Unit Objectives| 1-7: En Español | 1-7: Em Português |
Unit Objectives
Preparation for Online and Class
Discussion
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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. |
Online and Class Discussion
Unit Wrap-up MaterialsDiscussion Summary Prepared by: Mark Kochen, Brian Vote, Trevor Dickerson, Kyle TackettAcid deposition is more than just acid rain. It also includes dry deposition of particles and the capture of acidic vapors at the earth´s surface. The pH of rain is naturally acidic, with a pH of around 5.65. Precipitation with a pH lower than 5.65 is considered acidic. The atmosphere can transform anthropogenic air pollutants. An example of this is SO2 being released and then being changed to SO4 in the earth´s atmosphere. It then combines with H2O to make sulfuric acid (H2SO4). Oxides of nitrogen becoming nitric acid is another example of this. Acid deposition can be both positive and negative. Some soils are low in sulfur, so sulfur deposited from acid deposition is not considered to be detrimental. This can occur in Iowa. An example of a negative effect can be found in lakes and ponds. These areas accumulate the acid from runoff. The increase causes problems if it happens during spawning. Some of the major U.S. cities with smog problems are Denver, L.A., and Houston. This happens because the pollutants cannot escape. This is caused by an unstable lower atmosphere capped by a stable upper atmosphere. This is known as temperature inversion. Generally speaking, damage from acid deposition does not occur over large scale areas. The most damage occurs around the source of emission. One topic we would like to point out from the dialogs, is that of acid deposition being linked to Alzheimer´s. The linkage is that acid rain is causing an increase in aluminum in the food we eat. More information can be found on this topic at:
 | 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. |
| Effects of Pollution on Cultural Monuments |
| 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. |
