This type of cancer has

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the ability to spread quickly throughout the body and invade other cells. On the other hand, non-melanoma skin cancer is not to be taken lightly either, but is a less seriousform of the disease. Non-melanoma skin cancers are not usually life threatening, andremoval is relatively routine. However, treatment does include radiation therapy or surgery. The concern of many is that sunburn may lead to increased risk of acquiring skincancer. Some forms of cancer are associated with sunburn, while other forms are not.Melanoma skin cancer is a form that sunburns may play a leading role in. Jan van der Leun, a Dutch scientist, explains that, light hitting the outer layer of the skin, theepidermis, triggers the production of some substances which diffuse into the dermis

below. The dermis is filled with blood vessels, and the chemical substances cause themto dilate, making the skin red and warm to the touch (Nilsson, 83).

The bottom line is that UV ray exposure increases the risk of skin cancer. However,controversy lies around the question of whether or not the depletion of the ozone layer will lead to more sunburns, and in turn, more skin cancer. Some scientists suggest thatthe skin will gradually adapt to higher UV-B levels as the ozone gradually depletes(Nilsson, 83). The opponent to this theory would state that the thinning of the ozonelayer would lead to more human UV-B exposure. This increased UV-B exposure would,in turn, increase the damage to the DNA making it difficult for the cell to correct thedamage before it divides. This damage accumulates over time and increases the chancesthat a cell will turn cancerous. In addition, since UV-B radiation damages the immunesystem, it is much more likely that a cell will turn cancerous. In animal studies,immunosuppressive effects caused by UV-B have indeed been shown to play animportant role in the outcome of both melanoma and non-melanoma skin cancers(Nilsson, 105). Furthermore, Nilsson (81) states that for the non-melanoma skincancers, the evidence is compelling and there are estimates that each percentage decreasein the stratospheric ozone will lead to a two percent increase in the incidence of thesecancers. Thus, if the ozone depletes by ten percent over a certain time period, 250,000

more people would be affected by these cancers each year (Nilsson, 81).Due to controversy in the scientific community, it is difficult to clearly state whether or not ozone depletion will lead to an increased risk of skin cancers, but scientists agree onthe fact that UV-B radiation plays a large role in the formation of cancer. Thus, it mayvery well be that as the UV filter we call the ozone layer thins, the increased amount of UV-B radiation posed on human skin may contribute to an increased amount of skincancer. Yet, one can only weigh all the evidence and speculate, for science has yet to

provide a cut and dry answer for society to base its judgments on.

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V. Ozone depletion and immuno-suppressionOzone depletion is also suggested to cause immuno-suppression. This theory was firstexplored in the 1960s when guinea-pigs, who were exposed to an allergen, showed alowered immune system response after they had been irradiated with UV (Nilsson, 101).In addition, another study showed that UV radiation had the same effect on animals as X-ray treatment and chemical immuno-suppression. Logically, all three factors suppressedthe immune system.

Scientists Edward de Fabo and Frances Noonan conducted a study to investigate exactlywhich portion of the UV spectrum has the power to suppress the immune system. In thisexperiment, de Fabo and Noonan employed filters that were able to separate UV radiationwavelength by wavelength. They subjected mice to UV rays and measured the effects at

precise intervals on the UV range. When de Fabo and Noonan started to match the partsof the spectrum that gave the most immuno-suppression with the absorption spectra of different compounds in the skin, they found an almost perfect match UCA, thecompound previously thought of as sunscreen (Nilsson, 102). Nilsson (107) describesurocanic acid (UCA) as antenna-like because it attracts UV rays. When UV radiation hitsthe skin, it causes UCA within the skin to change molecular structure from trans -UCA tocis -UCA. This transformation interacts with a number of cells in the skin and sends asignal to the immune system, causing it to hinder its reaction. If the UVA has causeddamage to the DNA, then the possibility exists for a cancer growth (See Figure 8).

Figure 8: UV radiation causes the transformation of trans-UCA to the form cis-UCA,damaging DNA and causing the immune system to suppress.

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VI. What about other illnesses?Like immuno-suppression and skin cancer, science is not able to provide society with aconfident answer to the question: Will the depletion of the ozone layer cause an increasednumber of cataract cases? Cataracts are a condition that begin with blurry vision and insome cases, develop into blindness. It has been proven that UV light can damage theDNA, membranes, and proteins in the eye, and in animal studies, this damage hasresulted in scattered light and the formation of opaque areas in the eye. It was estimated

by the Environmental Effects Panel of the United Nations Environment Programme thatfor each percent decrease in ozone, the number of people developing blindness wouldincrease by approximately 100,000 to 150,000 people (Nilsson, 113). However, thisestimation was contradicted by a team of Dutch scientists, who stated, it is notscientifically justifiable to quantify the effects of UV radiation on the eye, if such effectsare present under normal circumstances (Nilsson, 113). The UNEP then published anupdated statement and included information that poor diet and diseases, such as diabetes,also contribute to cataract development. Thus, it must be recognized that cataracts can

result from poor nutrition, poor hygiene, and diabetes, and not solely from increased UVradiation.

