Sulfate formation in atmospheric ultrafine particles at Canadian inland and coastal rural environments
Bibliographic record
Abstract
[1] Sulfate formation and growth in the various modes of ultrafine particles were explored using samples collected at seven inland rural sites and a remote coastal site in Canada. Two concentration regimes demarcated at a value of 0.03 μg m−3 were identified for nucleation-mode (aerodynamic diameter <0.05 μm) sulfate. In the ≥0.03 μg m−3 regime at the inland sites, strong nucleation of sulfate particles from the enhanced chemical conversion of SO2 to gaseous sulfuric acid was evident, as supported by the moderate to good correlations between the nucleation-mode sulfate and the ambient SO2 concentration as well as the elevated concentrations of O3 and NOy. However, the nucleation- and Aitken-mode sulfate did not correlate with SO2 in the ≥0.03 μg m−3 regime at the coastal site. At the sites where the ≥0.03 μg m−3 regime occurred frequently, the Aitken-mode (aerodynamic diameter 0.05–0.1 μm) sulfate was mainly from the growth of nucleation mode; the condensational growth is found to be more important than the coagulation growth at inland sites, but the coagulation growth became more important at the coastal site. The equivalent ratios of NH4+ to (SO42− + NO3−) during high-concentration episodes varied from 0.7 to 1.5 in the nucleation mode and were almost unity in the Aitken mode. The equivalent ratio in the nucleation mode ranged from 1.2 to 1.5 at a few inland sites, suggesting that ammonium organic acid salts could be present and could play important roles in the growth of the nucleation-mode particles, but they were unlikely important in the growth of the Aitken mode particles.
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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 | 0.001 |
| Science and technology studies | 0.003 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 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".