Contamination due to plasma-generated particles is one of the major issues affecting the yield loss in microelectronics fabrication. Laser light scattering performed in situ during the process provides important information about particle distributions both spatially resolved and as a function of time. It is therefore well suited for the investigation of the transient behavior of process-generated particles that can influence the performance of etching or deposition plasmas. The present light scattering system allows the quantitative determination of particle size and number density by detecting the scattering intensity at two separate angles (angular dissymmetry) and/or at two different polarization states (polarization dissymmetry), respectively. A special calibration procedure is required in order to obtain quantitative results for particle size and number density. Based on this analysis, we report the temporal evolution of the spatial distribution of aluminum particles in an argon discharge. We examine the transition from a continuous cloud of particles filling the entire interelectrode gap to a narrow band of intense scattering near the grounded electrode. Other changes of light scattering patterns with time have been observed under other conditions. The implications of these observations in terms of particle generation and evolution in gas discharge plasmas are discussed.