Atmospheric Chemistry of Perfluorinated Carboxylic Acids: Reaction with OH Radicals and Atmospheric Lifetimes
Bibliographic record
Abstract
Relative rate techniques were used to study the kinetics of the reactions of OH radicals with a homologous series of perfluorinated acids, F(CF 2 ) n COOH ( n = 1, 2, 3, 4), in 700 Torr of air at 296 ± 2 K. For n > 1, the length of the F(CF 2 ) n group had no discernible impact on the reactivity of the molecule. For n = 1, k (OH + F(CF 2 ) n COOH) = (9.35 ± 2.08) × 10 -14 cm 3 molecule -1 s -1 . For n = 2−4, k (OH + F(CF 2 ) n COOH) = (1.69 ± 0.22) × 10 -13 cm 3 molecule -1 s -1 . Dimerization constants for 2F(CF 2 ) n COOH = (F(CF 2 ) n COOH) 2 were determined to be 0.32 ± 0.03 Torr -1, 0.30 ± 0.03 Torr -1, 0.41 ± 0.04 Torr -1, and 0.46 ± 0.05 Torr -1 for n = 1, 2, 3, 4, respectively. Atmospheric lifetimes of F(CF 2 ) n COOH with respect to reaction with OH radicals are estimated to be approximately 230 days for n = 1 and 130 days for n > 1. Reaction with OH radicals is a minor atmospheric fate of F(CF 2 ) n COOH. The major atmospheric removal mechanism for F(CF 2 ) n COOH is believed to be wet and dry deposition which probably occurs on a time scale of the order of 10 days.
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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 | 0.001 |
| 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 | 0.001 | 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".