Performance of a capillary dilution system for high-concentration sampling of ultrafine aerosols

Type de document

Études primaires

Année de publication

2018

Langue

Anglais

Titre de la revue

Aerosol Science and Engineering

Première page

92

Dernière page

97

Résumé

To characterize particle properties, a proper conditioning of aerosol samples is required for most aerosol measurement systems. Ultrafine particles are often generated in high concentrations, resulting in the need for dilution prior to measurement. Reasons for this sample dilution include the prevention of condensation of volatile compounds onto the particle surface, the suppression of chemical reactions and simply to bring the particle concentration below the maximum tolerable value for the measuring instruments. A number of different approaches are taken to dilute samples. In this article, a new type of dilution system designed for submicron aerosols with high concentrations is presented and its performance compared with design expectations. The new dilution instrument is based on a capillary/filter technique. Small capillary transports a tiny proportion of the sample and the greater part will be filtered and used as diluting gas. The shuffling between the two parts takes place inside a filter. Therefore, the dilution ratio is determined by the diameter of the capillary and the flow rate. With this principle, the dilution process is realized in a single step and on a fast time scale. Calibration measurements showed a linear relation between the dilution ratio and the control parameters within ± 2%. The dilution ratio was found to be independent of particle diameter in the size range between 10 and 400 nm. The dilution ratio scan for the proposed system can be varied continuously from moderate to very high dilutions (from 1:10 to 1:103); this range could be extended with minor modifications. The proposed instrument was built on a small and portable scale. The described dilution system opens a wide range of applications for particle sampling. © 2018, The Author(s).

Mots-clés

Échantillonnage dans l'air, Air sampling, Aérosol, Aerosol, Particule ultrafine, Ultrafine particle

Numéro de projet IRSST

n/a

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