ABSTRACT

This chapter reviews the history of the Liesegang ring (LR) observation and its application to the chemical identification of aerosol particles. The aerosol centrifuge was calibrated by latex particles of known size and at well-controlled humidity. Essential to the practical application of LR technique for detecting several important constituents of an atmospheric aerosol is the determination of the ring magnification factor which depends on several environmental parameters and on the sampling and evaluation process. A considerable difference was found between the magnification factor corresponding to lower relative humidity maintained during the aerosol passage from the generator to the aerosol centrifuge and factors obtained at a higher relative humidity. Several techniques have been applied to aerosol particle sampling and LR identification in the atmosphere. One of the great advantages of the time-consuming LR technique for sample evaluation is the identification of mixed particles.