Charging equivalent diameter relation for sodium chloride and soot aggregates using electrical low-pressure impactor
Bibliographic record
Abstract
The average number of charges on non-spherical particles after charging is much higher than for spherical particles of the same mobility equivalent diameter. This makes it difficult to interpret measurements from instruments employing chargers like the electrical low-pressure impactor (ELPI+), which is often used to measure aerosols of varying shapes. Previous efforts to determine this difference have used non-spherical particles classified by a differential mobility analyzer (DMA). However, the presence of multiple charged particles introduces uncertainty, in part given that the multiple charged fractions from the classifier itself are impacted by particle morphology. To largely eliminate this issue, we classify the particles first with an Aerodynamic Aerosol Classifier (AAC) prior to classification with a DMA. Three different aerosols - polyethylene glycol (PEG - spherical), sodium chloride (NaCl - cube-like), and soot aggregates were tested. PEG and NaCl were generated using an atomizer while soot was produced from a laminar inverted flame with either ethylene or propane as the fuel. Both NaCl and soot particles showed a higher average charge than PEG. The charge carried by these particles is a function of the details of the charger, including penetration and ion concentration time, which is minimized by using charging equivalent diameter (dqe). We found this relation to be dqe(NaCl) = 1.106 dm1.014 and dqe(Soot) = 1.489 dm1.088 (where dm is mobility diameter in μm).Copyright © 2025 American Association for Aerosol Research
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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 | 0.001 |
| 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".