Research has been conducted to investigate a link between cataracts and UV radiation.Some epidemiological studies have shown that UV-B radiation and formation of cataractsdo have a positive relationship. For example, a study conducted with Chesapeake Bayfishermen asked these fishermen to disclose whether or not they wore sunglasses whileworking and during outdoor recreational activities. Then, radiation measurements weretaken throughout the area to probe for a correlation. The results of this study showed aweak positive dose-response relationship with UV-B exposure (Nilsson, 117). Thus, inthis study, one would argue that increased UV radiation would lead to increased rates of cataracts. Many other studies have been conducted to examine this phenomenon, and

none have shown a strongly correlated causal relationship between UV-B and cataracts, but many suggest the possibility of a relationship. In summary, there is again no cut anddry answer explaining what will happen to the number of cases of cataracts as the ozonelayer depletes, but when one examines the effects of UV-B radiation on the eyes, it issuggested that ozone depletion is likely to increase ones risk of developing cataracts.

A short-term health problem that will increase as the level of ozone decreases issnowblindness or welders arc flash. This phenomenon is a result of sunburn of theconjunctiva and cornea and is characterized by blurred vision, severe pain, photophobia,

profuse tearing, and eyelid spasms (Ozone.org, 1998). The condition occurs after exposure to UV-B radiation and does not result in permanent damage. The symptomsusually vanish after a few days. It is obvious to recognize the controversy surrounding

theories which state that depletion of the ozone layer causes health problems. While oneresource may provide the reader with one answer, the next source may provide theopposite theory. It is evident that UV radiation causes various health problems, but whatis not so clear is to what degree a depleting ozone layer will magnify the occurrence of these problems.

VII. Ozone depletion: Not a farmers best friend.

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Another common, yet, highly debated concern with regards to the depleting ozone layer is crop and plant damage. As it has been well stressed, depletion of the ozone layer results in higher UV-B radiation on the earths surface. Ironically, while plants use lightas their main fuel for growth, a delicate balance must be achieved in order for the plant tosurvive. If a plant is exposed to too much UV radiation, the DNA of the plant may

become damaged due to penetration of harmful UV radiation into sensitive areas of the plant. UV radiation also causes problems in the photosynthetic machinery by hamperingthe photosynthesis process, the cell membrane by altering the transportation of essential

potassium, and the cells skeleton by affecting cell growth and morphology. With thisinformation taken into account, it would seem logical that increased UV radiation fromthe depleting ozone layer would lead to plant damage. However, it is not that simple.Some plants actually employ a mechanism that allows them to protect themselves fromUV damage. Thus, research suggests that if ozone depletion became serious enough, the

plants without the protective mechanisms would die out, but the plants with thesemechanisms would be able to replace the extinct plants, and not affect the level of

productivity in the ecosystem (Nilsson, 54). Thus, much depends on which plants

survive.To further investigate the affect of UV radiation on plants, experiments have been doneto study the effects of UV-B levels on crop yield (Nilsson, 52). The results concludedthat in approximately 50% of the crops, an increased UV-B level lead to a decrease incrop yield. Specifically, the corn yield was reduced by 28 percent; and beans, squash,and various forms of peas were also found to be sensitive to UV-B radiation. One wouldlogically conclude that the depletion of the ozone layer would lead to a reduction in theyield of crops. However, science may offer a solution by being able to breed crops thatare resistant to UV radiation.

The answer to the question of decreased crop yield and existence of plants as a result of athinning ozone layer is not scientifically definitive. However, it is important because if

the ability of plants to intake carbon dioxide and regulate the amount of carbon dioxide inthe air is altered, the consequences for society are detrimental.

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VIII. Collaborative Global Government EffortsAs a result of the many concerns that a thinning ozone layer poses to society and theenvironment, the U.S. government and many international agencies have been relativelyactive in attempting to monitor, regulate, and solve the problem. Perhaps the most wellknown acts to help control the depletion of the ozone layer were the Montreal Protocol,and the London Ozone amendment to the Montreal Protocol. On September 14, 1987,delegates from 43 countries met to discuss threats of the thinning ozone layer. After much discussion, the delegates agreed to halt production and consumption of CFCs at1986 levels by the year 1990. In addition, nations also agreed to reduce CFCs 20 percent

by January 1, 1994 and an additional 30 percent by January 1, 1999 (Roan, 208-9). Thiswas known as the Montreal Protocol. Even though this protocol helped the state of theozone layer, the results were not significant enough. Thus, shortly after theimplementation of the protocol, in 1990, it was amended. This amendment recruitedmore countries, bringing the total number involved to almost 100. The new goals were toeliminate the use of all CFCs by the year 2000, and to help set up a fund so that

developing countries may find alternates to using CFCs. The name of this amendmentwas the London Ozone Agreement. Thus, many nations recognized the need for rapidand dramatic action in fighting the war with CFC responsible ozone depletion.

