Formation of Gas-Phase Hydrogen Peroxide via Multiphase Ozonolysis of Unsaturated Lipids
Bibliographic record
Abstract
Gas-phase H 2 O 2 is a prominent oxidant in the atmosphere. It also induces lung tissue damage and forest decline. Although it is known that ozonolysis of gas-phase alkenes leads to H 2 O 2 formation at high relative humidities (RHs), little is known about this chemistry via gas-surface heterogeneous oxidation. Here, we quantitatively investigated the formation of H 2 O 2 from surface ozonolysis of unsaturated lipids commonly found in human skin oil and atmospheric aerosol. This process is initiated by water reacting with Criegee intermediates (CIs), forming α-hydroxyhydroperoxides (α-HHPs) as the key intermediate products. α-HHPs are thermally stable molecules that act as reservoirs of H 2 O 2 under dry conditions, prior to rapid decomposition to release H 2 O 2 in the presence of water vapor. The upper limit of the α-HHP lifetime derived from oxidized methyl oleate was roughly 2 min at 50% RH. The molar H 2 O 2 yields (relative to ozone consumption) vary from 7% to 35% for triolein, methyl oleate, and squalene, with no significant dependence on relative humidity from 50% to 80%. In contrast, oleic acid has the lowest H 2 O 2 yield (∼2%), likely due to a more competitive reaction between CIs and its carboxylic acid headgroup. The implications of this chemistry in atmospheric and indoor environments are discussed.
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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 | 0.000 | 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) | 0.001 | 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".