ABSTRACT
It is commonly acknowledged that facepiece leakage is dependent on the particle size. However, the relationship between particle size and facepiece leakage was not reported until the last few years. Holton, Willeke and coworkers 1 conducted a study to measure particle size-dependent leakage into and losses inside a respirator, the mechanism occurring at the leak site and the flow dynamics inside the respirator. Particles with sizes between 0.07 and 4.4 μm were selected for testing. The fine test aerosol was generated from a mixture of smoke from burning incense and a nebulized corn oil. The two larger aerosols were generated from limestone dust and conr oil. Three types of aerosol measurement systems were used in this study: an electrostatic aerosol classifier (EAC) and a condensation nuclei counter measured particles 0.1 μm or less; an active-scattering aerosol spectrometer (ASAS) measured particles between 0.1 and 3.0 μm; and an aerodynamic particle size (APS) measured aerodynamic diameters between 0.5 and 16 μm.
