Design and performance evaluation of a laboratory-made 200 nm precut electrical cascade impactor

Abstract

Increasing public concern regarding air quality has led to the development of efficient aerosol-monitoring techniques. Among the various aerosol measurement instruments based on electrical methods, in this study, an electrical cascade impactor (ECI) was designed and fabricated in our laboratory and was used to measure the real-time size distribution of submicron-sized aerosols. In the study by Park et al. (2007), it was assumed that the size distribution of incoming particles follows a unimodal lognormal distribution. However, in this study, the distribution of particles captured at each stage (including the Faraday cage) was assumed to be a unimodal lognormal distribution; hence, the incoming particles may follow any size distribution. After the particle charging characteristics were obtained for different particle sizes, experiments were performed with monodisperse test particles to determine the collection efficiency of each stage. The current measured in each stage was converted into a number based size distribution of aerosols by using the data inversion algorithm, which utilized the experimentally obtained collection efficiency. Then, a performance evaluation was performed, both in the laboratory and in the field. The results obtained by our ECI were in agreement with the scanning mobility particle sizer (SMPS) data.