Sizing Particles in Gases by an Advanced Optical Procedure

Several types of sensors capable of detecting fumes are commercially available. A well-established procedure for sizing particles suspended in liquid solvent is called Dynamic Light Scattering (DLS) and is based on assessing the diffusion coefficient of the particles from the fluctuations of the scattered light recorded in the scattered light intensity time series. This work highlights the difficulties encountered in an attempt to use DLS for sizing particles suspended in air and the particular, narrow experimental conditions chosen in designing and setting such a DLS experiment. The experimental setup was tested on combustion gases and the results of the preliminary experiment are presented in detail. The results stand as a proof of concept for using DLS in sizing particle in gases and in designing a sensor for fumes detection that can indicate the average size of the particles over an extended range.