Newsletter the ozone Ozone layer The future Ultraviolet What you can do light &ozone Fixing theOzone depletion problem Teamwork
Ozone layerThe ozone layer is a layer of Earth’s atmosphere which containshigh concentrations of ozone (O3). This layer absorbsthe suns ultraviolet light, which damages life on Earth.It is mainly located in the lower portion of the stratosphere from 20to 30 kilometers above Earth.The ozone layer was discovered in 1913 by the French physicistsCharles Fairy and Henri Buisson. Its properties were explored indetail by the British meteorologist G.M.B Dobson, who developeda simple spectrophotometer that could be used to measurestratospheric ozone from the ground. Between 1928 and 1958stations, Dobson established a worldwide network of ozonemonitoring which continue to operate to this day.
Ultraviolet light and ozoneThe ozone is important to life because it absorbs harmful ultraviolet .(UV) radiation coming from the sun :UV radiation is divided into three categories based on its wavelengthUV-A (400–315 nm), UV-B (315–280 nm), and UV-C (280–100 nm). .UV-C , which would be very harmful to all living thingsUV-B radiation can be harmful to the skin and is the main cause ofsunburn , it also causes genetic damage, resulting in problems such as .skin cancerThe ozone layer is very effective at examine UV-B; for radiation with awavelength of 290 nm. the intensity at the top of the atmosphere is 350,million times stronger than at the Earth`s surface. Nevertheless.some UV-B reaches the surface
Ozone depletion The ozone layer can be depleted by CFCs, nitric oxide (NO), nitrous oxide (N2O), hydroxyl (OH), atomic chlorine (Cl), and atomic bromine (Br). While there are natural sources for all of these species. the concentrations of chlorine and bromine have increased markedly in recent years due to the release of large quantities of man-made organ halogen compounds, especially chlorofluorocarbons (CFCs) and .bromofluorocarbonsThese compounds rise to the stratosphere, where the radiation breaksdown them into molecules,These molecules become unable to absorb ultraviolet radiation. Thus.dangerous ultraviolet-B radiation reach the Earth’s surfaceIn the 1970s,Scientists have noticed that the ozone overAntarctica became thinner each spring. By 1992, this area wasmore than twice as large as the continental United States.
Fixing the problemIn 1979, many countries, including the U.S., banned CFCsfrom being made or used. This was a big step toward fixingthe problem. Today, no spray cans contain CFCs. Otherchemicals are gradually replacing the CFCs in air .conditionersBut the CFCs already in the atmosphere can take up to 50years to reach the stratosphere. Once there, they hang .around in the stratosphere for many years, doing damageAlso, the products that still contain CFCs need to be treatedwith care. One example of this is a car air conditioner. Whenthe air conditioner breaks, or the car is taken to a junkyard, the CFCs need to be carefully taken out and recycled or .stored so that they dont leak into the air
The futureScientists originally predicted that theozone layer would be the thinnestaround 2008, then start recovering. Butnew research shows that other airpollution problems are slowing down.the ozone layers ability to rebound
What you can doEncourage people with cars to have their airconditioners fixed by mechanics who arecertified to handle. In Wisconsin, by law,mechanics have to be specially certified to .work with CFCs Protect your skin and eyes from.harmful UV rays when youre outside
TeamworkEditor: Afaf AlkhalilDesigner :Batool AbdeenPublisher :Alia Dweko& Marwa AttarAlkods High SchoolGrade: second secondary scientificSupervisor:Mrs. Tonia Bitartoniabitar@gmail.comResourceshttp://www.izotope.com/products/audio/ozone/http://www.ozone.org/