ISB 202 1nd Edition Lecture 21Outline of Last Lecture I. BiodiversityOutline of Current Lecture II. OzoneIII. Ozone Depletion and thinning impactIV. Ozone Depletion SolutionV. Acid DepositionCurrent LectureOzone - Global Atmospheric Issueso Global Warmingo Ozone Depletiono Acid Rain 1839 - German Chemist (Christian Freidrich Schonbein) Smell associated with Thunderstorms Ozone = “to smell” in Greek “Good Ozone”o Stratospherico Shields Planet from harmful UV Radiation “Bad Ozone”o Ground Levelo Air PollutantThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o Damages Plantso Reduces PhotosynthesisOzone Depletion CFCs – Chlorofluorocarbonso Freono Coolantso Refrigerantso Aerosol Spray Canso Asthma Inhalerso Cleanerso Foam Packaging Bromine- CFCso A single CFC can convert up to 100,000 molecules of ozoneo Takes up to 20 years to rise up to Stratosphereo Last 75 – 111 years Ozone Destructiono Ozone Formation Catalyzed by Sunlighto Results in seasonal thinning of Ozone at poleso Ozone Protectiono 95% of harmful UV Rays Preventedo UV-A – Skin Agingo UV-B – CancerOzone Thinning Impacts Suppressed Immune System Skin Cancer Cataracts Damages Terrestrial Plants Reduces Photosynthesis Reduce Crop Yields Uncertain Impacts Terrestrial Organisms Potential Impacts Symbiotic Relationships Impact Crop Yields and Ecosystem Functions Single Celled Organisms Aquatic EcosystemsOzone Depletion Solutions Phase out use of CFCs and other Ozone depleting substances 1987 – Montreal Protocol 1992 – Copenhagen Protocol Montreal Protocolo Montreal Protocol (1987) phased out use of CFCs. HCFCs were substituted, which release less chlorine.o Very successful - CFCs cut by 95%o In 1995, Rowland, Molina and Crutzen shared Nobel Prize for work on ozone problem.Acid Deposition Acid precipitation - deposition of wet acidic solutions or dry acidic particles from the airo Unpolluted rain generally has pH of 5.6. Carbonic acid from atmospheric CO2o H2SO4 and HNO3 from industrial and automobile emissions are the 2 main cause of acid precipitation.o pH of 5 or less in freshwater lakes damages aquatic life Forest Damage Buildings and Monumentso Limestone and marble are destroyed by air pollution at an alarming rate.o Corroding steel in reinforced concrete weakens buildings, roads, and bridges. Smog and Haze reduce visibility. Air Pollution Controlo Sulfur Removal Switch from soft coal with a high sulfur content to low sulfur coal. Change to another fuel (natural gas).o Nitrogen Oxides Best method is to prevent creation- Staged Burners- Selective Catalystso Hydrocarbon Control Use closed systems to prevent escape of fugitive emissions. Clean Air Legislation Clean Air Act (1963) - First national air pollution control Clean Air Act (1970) rewrote original.o Identified critical pollutants.o Established ambient air quality standards. Primary Standards - human health Secondary Standards - materials, crops, visibility, climate and comfort Clean Air Legislationo Source review in 1977 allowed old plants to be grandfathered in, but required new equipment to meet air pollution
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