Acid-Rain

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By: hakim2010 (26 month(s) ago)

Thank you very much This is good work

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Acid Deposition : 

Acid Deposition Acid rain, snow, fog, and dry deposition 23 April 2009 Acid-Rain.ppt 1

pH scale : 

pH scale 23 April 2009 Acid-Rain.ppt 2 Measure of acidity/alkalinity of solution 7 = neutral Less than 7 = acidic More than 7 = alkaline Logarithmic scale Change from 7 to 6 means 10X more acidic

pH scale : 

pH scale 23 April 2009 Acid-Rain.ppt 3 Rain is naturally acidic pH = 5.5 CO2 + H2O  H2CO3 “Carbonic acid” (as in Coke)

Formation of Acids : 

Formation of Acids Secondary pollutants produced by chemical reactions of primary pollutants with air molecules Sulfur in coal + O2  SO2 SO2 + H2O  H2SO3 (sulfurous acid) 2H2SO3 + O2  2H2SO4 (sulfuric acid). 23 April 2009 Acid-Rain.ppt 4

Formation of Acids : 

Formation of Acids 23 April 2009 Acid-Rain.ppt 5 Sources of primary pollutants Deposition of secondary pollutants

Sources & Deposition of Acid Rain : 

Sources & Deposition of Acid Rain 23 April 2009 Acid-Rain.ppt 6 Northeastern States Ohio Valley Western Europe Western Russia

Effects of Acid Deposition : 

Effects of Acid Deposition 23 April 2009 Acid-Rain.ppt 7 Depends on Transport downwind Buffering in soils (alkalinity) On thin, non-buffering soils On buffers carbonate rocks, limestone often used for buildings, Limestone and concrete structures

Effects of Acid Deposition : 

Effects of Acid Deposition 23 April 2009 Acid-Rain.ppt 8 Forests Leaching of cations (+) from soils Increased dissolved aluminum in soils Deaths of sugar maples in New England

Effects of Acid Deposition : 

Effects of Acid Deposition 23 April 2009 Acid-Rain.ppt 9 Lakes, rivers Acidified 41% of Adirondack lakes Reduced capacity to neutralize any more acid Deduced diversity and abundance of aquatic ecosystems

Acid Deposition : 

Acid Deposition 23 April 2009 Acid-Rain.ppt 10 Is acid deposition getting better? Scrubbers on coal-fired power plants Reduced sulfate (SO4) emissions Increased use of cars Increased nitrogen oxide emissions (NOx) Some improvement, more needed

Clean Air Acts 1970 & 1990 : 

Clean Air Acts 1970 & 1990 “Concentrations of major pollutants decreased 32%,” 1970-1997. How was 32% calculated? Is this an average? Costs of compliance = $436 billion Health benefits = $2.7 – 14.6 trillion 23 April 2009 Acid-Rain.ppt 11