On-line Characterisation of Aerosols – Comparability and Combination of Selected Measuring Devices

Abstract

A scanning mobility particle sizer (SMPS, TSI Model 3934) and a white-light optical particle counter (OPC, as described by Umhauer 1983) are combined. With these two instruments, fast and non-intrusive on-line measurements of particle size distributions in a range of 15 nm up to 15 μm are possible. A filter provides the possibility of taking samples in order to analyse the morphology and chemical composition of the aerosol. Both liquid and solid airborne particles in diluted suspensions can be measured. The complete system is able to cope with particle concentrations of up to 107 particles/cm3 without dilution of the aerosol. Since the measuring principles of the combined devices are based on different physical properties, careful calibration is necessary. Both theoretical calculations and experimental methods are used for calibration purposes. The measuring results of different devices are compared during simultaneous characterisation of several aerosols. The performance of the combined measuring system is demonstrated by means of comparison with a common cascade impactor in the laboratory as well as during industrial application.