In advanced electronics manufacturing, including semiconductor and display production, generation of particles during manufacturing process has been occured. Consequently, the monitoring of particle concentrations in pipelines prior to air emission is essential for efficient particle removal. To accurately measure high particle concentrations, dilution devices have been developed to control the particle concentrations to the detection range of measurement instruments. In this study, the development of the dilution device was optimized via computational fluid dynamics (CFD) simulations using both Eulerian and Lagrangian methods. The experiment results demonstrated that the dilution device exhibited an error of 18% between the experimental and theoretical values at a maximum dilution ratio of 35 for nano-sized polystyrene latex particles. Additionally, the experiments with SiO₂particles validated the dilution efficiency of device, showing an error of 12% between the experimental and theoretical values. This study validated the performance of the developed dilution device for accurately measuring high particle concentrations before the removal of particles. The device demonstrates considerable potential for real-time particle monitoring, thereby enhancing the operational stability, efficiency, and maintenance of particle removal systems.