Comparison of Various Methods for Processing Cascade Impactor Data

This study proposes a method of processing cascade impactor data, called the “calibration matrix method,” and compares it with usual methods. This method takes into account the real collection efficiency curves obtained from cascade impactor calibration, in contrast to the usual methods which assume that cascade impactor collection efficiency is ideal. The comparison between the new and usual methods was carried out for sodium fluoride aerosols generated with five different nebulizers (Multisonic®, LS260 kit2601®, Sidestream®, PariLC+® and Aeroneb Go®) and one dry powder (terbutaline, Astra Zeneca, France), sized with the 8-stage Marple Model 298 Personal cascade impactor. Particle size distributions were represented as differential and cumulative distributions. Statistical differences were highlighted between the calibration matrix method and the usual methods in terms of MMAD and respirable fractions for all aerosols. The largest differences were 28% in terms of MMAD and 64% in terms of respirable fraction.