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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 positive ion clusters produced during the presence of various tubing materials in front of the charger. The different tubing materials evaporate impurities to the system that are causing a dramatic change in the pattern of the mobility/size distribution of the ions generated in the 241Am charger. With contaminants present, the mean mobility equivalent diameter is shifted towards bigger sizes.
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f0020: Comparison of the size distribution of positive ion clusters produced during the presence of various tubing materials in front of the charger. The different tubing materials evaporate impurities to the system that are causing a dramatic change in the pattern of the mobility/size distribution of the ions generated in the 241Am charger. With contaminants present, the mean mobility equivalent diameter is shifted towards bigger sizes.

Mentions: The measured size distributions of positive ions produced by an 241Am α-source in purified pressurized air using different tubing materials as air duct in front of the charger are shown in Fig. 4. In total, three additional tubing configurations where investigated: tubing made of polycarbonate, polyurethane, and a PVC fabric hose. The data indicated in the following as “clean and dry” always refers to the experiments with the short 10 cm PTFE-connection tube in front of the charger. These tubing materials were chosen as they represent the typical air ducts used in experimental setups for aerosol measurements.


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 positive ion clusters produced during the presence of various tubing materials in front of the charger. The different tubing materials evaporate impurities to the system that are causing a dramatic change in the pattern of the mobility/size distribution of the ions generated in the 241Am charger. With contaminants present, the mean mobility equivalent diameter is shifted towards bigger sizes.
© Copyright Policy
Related In: Results  -  Collection

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

f0020: Comparison of the size distribution of positive ion clusters produced during the presence of various tubing materials in front of the charger. The different tubing materials evaporate impurities to the system that are causing a dramatic change in the pattern of the mobility/size distribution of the ions generated in the 241Am charger. With contaminants present, the mean mobility equivalent diameter is shifted towards bigger sizes.
Mentions: The measured size distributions of positive ions produced by an 241Am α-source in purified pressurized air using different tubing materials as air duct in front of the charger are shown in Fig. 4. In total, three additional tubing configurations where investigated: tubing made of polycarbonate, polyurethane, and a PVC fabric hose. The data indicated in the following as “clean and dry” always refers to the experiments with the short 10 cm PTFE-connection tube in front of the charger. These tubing materials were chosen as they represent the typical air ducts used in experimental setups for aerosol measurements.

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