case study on ozone layer

8/4/2019 Case Study on Ozone Layer

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ANTRACTICA OZONEANTRACTICA OZONELAYERLAYER

GUDIED BY:GUDIED BY:--

Mrs.Reena singhMrs.Reena singhPresented by:Presented by:--GroupGroup--IIIIII(E.C.E.)(E.C.E.)


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COMPILED BY:COMPILED BY:--

VIKASH KUMAR(419/08)VIKASH KUMAR(419/08)

ANKUR GOYAL(420/08)ANKUR GOYAL(420/08)

SUMAN SANYA(421/08)SUMAN SANYA(421/08)

ABHISHEK SINGH(422/08)ABHISHEK SINGH(422/08)

MOKSH KUMAR SINGH(423/08)MOKSH KUMAR SINGH(423/08)

PRAKASH PRATIK(424/08)PRAKASH PRATIK(424/08)

ANSHU AYUSHYA(425/08)ANSHU AYUSHYA(425/08) ALOK KUMAR(426/08)ALOK KUMAR(426/08)

RAVI KUMAR JYOTI(427/08)RAVI KUMAR JYOTI(427/08)


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INDEXINDEX

1.WHAT IS OZONE?1.WHAT IS OZONE?

2.WHERE IS THE OZONE?2.WHERE IS THE OZONE?

3.ISNT OZONE BAD NEWS?3.ISNT OZONE BAD NEWS?

4.WHY IS A OZONE HOLE A PROBLEM?4.WHY IS A OZONE HOLE A PROBLEM?


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5.HOW DOES A OZONE HOLE FORM5.HOW DOES A OZONE HOLE FORM

OVER ANTRACTICA?OVER ANTRACTICA?

6.WHAT CAUSES THE OZONE6.WHAT CAUSES THE OZONE

DEPLITION?DEPLITION?

7.IS THE OZONE HOLE GOING TO7.IS THE OZONE HOLE GOING TO

STAY OVER ANTRACTICA?STAY OVER ANTRACTICA?

8.CAN THE OZONE HOLE RECOVER?8.CAN THE OZONE HOLE RECOVER?


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What is ozone?What is ozone?

Ozone is a gas* made of oxygenOzone is a gas* made of oxygenatoms.atoms.

Usually oxygen atoms hang aroundUsually oxygen atoms hang aroundin pairsin pairs -- this is the sort of oxygenthis is the sort of oxygenthat we breathe and that helpsthat we breathe and that helpsthings to burn.things to burn.

Oxygen sometimes however willOxygen sometimes however willform a molecule with three oxygenform a molecule with three oxygenatoms, this is what we call ozone:atoms, this is what we call ozone:


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O2O2 -- two oxygen atomstwo oxygen atoms -- ordinary commonordinary commonor garden oxygenor garden oxygen

O3O3 -- three oxygen atomsthree oxygen atoms OzoneOzone

Ozone has a the particularly usefulOzone has a the particularly usefulcharacteristic that it can absorb largecharacteristic that it can absorb largequantities of ultraquantities of ultra--violet (uv) lightviolet (uv) light -- moremoreof that soon.of that soon.


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Where is the ozone?Where is the ozone?

Most of the ozone on earth isn't on earthMost of the ozone on earth isn't on earthat all, but in the layer of the earth'sat all, but in the layer of the earth'satmosphere called theatmosphere called the stratosphere.stratosphere.

This is the upper layer of the atmosphereThis is the upper layer of the atmosphereand starts between 12.9 to 19.3 km (8 toand starts between 12.9 to 19.3 km (8 to12 miles) above our heads and goes12 miles) above our heads and goesupwards to almost 50 km (30 miles).upwards to almost 50 km (30 miles).

The stratosphere has virtually no cloudsThe stratosphere has virtually no cloudsor other form of weather, it's thinnest ator other form of weather, it's thinnest atthe equator and thickest at the poles.the equator and thickest at the poles.


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Ozone is formed in the stratosphereOzone is formed in the stratosphereby the action of sunlight on oxygenby the action of sunlight on oxygen

molecules.molecules.

In particular it is the high energy ultraIn particular it is the high energy ultra--violet lightviolet lightin sunlight that is effective, it causes an oxygenin sunlight that is effective, it causes an oxygenmolecule to split into two oxygen atoms:molecule to split into two oxygen atoms:

O2O2 ------------------>> OO ++ OO


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One of these then joins with anotherOne of these then joins with anotheroxygen molecule to form a molecule ofoxygen molecule to form a molecule ofozone:ozone:

OO ++ O2O2 ------------------>> O3O3 Ozone may also be destroyed by joiningOzone may also be destroyed by joining

with a lone oxygen atom to get back towith a lone oxygen atom to get back tooxygen again.oxygen again.

