Long‐term trends in atmospheric concentrations of sulfate, total sulfur, and trace elements in the northeastern United States
Bibliographic record
Abstract
Concentrations of K, Sc, Mn, Fe, Zn, As, Se, Sb, Hg, and Pb were determined in quarterly composites of daily aerosol samples collected at Mayville, and 530 km downwind at Whiteface Mountain (1.5 km altitude), New York, for ∼20 years. SO4 concentrations [SO4] were determined in individual daily samples. Continuous hourly SO2 data are also available for much of the period. [SO4] at Mayville were twice that at Whiteface Mountain, and total S (S as SO2 + SO4) burden was fourfold higher at Mayville. From 1979 through 2002, [SO4] decreased by 59% at Whiteface Mountain, and at Mayville the decrease was 30% from 1984 to 2002. From 1979 to 2002, SO2 emissions in eight states upwind of and contiguous with New York State (Ohio, Pennsylvania, Indiana, Illinois, Wisconsin, Kentucky, West Virginia, and Ontario, Canada) decreased by 49%. A linear relationship was observed between atmospheric [SO4] and [total S] burden at the two sites with the cumulative SO2 emissions. These observations suggest that any further reductions in SO2 emissions would result in a proportional decrease in [SO4] and [total S] across New York State and possibly across the northeastern United States. The data at Whiteface Mountain suggest that beginning in 1997, the decrease in [SO4] and [total S], relative to SO2 emissions, may be faster than the earlier period. Like [SO4] and [total S], the trace element concentrations were twofold to fivefold higher at Mayville than at Whiteface Mountain. The concentrations at both sites showed an unmistakable decrease over time. The largest decreases were observed for Hg (16%/year at Whiteface Mountain and 10%/year at Mayville) and Pb (14%/year at Whiteface Mountain and 10%/year at Mayville). The remaining elements (except Sb), including the crustal elements K, Mn, Sc, and Fe, showed a decreases of 3–5%/year. Trends for Sb at Whiteface Mountain and for Mn at Mayville could not be accurately discerned, apparently due to some nearby emissions. Apparently, the reductions in the emissions of SO2 and particulate matter have also resulted in the decrease of atmospheric burden of trace elements and an improvement in air quality.
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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 | 0.000 | 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".