Abstract: Separator is the key element in the device for atmospheric particulates monitoring,and its performance directly affects the real and accurate monitoring data of PM_2.5,PM₁ and other ambient air particulate matter mass concentration.In this study,the standard particles of polystyrene microspheres (PSL) with particle size ranging from 0.6 to 4 μm,monodisperse aerosol generator,mixing (shitter) device and particle quantity concentration measurement instrument were integrated to build a general system suitable for PM₁ and PM_2.5 selector performance test.The test results showed that the PSL particles generated in the system could maintain a stable number concentration,and had a good consistency between the cut gas path and the non-cut gas path,and could quickly complete the cutting efficiency test of a PM₁ or PM_2.5 selector within 3 hours.Based on this system,one type of PM₁ selector and three types of PM_2.5 separators were tested.The results showed that the D₅₀ of three VSCC PM_2.5 selectors was 2.48,2.52,and 2.48 μm,the σ_g1 was 1.20,1.23 and 1.15,the σ_g2 was 1.21,1.21 and 1.16.The D₅₀ and σ_g of VSCC type PM_2.5 selector satisfied the request of the standard method of China and the United States and had a better performance than SCC and URG type PM_2.5 selectors.Besides,the D₅₀,σ_g1 and σ_g2,of the SCC PM₁ selector was 0.91 μm,1.20 and 1.18 separately.Considering the result of other PM₁ selector performance articles,we recommended the D₅₀ of PM₁ selector should be within (1.0±0.1)μm,and the σ_g of PM₁ selector should be under 1.20.