Investigations on the environmental chemistry of atmospheric mercury on local, regional and global scales
Bibliographic record
Abstract
Mercury is outstanding among the global environmental pollutants of continuing concern. Long-range atmospheric transport, its transformation to more toxic methylmercury compounds, and their bioaccumulation in the aquatic food-chain have motivated intensive international research in this field. The starting point of this habilitation thesis is a research study carried out to assess the mercury emissions and environmental impact from a partly demolished industrial plant in the Halle/Leipzig area as an example for the atmospheric dispersion of atmospheric mercury on a local scale. It was estimated that between 2 to 4 kg were emitted per day from the industrial complex and that about 30% of the emissions were deposited in the local vicinity of the plant, whereas 70% were available for long-range-transport at least on a regional scale. Since gaseous elemental mercury has an estimated average in the atmosphere of about 1 year, it is also subject to long-range-atmospheric transport on regional, hemispherical and even global scales. Observational data on the spatial and temporal distribution of atmospheric mercury are extremely limited. Analytical capabilities have been developed to generate input data for numerical simulation models to quantify the distribution, transport and deposition of atmospheric mercury over north-western and central Europe. The data sets presented in this work are currently in use as reference data for an international model intercomparison exercise under the UN-ECE Convention on Long-Range Transport of Air Pollutants, coordinated by EMEP-Meteorological Synthesizing Centre East in Moscow, Russia. Long-term measurements at a site located at the western Irish coast line have shown stable concentration levels of atmospheric mercury over several years despite reduced emissions in Europe. An increase of 4% per year was detected for air masses clearly of marine origin, possibly reflecting a trend in global emissions. A significant concentration gradient has been measured between the northern and southern hemisphere with an about 30% higher northern hemispheric mean. Finally, first measurements of atmospheric mercury have been carried out in Antarctica and are supplemented by data of a Canadian group obtained in the Arctic to assess the importance of polar regions as sinks in the global cycling of mercury. With the first annual time series of atmospheric mercury in the Antarctic it could be shown that the phenomenon of mercury depletion events (MDEs) do occur in the South polar region and that these events are positively correlated with ground level ozone concentrations during Antarctic spring. (orig.)
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".