Application research of light scattering principle in dust measurement system

In order to prevent harm caused by respiratory dust and to monitor mass concentration of individual exhalation dustꎬ a portable personal concentration monitoring test prototype was developed by using infrared light emitting photodiode as a light source according to principle of light scatteringꎬ and its pneumatic control circuit and optical control and detection circuit were designed. Thenꎬ prototype and comparison instrument were put in a self ̄made dust test device together with dust gas which featured a flow rate of 2 L / min and a particle size of 5 μm. The results show that when mass concentration of dust is between 0-150 mg / mꎬ measured voltage of prototype increases along with increase of dust concentrationꎬ and they maintain a good linear relationship. The relative error between measured concentration value of prototype by using regression equation and that of comparison instrument is within ±4%ꎬ indicating that the 中 国 安 全 科 学 学 报 China Safety Science Journal 第30卷 2020年 device meets requirements of relevant dust verification regulations.