Chemical aging of ambient organic aerosol from heterogeneous reaction with hydroxyl radicals
Bibliographic record
Abstract
The chemical transformation of ambient particles due to heterogeneous oxidation was investigated. Ambient aerosol particles sampled in Toronto, Ontario during September and October of 2007 were exposed to OH radicals in a flow tube reactor to simulate relevant atmospheric OH exposures. An Aerodyne Aerosol Mass Spectrometer measured changes in chemical composition and degree of oxidation of reacted ambient particles. Mass spectral changes of ambient particles exposed to OH revealed a loss in the hydrocarbon‐like organic fraction along with an increase in the oxygenated organic fraction. Furthermore, a minor fraction of the organic mass was lost through volatilization at high OH exposure. These observations indicate that an atmospheric OH exposure time of no more than 4 days for a typical OH concentration of 2 × 10 6 cm −3 causes enhanced oxidation of the organic matter in ambient particles. Therefore, heterogeneous oxidation may be an important chemical transformation pathway for ambient particles during regional transport.
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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 | 0.001 |
| 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 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".