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The Atmosphere Chapter 17. 100.1 km Mach 2.9 Watch. What’s In a Breath?. 0.934%. (Ne, He, H 2 , Kr, CH 4 , H 2 S ). 0.036% (a greenhouse gas responsible for planet being warm). <0.03%. 20.916% (allows: burning, rust, respiration). 78.084% (reacts with nothing).
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The AtmosphereChapter 17 100.1 km Mach 2.9 Watch
What’s In a Breath? 0.934% (Ne, He, H2, Kr, CH4, H2S) 0.036% (a greenhouse gas responsible for planet being warm) <0.03% 20.916% (allows: burning, rust, respiration) 78.084% (reacts with nothing)
And the Other Stuff… Bologna, Italy
“Thickness” of the Atmosphere • Gases zing about at 950 mph (425 m/sec) • Gravity concentrates them near the surface • Density decreases upward • Boiling water at high elevation
Atmospheric Pressure • 1-m Mercury Barometers • Inches or mm of mercury • 29.92 in = 1 atmosphere (avg) at mean sea level • 1 atm ~ 1 bar • The weatherman • Old men and mercury • Aneroid Barometers
Little ozone, temperature decreases rapidly Oxygen Ozone (heated by Sun, absorbs harmful radiation) Air too dense to rise beyond tropopause Temperature in the Atmosphere Heated directly by high-energy X-rays and UV radiation Space Ship One Water vapor, clouds, storms and bad weather (heated by Earth’s radiant heat)
Ozone and You • In stratosphere: • O2 2O O + O2 O3 (ozone) • Ozone very efficient at absorbing UV • In troposphere: • N2 + O2 + heat 2 NO … O3 • Linked to heart disease, cancer, asthma, loss of lung function
CFCs • 1970s, used in almost all refrigerators, air conditioners, propellants in aerosol cans • Stable • Work their way Into atmosphere and Destroy ozone … Come Back!
The Ozone Hole • Not literally a “hole”—more like a male pattern baldness
Other Pollutants • Donora, PA • 27-31 October 1948 • Smog settled over city • Sulfuric acid, nitrogen dioxide, fluorine trapped in valley by stagnant air • 20 dead, 800 animals respiratory illnesses • Plants dead in half-mile radius of steel, zinc works • 1/3 of town’s 14,000 people were sick Donora at noon, Oct. 29, 1948
Clean Air Act of 1970 • Amendment to CAA of ’63 Smog over Shanghai Primary Standards to protect “sensitive” groups: elderly, children, ashtmatics Secondary Standards to protect against decreased visibility, damage to animals, vegetation, crops, and buildings Superscripts=exceptions 1/y
Advancing the Clean Air Act • 1970 Amendments: • Environmental Protection Agency (EPA) to determine the limit of industrial pollutants • Controlling auto emissions by 90% • 1990 Amendments: • Contributors to ozone depletion phased out • Rules on toxic waste and acid rain
The Burning of Hydrocarbons • Form CO2 and/or water during burning
Impurities and Incomplete Burning • Benzene, methane (CH4), carbon monoxide (CO), sulfur dioxide (SO2), nitrogen oxide (NO2) • Mercury in rivers near Kittanning, PA: • Fish at 3.1-19x concentration of mercury than store-bought • Mercury linked to neurological disorders • 5-8x EPA’s acceptable risk depending on age • Minamata Disease Actually, the plant in Seward, PA
Acid Rain • In moist air, you get sulfuric and nitric acids which dissolve in water vapor, fall as rain • pH 7.0 (neutral) • Normal rain pH ~5.7 due to CO2 • 1986, in southern CA a fog reached pH = 1.7
Acid Rain • Too weak to irritate human skin but is devastating to delicate organisms and rock • Damages mountain forests • Germany 1982-1995: 8% unhealthy to 50% SICK • Acidifies lakes causing massive fish kills Acid-rain on forest in Jizera mountains of Czeck Repulic Actually, acid-mine drainage (this is extreme limit)
Rapidly weathers stone monuments • U.S. several billion $/yr repairing damage
Other Toxic Volatiles • Chemicals that readily evaporate into air • Pesticides – some is carried off by wind • Dioxin – formed in backyard burn barrels or wherever plastic polyvinyl chloride is burned • Gets into grass, ruminants • We eat meat: 0.0000000001 g/day • EPA: “at or near levels associated with adverse health effects” • Could cause cancer, birth defects, reproductive and immune disorders V child, blamed on Agent Orange
Particulates and Aerosols • Particulate: Small pieces of solid matter • Aerosols: Small particles suspended in air • Fly ash: Smoke, soot, clay/stuff that can’t burn