1. Advanced Placement Environmental Science Teacher
Acid Rain
Mark Ewoldsen, Ph.D.
Advanced Placement Environmental Science Teacher
La Cañada High School

2. Background Information

3. Atmosphere

4. Earth’s Atmosphere Compared to the size of the Earth (12000 km)
The atmosphere is very thin (120 km)

5. If the Earth is compared to this Orange
the Earth’s atmosphere would be thinner than the layer of pesticide on this Orange’s surface

6. Two Atmosphere Layers Stratosphere is above Troposphere
Ozone Layer blocks UV radiation
Troposphere is where we live
Weather & Global Warming
72% of all air is below the cruising altitude of commercial airliners (33000 ft)

7. Measuring Acid Rain Acid rain is measured using a "pH" scale.
The lower the pH, the more acidic
Pure water has a pH of 7.0
Normal rain is slightly acidic and has a pH of about 5.6 because of H2CO3
Rainfall with a pH less than 5.6 is acid rain
As of the year 2010, the most acidic rain falling in the US has a pH of about 4.3.

9. Two Forms…
Wet
Refers to acid rain, fog, sleet, cloud vapor and snow.
Dry
Refers to acidic gases and particles.

10. Compounds Two main contributers to acid deposition:
Sulfur Dioxide (SO2)
Nitrogen Oxides (NOx)
* 66% of all sulfur dioxides and 25% of all nitrogen oxides comes from electric power generation that produces energy by burning fossil fuels.

11. When gas pollutants e.g. sulphur dioxide, nitrogen dioxide dissolve in rain water, various acids are formed.
CO2 + H2O  H2CO3 (carbonic acid)
SO2 + H2O  H2SO3 (sulphorous acid)
NO2 + H2O  HNO2 (nitrous acid) + HNO3 (nitric acid)

12. sulfuric acid nitric acid Primary Pollutants SO2 NO2
Secondary Pollutants
H2SO4 HNO2
sulfuric acid nitric acid
Primary Pollutants
SO2
NO2
acidic precipitation
vegetation
direct toxicity
indirect health effects
water
Fossil fuels
Power plants
Industrial emissions
Auto emissions
soils
leaching of minerals
sediments
leaching aluminum

13. “Wet” Acid Rain Acidic water flows over and through the ground
Affects a variety of plants and animals.

14. “Dry” Acid Rain Dry deposition refers to acidic gases and particles.
About half of the acidity in the atmosphere falls back to earth through dry deposition.
The wind blows these acidic particles and gases onto/into buildings, cars, homes, and trees.

15. Nutrients Acidic water
dissolves the nutrients and helpful minerals in the soil
washes nutrients away before plants can use them to grow.
Acid rain also causes the release of substances, such as aluminum, that are toxic to plants

17. Effects on Wildlife
Generally, the young of most species are more sensitive to environmental conditions than adults.
At pH 5, most fish eggs cannot hatch.
At lower pH levels, some adult fish die.
Some acid lakes have no fish.

18. Effects on Wildlife
Both low pH and increased aluminum levels are directly toxic to fish.
Chronic stress that leads to lower
body weight
smaller size

19. Acid Rain and Forests Acid rain does not usually kill trees directly
Weakens trees
Damaging leaves
Limiting nutrients available
Toxic substances slowly released from the soil.

20. Mongolia
Germany

21. Great Smoky Mountains, NC

23. 1985 Sulfate Ion Concentrations 1985-2004
1985
1986
1984

24. Sulfate Ion Concentrations
1986
1987
1985

25. Sulfate Ion Concentrations
1987
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1986

26. Sulfate Ion Concentrations
1988
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1987

27. Sulfate Ion Concentrations
1989
1990
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28. Sulfate Ion Concentrations
1990
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1989

29. Sulfate Ion Concentrations
1991
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30. Sulfate Ion Concentrations
1992
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1991

31. Sulfate Ion Concentrations
1993
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32. Sulfate Ion Concentrations
1994
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33. Sulfate Ion Concentrations
1995
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34. Sulfate Ion Concentrations
1996
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35. Sulfate Ion Concentrations
1997
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36. Sulfate Ion Concentrations
1998
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37. Sulfate Ion Concentrations
1999
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38. Sulfate Ion Concentrations
2000
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39. Sulfate Ion Concentrations
2001
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40. Sulfate Ion Concentrations
2002
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41. Sulfate Ion Concentrations
2003
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42. Sulfate Ion Concentrations
2004
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2003