Improve The Photometer Method Of Respirable Mass Concentration Measurement Precision

In this paper, a respirable aerosol mass concentration measuring apparatus has been developed based on the photometer measurement method. The measuring apparatus consists of the photoelectic sensor, signal collecting & processing system, and periphery function system. Through the research of improving precision and related improvements, a measuring apparatus with high precision, good stability and low cost is completed successfully.First, lots of long time and continuous experiments are carried on the concentration measuring prototype and the reference standard apparatus SIDEPAK AM510 of TSI Company. Though comparing and analyzing the measuring results between measuring prototype and AM510, the problem of bad linearity and serious zero shift are found existed in measuring prototype, which will debase the measuring precision. In order to solve the problem, some improvements are implemented on photoelectic sensor and circuits. Experiments prove that the linearity is improved and zero shif is obviously decreased by those improvements, and the precision of prototype are advanced accordingly.Second, after completing the improvements mentioned above, the respirable aerosol mass concentration measuring apparatus is calibrated against the standard particles in SIMT. The relative error of measuring apparatus is within±10%, which comes up to the standard of JJG846-1993. The measurement range of this measuring apparatus is from 0 to 20mg/m3, resolution is 0.001mg/m~3,particle size range is 0.1～10μm .The research in this paper is practically useful to improve the precision of respirable aerosol mass concentration measuring apparatus. The measuring apparatus developed in this paper is the first respirable aerosol mass concentration measuring apparatus in domestic industry, which not only reaches the requirements of WS/T206-2001, but also has the independent intellectual property.