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UCM BIOL 1005 - Air PPT Continued

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BIOL 1005 1st Edition Lecture 21Outline of Last Lecture I. AirII. Human Intake Per DayIII. BackgroundIV. Threshold LevelV. Natural ProcessesVI. Human InfluenceVII. The AtmosphereVIII. Clean Air LegislationIX. Regulated PollutantsX. EffectsXI. Human HealthXII. Effects of Air PollutionXIII. Agriculture EffectsXIV. OzoneXV. Materials and Aesthetics XVI. Indirect ProblemsXVII. Photochemical SmogOutline of Current Lecture I. Acid DepositionII. Nitric AcidIII. Sulfuric AcidIV. Acid Deposition and HumansV. Acid Deposition and Aquatic SystemVI. Ozone LayerVII. UV EffectsVIII. How Ozone FiltersIX. So What Is The Problem?X. Ozone “Hole”XI. Global WarmingXII. Spaceship EarthXIII. Adding Carbon DioxideXIV. Result?XV. Probable EffectsCurrent LectureThese 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.I. Acid Deposition- Acid Precipitation - Deposition of wet, acidic solutions or dry, acidic particles from the air.- pH scale ranges from 0-14.- 7 = Neutral; <7 = Acidic; >7 = Basic- Unpolluted rain generally has pH of 5.6.- Carbonic acid from atmospheric CO2. - In industrialized areas, anthropogenic acids in the air often outweigh natural sources of acid.- Sulfuric acid and Nitric acid are the two sources- Aquatic Effects o Thin, acidic soils and oligotrophic lakes of southern Norway and Sweden have been severely affected by acid deposition.o Generally, reproduction is the most sensitive stage in fish life cycles.- Forest Damageo Air pollution and depositions of atmospheric acids are believed to be important causes of forest destruction in many areas.- 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.- Sulfuric acid- Nitric Acid- Some areas of U.S. more susceptible than others II. Nitric Acid- Nitrogen Oxide (NOx) + water vapor- Source of NOx – cars / transportationIII. Sulfuric Acid- Sulfur Oxide (SOx) + Water Vapor- Source is mainly from coal fired industries / power plants IV. Acid Deposition and Humans- Respiratory Diseases- Toxic Metal Leaching- Damage to Structures – especially limestone- Decreased Productivity – forest, fisheries, farmsV. Acid Deposition and Aquatic Systems-VI. Ozone Layer- Ultraviolet electromagnetic energy from the sun- Absorbed by biological tissue … breakdown of protein and DNA- Less than 1% of UV that strikes upper atmosphere of earth reaches surface of planet VII. UV Effects- Causes sunburns- 200,000 – 600,000 cases of skin cancer per year- ** over 99% of UV is filtered out by ozone in the stratosphereVIII. How Ozone Filters- UV strikes O3- O3 splits into 2 separate free O atoms- 3 of the O atoms reform back into O3IX. So What is the Problem?- Chlorine combines more easily with free O than does another O atom- Chlorofluorocarbons (CFCs) find their way to the stratosphere- UV breaks down CFC and releases Cl- Cl binds with free O and eliminates the possibility of O3 formation- Ozone filters out 99% of UV light- CFC• Used in refrigeration, air conditioners and heat pump units• Used in making plastic foams (styrofoam)• Used to clean computer chips• Some countries partially regulate nowX. Ozone “Hole”- Discovered over the South Pole in 1985- In 1989, another “hole” was discovered over the North Pole- 1986 Montreal Accord was signed – 50% reduction of CFCs by 1999- 1989 Helsinki Accord – phase out CFC use by 2000XI. Global Warming- Caused by “the greenhouse effect”- The heat trapping effect of carbon dioxide (CO2) and other “greenhouse gasses”XII. Spaceship Earth- Temperatures we are accustomed to are caused by a carbon dioxide concentration of approximately 0.03% (300 ppm)- 300 ppm levels caused by the photosynthesis – respiration cycle- During the last century, fossil fuel combustion has changed the picture- For every 1 pound of fuel burned, nearly 3 pounds of CO2 are formedXIII. Adding Carbon Dioxide- Each year approximately 2 billion tons of fossil fuel are burned- 5.5 billion tons of CO2- 1.7 billion tons of CO2 from burning tropical forestsXIV. Result?- In 1900 CO2 levels averaged 290 ppm- In 1989 CO2 levels averaged 350 ppmXV. Probable Effects- Average world temperature will increase by 3 to 18 0 F- Polar regions higher than equator- Ice caps melting?- Rainfall patterns change- Agriculture patterns change- Greenhouse effect: trapping and holding heat close to earth - US produces 2X carbon dioxide as other industrialized


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