dorsal/arxiv
View SchemaAspirated capacitor measurements of air conductivity and ion mobility spectra
| Authors | K. L. Aplin |
|---|---|
| Categories | |
| ArXiv ID | physics/0510149 |
| URL | https://arxiv.org/abs/physics/0510149 |
| DOI | 10.1063/1.2069744 |
| Journal | Review of Scientific Instruments, 76, 104501 (2005) |
Abstract
Measurements of ions in atmospheric air are used to investigate atmospheric electricity and particulate pollution. Commonly studied ion parameters are (1) air conductivity, related to the total ion number concentration, and (2) the ion mobility spectrum, which varies with atmospheric composition. The physical principles of air ion instrumentation are long-established. A recent development is the computerised aspirated capacitor, which measures ions from (a) the current of charged particles at a sensing electrode, and (b) the rate of charge exchange with an electrode at a known initial potential, relaxing to a lower potential. As the voltage decays, only ions of higher and higher mobility are collected by the central electrode and contribute to the further decay of the voltage. This enables extension of the classical theory to calculate ion mobility spectra by inverting voltage decay time series. In indoor air, ion mobility spectra determined from both the novel voltage decay inversion, and an established voltage switching technique, were compared and shown to be of similar shape. Air conductivities calculated by integration were: 5.3 +- 2.5 fS/m and 2.7 +- 1.1 fS/m respectively, with conductivity determined to be 3 fS/m by direct measurement at a constant voltage. Applications of the new Relaxation Potential Inversion Method (RPIM) include air ion mobility spectrum retrieval from historical data, and computation of ion mobility spectra in planetary atmospheres.
{
"annotation_id": "b947325f-f9e4-4e63-9d4a-524560820efa",
"date_created": "2026-03-02T18:01:04.220000Z",
"date_modified": "2026-03-02T18:01:04.220000Z",
"file_hash": "95036c90d3aa33d75190f073be84fe4df0216553942e7246a4c27217ab477888",
"private": false,
"record": {
"abstract": "Measurements of ions in atmospheric air are used to investigate atmospheric\nelectricity and particulate pollution. Commonly studied ion parameters are (1)\nair conductivity, related to the total ion number concentration, and (2) the\nion mobility spectrum, which varies with atmospheric composition. The physical\nprinciples of air ion instrumentation are long-established. A recent\ndevelopment is the computerised aspirated capacitor, which measures ions from\n(a) the current of charged particles at a sensing electrode, and (b) the rate\nof charge exchange with an electrode at a known initial potential, relaxing to\na lower potential. As the voltage decays, only ions of higher and higher\nmobility are collected by the central electrode and contribute to the further\ndecay of the voltage. This enables extension of the classical theory to\ncalculate ion mobility spectra by inverting voltage decay time series. In\nindoor air, ion mobility spectra determined from both the novel voltage decay\ninversion, and an established voltage switching technique, were compared and\nshown to be of similar shape. Air conductivities calculated by integration\nwere: 5.3 +- 2.5 fS/m and 2.7 +- 1.1 fS/m respectively, with conductivity\ndetermined to be 3 fS/m by direct measurement at a constant voltage.\nApplications of the new Relaxation Potential Inversion Method (RPIM) include\nair ion mobility spectrum retrieval from historical data, and computation of\nion mobility spectra in planetary atmospheres.",
"arxiv_id": "physics/0510149",
"authors": [
"K. L. Aplin"
],
"categories": [
"physics.ins-det",
"physics.ao-ph",
"physics.geo-ph"
],
"doi": "10.1063/1.2069744",
"journal_ref": "Review of Scientific Instruments, 76, 104501 (2005)",
"title": "Aspirated capacitor measurements of air conductivity and ion mobility spectra",
"url": "https://arxiv.org/abs/physics/0510149"
},
"schema_id": "dorsal/arxiv",
"source": {
"execution_id": "d796599a-70c8-4860-b848-1074660b978f",
"id": "arXiv Dataset IDs",
"type": "Model",
"variant": "snapshot-2026-03-01",
"version": "0.1.0"
},
"user_id": 1000002
}