B.1. Aerosols: particle sizes, deposition mechanisms, and size distributions (B1) Since the terminology relating to particle sizes and mechanisms varies somewhat in the literature, this report follows that used in Publication 66 (ICRP 1994a), Annex D, Deposition of Inhaled Particles. Main advantages Main disadvantages Filter Radioactive species Radioactivity concentration Radiochemical composition Physical diameter Shape 'Total' aerosol Easy to use Personal samplers available Penetration of radioactive particles into the matrix of some filter media Interference from other dusts Cascade impactor Radioactive species Radioactivity concentration Radiochemical composition Aerodynamic diameter Density 0.5-15 Direct measurement of aerodynamic diameter Personal samplers available Particle bounce and re-entrainment Low-pressure impactor Radioactive species Radioactivity concentration Radiochemical composition Aerodynamic diameter Density 0.05-15 Direct measurement of aerodynamic diameter Particle bounce and re-entrainment Measures aerodynamic, rather than thermodynamic diameter in submicron range Virtual impactor Radioactive species Radioactivity concentration Radiochemical composition Aerodynamic diameter Density 0.5-15 Direct measurement of aerodynamic diameter Higher loading capacity than cascade impactor Contamination of larger particles by smaller ones Cyclone Radioactive species Radioactivity concentration Radiochemical composition Aerodynamic diameter 0.5-20 High loading capacity Limited ability to separate submicron particles Elutriator Radioactive species Radioactivity concentration Radiochemical composition Aerodynamic diameter 5-50 Easy to use High loading capacity Large size of the instrument