Urban versus Remote Air Concentrations of Fluorotelomer Alcohols and Other Polyfluorinated Alkyl Substances in Germany
Bibliographic record
Abstract
Neutral, volatile polyfluorinated alkyl substances (PFAS) were measured in environmental air samples at two different sites in Northern Germany in spring 2005. The sampling locations were chosen to cover a metropolitan and a rural site, the Hamburg city center, and Waldhof, a background monitoring site. An optimized and validated analytical protocol was used to analyze two sets of parallel high-volume air samples. For both sampling locations as well as for individual samples, field blanks were taken to monitor possible background contamination. Gas chromatography coupled to mass spectrometry using positive chemical ionization (GC/ PCI-MS) was used for quantitative analyses. This article describes the first air concentration data of volatile PFAS outside North America reported in the peer-reviewed literature. The wide distribution of fluorotelomer alcohols (FTOHs), fluorinated sulfonamides, and sulfonamidoethanols (FOSAs/FOSEs) in German environmental air is presented. Furthermore, two volatile PFAS, i.e., N-methyl fluorooctane sulfonamide (NMeFOSA) and 4:2 FTOH, were determined for the first time in environmental air. Minimum-maximum sigmaFTOH concentrations of 64-311 pg/m3 (remote) up to 150-546 pg/m3 (urban) and minimum-maximum sigmaFOSA + FOSE concentrations between 12 and 54 pg/m3 (remote) and 29 and 151 pg/m3 (urban) were determined. 8:2 FTOH and 6:2 FTOH were found to be the predominant POPs determined in Waldhof so far. Blank contamination was found to be negligible. A significant correlation was found with the ambient temperature for the partitioning of airborne FOSEs between the gaseous and particulate phase (R = 0.853), whereas FTOHs and FOSAs were almost exclusively found in the gaseous phase. Furthermore, highest airborne PFAS concentrations were determined at relatively high ambient temperatures. Correlation coefficients (R) for sigmaFTOH and sigmaFOSA + FOSE concentrations with temperature were 0.954 and 0.968, respectively. Finally, the PFAS concentrations determined in this study are set into context with levels of "classical" persistent organic pollutants (POPs) in the same region and PFAS data available for North America.
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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 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".