Abstract: To address issues such as separation efficiency deviation and frequent manual maintenance caused by the prolonged operation of separators, there is an urgent need for a without separator method to detect the concentration of respirable dust. Based on numerical simulation of light scattering theory, the relationship between dust particle size and light scattering characteristics is studied. A high-resolution light scattering prototype has been developed, and an experimental system using Arizona A1 standard dust has been constructed to study the light scattering properties of respirable dust particles of various sizes. Based on the BMRC (British Medical Research Council) separation curve, a respirable dust concentration detection model that correlates dust particle size with light scattering characteristics has been established. This work has led to the preliminary development of a without separator respirable dust concentration detection technology. After experimental verification, it was found that the respirable dust concentration detection technology without separators can accurately detect the respirable dust concentration limit of ≤55.2 mg/m³ with a detection error of 29.1%. Currently, this technology is only suitable for detecting respirable dust concentrations at low levels.