Impact of Technologies on the Atmosphere

1
Impact of Technologies on the Atmosphere

• London or Industrial Smog
• Los Angeles or Photochemical Smog

2
Atmosphere is divided into regions based on
temperature changes
Cunningham/Saigo, Environmental Science,
6th,McGraw-Hilll, NY, 2001, 376
3
Industrial or London Smog

• Pollution in the Troposhere

4
Fossil Fuel Risks London Smog

• Smog is the combination of the words, smoke and
  fog
• When smog is produced by burning of coal (C and
  3 S and minerals) it is called London or
  Industrial Smog
• Named after city of London where in a 5 day
  period in December of 1952 it contributed to
  deaths of 8000 people

5
Cause of London Smog
Hill/Kolb, Chemistry for Changing Times, 7th,
Prentice Hall, NJ,1995, 347
6
Formation of London Smog - Carbon Reactions

• Some C burns to produce CO2
• C O2 ? CO2
• Some C burns to form CO
• 2 C O2 ? 2 CO
• Some C remains unburned and makes up smoke and
  soot

7
Formation of London Smog - Sulfur Reactions

• S burns to produce SO2
• S O2 ? SO2
• Further air oxidation produces SO3
• 2 SO2 O2 ? 2 SO3
• SO3 ultimately produces sulfuric acid
• SO3 H2O ? H2 SO4

8
Formation of London Smog - Particulate Matter

• Particulate matter - solid or liquid particles of
  greater than molecular size
• Large particles are visible as dust and smoke
  while small particles of 1 ?m (called aerosols)
  are invisible
• Minerals do not burn but form small particles
  that are carried out in smoke as fly ash

9
Health Effects of London Smog Carbon Monoxide

• CO bonds reversibly to iron in hemoglobin more
  strongly than does O2 blocking the transport of
  O2
• Oxygen deprivation causes heart to work harder -
  heart attack possible

10
CO bonds more tightly to hemoglobin than does
oxygen causing oxygen deprivation to living cells
Hill/Kolb, Chemistry for Changing Times, 7th,
Prentice Hall, NJ,1995, 353
11
Bloomfield, Chemistry and the Living Organism,
5th, Wiley, NY, 1997, 385
12
Effects of London Smog Particulates S-compounds

• Particulate matter of soot and fly ash plus the
  sulfur oxides and sulfuric acid all cause severe
  lung damage
• The alveoli lose their resilience making it
  difficult to expel the CO2 - leads to emphysema,
  which can be fatal
• Sulfur compounds also damage plants, farm crops
  and produce acid rain

13
Remediation of S-Damage

• Source reduction - can remove S from the coal by
  pulverizing and exposing to magnet to remove FeS2
  - expensive
• End-of-pipe treatment - allow the SO2 to form and
  then absorb it in lime
• The waste CaSO3 must then be disposed of in a
  landfill

14
Removal of SO2 from Effluent Stream
Chang, Chemistry, 5th, McGraw Hill, NY, 1994, 727
15
Photochemical or Los Angeles Smog

• Pollution in the Troposphere

16
The Cause of LA Smog
Chang, Chemistry, 5th, McGraw Hill, NY, 1994, 727
17
Fossil Fuel Risks Smog (LA)

• High temperature combustion using air as source
  of oxygen (such as in the engine of an
  automobile) produces NO
• N2 O2 ? 2 NO (colorless gas)
• NO reacts spontaneously with O2
• 2 NO O2 ? 2 NO2 (dark brown gas)

18
Downtown LA on a Smoggy Day
Hill/Kolb, Chemistry for Changing Times, 7th,
Prentice Hall, NJ,1995, 352
19
LA or Photochemical Smog

• Sunlight causes the production of ozone
• Ozone reacts with hydrocarbons in gasoline to
  produce aldehydes
• Hydrocarbons also react with NO2 and O2 to
  produce peroxyacetylnitrates (PAN) CH3COO-ONO2

20
Formation of Photochemical Smog
Hill/Kolb, Chemistry for Changing Times, 7th,
Prentice Hall, NJ,1995, 354
21
Conc.of Air Pollutants vs Time in Los Angeles
Chang, Chemistry, 5th, McGraw Hill, NY, 1994, 729
22
Health Effects of Photochemical Smog

• Aldehydes and PAN are eye and lung irritants
• Ozone is capable of impairing the elasticity of
  lungs causing death if sufficient exposure

23
Effect of Ozone on Rubber Tires
Ozone breaks the double bond between carbon atoms
in rubber causing tires to lose elasticity and to
crack
Chang, Chemistry, 5th, McGraw Hill, NY, 1994, 727
24
Remediation of LA Smog - Catalytic Coverter
Tro, 226