Long-term air concentrations, wet deposition, and scavenging ratios of inorganic ions, HNO <sub>3</sub> and SO <sub>2</sub> and assessment of aerosol and precipitation acidity at Canadian rural locations
Bibliographic record
Abstract
Abstract. This study analyzed long-term air concentrations and annual wet deposition of inorganic ions and aerosol and precipitation acidity at 30 Canadian sites from 1983–2011. Scavenging ratios of inorganic ions and relative contributions of particulate- and gas-phase species to NH4+, NO3−, and SO42− wet deposition were determined. Long-term median atmospheric NH4+, NO3−, and SO42− between sites ranged from 0.1–1.7, 0.03–2.0, and 0.6–3.5 μg m−3, respectively. Their median annual wet deposition varied from 0.2–5.8, 0.8–23.3, and 0.8–26.6 kg ha−1 a−1. Geographical patterns of atmospheric Ca2+, Na+, Cl−, NH4+, NO3−, and SO42− were similar to wet deposition and attributed to anthropogenic sources, sea-salt emissions, and agricultural emissions. Decreasing trends in atmospheric NH4+ (1994–2010) and SO42− (1983–2010) were prevalent. Atmospheric NO3− increased from 1991–2001 and declined from 2001–2010. These results are consistent with SO2, NOx and NH3 emission trends in Canada and the U.S. Widespread declines in annual NO3− and SO42− wet deposition ranged from 0.07–1.0 kg ha−1 a−1 (1984–2011). Acidic aerosols and precipitation impacted southern and eastern Canada more than western Canada; however both trends have been decreasing since 1994. Scavenging ratios of particulate NH4+, SO42− and NO3− differed from literature values by 22 %, 44 % and a factor of 6, respectively, because of the exclusion of gas scavenging. Average gas and particle scavenging contributions to wet NO3− deposition were 72±23 % for HNO3 and 28±23 % for particulate NO3−. SO2 and particulate SO42− contributed 37±20 % and 63±20 % to wet SO42− deposition, respectively. NH3 and particulate NH4+ contributed 30±19 % and 70±19 % to wet NH4+ deposition.
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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 | 0.001 | 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) | 0.001 | 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".