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Ozone and healthOzone in air pollution

There is a great deal of evidence to show that high concentrations (ppm) of ozone,created by high concentrations of pollution and daylight UV rays at the earths surface,can harm lung function and irritate the respiratory system .[16][23] A connection has also

been shown to exist between increased ozone caused by thunderstorms and hospitaladmissions of asthma sufferers. [24] Air quality guidelines such as those from the WorldHealth Organization are based on detailed studies of what levels can cause measurablehealth effects .

A common British folk myth dating back to the Victorian era holds that the smell of thesea is caused by ozone, and that this smell has bracing health benefits. [25] Neither of these is true. The characteristic smell of the sea is not caused by ozone, but by the

presence of dimethyl sulfide generated by phytoplankton , and dimethyl sulfide, likeozone, is toxic in high concentrations. [26]

The United States Environmental Protection Agency has developed an Air Quality indexto help explain air pollution levels to the general public. 8-hour average ozoneconcentrations of 85 to 104 ppbv are described as Unhealthy for Sensitive Groups, 105

ppbv to 124 ppbv as unhealthy and 125 ppb to 404 ppb as very unhealthy. [27] TheEPA has designated over 300 counties of the United States, clustered around the mostheavily populated areas (especially in California and the Northeast), as failing to complywith the National Ambient Air Quality Standards .

Health Effects of UV Radiation

Overexposure to UV radiation is the main cause of skin cancer. UV rays can trigger thedevelopment of skin cancer by creating changes in the cells of the skin. In some cases,the UV rays cause direct damage to the cells. Tans and sunburns, for example, are bothsigns that UV rays have damaged the skin. In other cases, UV rays can cause skin cancer indirectly, by weakening the immune mechanisms in skin and the rest of the body.

Most often, skin cancer is the result of overexposure to UV rays from the sun. There arethree types of skin cancer: basal cell carcinoma, squamous cell carcinoma, and malignantmelanoma. The last one can be fatal if not treated early. Many studies of skin cancer

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show links between malignant melanomas and an individuals intolerance to sunexposure. The studies indicate that people who have suffered severe and frequentsunburns during childhood are at greater risk of developing melanoma. The features mostclosely associated with intolerance to sun exposure include fair or freckled skin, blueeyes, and light-coloured or reddish hair.

The two other types of skin cancer tend to develop later in life on areas of skin that have been exposed repeatedly to the sun, such as the face, neck, or hands. Basal and squamouscell carcinomas progress slowly and rarely cause death because they usually do notspread to other parts of the body.

Overexposure to ultraviolet radiation has also been linked to a number of other healtheffects, including sunburns, cataracts, premature aging of the skin, and weakening of theimmune system.

Minimizing Your Risk There is no quick fix for the ozone layer. Once they get into the environment, ozone-depleting chemicalsdisintegrate very slowly, so they are likely to be with us for a long time. While governments around the worlddeal with the source of the problem, it is important to take steps to avoid overexposure to ultraviolet radiation.

These guidelines will help you protect your family from the suns harmful rays:

Seek shade if you are taking part in outdoor activities when the UV index is threeor higher.

Cover up. Wear long-sleeved shirts, long pants, gloves, and a broad-brimmed hator visor. Avoid see-through clothing when possible.

Avoid sunbathing for the purpose of tanning, especially between 11:00 a.m. and4:00 p.m. in the summer when the suns rays are strongest.

Use sunscreen lotion and reapply it often, as directed on the label. Look for abroad spectrum sunscreen with a sun protection factor (SPF) of at least 15.

Wear sunglasses that screen out ultraviolet radiation. Your eyes have no built-indefence against the sun, and damage to the eye from UV rays can lead tocataracts.

Do not think you are safe just because the sky is cloudy. The suns harmful rayscan get through fog, haze, and light cloud cover.

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Children Need Extra ProtectionChildren and teenagers have more sensitive skin than adults, so they need extra protectionif they are going to be out in the sun for a long time. Sunburn may increase the risk of skin cancer later in life, so it is best to get children used to wearing protective clothingand sunscreen lotion from the start.

At the very least, young children should wear a sunhat, T-shirt, and shorts. When you putsunscreen on children, pay special attention to the parts that are most exposed, includingtheir ears, face, neck, shoulders and back, knees, and the tops of their feet. Avoid usingsunscreen on babies. Cover them and keep them in the shade instead.

