Particle Loss Calculator - A new software tool for the assessment of the performance of aerosol inlet systems

Abstract

Most aerosol measurements require an inlet system to transport aerosols from a select sampling location to a suitable measurement device through some length of tubing. Such inlet systems must be optimized to minimize aerosol sampling artifacts and maximize sampling efficiency. In this study we introduce a new multifunctional software tool (Particle Loss Calculator, PLC) that can be used to quickly determine aerosol sampling efficiency and particle transport losses due to passage through arbitrary tubing systems. The software employs relevant empirical and theoretical relationships found in established literature and accounts for the most important sampling and transport effects that might be encountered during deployment of typical, ground-based ambient aerosol measurements through a constant-diameter sampling probe. The software treats non-isoaxial and non-isokinetic aerosol sampling, aerosol diffusion and sedimentation as well as turbulent inertial deposition and inertial deposition in bends and contractions of tubing. This software was validated through comparison with experimentally determined particle losses for several tubing systems bent to create various diffusion, sedimentation and inertial deposition properties. As long as the tube geometries are not "too extreme", agreement is satisfactory. We discuss the conclusions of these experiments, the limitations of the software and present three examples of the use of the Particle Loss Calculator in the field.