UltraUltra--violet light is required for ozoneviolet light is required for ozone

to form in the stratosphere, but thento form in the stratosphere, but thenthe ozone absorbs the ultrathe ozone absorbs the ultra--violetvioletlight so stopping it reaching deeperlight so stopping it reaching deeperinto the earth's atmosphere.into the earth's atmosphere.


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The result is that levels of ozoneThe result is that levels of ozoneare greatest at around 20km upare greatest at around 20km up..

This is good news for us as it stopsThis is good news for us as it stopslots of ultralots of ultra--violet light gettingviolet light gettingthrough to us and also keeps thethrough to us and also keeps theozone high up in the atmosphere outozone high up in the atmosphere out

of the way.of the way.


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Isnt ozone bad news?Isnt ozone bad news?

Ironically, at ground level ozoneIronically, at ground level ozoneis very bad news. It is a majoris very bad news. It is a majorcomponent of photochemicalcomponent of photochemical

smog.smog. It is caused by the effect of ultraIt is caused by the effect of ultra--

violet light on nitrogen oxide fromviolet light on nitrogen oxide from

vehicle exhausts and so particularlyvehicle exhausts and so particularlyaffects built up areas in regions ofaffects built up areas in regions ofhigh sunshine.high sunshine.


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Ozone affects lung function, it canOzone affects lung function, it canaggravate asthma and other chronicaggravate asthma and other chronicrespiratory tract and lung diseases andrespiratory tract and lung diseases and

can reduce lung function in the short termcan reduce lung function in the short termor even permanently on repeatedor even permanently on repeatedexposure.exposure.

Ozone has an effect like sunburn on theOzone has an effect like sunburn on the

lining of the respiratory tract damaginglining of the respiratory tract damagingthe cellsthe cells


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Ozone in the stratosphere is nicelyOzone in the stratosphere is nicelyout of the way and has the wonderfulout of the way and has the wonderfulbenefit to life on earth that itbenefit to life on earth that it

specifically absorbs the harmful ultraspecifically absorbs the harmful ultra--violet light from the sun while lettingviolet light from the sun while letting

other light wavelengths through.other light wavelengths through.


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If there is a hole in the ozone layer then this means thatIf there is a hole in the ozone layer then this means thatmore harmful ultramore harmful ultra--violet rays get through than are goodviolet rays get through than are goodfor us or many other life forms, plant or animal.for us or many other life forms, plant or animal. Too muchToo muchultraultra--violet light can result in:violet light can result in:

Skin cancerSkin cancer

Eye damage such as cataractsEye damage such as cataracts Immune system damageImmune system damage Reduction in phytoplankton in the oceans that forms theReduction in phytoplankton in the oceans that forms the

basis of all marine foodchains including those in Antarctica.basis of all marine foodchains including those in Antarctica. Damage to the DNA in various lifeDamage to the DNA in various life--forms So far this hasforms So far this has

been as observedbeen as observed in Antarctic icein Antarctic ice--fish that lack pigments tofish that lack pigments to

shield them from the ultrashield them from the ultra--violet light (they've neverviolet light (they've neverneeded them before)needed them before)


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Whydoes a ozone hole form overWhydoes a ozone hole form over

antractica?antractica? The ozone hole is caused by the effectThe ozone hole is caused by the effect

of pollutants in the atmosphereof pollutants in the atmospheredestroying stratospheric ozone.destroying stratospheric ozone.

During the Antarctic winter somethingDuring the Antarctic winter somethingspecial happens to the Antarctic weather:special happens to the Antarctic weather:--

1.1. strong winds blowing around thestrong winds blowing around thecontinent formcontinent form, this is known as the, this is known as the

"polar vortex""polar vortex" -- this isolates the air overthis isolates the air overAntarctica from the rest of the world.Antarctica from the rest of the world.


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2.Secondly, special clouds form2.Secondly, special clouds formcalled Polar Stratosphericcalled Polar StratosphericClouds.Clouds. Clouds don't normally formClouds don't normally formin the stratosphere and these turnin the stratosphere and these turnout to have the effect ofout to have the effect ofconcentrating the pollutants thatconcentrating the pollutants that

break down the ozone, so speedingbreak down the ozone, so speedingthe process upthe process up


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By the time spring arrives and the sun comesBy the time spring arrives and the sun comesback after the long polar night, the ozone levelsback after the long polar night, the ozone levelsare severely depleted around the Antarcticare severely depleted around the Antarcticcontinent causing the "ozone hole".continent causing the "ozone hole".

Unfortunately, there then follows a particularlyUnfortunately, there then follows a particularlylong period of high sunshine and long days, justlong period of high sunshine and long days, justto make the effect of the ozone hole worse.to make the effect of the ozone hole worse.

