2015 Spring.Includes bibliographical references.Industrial hygienists lack the proper instruments to measure size distributions of inhalable particulate matter (0-100 μm) as defined by ACGIH/ISO/CEN. The Portable Inhalable Particle Spectrometer (PIPS) was designed to size-segregate IPM in calm-air environments – which constitute a majority of workplaces. The PIPS uses an upward air velocity to restrict particle aspiration into the device to diameters above a specified cut-size. A vertical test chamber was also designed to facilitate aerosol dispersion and experimental evaluation of the PIPS. Two PIPS tubes were tested (1.5 cm and 5 cm) at four face velocities (0.6, 1.35, 2.5 and 3.5 cm·s⁻¹) that correspond to cut-sizes of 20, 30, 40 and 50 μm in aerodynamic diameter, respectively. The observed performance of the PIPS deviated from model estimates as face velocity or tube diameter was increased. The fluid regime present inside the chamber, due to the operating PIPS, likely influenced the measured sampling efficiency of the PIPS
