the atmosphere chapter 17 100.1 km mach 2.9 watch
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TRANSCRIPT
What’s In a Breath?
78.084% (reacts with
nothing)
20.916% (allows:
burning, rust, respiration)
0.036% (a greenhouse gas
responsible for planet being warm)
0.934%
<0.03%
(Ne, He, H2, Kr, CH4, H2S)
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
Temperature in the Atmosphere
Water vapor, clouds, storms and bad weather (heated by
Earth’s radiant heat)
Air too dense to rise beyond tropopause
Oxygen Ozone (heated by Sun, absorbs
harmful radiation)
Little ozone, temperature decreases rapidly
Heated directly by high-energy X-rays and UV
radiationSpace Ship One
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=exceptions1/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 (CHBenzene, methane (CH44), carbon monoxide (CO), ), carbon monoxide (CO),
sulfur dioxide (SOsulfur dioxide (SO22), nitrogen oxide (NO), nitrogen oxide (NO22))
– Mercury in rivers near Kittanning, PA: Mercury in rivers near Kittanning, PA: • Fish at 3.1-19x concentration of mercury than store-boughtFish at 3.1-19x concentration of mercury than store-bought• Mercury linked to neurological disordersMercury linked to neurological disorders• 5-8x EPA’s acceptable risk depending on age5-8x EPA’s acceptable risk depending on age
– Minamata DiseaseMinamata 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 RainAcid Rain
• Too weak to irritate human skin but is Too weak to irritate human skin but is devastating to delicate organisms and rockdevastating to delicate organisms and rock– Damages mountain forestsDamages mountain forests
• Germany 1982-1995: 8% unhealthy to 50% SICK Germany 1982-1995: 8% unhealthy to 50% SICK
– Acidifies lakes causing massive fish killsAcidifies 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
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