Th-810 instrument is designed to continuously monitor the emission of low concentration particulate matter with smoke emission less than 50mg / m3, following the national environmental protection strategy. The instrument adopts the principle of β - ray method. In order to prevent the condensation of flue gas, the whole sampling process of the instrument is heated. The heating temperature can be adjusted below 180 ℃. The instrument adopts constant velocity tracking method or constant current sampling method. The sampling tube is equipped with pitot tube and smoke temperature measurement at the same time. The test part of the instrument is equipped with industrial air conditioner to ensure the stable operation of the system. Compared with similar products at home and abroad, it has the advantages of compact structure, easy maintenance and all-weather work