Trends in atmospheric ammonia at urban, rural, and remote sites across NorthAmerica
Bibliographic record
Abstract
Abstract. Interannual variabilities in atmospheric ammonia (NH3) during the most recent 7–11 years were investigated at 14 sites across North America using the monitored data obtained from NAPS, CAPMoN and AMoN networks. The long-term average of atmospheric NH3 ranged from 0.8 to 2.6 ppb, depending on location, at four urban and two rural/agricultural sites in Canada. The annual average at these sites did not show any deceasing trend with largely decreasing anthropogenic NH3 emission. An increasing trend was actually identified from 2003 to 2014 at the downtown Toronto site using either the Mann–Kendall or the ensemble empirical mode decomposition method, but “no” or “stable” trends were identified at other sites. The ∼ 20 % increase during the 11-year period at the site was likely caused by changes in NH4+–NH3 partitioning and/or air–surface exchange process as a result of the decreased sulfur emission and increased ambient temperature. The long-term average from 2008 to 2015 was 1.6–4.9 ppb and 0.3–0.5 ppb at four rural/agricultural and at four remote US sites, respectively. A stable trend in NH3 mixing ratio was identified at one rural/agricultural site while increasing trends were identified at three rural/agricultural (0.6–2.6 ppb, 20–50 % increase from 2008 to 2015) and four remote sites (0.3–0.5 ppb, 100–200 % increase from 2008 to 2015). Increased ambient temperature was identified to be a cause for the increasing trends in NH3 mixing ratio at four out of the seven US sites, but what caused the increasing trends at other US sites needs further investigation.
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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 | 0.000 | 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) | 0.001 | 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".