Ozone is a colorless gas,consist of 3 oxygenmolecules,found in the upper atmosphere of the Earth andformed by the action of ultraviolet radiation on oxygen.Ozone forms a layer in the stratosphere, which protects lifeon Earth from the harmful effects of ultraviolet radiation.The ozone layer is a region in the stratosphere, between17 and 25 km above the earth’s surface.Without the ozone layer WE WOULD ALL DIE (because UVlight kills all living tissue).This layer absorbs about 97-99% 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 O 3• 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 gaseso 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)o Hyrdobromofluorocarbon(HBFCs)o Bromochloromethane(BCM)
What is CFC (freon)?? A hydrocarbon or haloalkan that contain chlorine,flourine and carbon atoms CFC or freon damage the ozone layer when released in the envionment,but also saves lives by keeping food from spoiling , fire fighting and sterilization of surgical tools. Non toxic Non-flammable Noncorrosive Inexpensive long-lived“Dream Chemical” U.S government banned the production of freon.
Air ConditionersRefrigeratorsFire extenguisherSpray cansPesticidesInsulation materialsCleaners for electronic partsSterilizing medical instruments
United States accounts for largest part of world-wide consumption o CFC’s 29% of global consumption of CFC is from US Americans use six times more CFC’s than globalaverage Vehicle air conditioners accounted for about75% of annual CFC emissions in the US in 1990 Since 1978 the use of CFC’s in aerosol cans hasbeen banned in many countries; however,worldwide, aerosol cans still account of 25% ofCFC emissions.
The Antarctic ozone hole was discovered in 1985 by Britishscientists Joesph Farman, Brian Gardiner, and Jonathan Shanklin ofthe British Antarctic Survey.
Skin cancerPremature aging (photoaging) of theskinSun burn
This long-wavelength (low-energy) form of UV This shorter-wavelength (high-energy) form of UV radiationradiation causes aging of the skin, tanning, and causes sunburn, premature aging, and wrinkling. It is largelysometimes sunburn. It penetrates deeply and may responsible for basal and squamous cell carcinomas andcontribute to skin cancer. plays a role in malignant melanoma. Ultraviolet A Ultraviolet B HairThin layer of dead cells Squamous cells Epidermis Basal layer Sweat gland Melanocyte cells Dermis Blood vessels Basal cell Squamous Cell Carcinoma Basal Cell Carcinoma Melanoma
Each 1% loss of ozone leads to a 2% increase in UVradiation striking the earth.A 2% increase in UV radiation results in a 5% to 7%increase in skin cancer, including a 1% increase indeadly malignant melanomaAn additional 940,000 cases annually of basal-celland squamous-cell skin cancerAn additional 30,000 cases annually of melanomaskin cancer (often fatal). There are 9,000 Americandeaths 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 LayerStop producing CFCs orReduce emission of ozone deplating chemicals thatcontains 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