1-7: Acid Deposition

Pre-Class Preparation

Objectives

• To examine how acid constituents of the atmosphere enter the biosphere and lithosphere and the consequences thereof.
• To understand the anthropogenic role in creating chemically reactive compounds in the lower atmosphere.

Procedure

1. Read the learning unit.

   Class images

2. Take the learning unit quiz. Quizzes are available from your portfolio. You may access your portfolio via the list of students participating in this years course, as represented by the icon below.
   
   
3. Additional Required Reading. Although you are not ultimately responsible for content listed in this section, we encourage you to fully explore the links in order to provide a better scope on the upcoming class discussion.

   	The Links Between Climate Change and Acid Rain Policies. (From the United Nations Environment Programme, UNEP)
   	Updated Values of Precipitation pH.
   	Houghton, J. T., G. J. Jenkins, and J. J. Ephraums, 1990: Climate Change, The IPCC Scientific Assessment. Cambridge University Press. p. 30-33.

Class Discussion

• Problem to ponder...
  Ozone molecules created in an urban environment as part of photochemical smog are quickly destroyed. So why, if ozone is so reactive, do concentrations build up in the morning rush hour?

• Class Discussion Summary: by class members Suzie Loadholt and Alison Haase

  NEPA (1969) set the stage for the general area of the work in the environmental fields. Acid deposition is not the same as acid rain, and includes dry deposition, rain deposition, as well as lost from the atmosphere in a vapor phase. Anthropogenic pollutants can be gases, solids, or liquids. Oxides of nitrogen are produced by increases temperature burning. Reactive materials cause more concern to atmospheric pollution at high levels because they have the ability to travel great distances and have a greater impact on the environment. Water bodies are areas that may become repositories for acid deposition, especially in the spring from snowmelt. Low level atmospheric conditions such as wind and temperature play a large role in pollutant deposition. In coastal areas pollutants can get caught in sea breezes and pose a threat to surrounding areas. Dimethyl sulfide is emitted by certain ocean plants which enhances itīs precipitation. Tolerance of different acidity levels of aquatic life depends on the species. The eastern U.S. experiences higher levels of acid deposition than the western half, especially in the New England areas.

Post-Class Activities

• Participate in the electronic dialog. Use this forum for:
  • continuing class discussion;
  • posing new questions to students or the instructor;
  • responding to issues/questions raised by students in class/electronic dialog.

  Visitor Access (Visitors are welcome to participate in the dialog. Just click on the icon below)	Student Access (Students must post all dialog from their portfolio. Click on the icon below to access the student list.)

• Recommended Reading Materials

  	Sensitivity, Critical Load, and Target Load for Acid Deposition on Ecosystems
  	Keeley, Jon E. and C. J. Fotheringham, 1997: Trace Gas Emissions and Smoke-Induced Seed Germination (summary). Science, 276, 1248-1250.
  	Legge, A. H., and S. V. Krupa, 1994: Acid Deposition: Sulphur and Nitrogen Oxides. (TD 195.54).
  	Record, Rubenick, Kindya, 1982: Acid Rain Information Book. (TD196.A25).
  	Roberts, L., 1991: Learning from an acid rain program. Science 251 1302-1305.

• References

  	Acid Rain Program
  	Atmospheric Chemistry and Air Quality Glossary
  	Clean Air Act, including Plain English Guide to the Clean Air Act
  	Hot Links to Web Sites on Acid Rain. (From Northern Environmental Chemistry.)
  	National Atmospheric Deposition Program
  	Pollution Standards Index [PSI] - an explanation of what PSI values mean to health)
  	Andreae, M.O. and P.J.Crutzen, 1997: Atmospheric Aerosols: Biogeochemical Sources and Role in Atmospheric Chemistry. Science, 276, 1052-1057.
  	Finlayson-Pitts, B.J. and J.N. Pitts Jr., 1997: Tropospheric Air Pollution: Ozone, Airborne Toxics, Polycyclic Aromatic Hydrocarbons, and Particles. Science, 276, 1045-1050.
  	Kley, D., 1997: Tropospheric Chemistry and Transport. Science, 276, 1043-1045.