Transcript Fossil Fuels - Snow College

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
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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
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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