THE AIR THAT WE BREATHE: NEUTRAL PFAS IN INDOOR AND OUTDOOR AIR
Bibliographic record
Abstract
Neutral, volatile perfluorinated alkyl substance (PFAS) precursors, such as fluorotelomer alcohols (FTOHs), perfluorooctane sulfonamides (FOSAs), and perfluorooctane sulfonamide ethanol (FOSEs) are industrial (by)products that are commonly present in indoor environments, and have been found in urban, industrial, and even rural locations. They have also been detected in remote regions, such as the Arctic, suggesting that these compounds are transported long distances in the. However, measuring volatile and neutral PFAS in air and water has proven to be challenging. Therefore, in order to accurately measure these compounds in different indoor and outdoor environments from urban, rural, industrial and remote regions, we proposed the use of apolar polyethylene (PE) sheets as a passive detection tool for air and water. The compounds of interest in this study included 6:2 FTOH, 8:2 FTOH, 10:2 FTOH. 8:2 FTAcr, 10:2 FTAcr, MeFOSA, MeFOSE, EtFOSA, and EtFOSE. Indoor sampling locations included classrooms, offices and laboratories from the University of Rhode Island, kindergarten classrooms and an outdoor clothing store in northern California, and classrooms, offices, laboratories and homes from the central valley of Jalisco, Mexico. Outdoor sampling of air and water included the North American Great Lakes, the Canadian Arctic, and Dhaka, Bangladesh. Studies were evaluated using two types of pre-cleaned PE passive samplers differentiated by thickness, and samples were analyzed by gas chromatography-mass spectrometry. These PE sheets were used to determine the partitioning coefficients (KPEa) and uptake of the volatile PFAS by these samplers. Results from the kinetic study showed that after 14 days of exposure equilibrium of the compounds into the PE sheets had been reached. Passive samplers were then paired with Radiello active samplers at an outdoor gear and clothing store to determine the KPEa of each compound. Partitioning between both PE sheets suggests that interactions of the passive samplers with the volatile PFAS are occurring by absorption. Gas-phase concentrations were paired with concurrently analyzed dust samples taken at the same locations in Californian kindergartens, and indoor air concentrations were linked to carpet and dust concentrations and the ventilation rates of the indoor environments. Results from all indoor studies indicated that volatile and neutral PFAS are ubiquitous in these environments, but that composition and concentration will vary depending on the contents of each location such as furniture, carpet, clothing, as well as ventilation rates. Volatile 6:2 FTOH was dominant in the U.S. indoor locations which was likely a reflection of the banning of longer chained
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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 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".