Atmospheric Halocarbon Measurements with a focus on East and South-East Asia
Bibliographic record
Abstract
A large variety of halocarbon species are present in the atmosphere and can significantly impact stratospheric ozone depletion and/or global warming. Compound use has been phased out, reduced and replaced for some species under global control measures such as the Montreal and Kyoto Protocols. However, relatively long atmospheric lifetimes, imperfect substitutes and incomplete reductions in usage mean that global abundances of halocarbon species still require regular monitoring. This is especially true for the rapidly developing East and South-East Asian regions where widespread emissions have been repeatedly reported in recent years. \nTo detect a variety of halocarbon mixing ratios, air samples are cryotrapped and analysed via gas chromatography couple with mass spectrometry (GC-MS). Highly sensitive and precise instrumentation widens this range further and the automation of the analysis system would improve and extend sample throughput. A semi-automated inlet system for a GC-MS set-up was constructed and cryotrapping with liquid nitrogen was tested successfully. \nIn the atmosphere, anthropogenic emissions are the main source of many halocarbons, however methyl halides also have large natural sources including from cultivated crops like rice. Using genetically mapped and altered Arabidopsis thaliana and Physcomitrella patens, methyl halide emission rates were calculated. Differences found when compared to wild type plants indicated the potential for developing ‘ozone-safe’ crops through manipulation of the HOL-gene, which may particularly benefit Asian emissions. \nThree short-term sampling campaigns based in Taiwan assessed abundances of mainly anthropogenically-sourced halocarbons in East Asia. Backwards trajectory modelling was used to estimate potential source regions and both enhanced and close to background mixing ratios were observed for a range of species. Pollution events and interspecies correlations were found for many halocarbons with poorly understood sources such as CFC-113a and HCFC-133a. \nA further short-term campaign based in Bachok, Malaysia assessed long-range transport of ozone-depleting species to South-East Asia during the cold surge phenomenon of the winter monsoon, when rapid vertical transport may occur. Short-lived species were observed at significantly high abundances suggesting their potential impact on stratospheric ozone may have been previously underestimated. \n
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.000 |
| 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 teacher head, 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".