Influence of Relative Humidity and Composition on PM<sub>2.5</sub> Phases in Northeast Asia
Bibliographic record
Abstract
In Northeast Asia, the elevated levels of fine particulate matter (PM 2.5 ) are an environmental concern, yet their physicochemical properties have been poorly characterized. Herein, we determined the phase states of PM 2.5 in 92 filter samples collected from four different cities─Beijing, Seoul, Seosan, and Ulaanbaatar─during 2020–2022, within a temperature range of ∼290–293 K. We noted a distinct trend in the boundary relative humidity (RH) of liquid and semisolid phases within these PM 2.5 samples. As the inorganic fraction increased, the RH of the liquid phase decreased, whereas that of the semisolid phase increased. This behavior was strongly influenced by the chemical composition of PM 2.5 . By incorporating ambient RH data from each city, we estimated the prevalent PM 2.5 phase states within the planetary boundary layer of Northeast Asia. Our findings revealed that the dominant phase states of PM 2.5 in these urban areas were liquid and semisolid. Additionally, we showed a critical threshold based on the aerosol liquid water content (ALWC) in PM 2.5: a primarily liquid phase for ALWC/PM 2.5 ratios of ≥∼0.5 and a predominantly semisolid phase for ALWC/PM 2.5 ratios of <∼0.5. These insights could contribute to a better understanding of the mechanisms underlying aerosol pollution in Northeast Asia.
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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".