LD-5C-----an intelligent multifunctional portable microcomputer laser dustmate meets advanced need of international market in new century. With continuous monitoring of dust concentration, it can collect PM2.5, PM.5, PM10, or TSP various cutting-compatible. The instrument applies to public places PM10 concentrations of rapid determination, central air-conditioning exhaust PM10 concentration detection, mining scene about labor health dust concentration detection, respirable concentration monitor in environmental protection, and air purifier efficiency evaluation and so on.