The concentration of ozone in theThe concentration of ozone in theatmosphere is measured in "Dobson Units",atmosphere is measured in "Dobson Units",the average concentration of ozone in thethe average concentration of ozone in theatmosphere is about 300 Dobson Units. Theatmosphere is about 300 Dobson Units. Theozone hole is considered to be wherever theozone hole is considered to be wherever theconcentration drops below 220 Dobson Units.concentration drops below 220 Dobson Units.


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The following pictures areThe following pictures areprovided courtesy of NASA.provided courtesy of NASA.

They show the extent of ozoneThey show the extent of ozonethinning.thinning.

Dark blue and purple colorsDark blue and purple colorscorrespond to the thinnest ozone,correspond to the thinnest ozone,

while light blue, green, and yellowwhile light blue, green, and yellowpixels indicate progressively thickerpixels indicate progressively thickerozone.ozone.


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October 1999 (average)October 1999 (average)Historically, the Antarctic ozone holeHistorically, the Antarctic ozone hole

was largest during October. In recentwas largest during October. In recentyears however, September has beenyears however, September has beenthe peak month.the peak month.


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September 7th 2000September 7th 2000

The ozone hole grew quicker than usual and exceptionally large.The ozone hole grew quicker than usual and exceptionally large.By the first week in September the hole was the largest ever atBy the first week in September the hole was the largest ever atthat time. For the first time it reached towards South America andthat time. For the first time it reached towards South America andto regions of high population.to regions of high population.


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September 2006 averageSeptember 2006 averageFrom September 21 to 30, 2006, the averageFrom September 21 to 30, 2006, the average

area of the ozone hole was the largest everarea of the ozone hole was the largest everobserved, at 10.6 million square miles. A littleobserved, at 10.6 million square miles. A littleover a week later, instruments recorded theover a week later, instruments recorded thelowest concentrations of ozone ever observedlowest concentrations of ozone ever observedover Antarctica, making the ozone hole theover Antarctica, making the ozone hole the


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Whatcauses the ozone depletion?Whatcauses the ozone depletion?

Ozone is mainly broken down by chemicalsOzone is mainly broken down by chemicalscalled ChloroFluoroCarbons CFC'scalled ChloroFluoroCarbons CFC's and alsoand alsoby nitrogen oxides.by nitrogen oxides.

CFC's ironically were first used in largeCFC's ironically were first used in largequantities because they were thought toquantities because they were thought tobe safe and inert (unreactive) chemicals.be safe and inert (unreactive) chemicals.

They are a group of chemically similarThey are a group of chemically similargases used in refrigeration systems, airgases used in refrigeration systems, air

conditioners, aerosols, solvents and in theconditioners, aerosols, solvents and in theproduction of some types of packaging.production of some types of packaging. Nitrogen oxides are a byNitrogen oxides are a by--product of fuelproduct of fuel

burning, e.g. aircraft exhausts.burning, e.g. aircraft exhausts.


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CFSS donot occur naturally, they are manCFSS donot occur naturally, they are man--made chemicals.made chemicals. They are very useful when they are where they areThey are very useful when they are where they are

supposed to be, and doing what they are supposed to besupposed to be, and doing what they are supposed to bedoing.doing.

But once released into the atmosphere they are a seriousBut once released into the atmosphere they are a serious

pollutant.pollutant. The problem is it took us many years to realise this duringThe problem is it took us many years to realise this during

which we thought they were perfectly harmless, but in factwhich we thought they were perfectly harmless, but in factwere building up to levels that will take decades for them towere building up to levels that will take decades for them todisappear again even if we stop producing them altogether.disappear again even if we stop producing them altogether.

The actual reactions that destroy ozone are veryThe actual reactions that destroy ozone are verycomplicated.complicated.

They take place on the surface of the ice particles of theThey take place on the surface of the ice particles of thePolar Stratospheric Clouds andPolar Stratospheric Clouds and it takes only a smallit takes only a smallamount of CFC to destroy an awful lot of ozone.amount of CFC to destroy an awful lot of ozone.


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Is the ozone hole going to stay overIs the ozone hole going to stay over

Antractica?Antractica? Since the annual thinning of the ozoneSince the annual thinning of the ozone

layer over Antarctica was first discovered,layer over Antarctica was first discovered,measurements have been carried out in allmeasurements have been carried out in allregions.regions.

Ozone depletion has been measuredOzone depletion has been measuredeverywhere in the world except in theeverywhere in the world except in thetropics.tropics.

Depletion is usually worse the further fromDepletion is usually worse the further from

the equator and recently an Ozone holethe equator and recently an Ozone hole(as defined by a distinct area of very low(as defined by a distinct area of very lowozone levels) has been detected above theozone levels) has been detected above theNorth Pole in the arctic.North Pole in the arctic.


