Biogenic isoprene in the Lower Fraser Valley, British Columbia
Bibliographic record
Abstract
Tropospheric ozone is formed by photochemical reactions between nitrogen oxides (NOx) and volatile organic compounds. In some regions, biogenic isoprene may be a significant contributor to the production of tropospheric ozone. The contribution of biogenic isoprene is an important aspect of regional ozone chemistry as it represents an ozone precursor that cannot be eliminated through emissions controls. The purpose of this study was to evaluate the contribution of isoprene to the production of tropospheric ozone in the Lower Fraser Valley, British Columbia. Seasonal trends and diurnal profiles were used to examine isoprene's relationship with temperature, to determine its source, and to investigate the chemical and physical factors that limit the ambient levels of isoprene present in the region. Total isoprene levels in the Lower Fraser Valley were low, and evidence suggested that a substantial fraction originated from anthropogenic rather than biogenic sources. Diurnal isoprene profiles were generally flat, and the times of the highest concentrations did not coincide with peak NOx levels nor with the times of optimal ozone‐producing meteorological conditions. These results are consistent with those of previously reported studies and suggest that biogenic isoprene may not be as important to the tropospheric ozone chemistry in the Lower Fraser Valley as it is in some southern U. S. cities. An edited version of this paper was published by AGU. Copyright 1998 American Geophysical Union.
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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 | 0.001 | 0.002 |
| Science and technology studies | 0.002 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".