Atmospheric Characterization of Legacy and Emerging Flame Retardants in the Canadian Arctic and Great Lakes Basin
Bibliographic record
Abstract
High Resolution Image Download MS PowerPoint Slide Atmospheric concentrations of flame retardants (FRs)─including polybrominated diphenyl ethers (PBDEs) and non-PBDE halogenated flame retardants (HFRs)─were assessed using long-term measurements from two remote Canadian locations: Alert (2002–2019) in the High Arctic and Point Petre (2005–2022) in the Great Lakes region. Organophosphate esters (OPEs) were additionally characterized at Point Petre. At Alert, PBDE concentrations declined with estimated half-lives of 4–9 years, consistent with regulatory phase-outs under the Stockholm Convention. However, slight increases in PBDE concentrations after ∼2014 suggest revolatilization from local surfaces. Non-PBDE HFRs such as Dechlorane Plus were detected at both sites, but low detection frequencies precluded trend analysis. At Point Petre, PBDEs also showed a declining trend, with an estimated half-life of 6.60 years for Σ 15 PBDEs, while OPEs measured from 2018 to 2022 were frequently detected, often at higher concentrations than PBDEs and non-PBDE HFRs. Gas–particle partitioning of OPEs was evaluated using field-derived particle-phase fractions and compared to model predictions. Substantial discrepancies, especially for low molecular weight OPEs, suggest that current models may misrepresent their atmospheric behavior, partly due to omission of activity coefficients that influence sorption. These findings highlight the shifting profiles of flame retardants in remote air and point to the need for improved models that account for physicochemical factors governing their atmospheric behavior.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".