Comparative Evaluation of Overexposure Potential Indices used in Solvent Substitution
Bibliographic record
Abstract
BACKGROUND: Overexposure potential indices (OPIs) can be defined as ratios between different measures of the volatility of a substance and its 8-h occupational exposure limit. OBJECTIVES: The overall objective of this study was to compare three OPIs, using a list of commonly used or recommended solvents as both single substances and mixtures. The three indices studied differ in the way they characterize volatility: vapour pressure for the vapour hazard ratio (VHR), calculated emission rate for the 'SUBstitution FACtor' (SUBFAC) index obtained from the former Danish SUBTEC software and discrete values based on relative evaporation rate for the Måleteknisk Arbejdshygiejnisk Luftbehov (MAL) index which is part of regulations in Denmark. METHODS: A list of 56 pure solvents and of 50 mixtures of solvents was used for the comparison. For mixtures, VHR was calculated both as VHR(mi), where the mixture is considered as ideal, and as VHR(mc) (corrected) with the introduction of activity coefficients to take into account the nonideal behaviour of components. Activity coefficients were a standard feature of SUBFAC for mixtures (SUBFAC(m)) but are not used when calculating MAL for mixtures (MAL(m)). RESULTS: Pure solvents rank in overall similar order with the three systems and correlation was excellent between VHR and SUBFAC (R = 0.99) and good between VHR and MAL (R = 0.75). For solvent-based mixtures, correlation is excellent between VHR(mi) and VHR(mc) (R = 0.98) and between VHR(mc) and SUBFAC(m) (R = 0.98) but moderate between VHR(mi) and MAL(m) (R = 0.52). Ratios between VHR(mc) and VHR(mi) varied between 0.57 and 2.7, thus spanning an approximately 5-fold range, and averaged 1.2. Worse correlations involving the MAL index are attributed to the discrete nature of its numerator. CONCLUSIONS: Overall, these results favour using the simple and more easily available VHR when comparing pure substances. In the case of mixtures, the effect of nonideality may be important in certain cases. As a precaution, since no integrated tool is available presently to easily calculate OPI values corrected for nonideality, substitution should be recommended only as long as the non-corrected VHR value for an alternative solvent is at least 5-fold less than that of the solvent to replace.
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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 | 0.004 | 0.007 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.004 | 0.003 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| 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".