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Air Pollution and Acid Rain. Our Atmosphere. Only several miles thick Supports all life on the planet Roughly 80% N 2 , 20% O 2 , + CO 2 + Ar, H 2 0 Troposphere – the air we breath Stratosphere – where the ozone layer is. Natural Air Pollution. Volcanoes – ash, mercury vapor, H 2 S, etc
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Our Atmosphere • Only several miles thick • Supports all life on the planet • Roughly 80% N2, 20% O2, + CO2 + Ar, H20 • Troposphere – the air we breath • Stratosphere – where the ozone layer is
Natural Air Pollution • Volcanoes – ash, mercury vapor, H2S, etc • Trees – hydrocarbons • Mentioned in 17th century by Shakespeare • San Gabriel valley in southern California called smoky valley by Native Americans
Smog • Smoke + fog • First coined by Dr. Harold deVoeux in London in 1911 • Bad case of smog in which 1150 people died • Bad case in Pennsylvania in 1948 • 18 died and 6000 got sick • In 1900 in SLC, people wrote that usually when they went to work with a white shirt, they would come home with a grey one in the winter
Inversions • Trap pollutants and concentrate them • Require: • No wind • Warm air over cold • Bowl type area • Common along the Wasatch Front • Why not here?
Industrial or Reducing Smog • Mostly from combustion of coal and oil • Major ingredient – SO2 – along with: • Fly ash • Smoke • Partially oxidized organics • Is generally decreasing in the US.
Photochemical or Oxidizing Smog • Mainly from the internal combustion engine • Major components: • NO • NO2 • Hydrocarbons • Ozone (O3) • Sunlight contributes by producing secondary pollutants
NOx’s • N2 + O2 + high temperatures → NO • Lightening and auto engines • 2NO + O2 → 2NO2 • With light, (UV), and VOC’s NO2 → O3 • VOC’s are Volatile Organic Compounds • So all are interrelated • With water → Nitric and Nitrous acids • Source of acid rain • Also source of haze
Ozone • O3 – secondary pollutant • Produced from NOx’s • Difficult to control • Good ozone vs. bad ozone? • Big health hazard • Oxidizes the lining in the lungs
Unburned Hydrocarbons • Sources? • Urban – gasoline, diesel, charcoal fluid, solvents, and trees • Ephraim? • Turkeys and cows and sheep • PAH’s – polynuclear aromatic hydrocarbons • Like benzo(α)pyrene • Carcinogens • In coal, cigarette, campfire smoke
Sulfur Dioxide • Main component of industrial smog • Coal – FeS2 (Pyrite or fool’s gold) • Oil – mercaptans – R-SH • Power plants – biggest problem • 1000 MW plant – 700 tons of coal/hr • Produces 56 tons of SO2/hr • 1990 Clean Air Act • Cut SO2 in half by 2000 (-10 mill. Tons/year)
Sulfur Dioxide • How do we clean up? • Taller stacks – “the solution to pollution is dilution”
Sulfur Dioxide • How do we clean up? • Taller stacks – “the solution to pollution is dilution” • Treat before stacks with lime or sodium carbonate • Attacks buildings, plants, and animals • Major contributor to acid rain.
Acid Rain • Rain is already acidic - CO2 & NO2 • pH of normal rain = 5.6 • Below 5.6 is acid rain • From SO2 and NOx’s • Affects: • Lakes – need to be limed • Minerals available to plants • Stomata of leaves • Buildings
H32 – C14 • 1 - 3, 5 - 9, 11 - 14, 16 - 18, 20 - 21, 43 - 45, 47, 48, 50 - 52, 63 - 65