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The effect of carrier gas contaminants on the charging probability of aerosols under bipolar charging conditions.

Steiner G, Reischl GP - J Aerosol Sci (2012)

Bottom Line: A recently developed high resolution mobility spectrometer allows the precise determination of the ions' electrical mobility; an empirical mass-mobility relationship was used to approximate the corresponding ion masses.Since the ion properties control the charging process of aerosols, it was further investigated how the different ion properties affect the calculation of the charging probabilities of aerosols.The results show that despite large variations of the ions' properties, only a minor effect on the calculated charging probabilities can be found.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Wien, Austria ; Department of Physics, University of Helsinki, P.O. Box 64, 00014, Finland.

ABSTRACT
This work concentrates on the experimental determination of the properties of ionic molecular clusters that are produced in the bipolar ionic atmosphere of a radioactivity based (241)Am charger. The main scope of this study was to investigate the dependency of the ions' properties on carrier gas contaminants caused by the evaporation of trace gases from different kinds of frequently encountered tubing materials. A recently developed high resolution mobility spectrometer allows the precise determination of the ions' electrical mobility; an empirical mass-mobility relationship was used to approximate the corresponding ion masses. It was found that impurities in the carrier gas dramatically change the pattern of the ion mobility/size distribution, resulting in very different ion properties that strongly depend on the carrier gas composition. Since the ion properties control the charging process of aerosols, it was further investigated how the different ion properties affect the calculation of the charging probabilities of aerosols. The results show that despite large variations of the ions' properties, only a minor effect on the calculated charging probabilities can be found.

No MeSH data available.


Related in: MedlinePlus

Comparison of the size distribution of negative ion clusters produced during the presence of various tubing materials in front of the charger. Similar to the positive ions, the pattern of the size distribution changes with contaminants present in the system. Again, the mean mobility equivalent diameter is shifts towards bigger cluster sizes.
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f0025: Comparison of the size distribution of negative ion clusters produced during the presence of various tubing materials in front of the charger. Similar to the positive ions, the pattern of the size distribution changes with contaminants present in the system. Again, the mean mobility equivalent diameter is shifts towards bigger cluster sizes.

Mentions: Similar results were obtained for negative ions (Fig. 5). At clean conditions, almost only a single peak at 0.96 or 0.98 nm characterizes the size distribution of negatively charged ions. Using different tubing materials, that evaporate various chemical compounds from their inner surface into the previously carefully purified air, again strongly alters the ions' size distribution. For polycarbonate and polyurethane tubing, the initially unimodal size distribution now features three different well pronounced size peaks. The PVC fabric hose again shows a little bit different pattern, but this time with additionally generated clusters at larger sizes with less pronounced corresponding peaks, indicating a larger amount of evenly distributed cluster species.


The effect of carrier gas contaminants on the charging probability of aerosols under bipolar charging conditions.

Steiner G, Reischl GP - J Aerosol Sci (2012)

Comparison of the size distribution of negative ion clusters produced during the presence of various tubing materials in front of the charger. Similar to the positive ions, the pattern of the size distribution changes with contaminants present in the system. Again, the mean mobility equivalent diameter is shifts towards bigger cluster sizes.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3473358&req=5

f0025: Comparison of the size distribution of negative ion clusters produced during the presence of various tubing materials in front of the charger. Similar to the positive ions, the pattern of the size distribution changes with contaminants present in the system. Again, the mean mobility equivalent diameter is shifts towards bigger cluster sizes.
Mentions: Similar results were obtained for negative ions (Fig. 5). At clean conditions, almost only a single peak at 0.96 or 0.98 nm characterizes the size distribution of negatively charged ions. Using different tubing materials, that evaporate various chemical compounds from their inner surface into the previously carefully purified air, again strongly alters the ions' size distribution. For polycarbonate and polyurethane tubing, the initially unimodal size distribution now features three different well pronounced size peaks. The PVC fabric hose again shows a little bit different pattern, but this time with additionally generated clusters at larger sizes with less pronounced corresponding peaks, indicating a larger amount of evenly distributed cluster species.

Bottom Line: A recently developed high resolution mobility spectrometer allows the precise determination of the ions' electrical mobility; an empirical mass-mobility relationship was used to approximate the corresponding ion masses.Since the ion properties control the charging process of aerosols, it was further investigated how the different ion properties affect the calculation of the charging probabilities of aerosols.The results show that despite large variations of the ions' properties, only a minor effect on the calculated charging probabilities can be found.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Wien, Austria ; Department of Physics, University of Helsinki, P.O. Box 64, 00014, Finland.

ABSTRACT
This work concentrates on the experimental determination of the properties of ionic molecular clusters that are produced in the bipolar ionic atmosphere of a radioactivity based (241)Am charger. The main scope of this study was to investigate the dependency of the ions' properties on carrier gas contaminants caused by the evaporation of trace gases from different kinds of frequently encountered tubing materials. A recently developed high resolution mobility spectrometer allows the precise determination of the ions' electrical mobility; an empirical mass-mobility relationship was used to approximate the corresponding ion masses. It was found that impurities in the carrier gas dramatically change the pattern of the ion mobility/size distribution, resulting in very different ion properties that strongly depend on the carrier gas composition. Since the ion properties control the charging process of aerosols, it was further investigated how the different ion properties affect the calculation of the charging probabilities of aerosols. The results show that despite large variations of the ions' properties, only a minor effect on the calculated charging probabilities can be found.

No MeSH data available.


Related in: MedlinePlus