Coal Tar Pitch Volatiles and Polycyclic Aromatic Hydrocarbons Exposures in Expansion Joint-Making Operations on a Construction Site: A Case Study
Why this work is in the frame
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Bibliographic record
Abstract
This case study describes occupational exposures to coal tar pitch volatiles (CTPV) as benzene soluble fraction (BSF), polycyclic aromatic hydrocarbons (PAHs) and total particulates at a unique operation involving the use of coal tar in the making of expansion joints in construction of a multi-level airport parking garage. A task-based exposure assessment approach was used. A set of 32 samples was collected and analyzed for total particulate and CTPV-BSF. Twenty samples of this set were analyzed for PAHs. Current American Conference of Governmental Industrial Hygienists (ACGIH(R)) respective threshold limit value-time weighted average (TLV-TWA) for insoluble particulates not otherwise specified (PNOS) is 10 mg/m(3) as inhalable dust, which roughly corresponds to 4 mg/m(3) total particulate; for CTPV as BSF the TLV is 0.2 mg/m(3), and for specific PAHs such as benzo(a)-pyrene (B[a]P), ACGIH suggests keeping exposure as low as practicable. The recommended Swedish exposure limit for B(a)P is 2 microg/m(3). The highest exposure levels measured were 12.8 mg/m(3) for total particulate, 1.9 mg/m(3) for coal tar pitch volatiles as BSF, and 12.8 microg/m(3) for B(a)P. Several of the CTPV-BSF results were over the TLV of 0.2 mg/m(3). The data set is limited; therefore, caution should be used in its interpretation.
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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 | 0.001 | 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 | 0.001 | 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 it