Abstract
Isokinetic dust-sampling does not guarantee a true concentration measurement of particles when the particles and the sampling probe are electrified. The measured concentration is lower than the true concentration when both the particles and the probe are electrified to the same polarity. If the polarities of their electrostatic charges are opposite, the measured concentration is higher than the true concentration. The effect becomes predominant as the particle inertia becomes smaller.
The sampling error takes a maximum in a certain range of particle diameter depending on the sampling conditions. Further, the smaller the probe, the larger the electrostatic effects. The effect of the induced force is, however, very weak and is negligible in actual cases. The results obtained in this paper give a better understanding of experimental results left unexplained.
