Abstract
Three aerosol sizing and counting instruments were combined into a single automatic system capable of continuously providing data pertinent to the physical properties of airborne particulates. Particle sizes are determined by either condensation, light scattering, or electrical phenomena. All three methods are required to measure broad-size aerosol spectrums, as each individual method possesses accurate sizing characteristics over a limited size range. The instruments, combined into a unitized system, provide data on particles within various interval widths and group the respective sized particles according to the interval midpoint. An appropriate electrical signal, indicative of the number of particles present, is recorded by electronic instrumentation, and subsequent calculations result in a complete number-size distribution. This paper describes the union of the condensation nuclei counter, the light-scattering counter, and the electrical particle counter with associated data acquisition equipment to produce a workable system. Data reduction, as applied to the determination of a number-size distribution, is also discussed.