Quantification of the kinetics of ozone uptake by tree pollen and the extent of modification
Bibliographic record
Abstract
Understanding the interaction between ozone and pollen is crucial, as it may influence pollen allergenicity and reproductive viability. This study investigates the kinetic uptake of ozone by pollen, and the its resulting modification, revealing significant variability among 12 tree pollen species.Exposure of pollen to moderate ozone levels (130 – 150 ppb) in small air chambers facilitated the measurement of ozone uptake until total surface saturation. This yielded initial uptake coefficients (0.6 – 6.4 x 10-5) and total adsorbed ozone (9.4 – 2200 ng O3 per mg of pollen). Using this information, we calculate the number of reactive sites on pollen surfaces (1013 – 1016 sites cm-2) and observed rate coefficients (kobs) ranging from 10-15 – 10-17 cm3 sites-1 s-1. Notably, Ash pollen, similar in size to Birch pollen, exhibited 25 times greater ozone uptake, indicating a dependence on pollen type. Molecular modifications induced by ozone were explored using optical spectroscopy, identifying potential chemical markers and emphasizing molecular diversity among pollen species. Antioxidant molecules, like carotenoids in Ash, indicated a protective role for the pollen coat, suggesting that significant ozone uptake may not harm pollination.Using a box model with plausible rates for pollen emission and deposition, we were able to calculate the extent of pollen modification by ozone in airborne pollen under environmentally relevant conditions. Depending on the pollen species, the extent of oxidation in airborne pollen ranged from 24% - 97%, and was highest in the late afternoon. Sensitivity analysis shows that the extent of oxidation is sensitive to uptake kinetics, ozone concentrations, and assumptions about mixing height. Under typical conditions, tree pollen grains are airborne for long enough that they will experience a significant proportion of the total potential modifications induced by ozone exposure.
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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) | 0.000 | 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 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".