Collecting Airborne Organochlorines on Polyurethane Foam: Comparison of Field Observations with a Breakthrough Model
Bibliographic record
Abstract
High Resolution Image Download MS PowerPoint Slide Polyurethane foam (PUF) is widely used for active air sampling (AAS) of gaseous semivolatile organic compounds (SVOCs). PUF efficiently collects SVOCs with moderate to low volatility, but applications are limited for the more volatile SVOCs due to breakthrough from the PUF trap. The collection efficiency can be predicted by frontal chromatography theory with knowledge of several parameters: the sampled air volume, the breakthrough volume which depends on the PUF/air partition ratio ( K PA ), and the number of theoretical plates ( N ) in the PUF trap. Here we evaluate data from two Canadian air monitoring programs in which front and back PUF traps (P1 and P2) were used to check for breakthrough, as indicated by the back/front ratio (P2/P1) of collected SVOCs. A frontal chromatography model was used to relate collection efficiency of hexachlorobenzene (HCB) and α-hexachlorocyclohexane (α-HCH) to their observed P2/P1 ratios under assumed scenarios of K PA and N, and apparent N -values for the PUF traps were derived. Results were applied to correcting observed air concentrations of HCB for breakthrough loss. The choice of K PA greatly influenced the adjusted air concentrations and their variation with temperature.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 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".