Ozone is a colorless gas,consist of 3 oxygen Ozone is a colorless gas,consist of 3 oxygen molecules,found in the upper atmosphere of the Earth and molecules,found in the upper atmosphere of the Earth and formed by the action of ultraviolet radiation on oxygen. formed by the action of ultraviolet radiation on oxygen. Ozone forms a layer in the stratosphere, which protects life Ozone forms a layer in the stratosphere, which protects life on Earth from the harmful effects of ultraviolet radiation.on Earth from the harmful effects of ultraviolet radiation.

The ozone layer is a region in the stratosphere, between The ozone layer is a region in the stratosphere, between 1717 and and 2525 km above the earth’s surface. km above the earth’s surface.

Without the ozone layer Without the ozone layer WE WOULD ALL DIEWE WOULD ALL DIE (because UV (because UV light kills all living tissue).light kills all living tissue).

This layer absorbs about This layer absorbs about 97-99% 97-99% of the harmfull UV rays.of the harmfull UV rays.

Ozone Absorption in the UV Band• UV radiation includes wavelengths from 200 to 400 nm

• UV-A 320-400 nm• UV-B 200-320 nm• UV-C 200-290 nm

• UV-C• Nearly all UV-C is absorbed in the upper atmosphere

• UV-B• 90% of UV-B is absorbed by the atmosphere, mostly by O3

• UV-A• Not strongly absorbed by the atmosphere

o Presence of chloroflurocarbones(CFCs)o Hydrofluorocarbons (HCFCs): They are much less harmful to

stratospheric ozone than CFCs,But HCFCs they still cause some ozone destruction and are potent greenhouse gases

o methyl chloroform (used in industry — for vapour degreasing, some aerosols, cold cleaning, adhesives and chemical processing)

o Presence of halons (used in fire extinguishers).o Presence of oxides of nitrogeno Presence of bromide such as methyl bromine (used as a

pesticide).o Hydrogen chlorideo Carbon tetrachloride(industrial solvent)industrial solvent)o Hyrdobromofluorocarbon(HBFCs)o Bromochloromethane(BCM)

o Presence of chloroflurocarbones(CFCs)o Hydrofluorocarbons (HCFCs): They are much less harmful to

stratospheric ozone than CFCs,But HCFCs they still cause some ozone destruction and are potent greenhouse gases

o methyl chloroform (used in industry — for vapour degreasing, some aerosols, cold cleaning, adhesives and chemical processing)

o Presence of halons (used in fire extinguishers).o Presence of oxides of nitrogeno Presence of bromide such as methyl bromine (used as a

pesticide).o Hydrogen chlorideo Carbon tetrachloride(industrial solvent)industrial solvent)o Hyrdobromofluorocarbon(HBFCs)o Bromochloromethane(BCM)

What is CFC (freon)??What is CFC (freon)??A hydrocarbon or haloalkan that contain A hydrocarbon or haloalkan that contain chlorinechlorine,,flourineflourine and and carboncarbon atoms atomsCFC or freon damage the ozone layer when released in CFC or freon damage the ozone layer when released in

the envionment,but also saves lives by keeping food from the envionment,but also saves lives by keeping food from spoiling , fire fighting and sterilization of surgical tools.spoiling , fire fighting and sterilization of surgical tools.

Non toxicNon toxicNon-flammableNon-flammableNoncorrosiveNoncorrosive InexpensiveInexpensive long-livedlong-lived““Dream ChemicalDream Chemical””

U.S government banned the production of freon.U.S government banned the production of freon.

• CFC-11 (trichlorofluoromethane - CFCl3)• CFC-12 (dichloro-difluoromethane - CF2Cl2)• CFC-113 (trichloro-trifluoroethane - C2F3Cl3)• CFC-114 (dichloro-tetrfluoroethane - C2F4Cl2)• CFC-115 (chloropentafluoroethane - C2F5Cl)

Air ConditionersRefrigeratorsFire extenguisherFire extenguisherSpray cansPesticidesInsulation materialsCleaners for electronic partsSterilizing medical instruments

Air ConditionersRefrigeratorsFire extenguisherFire extenguisherSpray cansPesticidesInsulation materialsCleaners for electronic partsSterilizing medical instruments

United States accounts for largest part of world-wide United States accounts for largest part of world-wide consumption o CFC’sconsumption o CFC’s

United States accounts for largest part of world-wide United States accounts for largest part of world-wide consumption o CFC’sconsumption o CFC’s

