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Air Pollution and Acid Rain 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