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There is a lot to learn about theThere is a lot to learn about thebreakdown of ozone in the atmosphere.breakdown of ozone in the atmosphere.Warmer region, non polar depletion ofWarmer region, non polar depletion of

ozone in particular is not properlyozone in particular is not properlyunderstood.understood.

So for the time being the "ozone hole"So for the time being the "ozone hole"seems to be an Antarctic phenomena, butseems to be an Antarctic phenomena, buta less severe thinning of the ozone layer isa less severe thinning of the ozone layer ispretty much a worldpretty much a world--wide thing.wide thing.

How acute and important it will be in theHow acute and important it will be in thefuture is not known.future is not known.


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Can the ozone hole recover?Can the ozone hole recover?

The way to stop the formation, growth andThe way to stop the formation, growth andspread of ozone thinning is to reduce thespread of ozone thinning is to reduce theproduction of those chemicals that causeproduction of those chemicals that causethe destruction of ozone, namely CFC's andthe destruction of ozone, namely CFC's andnitrogen oxides.nitrogen oxides.

In 1987, theIn 1987, the Montreal ProtocolMontreal Protocol was signed bywas signed bymany nations whereby those nations that signedmany nations whereby those nations that signedagreed to reduce their emissions of CFC's to aagreed to reduce their emissions of CFC's to ahalf (of the 1987 levels) by 2000.half (of the 1987 levels) by 2000.

Potential problems come from nations that do notPotential problems come from nations that do not

see the reduction of CFC's to be a priority, andsee the reduction of CFC's to be a priority, andalso from the huge quantity of refrigeration andalso from the huge quantity of refrigeration andair conditioning systems in the world that stillair conditioning systems in the world that stillcontain CFC's.contain CFC's.


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If they are not disposed of correctly, thenIf they are not disposed of correctly, thenthe CFC's will escape into the atmospherethe CFC's will escape into the atmosphereand continue to destroy ozone.and continue to destroy ozone.

The problem is far from settled and isThe problem is far from settled and isunder investigation by research teams allunder investigation by research teams allover the world. The latest estimates areover the world. The latest estimates arethat as long as production and release ofthat as long as production and release of

CFC's is regulated properly, global ozoneCFC's is regulated properly, global ozonelevels should recover by 2050.levels should recover by 2050.


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Latest ozone news:Latest ozone news:--

17th September 200517th September 2005

""The 2005 hole is larger and deeper than the holes thatThe 2005 hole is larger and deeper than the holes thatformed when the discovery was made but the situationformed when the discovery was made but the situationwould be much worse if the Montreal Protocol had not comewould be much worse if the Montreal Protocol had not comeinto force. This agreement shows us that global action byinto force. This agreement shows us that global action bygovernments to stop the release of ozone depletinggovernments to stop the release of ozone depletingchemicals really can help society to successfully mitigate achemicals really can help society to successfully mitigate aglobal environmental problem. We are still experiencingglobal environmental problem. We are still experiencinglarge losses of Antarctic ozone each spring because CFCslarge losses of Antarctic ozone each spring because CFCsand other chemicals live for a long time in our atmosphere.and other chemicals live for a long time in our atmosphere.However, the ban ensures that we will see an improvementHowever, the ban ensures that we will see an improvementin the future. We now need to take similar actions toin the future. We now need to take similar actions tocontrol greenhouse gasses, otherwise we will bequeathcontrol greenhouse gasses, otherwise we will bequeathfuture generations a significantly different climate from thatfuture generations a significantly different climate from thatof today."of today."--Jonathan ShanklinJonathan Shanklin

( one of the original discoverers of the ozone hole)( one of the original discoverers of the ozone hole)


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Covering an area of around 22 millionCovering an area of around 22 millionsquare kilometres this year's hole is a littlesquare kilometres this year's hole is a littlesmaller than the recordsmaller than the record--breaking event inbreaking event inAugust 2003.August 2003.

Measurements made during August andMeasurements made during August andSeptember at BAS Halley and RotheraSeptember at BAS Halley and RotheraResearch Stations reveal a 50% reductionResearch Stations reveal a 50% reductionon normal ozone levels over the base ofon normal ozone levels over the base ofthe Antarctic Peninsula and the Weddellthe Antarctic Peninsula and the WeddellSea, and a 20% reduction over the tip ofSea, and a 20% reduction over the tip ofSouth America and the Falkland Islands.South America and the Falkland Islands.

..


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The increased ultra violet lightThe increased ultra violet lightreaching the surface poses a medicalreaching the surface poses a medicalhazard to people living under thehazard to people living under the?hole' and without suitable protection?hole' and without suitable protectionpeople face the prospect of rapidpeople face the prospect of rapidsunburn and potentially more serioussunburn and potentially more serious

skin damageskin damage


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case study on ozone layer

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