Analysis of passive-sampler monitored atmospheric ammonia at 74 sites across southern Ontario, Canada
Bibliographic record
Abstract
Abstract. Weekly/biweekly concentrations of atmospheric NH3 were collected using passive samplers at 74 sites across southern Ontario, Canada during the period from June 2006 to March 2007 with tens of sites running as early as March 2006. The annual average of NH3 (AAN) at all the sites across southwestern Ontario was over 1 µg m–3, a value that was recently proposed as the new critical level for protecting vegetation. High ANN values (3.6–6.1 µg m–3) were observed at eight sites located inside the intensive livestock production zones. The AAN values at the sites across southeastern Ontario were generally less than 1 µg m–3 and the values were less than 0.4 µg m–3 at non-agricultural sites. Regional transport from the southwest region to the southeast region was identified to be the main contributor to the observed NH3 at the southeastern non-agricultural sites. However, different transport mechanisms were proposed in different seasons. The transport of NH3 produced through bi-directional air-surface exchange along air mass trajectories was believed to be the main mechanism in the hot seasons while the transport of NH4NO3 produced at source locations followed by its evaporation at receptor sites was thought to be dominant in the cold seasons. A sharp increase in NH3 concentration was surprisingly observed at 20 out of the 74 sites during the coldest two weeks when ambient temperature was lower than −7 °C, and cannot be explained by known sources or with existing knowledge. Recently developed NH3 emission inventory for southern Ontario was also evaluated with the measurement data and emissions within two small zones were identified to be potentially underestimated.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 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 | 0.001 | 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".