Interlaboratory comparison exercise for micro-aerosol size measurement by cascade impactor

This study presents an interlaboratory comparison (ILC) exercise focused on measuring micro-aerosol size distributions using cascade impactors. The aerodynamic particle size distribution (APSD) is a critical parameter for understanding aerosol behaviour, particularly for health-related applications. The ILC conducted at the Institut de Radioprotection et de Sûreté Nucléaire (IRSN) aims to assess the performances of participating instruments measuring aerodynamic diameter, cascade impactors and an Aerodynamic Particle Sizer (APS) for real time monitoring. The experiments were performed in a custom test bench able to generate aerosols in a size range from 0.2 to 4 µm within a controlled environment. Performance evaluations of the participating instruments considering five distinct aerosol size distributions were assessed, and two methods – Henry's method and lognormal adjustment – were used to calculate the mass median aerodynamic diameter (MMAD) and the geometric standard deviation (σ g ). Statistical analysis using ζ-score and Z'-score ensured the reliability of the results across participating instruments. The findings demonstrates that most instruments performed within acceptable limits, though variations observed in some cases, particularly for smaller particle sizes. This work highlights the feasibility of standardized ILCs for APSD measurement and offers a framework for improving accuracy and consistency in aerosol size distribution assessments.