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Impact of Technologies on the Atmosphere

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Effects of acid rain on a to mbstone that was carved in 1817 in England ... Fish kills can arise from a variety of causes, including acid rain. ... – PowerPoint PPT presentation

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Title: Impact of Technologies on the Atmosphere


1
Impact of Technologies on the Atmosphere
  • Acid Rain

2
Acid Rain
  • Natural rainwater has a pH 5.6 due to carbon
    dioxide reacting with water
  • CO2 H2O ? H2CO3 ? H HCO3 -
  • Acid rain is rain having pH
  • In US, rain averages pH of 4.1 to 6.1

3
pH of Rainfall
Buell/Girard, Chemistry, Prentice Hall, NJ, 1994,
230
4
http//www.oceansonline.com/water_props.htm
5
Sources of Acid Rain
  • Natural source - volcanoes
  • Anthropogenic (human activities) - burning of
    fuels containing S
  • S O2 ? SO2
  • 2 SO2 O2 ? 2 SO3
  • SO3 H2O ? H2 SO4

6
Sources of Acid Rain
  • Anthropogenic - combustion at high temperature in
    the presence of air
  • N2 O2 ? 2 NO (colorless gas)
  • 2 NO O2 ? 2 NO2 (dark brown gas)
  • 4 NO2 O2 2 H2O ? 4HNO3

7
Annual emissions of gases causing acid rain
Schwartz et al, Chemistry in Context, ACS, DC,
1994, 163
8
Production of Acid Rain
Hill/Petrucci, General Chemistry, Prentice Hall,
NJ, 1996, 546
9
Acid Rain
http//www.geog.ouc.bc.ca/physgeog/contents/table.
html
10
Acid dissolves metals and stone, particularly
marble CaCO3 H ?
Ca2 HCO3 -
Effects of acid rain on a to
mbstone that was carved in 1817 in England
Raven et al, Environment, Saunders, NY, 1995, 450
11
Dissolving of Soil Components by Acid Rain
http//www.geog.ouc.bc.ca/physgeog/contents/table.
html
12
Effects of Acid Rain on Soil
  • Minimal in regions having limestone
  • CaCO3 H ? Ca2 HCO3 -
  • Regions having granite rock, leaching of clay
    (Al2Si2O5(OH)4 ) occurs
  • Al2Si2O5(OH)4 6 H ? 2 Al3 2 SiO2 5 H2O
  • Al3 can kill trees and fish

13
Granite
Buell/Girard, Chemistry, Prentice Hall, NJ, 1994,
232
14
Effect of Acid Rain on Trees
Raven et al, Environment, Saunders, NY, 1995, 449
15
Blue Ridge Mountains, NC
Buell/Girard, Chemistry, Prentice Hall, NJ, 1994,
232
16
Fish kills can arise from a variety of causes,
including acid rain. These dead fish are on the
shore of Lake Michigan.
Schwartz et al, Chemistry in Context, ACS, DC,
1994, 171
17
Other Effects of Acid Rain
  • Oxidation of sulfur dioxide can also produce
    aerosols of ammonium sulfate which reduce
    visibility
  • Visibility in East US is 1-25 miles while in the
    West it is 50-70 miles

18
Sulfate Aerosol Haze
Discover, Geology Issue Number 1, Disney
Magazines, 1993, 50
19
Sulfate Aerosol Haze
Stanitski et al, Chemistry in Context, 3rd, ACS,
DC, 2000, 248
20
Society's Response
  • Clean Air Act of 1990 requires utilities to cut
    SO2 emissions to half the 1980 level (about 19
    million tons) by 2010
  • Power plants have annual SO2 emission allowances
    which can be traded

21
Industries' Source Reduction Responses
  • Using old technologies described earlier (coal
    flotation or scrubbing)
  • New technology S-eating bacteria to clean coal
  • Burning higher grade coal which is expensive

22
Joesten et al, Chemistry Impact on Society,
Saunders, NY, 1988, 172
23
Industries End-of-Pipe Responses
  • End-of-pipe responses rely on the Arrhenius
    acid/base neutralization reaction
  • For soils, limestone is added
  • CaCO3 H ? Ca2 HCO3 -
  • For lakes, lime is added
  • CaO H ? Ca2 H2O

24
Application of Agricultural Limestone to Soil
Chang, Chemistry, 5th, McGraw Hill, NY, 1994, 727
25
Liming an Acid Lake in Sweden
Stanitski et al, Chemistry in Context, 3rd, ACS,
DC, 2000, 251
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