It is important to protect against ultraviolet radiation all year round; not just in thesummer. You can continue to enjoy outdoor activities, as long as you take steps to protectyourself when the UV index is three or higher to avoid sunburns and overexposure.

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DISCUSSIONRegardless of the details of the arguments, it is obvious that the depletion of the ozonelayer is a serious problem that poses many consequences to society. Although scientificcontroversy exists, the possibility seems high that the depletion of the ozone layer will

prove detrimental if action is not taken. For example, research shows the strong possibility of a number of health risks associated with increased UV-B exposure as adirect result of the thinning ozone layer. These health risks include skin cancer, immuno-suppression, cataracts, and snowblindness.

Furthermore, the possibility that increased UV-B radiation results in lower crop yieldsshould provide a wake up call to those who feel the thinning ozone layer is not a

problem. For if we are not able to breed UV-B resistant plants, the worlds food supplywould become dramatically decreased, resulting in higher levels of famine andmalnutrition.

Studies from Antarctica tell society that increased UV radiation can directly affect the

food chain. Recall the decrease in food supply as a result of reduced levels of photoplankton in Antarctica. This may seem like an isolated, non-significant, and remote problem; however, this incident illustrates the dangers of reduced food supply andalteration of the food chain as a result of the thinning ozone layer. Even though the

photoplankton were located at the bottom of the food chain, the whole chain wasaffected. In the future, problems like this could potentially affect the global food weband result in an overall decrease in food supply. Thus, realize that the dangers posed byozone depletion are real now, and will be in the future, if action is not taken.

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Take Action: Teamwork does the trick Although the earth will be able to heal itself if the CFC level continues to stay as it is,the depletion of the ozone layer is still a problem that society should be concerned with.In order for earth to repair the damage humans have posed on the ozone layer, societymust take an active role. There are many tasks individuals can involve themselves in tohelp combat the problem of ozone depletion. First of all, one can simply check productlabels for ozone friendly status. Many companies have gone to great lengths to removeCFCs from their products. These products do not do as much damage to the ozone layer,and thus, are denoted as ozone friendly. A collaborative effort by society not using

products with CFCs is a major step toward the healing of the ozone layer.

Unfortunately, many products still used in society are detrimental to the ozone layer. For example, CFCs marketed under the trade name Freon are used in appliances withrefrigerants such as refrigerators and air conditioners. When individuals must dispose of

products with refrigerants in them, certain actions must be taken in order to prevent theCFCs from escaping from the disposed product. For example, when an agency, such as awaste hauling company, comes to pick up the unwanted appliance, check to make surerefrigerant-recovery equipment is used by the agency. This equipment allows for thedisposal of refrigerants without damage to the ozone layer.

Society can also help the problem of ozone depletion through education, as well asthrough various donations. If individuals contribute time or money to environmentalagencies focused on healing the ozone layer, the agencies will be able to organizeactivities promoting the understanding of the ozone problem. If society is educatedthrough these means, more individual efforts will be taken to make ozone smartdecisions such as using ozone friendly products.

Although thinning ozone may not directly affect the generation growing up today, future

generations depend on the actions taken now. Thus, it is important for society torecognize that the thinning ozone layer is a problem and to take action in order to ensurethe safety and survival of future generations.

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SUMMARYThe ozone layer is essential for protecting society from harmful UV radiation by acting asa filter. However, this protective layer has been thinning due to three main sources:human activity, natural sources, and volcanoes. Human activity is responsible for themost damage to the ozone layer, thus, society should recognize that much can be done to

prevent ozone layer damage.

In 1985, in a region over Antarctica, the yearly polar vortex had caused the ozone layer todeplete so greatly, that it could be classified as a hole. In 1996, this hole was largeenough to cover Antarctica.

The depletion of the ozone layer does not come without problems. Scientific researchhas suggested the probability that increased UV-B radiation as a result of the thinningozone layer leads to increased cases of skin cancer, immuno-suppression, cataracts, andsnow blindness due to radiation damage of the DNA. Additionally, experiments haveshown a correlation between increased UV radiation and crop damage due to UV

radiation damaging the plants DNA. Some scientists, however, feel that this will not bea problem in the future due to the possibility of breeding UV resistant crops and plants.

Many national governments and agencies recognized the problem of ozone depletion, andtherefore, united in 1987 to sign the Montreal Protocol. This agreement wasimplemented to decrease CFC levels in order to help protect the thinning ozone layer.

Clearly, ozone depletion is a dangerous problem due to possible disease outbreaks andfamine as a result of increased UV-B radiation. However, society can collectivelyattempt to combat this problem by relatively simple means such as education and the

practice of ozone smart behavior. For if society acts now, future generations will behanded a safe and healthy planet.

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Ozone Layer Project

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Transcript of Ozone Layer Project