Transcript The Atmosphere

The Atmosphere
Chapter 17
100.1 km
Mach 2.9
Watch
What’s In a Breath?
0.934%
0.036%
<0.03%
(Ne, He, H2,
Kr, CH4, H2S)
(a greenhouse gas
responsible for
planet being warm)
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
Temperature in the Atmosphere
Space
Ship One
Heated directly by highenergy X-rays and UV
radiation
Little ozone, temperature
decreases rapidly
Oxygen  Ozone
(heated by Sun, absorbs
harmful radiation)
Air too dense to rise
beyond tropopause
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
Acid-rain on forest in Jizera mountains of Czeck Repulic
Actually, acid-mine drainage (this is extreme limit)
• 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
• 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