Mark Ewoldsen, Ph.D.

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Acid Rain

• Mark Ewoldsen, Ph.D.
• Advanced Placement Environmental Science Teacher
• La Cañada High School

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Background Information
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Atmosphere
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Earths Atmosphere

• Compared to the size of the Earth (12000 km)
• The atmosphere is very thin (120 km)

http//www.gsfc.nasa.gov/gsfc/earth/pinatuboimages
.htm
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• If the Earth is compared to this Orange
• the Earths atmosphere would be thinner than the
  layer of pesticide on this Oranges surface

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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)

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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.

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Two Forms

• Wet
• Refers to acid rain, fog, sleet, cloud vapor and
  snow.

• Dry
• Refers to acidic gases and particles.

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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.

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• 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)
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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
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Wet Acid Rain

• Acidic water flows over and through the ground
• Affects a variety of plants and animals.

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Dry Acid Rain

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

http//svr1-pek.unep.net/soechina/images/acid.jpg
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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

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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.

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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

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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.

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Mongolia
Germany
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Great Smoky Mountains, NC
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http//nadp.sws.uiuc.edu/amaps2/
Sulfate Ion Concentrations 1985-2004
1985
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Sulfate Ion Concentrations 1985-2004
1986
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Sulfate Ion Concentrations 1985-2004
1987
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Sulfate Ion Concentrations 1985-2004
1988
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Sulfate Ion Concentrations 1985-2004
1989
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Sulfate Ion Concentrations 1985-2004
1990
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Sulfate Ion Concentrations 1985-2004
1991
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Sulfate Ion Concentrations 1985-2004
1992
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Sulfate Ion Concentrations 1985-2004
1993
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Sulfate Ion Concentrations 1985-2004
1994
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Sulfate Ion Concentrations 1985-2004
1995
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Sulfate Ion Concentrations 1985-2004
1996
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Sulfate Ion Concentrations 1985-2004
1997
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Sulfate Ion Concentrations 1985-2004
1998
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Sulfate Ion Concentrations 1985-2004
1999
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Sulfate Ion Concentrations 1985-2004
2000
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Sulfate Ion Concentrations 1985-2004
2001
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Sulfate Ion Concentrations 1985-2004
2002
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Sulfate Ion Concentrations 1985-2004
2003
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Sulfate Ion Concentrations 1985-2004
2004