29% of global consumption of CFC is from US29% of global consumption of CFC is from USAmericans use six times more CFC’s than global Americans use six times more CFC’s than global

averageaverageVehicle air conditioners accounted for about Vehicle air conditioners accounted for about

75% of annual CFC emissions in the US in 199075% of annual CFC emissions in the US in 1990Since 1978 the use of CFC’s in aerosol cans has Since 1978 the use of CFC’s in aerosol cans has

been banned in many countries; however, been banned in many countries; however, worldwide, aerosol cans still account of 25% of worldwide, aerosol cans still account of 25% of CFC emissions.CFC emissions.

The Antarctic ozone hole was discovered in 1985 by British scientists Joesph Farman, Brian Gardiner, and Jonathan Shanklin of the British Antarctic Survey.

Figure 21-22Page 485

Year1970 1975 1990 2000 200519851955 1960 1965 1980 1995

400

350

300

250

200

150

100

Tota

l ozo

ne (D

obso

n un

its)

October monthly means

20

00

19

90

19

80

19

70

19

60

19

50

19

50100

200

300

400

20

00

19

90

19

80

19

70

19

60

19

50

19

50 100

200

300

400

20

00

19

90

19

80

19

70

19

60

19

50

19

50100

200

300

400

ozone layer depletio (4).FLV

Skin cancerSkin cancer

Premature aging (photoaging) of the Premature aging (photoaging) of the skinskin

Sun burnSun burn

Thin layer of dead cells

Squamous cells Epidermis

Basal layer Sweat gland

Melanocyte cellsDermis

Blood vesselsBasal cell

Hair

This long-wavelength (low-energy) form of UV radiation causes aging of the skin, tanning, and sometimes sunburn. It penetrates deeply and may contribute to skin cancer.

This shorter-wavelength (high-energy) form of UV radiation causes sunburn, premature aging, and wrinkling. It is largely responsible for basal and squamous cell carcinomas and plays a role in malignant melanoma.

Ultraviolet A Ultraviolet B

Basal Cell Carcinoma MelanomaSquamous Cell Carcinoma

Each 1% 1% loss of ozone leads to a 2% 2% increase in UV radiation striking the earth.A 2% 2% increase in UV radiation results in a 5% to 7% 5% to 7% increase in skin cancer, including a 1% 1% increase in deadly malignant melanomaAn additional 940,000940,000 cases annually of basal-cellbasal-cell and squamous-cell skin cancersquamous-cell skin cancerAn additional 30,000 30,000 cases annually of melanoma skin cancer (often fatal). There are 9,0009,000 American deaths per year from this now.

Protect the skin against the solar radiation using skin creams with SPF or other sunscreen.

• Stay out of the sun especially between 10 A.M and 3 P.M

• Donot expose yourself to the sun if you are taken antibiotics and contraceptive pills

• Examine your skin and scalp at least once a month for moles or warts that change in size,shape,color,or sores that keep oozing,bleeding and crusting over.if you observe any of this signs,consult a doctor immediately.

Solutions : Protecting the Ozone LayerSolutions : Protecting the Ozone LayerSolutions : Protecting the Ozone LayerSolutions : Protecting the Ozone LayerStop producing CFCs orReduce emission of ozone deplating chemicals that contains CFC.Reduce the uses of aerosol sprays.Uses of aerosol spray that is free in CFCs compound instead.properly recycle old CFCsUse safe alternativesEducate other governments for environmental policiesMontreal Protocol 36 nations: Goal: reduce CFCs by 35% by 2000Copenhagen Protocol

Stop producing CFCs orReduce emission of ozone deplating chemicals that contains CFC.Reduce the uses of aerosol sprays.Uses of aerosol spray that is free in CFCs compound instead.properly recycle old CFCsUse safe alternativesEducate other governments for environmental policiesMontreal Protocol 36 nations: Goal: reduce CFCs by 35% by 2000Copenhagen Protocol

http://www.bom.gov.au/lam/Students_Teachers/ozanim/ozoanim.shtmlwww.theozonehole.com/ozonedestruction.html australia.jrn.msu.edu/.../ozonepage.htmlhttp://www.nas.nasa.gov/About/Education/Ozone/ozonelayer.htmlhttp://www.bcairquality.ca/101/ozone-depletion-intro.htmlhttp://www.ozonedepletion.info/education/ozone.html