INTRODUCTION
PM2.5 laser dust sensor is a digital universal particle concentration sensor,it can be used to obtain the number of suspended particulate matter in a unit volume of air within 0.3 to 10 microns, namely the concentration of particulate matter, and output with digital interface, also can output quality data of per particle. The sensors can be embedded in a variety of concentrations of environment-related instruments suspended particulate matter in the air ,to provide timely and accurate concentration data.