CHED 1120 |
| Continuous snow accumulation in the polar regions (e.g., Antarctica) preserves the history of atmospheric chemical composition, as atmospheric chemical substances, natural as well as pollutant, are deposited with snowfall. Reconstruction of the chronological history via ice cores can provide valuable information on the sources of the chemical substances, their role in atmospheric processes, and their impact on the environment. For example, organic compounds emitted by natural terrestrial sources (e.g., vegetation) undergo oxidation in the atmosphere which produces small carboxylic acids such as formic and acetic acids. In this research project, an analytical method using ion chromatography was developed to measure extremely low concentrations of formic and acetic acids in Antarctica snow. The method was then used to determine the concentrations of these two weak organic acids in South Pole snow pit samples covering a period of ten years. The results show that, at the South Pole, formic and acetic acid concentrations are at the low ppb (nanogram per gram of snow) levels. These concentrations also show inter-annual as well as intra-annual variations, which may be related to source strength and atmospheric oxidation efficiency. Longer (> 100 years) records of formic and acetic acids will be obtained with the future analysis of long ice cores. |
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Undergraduate Research Poster Session: Environmental Chemistry
2:00 PM-4:00 PM, Monday, March 26, 2007 Hyatt Regency Chicago -- Riverside Center, Poster
Division of Chemical Education |