Concentrations and emissions of trichlorotrifluoroethane (CFC-113) from eastern china inferred from atmospheric observations
Bibliographic record
Abstract
Abstract Trichlorotrifluoroethane (C2Cl3F3, CFC-113) is a long-lived ozone-depleting substance (ODS) regulated under the Montreal Protocol and a potent greenhouse gas (GHG). Production and consumption of chlorofluorocarbons (CFCs) were phased out after 2007 in China, while unexpected increases in CCl3F (CFC-11) emissions from eastern China after 2012 were inferred from atmospheric observations. However, atmospheric concentrations and emissions of CFC-113 in China over the past few years are unclear. In this study, we conducted hourly observation of atmospheric CFC-113 concentrations in 2021 in eastern China, explored the potential CFC-113 emission sources using a dispersion model, and estimated the CFC-113 emissions using an interspecies correlation method. Results show that pollution events of CFC-113 were observed frequently, and the concentrations were higher than those of global background stations with similar latitudes. The dominant potential emission regions of CFC-113 were located in the eastern-central Yangtze River Delta region and Shandong province. The estimated mean CFC-113 emission from eastern China in 2021 was 0.88 ± 0.19 Gg/yr (5350 ± 1155 CO2-equivalent Gg/yr), which was higher than 0 Gg/yr (0 CO2-equivalent Gg/yr) in 2008−2021, as reported by bottom-up studies that considered CFC-113 to be phased out in China after 2007. Therefore, substantial CFC-113 emissions still existed in eastern China in 2021, which are of importance to protecting the ozone layer and mitigating the effects of climate change.
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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 | 0.001 |
| 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) | 0.000 | 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".