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This week. Monday—Pollution control/scrubbing. Wednesday—Prof. Eric Zimmerman—global ozone and the ‘ozone hole’ Chapter 10 Friday-Dr. Carrie Morrill/NOAA How do we know current and historic climate information? No HW will be distributed Wed., Fri. Chapter 9—air pollution.
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This week Monday—Pollution control/scrubbing. Wednesday—Prof. Eric Zimmerman—global ozone and the ‘ozone hole’ Chapter 10 Friday-Dr. Carrie Morrill/NOAA How do we know current and historic climate information? No HW will be distributed Wed., Fri.
Chapter 9—air pollution Meaning– immediate and local hazards to health and materials, not climate change. Lead SO2 NOX Mercury Ozone Hydrocarbons Radon
All substances are poisons; there is none which is not a poison. The right dose distinguishes a poison and a remedy. Paracelsus 1493-1541
Acceptable levels (mg/kg=ppm, by weight)(in soil/dust) • Mercury 2 • Cadmium 3 • Selenium 3 • Arsenic 20 • Boron 25 • Copper 50 • Lead 100 • Titanium 500 (1 ppm=1 gram in one ton)
TetraEthyl Lead ‘antiknock’ additive to gasoline, 1:1260 mixture • >30 mg/liter of air7 point drop in IQ • 10 mg/liter 4 point drop in IQ • Clogs catalytic converters Phased out as of 1972 in US
Sulfur, SO2,sulfuric acid Sulfur can be 3-10% of coal, <1% for some western coal. Wash the coal at the mine—coal dust floats, sulfur minerals sink. S burns to SO2sulfuric acid in the air. ‘Scrub’ the exhaust gas—CaO with water CaSO4, gypsum
Sulfur Cap and Trade 1990 Clean Air Act set a national cap on SO2 from power plants, 9.5 million tons in 2000, 8.95 Mt in 2010. Was 17.3 Mt in 1980. Permits based on existing emissions. Can be bought and sold. Monitored by on-site equipment, reported to EPA. www.epa.gov/airmarkets
SSO2 Reaction S + O2SO2 Relative weights Carbon =12 Oxygen =16, O2=32 Sulfur (S)=32 32 grams of S 32+2x16= 64 grams of SO2 32 tons of S64 tons of SO2 1 ton of S64 / 32 = 2 tons of SO2
Three ways to count • By atoms, as in balancing chemical reactions. • By weight, as in liquids or solids, often ppm. • By volume, in the atmosphere, often ppmv. All molecules use the same volume.
Parts per million • S+O2SO2 Balance atoms • S has relative weigh= 32, O=16one gram of S2 grams of SO2 Allows ppm by MASS • All molecules of gas occupy the same volume. ppmv=ppm (mass) * mass of air molecule/mass of SO2 molecule = ppm *29/64 Or—for CO2, ppmv=29/44 x ppm (mass)
The EPA—est. 1970 • Congress enacts a law, the EPA establishes and enforces regulations. • Also- carries out research, education, assistance in compliance • Major Acts Clean Air Act Clean Water Act Toxic Substances Control Act
“Clean Coal” Cleaner deposits Clean before shipping/burning Clean the fumes, SO2, mercury, particulates. CO2—Chapter 10
Radon An inert radioactive gas that seeps in, and is inhaled into the lungs where it emits ionizing radiation. Second only to cigarettes as a source of lung cancer, with 20,000 deaths per year. Depends on locale, basement. Very hard to stop.
Radon • NO safe level, action suggested at 4 pCi/liter. • At 20 pCi/liter, smoker 26% lung cancer, • never-smoker 3.6% lung cancer
This week Wednesday—Ozone, Prof. Zimmerman Friday—Dr. Morrill/NOAA How do we know so much about past and present climate, CO2,tempertature? Next Monday—climate change– Section 10.3
Wyoming has vast deposits of coal holding only 1% sulfur (S) by weight. The power company customers for this coal sell 10 GWe to their market, at an average efficiency of 32%. (3) How many tons (or metric tonnes, but say which you mean) of coal holding 50% carbon must be mined in Wyoming each day? (3) How many tons (or tonnes) of SO2 will be produced each day? You will need to write a chemical equation that balances as you burn the free sulfur in the coal, with atomic weights of 32 for S and 16 for O. Oxygen occurs as the molecule O2. Yes, this is almost the same as a problem from last week. (6) Here comes the hard part. If all of this unscrubbed SO2 from one day is trapped in an inversion area of 10,000 square kilometers, 500 m thick, what will one day’s worth of SO2 yield as the concentration? Is this OK? Check Table 9.3 and use the 24 hour concentration. This assumes that such an inversion to trap SO2 will happen just once a year. (8) Go to www.esrl.noaa.gov/gmd/ccgg/trends and describe in your own words to an intelligent but untutored friend what the message in these graphs is telling us. It is fair to have and express an opinion about the future of these graphs.